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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Madhavan%2C+V&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Madhavan%2C+V&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Madhavan%2C+V&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.10447">arXiv:2411.10447</a> <span> [<a href="https://arxiv.org/pdf/2411.10447">pdf</a>, <a href="https://arxiv.org/format/2411.10447">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Ultrafast optical control of charge orders in kagome metals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lin%2C+Y">Yu-Ping Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Moore%2C+J+E">Joel E. Moore</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.10447v1-abstract-short" style="display: inline;"> We show that ultrafast optical pump pulses provide effective control over charge orders in the kagome metals $A$V$_3$Sb$_5$ with $A=$ K, Rb, and Cs. Starting from the real charge density waves (rCDWs) at the $p$-type Van Hove singularity, we conduct a thorough analysis of the post-pump dynamics by time-dependent Hartree-Fock theory. Our analysis uncovers distinct dynamical phenomena under linearly… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.10447v1-abstract-full').style.display = 'inline'; document.getElementById('2411.10447v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.10447v1-abstract-full" style="display: none;"> We show that ultrafast optical pump pulses provide effective control over charge orders in the kagome metals $A$V$_3$Sb$_5$ with $A=$ K, Rb, and Cs. Starting from the real charge density waves (rCDWs) at the $p$-type Van Hove singularity, we conduct a thorough analysis of the post-pump dynamics by time-dependent Hartree-Fock theory. Our analysis uncovers distinct dynamical phenomena under linearly and circularly polarized pumps. Linearly polarized pumps induce directional preferences in the rCDWs, accompanied by an enhancement in the flat band. Unexpectedly, charge nematicity also emerges and receives maximal enhancement at a resonant pump frequency, which we understand with a Rabi-oscillation-like model. On the other hand, circularly polarized pumps suppress the rCDWs uniformly and triggers imaginary CDWs (iCDWs) with charge loop currents. Our results can be directly compared to the pump-probe experiments on the kagome metals $A$V$_3$Sb$_5$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.10447v1-abstract-full').style.display = 'none'; document.getElementById('2411.10447v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7+19 pages, 6+7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.14688">arXiv:2406.14688</a> <span> [<a href="https://arxiv.org/pdf/2406.14688">pdf</a>, <a href="https://arxiv.org/format/2406.14688">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.110.145101">10.1103/PhysRevB.110.145101 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Absence of a bulk charge density wave signature in x-ray measurements of UTe$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kengle%2C+C+S">Caitlin S. Kengle</a>, <a href="/search/cond-mat?searchtype=author&query=Chaudhuri%2C+D">Dipanjan Chaudhuri</a>, <a href="/search/cond-mat?searchtype=author&query=Guo%2C+X">Xuefei Guo</a>, <a href="/search/cond-mat?searchtype=author&query=Johnson%2C+T+A">Thomas A. Johnson</a>, <a href="/search/cond-mat?searchtype=author&query=Bettler%2C+S">Simon Bettler</a>, <a href="/search/cond-mat?searchtype=author&query=Simeth%2C+W">Wolfgang Simeth</a>, <a href="/search/cond-mat?searchtype=author&query=Krogstad%2C+M+J">Matthew J. Krogstad</a>, <a href="/search/cond-mat?searchtype=author&query=Islam%2C+Z">Zahir Islam</a>, <a href="/search/cond-mat?searchtype=author&query=Ran%2C+S">Sheng Ran</a>, <a href="/search/cond-mat?searchtype=author&query=Saha%2C+S+R">Shanta R. Saha</a>, <a href="/search/cond-mat?searchtype=author&query=Paglione%2C+J">Johnpierre Paglione</a>, <a href="/search/cond-mat?searchtype=author&query=Butch%2C+N+P">Nicholas P. Butch</a>, <a href="/search/cond-mat?searchtype=author&query=Fradkin%2C+E">Eduardo Fradkin</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Abbamonte%2C+P">Peter Abbamonte</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.14688v3-abstract-short" style="display: inline;"> The long-sought pair density wave (PDW) is an exotic phase of matter in which charge density wave (CDW) order is intertwined with the amplitude or phase of coexisting, superconducting order \cite{Berg2009,Berg2009b}. Originally predicted to exist in copper-oxides, circumstantial evidence for PDW order now exists in a variety of materials. Recently, scanning tunneling microscopy (STM) studies have… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.14688v3-abstract-full').style.display = 'inline'; document.getElementById('2406.14688v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.14688v3-abstract-full" style="display: none;"> The long-sought pair density wave (PDW) is an exotic phase of matter in which charge density wave (CDW) order is intertwined with the amplitude or phase of coexisting, superconducting order \cite{Berg2009,Berg2009b}. Originally predicted to exist in copper-oxides, circumstantial evidence for PDW order now exists in a variety of materials. Recently, scanning tunneling microscopy (STM) studies have reported evidence for a three-component charge density wave (CDW) at the surface of the heavy-fermion superconductor, UTe$_2$, persisting below its superconducting transition temperature. Here, we use hard x-ray diffraction measurements on crystals of UTe$_2$ at $T = 1.9$ K and $12$ K to search for a bulk signature of this CDW. Using STM measurements as a constraint, we calculate the expected locations of CDW superlattice peaks, and sweep a large volume of reciprocal space in search of a signature. We failed to find any evidence for a CDW near any of the expected superlattice positions in many Brillouin zones. We estimate an upper bound on the CDW lattice distortion of $u_{max} \lesssim 4 \times 10^{-3} \mathrm脜$. Our results suggest that the CDW observed in STM is either purely electronic, somehow lacking a signature in the structural lattice, or is restricted to the material surface. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.14688v3-abstract-full').style.display = 'none'; document.getElementById('2406.14688v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 110, 145101 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.16432">arXiv:2405.16432</a> <span> [<a href="https://arxiv.org/pdf/2405.16432">pdf</a>, <a href="https://arxiv.org/format/2405.16432">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Revealing the hidden Dirac gap in a topological antiferromagnet using Floquet-Bloch manipulation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bielinski%2C+N">Nina Bielinski</a>, <a href="/search/cond-mat?searchtype=author&query=Chari%2C+R">Rajas Chari</a>, <a href="/search/cond-mat?searchtype=author&query=May-Mann%2C+J">Julian May-Mann</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+S">Soyeun Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Zwettler%2C+J">Jack Zwettler</a>, <a href="/search/cond-mat?searchtype=author&query=Deng%2C+Y">Yujun Deng</a>, <a href="/search/cond-mat?searchtype=author&query=Aishwarya%2C+A">Anuva Aishwarya</a>, <a href="/search/cond-mat?searchtype=author&query=Roychowdhury%2C+S">Subhajit Roychowdhury</a>, <a href="/search/cond-mat?searchtype=author&query=Shekhar%2C+C">Chandra Shekhar</a>, <a href="/search/cond-mat?searchtype=author&query=Hashimoto%2C+M">Makoto Hashimoto</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+D">Donghui Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+J">Jiaqiang Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Felser%2C+C">Claudia Felser</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Shen%2C+Z">Zhi-Xun Shen</a>, <a href="/search/cond-mat?searchtype=author&query=Hughes%2C+T+L">Taylor L. Hughes</a>, <a href="/search/cond-mat?searchtype=author&query=Mahmood%2C+F">Fahad Mahmood</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.16432v1-abstract-short" style="display: inline;"> Manipulating solids using the time-periodic drive of a laser pulse is a promising route to generate new phases of matter. Whether such `Floquet-Bloch' manipulation can be achieved in topological magnetic systems with disorder has so far been unclear. In this work, we realize Floquet-Bloch manipulation of the Dirac surface-state mass of the topological antiferromagnet (AFM) MnBi$_2$Te$_4$. Using ti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.16432v1-abstract-full').style.display = 'inline'; document.getElementById('2405.16432v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.16432v1-abstract-full" style="display: none;"> Manipulating solids using the time-periodic drive of a laser pulse is a promising route to generate new phases of matter. Whether such `Floquet-Bloch' manipulation can be achieved in topological magnetic systems with disorder has so far been unclear. In this work, we realize Floquet-Bloch manipulation of the Dirac surface-state mass of the topological antiferromagnet (AFM) MnBi$_2$Te$_4$. Using time- and angle-resolved photoemission spectroscopy (tr-ARPES), we show that opposite helicities of mid-infrared circularly polarized light result in substantially different Dirac mass gaps in the AFM phase, despite the equilibrium Dirac cone being massless. We explain our findings in terms of a Dirac fermion with a random mass. Our results underscore Floquet-Bloch manipulation as a powerful tool for controlling topology even in the presence of disorder, and for uncovering properties of materials that may elude conventional probes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.16432v1-abstract-full').style.display = 'none'; document.getElementById('2405.16432v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.05130">arXiv:2312.05130</a> <span> [<a href="https://arxiv.org/pdf/2312.05130">pdf</a>, <a href="https://arxiv.org/format/2312.05130">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> </div> <p class="title is-5 mathjax"> Superconducting Penetration Depth Through a Van Hove Singularity: Sr$_2$RuO$_4$ Under Uniaxial Stress </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mueller%2C+E">Eli Mueller</a>, <a href="/search/cond-mat?searchtype=author&query=Iguchi%2C+Y">Yusuke Iguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Jerzembeck%2C+F">Fabian Jerzembeck</a>, <a href="/search/cond-mat?searchtype=author&query=Rodriguez%2C+J+O">Jorge O. Rodriguez</a>, <a href="/search/cond-mat?searchtype=author&query=Romanelli%2C+M">Marisa Romanelli</a>, <a href="/search/cond-mat?searchtype=author&query=Abarca-Morales%2C+E">Edgar Abarca-Morales</a>, <a href="/search/cond-mat?searchtype=author&query=Markou%2C+A">Anastasios Markou</a>, <a href="/search/cond-mat?searchtype=author&query=Kikugawa%2C+N">Naoki Kikugawa</a>, <a href="/search/cond-mat?searchtype=author&query=Sokolov%2C+D+A">Dmitry A. Sokolov</a>, <a href="/search/cond-mat?searchtype=author&query=Oh%2C+G">Gwansuk Oh</a>, <a href="/search/cond-mat?searchtype=author&query=Hicks%2C+C+W">Clifford W. Hicks</a>, <a href="/search/cond-mat?searchtype=author&query=Mackenzie%2C+A+P">Andrew P. Mackenzie</a>, <a href="/search/cond-mat?searchtype=author&query=Maeno%2C+Y">Yoshiteru Maeno</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Moler%2C+K+A">Kathryn A. Moler</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.05130v2-abstract-short" style="display: inline;"> In the unconventional superconductor Sr$_2$RuO$_4$, uniaxial stress along the $[100]$ direction tunes the Fermi level through a Van Hove singularity (VHS) in the density of states, causing a strong enhancement of the superconducting critical temperature $T_\textrm{c}$. Here, we report measurements of the London penetration depth $位$ as this tuning is performed. We find that the zero-temperature su… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.05130v2-abstract-full').style.display = 'inline'; document.getElementById('2312.05130v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.05130v2-abstract-full" style="display: none;"> In the unconventional superconductor Sr$_2$RuO$_4$, uniaxial stress along the $[100]$ direction tunes the Fermi level through a Van Hove singularity (VHS) in the density of states, causing a strong enhancement of the superconducting critical temperature $T_\textrm{c}$. Here, we report measurements of the London penetration depth $位$ as this tuning is performed. We find that the zero-temperature superfluid density, here defined as $位(0)^{-2}$, increases by $\sim$15%, with a peak that coincides with the peak in $T_\textrm{c}$. We also find that the low temperature form of $位(T)$ is quadratic over the entire strain range. Using scanning tunneling microscopy, we find that the gap increases from $螖_0 \approx 350~渭$eV in unstressed Sr$_2$RuO$_4$ to $螖_0 \approx 600~渭$eV in a sample strained to near the peak in $T_c$. With a nodal order parameter, an increase in the superconducting gap could bring about an increase in the superfluid density through reduced sensitivity to defects and through reduced non-local effects in the Meissner screening. Our data indicate that tuning to the VHS increases the gap throughout the Brillouin zone, and that non-local effects are likely more important than reduced scattering. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.05130v2-abstract-full').style.display = 'none'; document.getElementById('2312.05130v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.15691">arXiv:2308.15691</a> <span> [<a href="https://arxiv.org/pdf/2308.15691">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41535-024-00660-4">10.1038/s41535-024-00660-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Atomic-Scale Visualization of a Cascade of Magnetic Orders in the Layered Antiferromagnet $GdTe_{3}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Raghavan%2C+A">Arjun Raghavan</a>, <a href="/search/cond-mat?searchtype=author&query=Romanelli%2C+M">Marisa Romanelli</a>, <a href="/search/cond-mat?searchtype=author&query=May-Mann%2C+J">Julian May-Mann</a>, <a href="/search/cond-mat?searchtype=author&query=Aishwarya%2C+A">Anuva Aishwarya</a>, <a href="/search/cond-mat?searchtype=author&query=Aggarwal%2C+L">Leena Aggarwal</a>, <a href="/search/cond-mat?searchtype=author&query=Singh%2C+A+G">Anisha G. Singh</a>, <a href="/search/cond-mat?searchtype=author&query=Bachmann%2C+M+D">Maja D. Bachmann</a>, <a href="/search/cond-mat?searchtype=author&query=Schoop%2C+L+M">Leslie M. Schoop</a>, <a href="/search/cond-mat?searchtype=author&query=Fradkin%2C+E">Eduardo Fradkin</a>, <a href="/search/cond-mat?searchtype=author&query=Fisher%2C+I+R">Ian R. Fisher</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.15691v3-abstract-short" style="display: inline;"> $GdTe_{3}… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.15691v3-abstract-full').style.display = 'inline'; document.getElementById('2308.15691v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.15691v3-abstract-full" style="display: none;"> $GdTe_{3}$ is a layered antiferromagnet which has attracted attention due to its exceptionally high mobility, distinctive unidirectional incommensurate charge density wave (CDW), superconductivity under pressure, and a cascade of magnetic transitions between 7 and 12 K, with as yet unknown order parameters. Here, we use spin-polarized scanning tunneling microscopy to directly image the charge and magnetic orders in $GdTe_{3}$. Below 7 K, we find a striped antiferromagnetic phase with twice the periodicity of the Gd lattice and perpendicular to the CDW. As we heat the sample, we discover a spin density wave with the same periodicity as the CDW between 7 and 12 K; the viability of this phase is supported by our Landau free energy model. Our work reveals the order parameters of the magnetic phases in $GdTe_{3}$ and shows how the interplay between charge and spin can generate a cascade of magnetic orders. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.15691v3-abstract-full').style.display = 'none'; document.getElementById('2308.15691v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">46 pgs.; 4 main figures, 20 supplementary figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Mater. 9, 47 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.04128">arXiv:2308.04128</a> <span> [<a href="https://arxiv.org/pdf/2308.04128">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Optical Manipulation of the Charge Density Wave state in RbV3Sb5 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Xing%2C+Y">Yuqing Xing</a>, <a href="/search/cond-mat?searchtype=author&query=Bae%2C+S">Seokjin Bae</a>, <a href="/search/cond-mat?searchtype=author&query=Ritz%2C+E">Ethan Ritz</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+F">Fan Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Birol%2C+T">Turan Birol</a>, <a href="/search/cond-mat?searchtype=author&query=Salinas%2C+A+N+C">Andrea N. Capa Salinas</a>, <a href="/search/cond-mat?searchtype=author&query=Ortiz%2C+B+R">Brenden R. Ortiz</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Fernandes%2C+R+M">Rafael M. Fernandes</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.04128v2-abstract-short" style="display: inline;"> Broken time-reversal symmetry in the absence of spin order indicates the presence of unusual phases such as orbital magnetism and loop currents. The recently discovered family of kagome superconductors AV$_3$Sb$_5$ (A = K, Rb, or Cs), hosting an exotic charge-density wave (CDW) state, has emerged as a strong candidate for this phase. While initial experiments suggested that the CDW phase breaks ti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.04128v2-abstract-full').style.display = 'inline'; document.getElementById('2308.04128v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.04128v2-abstract-full" style="display: none;"> Broken time-reversal symmetry in the absence of spin order indicates the presence of unusual phases such as orbital magnetism and loop currents. The recently discovered family of kagome superconductors AV$_3$Sb$_5$ (A = K, Rb, or Cs), hosting an exotic charge-density wave (CDW) state, has emerged as a strong candidate for this phase. While initial experiments suggested that the CDW phase breaks time-reversal symmetry, this idea is being intensely debated due to conflicting experimental data. In this work we use laser-coupled scanning tunneling microscopy (STM) to study RbV$_3$Sb$_5$. STM data shows that the Fourier intensities of all three CDW peaks are different, implying that the CDW breaks rotational and mirror symmetries. By applying linearly polarized light along high-symmetry directions, we show that the relative intensities of the CDW peaks can be reversibly switched, implying a substantial electro-striction response, indicative of strong non-linear electron-phonon coupling. A similar CDW intensity switching is observed with perpendicular magnetic fields, which implies an unusual piezo-magnetic response that, in turn, requires time-reversal symmetry-breaking. We show that the simplest CDW that satisfies these constraints and reconciles previous seemingly contradictory experimental data is an out-of-phase combination of bond charge order and loop currents that we dub congruent CDW flux phase. Our laser-STM data opens the door to the possibility of dynamic optical control of complex quantum phenomenon in correlated materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.04128v2-abstract-full').style.display = 'none'; document.getElementById('2308.04128v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">main text: 21 pages, 5 figures // Methods and Extended Data: 25 pages, 14 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.09423">arXiv:2306.09423</a> <span> [<a href="https://arxiv.org/pdf/2306.09423">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Visualizing the melting of the charge density wave in UTe2 by generation of pairs of topological defects with opposite winding </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Aishwarya%2C+A">Anuva Aishwarya</a>, <a href="/search/cond-mat?searchtype=author&query=May-Mann%2C+J">Julian May-Mann</a>, <a href="/search/cond-mat?searchtype=author&query=Almoalem%2C+A">Avior Almoalem</a>, <a href="/search/cond-mat?searchtype=author&query=Ran%2C+S">Sheng Ran</a>, <a href="/search/cond-mat?searchtype=author&query=Saha%2C+S+R">Shanta R. Saha</a>, <a href="/search/cond-mat?searchtype=author&query=Paglione%2C+J">Johnpierre Paglione</a>, <a href="/search/cond-mat?searchtype=author&query=Butch%2C+N+P">Nicholas P. Butch</a>, <a href="/search/cond-mat?searchtype=author&query=Fradkin%2C+E">Eduardo Fradkin</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.09423v2-abstract-short" style="display: inline;"> Topological defects are singularities in an ordered phase that can have a profound effect on phase transitions and serve as a window into the order parameter. In this work we use scanning tunneling microscopy to visualize the role of topological defects in the novel magnetic field induced disappearance of an intertwined charge density wave (CDW) in the heavy fermion superconductor, UTe2. By simult… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.09423v2-abstract-full').style.display = 'inline'; document.getElementById('2306.09423v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.09423v2-abstract-full" style="display: none;"> Topological defects are singularities in an ordered phase that can have a profound effect on phase transitions and serve as a window into the order parameter. In this work we use scanning tunneling microscopy to visualize the role of topological defects in the novel magnetic field induced disappearance of an intertwined charge density wave (CDW) in the heavy fermion superconductor, UTe2. By simultaneously imaging the amplitude and phase of the CDW order, we reveal pairs of topological defects with positive and negative phase winding. The pairs are directly correlated with a zero CDW amplitude and increase in number with increasing magnetic field. These observations can be captured by a Ginzburg Landau model of a uniform superconductor coexisting with a pair density wave. A magnetic field generates vortices of the superconducting and pair density wave order which can create topological defects in the CDW and induce the experimentally observed melting of the CDW at the upper critical field. Our work reveals the important role of magnetic field generated topological defects in the melting the CDW order parameter in UTe2 and provides support for the existence of a parent pair density wave order on the surface of UTe2. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.09423v2-abstract-full').style.display = 'none'; document.getElementById('2306.09423v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">29 Pages, includes manuscript and supplemental information, 4 Main figures and 8 Supplemental Figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.04993">arXiv:2209.04993</a> <span> [<a href="https://arxiv.org/pdf/2209.04993">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.abj8765">10.1126/science.abj8765 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spin-selective tunneling from nanowires of the candidate topological Kondo insulator SmB6 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Aishwarya%2C+A">Anuva Aishwarya</a>, <a href="/search/cond-mat?searchtype=author&query=Cai%2C+Z">Zhuozhen Cai</a>, <a href="/search/cond-mat?searchtype=author&query=Raghavan%2C+A">Arjun Raghavan</a>, <a href="/search/cond-mat?searchtype=author&query=Romanelli%2C+M">Marisa Romanelli</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+X">Xiaoyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+X">Xu Li</a>, <a href="/search/cond-mat?searchtype=author&query=Gu%2C+G+D">G. D. Gu</a>, <a href="/search/cond-mat?searchtype=author&query=Hirsbrunner%2C+M">Mark Hirsbrunner</a>, <a href="/search/cond-mat?searchtype=author&query=Hughes%2C+T">Taylor Hughes</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+F">Fei Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Jiao%2C+L">Lin Jiao</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2209.04993v1-abstract-short" style="display: inline;"> Incorporating relativistic physics into quantum tunneling can lead to exotic behavior such as perfect transmission via Klein tunneling. Here, we probe the tunneling properties of spin-momentum locked relativistic fermions by designing and implementing a tunneling geometry that utilizes nanowires of the topological Kondo insulator candidate, SmB6. The nanowires are attached to the end of scanning t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.04993v1-abstract-full').style.display = 'inline'; document.getElementById('2209.04993v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.04993v1-abstract-full" style="display: none;"> Incorporating relativistic physics into quantum tunneling can lead to exotic behavior such as perfect transmission via Klein tunneling. Here, we probe the tunneling properties of spin-momentum locked relativistic fermions by designing and implementing a tunneling geometry that utilizes nanowires of the topological Kondo insulator candidate, SmB6. The nanowires are attached to the end of scanning tunneling microscope tips, and used to image the bicollinear stripe spin-order in the antiferromagnet Fe1.03Te with a Neel temperature of ~50 K. The antiferromagnetic stripes become invisible above 10 K concomitant with the suppression of the topological surface states. We further demonstrate that the direction of spin-polarization is tied to the tunneling direction. Our technique establishes SmB6 nanowires as ideal conduits for spin-polarized currents. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.04993v1-abstract-full').style.display = 'none'; document.getElementById('2209.04993v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> Science 377, 6611, 1218-1222 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.04982">arXiv:2209.04982</a> <span> [<a href="https://arxiv.org/pdf/2209.04982">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41535-022-00513-y">10.1038/s41535-022-00513-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence for a robust sign-changing s-wave order parameter in monolayer films of superconducting Fe (Se,Te)/Bi2Te3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chen%2C+G">Guannan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Aishwarya%2C+A">Anuva Aishwarya</a>, <a href="/search/cond-mat?searchtype=author&query=Hirsbrunner%2C+M+R">Mark R. Hirsbrunner</a>, <a href="/search/cond-mat?searchtype=author&query=Rodriguez%2C+J+O">Jorge Olivares Rodriguez</a>, <a href="/search/cond-mat?searchtype=author&query=Jiao%2C+L">Lin Jiao</a>, <a href="/search/cond-mat?searchtype=author&query=Dong%2C+L">Lianyang Dong</a>, <a href="/search/cond-mat?searchtype=author&query=Mason%2C+N">Nadya Mason</a>, <a href="/search/cond-mat?searchtype=author&query=Van+Harlingen%2C+D">Dale Van Harlingen</a>, <a href="/search/cond-mat?searchtype=author&query=Harter%2C+J">John Harter</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S">Stephen Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Hughes%2C+T+L">Taylor L. Hughes</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2209.04982v1-abstract-short" style="display: inline;"> The Fe-based superconductor Fe (Se,Te) combines non-trivial topology with unconventional superconductivity and may be an ideal platform to realize exotic states such as high-order topological corner modes and Majorana modes. Thin films of Fe (Se,Te) are important for device fabrication, phase sensitive transport measurements and for realizing proposals to engineer higher-order modes. However, whil… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.04982v1-abstract-full').style.display = 'inline'; document.getElementById('2209.04982v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.04982v1-abstract-full" style="display: none;"> The Fe-based superconductor Fe (Se,Te) combines non-trivial topology with unconventional superconductivity and may be an ideal platform to realize exotic states such as high-order topological corner modes and Majorana modes. Thin films of Fe (Se,Te) are important for device fabrication, phase sensitive transport measurements and for realizing proposals to engineer higher-order modes. However, while bulk Fe (Se,Te) has been extensively studied with a variety of techniques, the nature of the superconducting order parameter in the monolayer limit has not yet been explored. In this work, we study monolayer films of Fe (Se,Te) on Bi2Te3 with scanning tunneling spectroscopy and Bogoliubov quasiparticle interference (BQPI). We discover that the monolayer Fe (Se,Te)/Bi2Te3 heterostructures host a robust, multigap superconducting state that strongly resembles the bulk. BQPI maps at the gap energies show a strong spatial modulation, oriented 45 degrees to the Fe-Se bond direction. Analysis of the phase-referenced quasiparticle interference signal reveals a sign-changing s-wave order parameter similar to the bulk. Moreover, we observe a unique pattern of sign changes in the BQPI signal which have not been observed in the bulk. Our work establishes monolayer Fe (Se,Te)/Bi2Te3 as a robust multi-band unconventional superconductor and sets the stage for explorations of non-trivial topology in this highly-tunable system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.04982v1-abstract-full').style.display = 'none'; document.getElementById('2209.04982v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> npj Quantum Mater. 7, 110 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.09491">arXiv:2207.09491</a> <span> [<a href="https://arxiv.org/pdf/2207.09491">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-023-06005-8">10.1038/s41586-023-06005-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic-field sensitive charge density wave orders in the superconducting phase of UTe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Aishwarya%2C+A">Anuva Aishwarya</a>, <a href="/search/cond-mat?searchtype=author&query=May-Mann%2C+J">Julian May-Mann</a>, <a href="/search/cond-mat?searchtype=author&query=Raghavan%2C+A">Arjun Raghavan</a>, <a href="/search/cond-mat?searchtype=author&query=Nie%2C+L">Laimei Nie</a>, <a href="/search/cond-mat?searchtype=author&query=Romanelli%2C+M">Marisa Romanelli</a>, <a href="/search/cond-mat?searchtype=author&query=Ran%2C+S">Sheng Ran</a>, <a href="/search/cond-mat?searchtype=author&query=Saha%2C+S+R">Shanta R. Saha</a>, <a href="/search/cond-mat?searchtype=author&query=Paglione%2C+J">Johnpierre Paglione</a>, <a href="/search/cond-mat?searchtype=author&query=Butch%2C+N+P">Nicholas P. Butch</a>, <a href="/search/cond-mat?searchtype=author&query=Fradkin%2C+E">Eduardo Fradkin</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.09491v2-abstract-short" style="display: inline;"> The intense interest in triplet superconductivity partly stems from theoretical predictions of exotic excitations such as non-abelian Majorana modes, chiral supercurrents, and half-quantum vortices. However, fundamentally new, and unexpected states may emerge when triplet superconductivity appears in a strongly correlated system. In this work we use scanning tunneling microscopy to reveal an unusu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.09491v2-abstract-full').style.display = 'inline'; document.getElementById('2207.09491v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.09491v2-abstract-full" style="display: none;"> The intense interest in triplet superconductivity partly stems from theoretical predictions of exotic excitations such as non-abelian Majorana modes, chiral supercurrents, and half-quantum vortices. However, fundamentally new, and unexpected states may emerge when triplet superconductivity appears in a strongly correlated system. In this work we use scanning tunneling microscopy to reveal an unusual charge density wave (CDW) order in the heavy fermion triplet superconductor, UTe2. Our high-resolution maps reveal a multi-component incommensurate CDW whose intensity get weaker with increasing field, eventually disappearing at the superconducting critical field, Hc2. To explain the origin and phenomenology of this unusual CDW, we construct a Ginzburg-Landau theory for a uniform triplet superconductor coexisting with three triplet pair density wave (PDW) states. This theory gives rise to daughter CDWs which would be sensitive to magnetic field due to their origin in a triplet PDW state, and naturally explains our data. Our discovery of a CDW sensitive to magnetic fields and strongly intertwined with superconductivity, provides important new information for understanding the order parameter of UTe2 and uncovers the possible existence of a new kind of triplet PDW order which has not been previously explored. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.09491v2-abstract-full').style.display = 'none'; document.getElementById('2207.09491v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 4 figures, Supplementary information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> Nature, 618, 928--933 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.02238">arXiv:2110.02238</a> <span> [<a href="https://arxiv.org/pdf/2110.02238">pdf</a>, <a href="https://arxiv.org/format/2110.02238">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.105.L220504">10.1103/PhysRevB.105.L220504 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Shot-noise and differential conductance as signatures of putative topological superconductivity in FeSe$_{0.45}$Te$_{0.55}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wong%2C+K+H">Ka Ho Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Mascot%2C+E">Eric Mascot</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Van+Harlingen%2C+D+J">Dale J. Van Harlingen</a>, <a href="/search/cond-mat?searchtype=author&query=Morr%2C+D+K">Dirk K. Morr</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2110.02238v1-abstract-short" style="display: inline;"> We present a theory for the differential shot noise, $dS/dV$, as measured via shot-noise scanning tunneling spectroscopy, and the differential conductance, $dI/dV$, for tunneling into Majorana zero modes (MZMs) in the putative topological superconductor FeSe$_{0.45}$Te$_{0.55}$. We demonstrate that for tunneling into chiral Majorana edge modes near domain walls, as well as MZMs localized in vortex… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.02238v1-abstract-full').style.display = 'inline'; document.getElementById('2110.02238v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.02238v1-abstract-full" style="display: none;"> We present a theory for the differential shot noise, $dS/dV$, as measured via shot-noise scanning tunneling spectroscopy, and the differential conductance, $dI/dV$, for tunneling into Majorana zero modes (MZMs) in the putative topological superconductor FeSe$_{0.45}$Te$_{0.55}$. We demonstrate that for tunneling into chiral Majorana edge modes near domain walls, as well as MZMs localized in vortex cores and at the end of defect lines, $dS/dV$ vanishes whenever $dI/dV$ reaches a quantized value proportional to the quantum of conductance. These results are independent of the particular orbital tunneling path, thus establishing a vanishing $dS/dV$ concomitant with a quantized $dI/dV$, as universal signatures for Majorana modes in two-dimensional topological superconductors, irrespective of the material's specific complex electronic bandstructure. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.02238v1-abstract-full').style.display = 'none'; document.getElementById('2110.02238v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.09633">arXiv:2108.09633</a> <span> [<a href="https://arxiv.org/pdf/2108.09633">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Observation of near EF Fermi-arc van Hove singularity with prominent coupling to phonon in a van der Waals coupled Weyl semimetal </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Z. Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+C">Cheng-Yi Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Hsu%2C+C">Chia-Hsiu Hsu</a>, <a href="/search/cond-mat?searchtype=author&query=Namiki%2C+H">Hiromasa Namiki</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+T">Tay-Rong Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Chuang%2C+F">Feng-Chuan Chuang</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">H. Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Sasagawa%2C+T">Takao Sasagawa</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2108.09633v1-abstract-short" style="display: inline;"> A van der Waals coupled Weyl semimetal material NbIrTe4 is investigated by combining scanning tunneling microscopy/spectroscopy and first principles calculations. We observe a sharp peak in the tunneling conductance near the zero bias energy, and its origin is ascribed to a van Hove singularity associated with a Lifshitz transition of the topologically none trivial Fermi arc states. Furthermore, t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.09633v1-abstract-full').style.display = 'inline'; document.getElementById('2108.09633v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.09633v1-abstract-full" style="display: none;"> A van der Waals coupled Weyl semimetal material NbIrTe4 is investigated by combining scanning tunneling microscopy/spectroscopy and first principles calculations. We observe a sharp peak in the tunneling conductance near the zero bias energy, and its origin is ascribed to a van Hove singularity associated with a Lifshitz transition of the topologically none trivial Fermi arc states. Furthermore, tunneling spectroscopy measurements show a surprisingly large signature of electron boson coupling, which presumably represents anomalously enhanced electron phonon coupling through the enhanced charge susceptibility. Our finding in van der Waals coupled material is particularly invaluable due to applicable exfoliation technology for searching exotic topological states by further manipulating near Fermi energy van Hove singularity in nanometer scale flakes and their devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.09633v1-abstract-full').style.display = 'none'; document.getElementById('2108.09633v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.09630">arXiv:2108.09630</a> <span> [<a href="https://arxiv.org/pdf/2108.09630">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Visualizing superconductivity in an inversion-symmetry-broken doped Weyl semimetal </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Olivares%2C+J">Jorge Olivares</a>, <a href="/search/cond-mat?searchtype=author&query=Namiki%2C+H">Hiromasa Namiki</a>, <a href="/search/cond-mat?searchtype=author&query=Pareek%2C+V">Vivek Pareek</a>, <a href="/search/cond-mat?searchtype=author&query=Dani%2C+K">Keshav Dani</a>, <a href="/search/cond-mat?searchtype=author&query=Sasagawa%2C+T">Takao Sasagawa</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2108.09630v1-abstract-short" style="display: inline;"> The Weyl semimetal MoTe$_2$ offers a rare opportunity to study the interplay between Weyl physics and superconductivity. Recent studies have found that Se substitution can boost the superconductivity up to 1.5K, but suppress the Td structure phase that is essential for the emergence of Weyl state. A microscopic understanding of possible coexistence of enhanced superconductivity and the Td phase ha… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.09630v1-abstract-full').style.display = 'inline'; document.getElementById('2108.09630v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.09630v1-abstract-full" style="display: none;"> The Weyl semimetal MoTe$_2$ offers a rare opportunity to study the interplay between Weyl physics and superconductivity. Recent studies have found that Se substitution can boost the superconductivity up to 1.5K, but suppress the Td structure phase that is essential for the emergence of Weyl state. A microscopic understanding of possible coexistence of enhanced superconductivity and the Td phase has not been established so far. Here, we use scanning tunneling microscopy (STM) to study a optimally doped new superconductor MoTe$_{1.85}$Se$_{0.15}$ with bulk Tc ~ 1.5K. By means of quasiparticle interference imaging, we identify the existence of low temperature Td phase with broken inversion symmetry where superconductivity globally coexists. Consistently, we find that the superconducting coherence length, extracted from both the upper critical field and the decay of density of states near a vortex, is much larger than the characteristic length scale of existing dopant derived chemical disorder. Our findings of robust superconductivity arising from a Weyl semimetal normal phase in MoTe$_{1.85}$Se$_{0.15}$, makes it a promising candidate for realizing topological superconductivity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.09630v1-abstract-full').style.display = 'none'; document.getElementById('2108.09630v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.04621">arXiv:2107.04621</a> <span> [<a href="https://arxiv.org/pdf/2107.04621">pdf</a>, <a href="https://arxiv.org/format/2107.04621">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.105.174520">10.1103/PhysRevB.105.174520 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Majorana fermion arcs and the local density of states of UTe$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yu%2C+Y">Yue Yu</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Raghu%2C+S">S. Raghu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.04621v1-abstract-short" style="display: inline;"> $\text{UTe}_2… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.04621v1-abstract-full').style.display = 'inline'; document.getElementById('2107.04621v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.04621v1-abstract-full" style="display: none;"> $\text{UTe}_2$ is a leading candidate for chiral p-wave superconductivity, and for hosting exotic Majorana fermion quasiparticles. Motivated by recent STM experiments in this system, we study particle-hole symmetry breaking in chiral p-wave superconductors. We compute the local density of states from Majorana fermion surface states in the presence of Rashba surface spin-orbit coupling, which is expected to be sizeable in heavy-fermion materials like UTe$_2$. We show that time-reversal and surface reflection symmetry breaking lead to a natural pairing tendency towards a triplet pair density wave state, which naturally can account for broken particle-hole symmetry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.04621v1-abstract-full').style.display = 'none'; document.getElementById('2107.04621v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.00698">arXiv:2107.00698</a> <span> [<a href="https://arxiv.org/pdf/2107.00698">pdf</a>, <a href="https://arxiv.org/format/2107.00698">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-021-24683-8">10.1038/s41467-021-24683-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence for Higher order topology in Bi and Bi$_{0.92}$Sb$_{0.08}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Aggarwal%2C+L">Leena Aggarwal</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+P">Penghao Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Hughes%2C+T+L">Taylor L. Hughes</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.00698v4-abstract-short" style="display: inline;"> Higher order topological insulators (HOTIs) are a new class of topological materials which host protected states at the corners or hinges of a crystal. HOTIs provide an intriguing alternative platform for helical and chiral edge states and Majorana modes, but there are very few known materials in this class. Recent studies have proposed Bi as a potential HOTI, however, its topological classificati… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.00698v4-abstract-full').style.display = 'inline'; document.getElementById('2107.00698v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.00698v4-abstract-full" style="display: none;"> Higher order topological insulators (HOTIs) are a new class of topological materials which host protected states at the corners or hinges of a crystal. HOTIs provide an intriguing alternative platform for helical and chiral edge states and Majorana modes, but there are very few known materials in this class. Recent studies have proposed Bi as a potential HOTI, however, its topological classification is not yet well accepted. In this work, we show that the (110) facets of Bi and BiSb alloys can be used to unequivocally establish the topology of these systems. Bi and Bi$_{0.92}$Sb$_{0.08}$ (110) films were grown on silicon substrates using molecular beam epitaxy and studied by scanning tunneling spectroscopy. The surfaces manifest rectangular islands which show localized hinge states on three out of the four edges, consistent with the theory for the HOTI phase. This establishes Bi and Bi$_{0.92}$Sb$_{0.08}$ as HOTIs, and raises questions about the topological classification of the full family of Bi$_{x}$Sb$_{1-x}$ alloys. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.00698v4-abstract-full').style.display = 'none'; document.getElementById('2107.00698v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications,2021 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.05166">arXiv:2101.05166</a> <span> [<a href="https://arxiv.org/pdf/2101.05166">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevMaterials.6.044201">10.1103/PhysRevMaterials.6.044201 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of a Smoothly Tunable Dirac Point in $Ge(Bi_{x}Sb_{1-x})_{2}Te_{4}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Howard%2C+S">Sean Howard</a>, <a href="/search/cond-mat?searchtype=author&query=Raghavan%2C+A">Arjun Raghavan</a>, <a href="/search/cond-mat?searchtype=author&query=Iaia%2C+D">Davide Iaia</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+C">Caizhi Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Fl%C3%B6totto%2C+D">David Fl枚totto</a>, <a href="/search/cond-mat?searchtype=author&query=Wong%2C+M">Man-Hong Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Mo%2C+S">Sung-Kwan Mo</a>, <a href="/search/cond-mat?searchtype=author&query=Singh%2C+B">Bahadur Singh</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">Raman Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Chiang%2C+T">Tai-Chang Chiang</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2101.05166v3-abstract-short" style="display: inline;"> State-of-the-art topological devices require the use topological surface states to drive electronic transport. In this study, we examine a tunable topological system, $Ge(Bi_{x}Sb_{1-x})_{2}Te_{4}$, for a range of 'x' values from 0 to 1, using a combination of Fourier Transform Scanning Tunneling Spectroscopy (FT-STS) and Angle-Resolved Photoemission Spectroscopy (ARPES). Our results show that the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.05166v3-abstract-full').style.display = 'inline'; document.getElementById('2101.05166v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.05166v3-abstract-full" style="display: none;"> State-of-the-art topological devices require the use topological surface states to drive electronic transport. In this study, we examine a tunable topological system, $Ge(Bi_{x}Sb_{1-x})_{2}Te_{4}$, for a range of 'x' values from 0 to 1, using a combination of Fourier Transform Scanning Tunneling Spectroscopy (FT-STS) and Angle-Resolved Photoemission Spectroscopy (ARPES). Our results show that the Dirac point shifts linearly with 'x', crossing the Fermi energy near x = 0.7. This novel observation of a smoothly tunable, isolated Dirac point crossing through the topological transport regime and having strong linear dependence with substitution can be critical for future topological spintronics applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.05166v3-abstract-full').style.display = 'none'; document.getElementById('2101.05166v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 Pages, 9 Figures, including Appendix</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Mater. 6, 044201 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.10096">arXiv:2011.10096</a> <span> [<a href="https://arxiv.org/pdf/2011.10096">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41535-022-00433-x">10.1038/s41535-022-00433-x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electric field effects on the band gap and edge states of monolayer 1T'-WTe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Maximenko%2C+Y">Yulia Maximenko</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+Y">Yueqing Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+G">Guannan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Hirsbrunner%2C+M+R">Mark R. Hirsbrunner</a>, <a href="/search/cond-mat?searchtype=author&query=Swiech%2C+W">Waclaw Swiech</a>, <a href="/search/cond-mat?searchtype=author&query=Hughes%2C+T+L">Taylor L. Hughes</a>, <a href="/search/cond-mat?searchtype=author&query=Wagner%2C+L+K">Lucas K. Wagner</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2011.10096v1-abstract-short" style="display: inline;"> Monolayer 1T'-WTe2 is a quantum spin Hall insulator with a gapped bulk and gapless helical edge states persisting to temperatures around 100 K. Recent studies have revealed a topological-to-trivial phase transition as well the emergence of an unconventional, potentially topological superconducting state upon tuning the carrier concentration with gating. However, despite extensive studies, the effe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.10096v1-abstract-full').style.display = 'inline'; document.getElementById('2011.10096v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.10096v1-abstract-full" style="display: none;"> Monolayer 1T'-WTe2 is a quantum spin Hall insulator with a gapped bulk and gapless helical edge states persisting to temperatures around 100 K. Recent studies have revealed a topological-to-trivial phase transition as well the emergence of an unconventional, potentially topological superconducting state upon tuning the carrier concentration with gating. However, despite extensive studies, the effects of gating on the band structure and the helical edge states have not yet been established. In this work we present a combined low-temperature STM and first principles study of back-gated monolayer 1T'-WTe2 films grown on graphene. Consistent with a quantum spin Hall system, the films show well-defined bulk gaps and clear edge states that span the gap. By directly measuring the density of states with STM spectroscopy, we show that the bulk band gap magnitude shows substantial changes with applied gate voltage, which is contrary to the na茂ve expectation that a gate would rigidly shift the bands relative to the Fermi level. To explain our data, we carry out density functional theory and model Hamiltonian calculations which show that a gate electric field causes doping and inversion symmetry breaking which polarizes and spin-splits the bulk bands. Interestingly, the calculated spin splitting from the effective Rashba-like spin-orbit coupling can be in the tens of meV for the electric fields in the experiment, which may be useful for spintronics applications. Our work reveals the strong effect of electric fields on the bulk band structure of monolayer 1T'-WTe2, which will play a critical role in our understanding of gate-induced phenomena in this system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.10096v1-abstract-full').style.display = 'none'; document.getElementById('2011.10096v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Mater. 7, 29 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.12798">arXiv:1912.12798</a> <span> [<a href="https://arxiv.org/pdf/1912.12798">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.102.115149">10.1103/PhysRevB.102.115149 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Correlating Structural, Electronic, and Magnetic Properties of Epitaxial VSe2 Thin Films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chen%2C+G">Guannan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Howard%2C+S+T">Sean T. Howard</a>, <a href="/search/cond-mat?searchtype=author&query=Maghirang%2C+A+B">Aniceto B. Maghirang III</a>, <a href="/search/cond-mat?searchtype=author&query=Cong%2C+K+N">Kien Nguyen Cong</a>, <a href="/search/cond-mat?searchtype=author&query=Cai%2C+K">Kehan Cai</a>, <a href="/search/cond-mat?searchtype=author&query=Ganguli%2C+S+C">Somesh C. Ganguli</a>, <a href="/search/cond-mat?searchtype=author&query=Sweich%2C+W">Waclaw Sweich</a>, <a href="/search/cond-mat?searchtype=author&query=Morosan%2C+E">Emilia Morosan</a>, <a href="/search/cond-mat?searchtype=author&query=Oleynik%2C+I+I">Ivan I. Oleynik</a>, <a href="/search/cond-mat?searchtype=author&query=Chuang%2C+F">Feng-Chuan Chuang</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1912.12798v2-abstract-short" style="display: inline;"> The electronic and magnetic properties of transition metal dichalcogenides are known to be extremely sensitive to their structure. In this paper we study the effect of structure on the electronic and magnetic properties of mono- and bilayer $VSe_2$ films grown using molecular beam epitaxy. $VSe_2$ has recently attracted much attention due to reports of emergent ferromagnetism in the 2D limit. To u… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.12798v2-abstract-full').style.display = 'inline'; document.getElementById('1912.12798v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.12798v2-abstract-full" style="display: none;"> The electronic and magnetic properties of transition metal dichalcogenides are known to be extremely sensitive to their structure. In this paper we study the effect of structure on the electronic and magnetic properties of mono- and bilayer $VSe_2$ films grown using molecular beam epitaxy. $VSe_2$ has recently attracted much attention due to reports of emergent ferromagnetism in the 2D limit. To understand this important compound, high quality 1T and distorted 1T films were grown at temperatures of 200 $^\text{o}$C and 450 $^\text{o}$C respectively and studied using 4K Scanning Tunneling Microscopy/Spectroscopy. The measured density of states and the charge density wave (CDW) patterns were compared to band structure and phonon dispersion calculations. Films in the 1T phase reveal different CDW patterns in the first layer compared to the second. Interestingly, we find the second layer of the 1T-film shows a CDW pattern with 4a $\times$ 4a periodicity which is the 2D version of the bulk CDW observed in this compound. Our phonon dispersion calculations confirm the presence of a soft phonon at the correct wavevector that leads to this CDW. In contrast, the first layer of distorted 1T phase films shows a strong stripe feature with varying periodicities, while the second layer displays no observable CDW pattern. Finally, we find that the monolayer 1T $VSe_2$ film is weakly ferromagnetic, with ~ $3.5 渭_B$ per unit similar to previous reports. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.12798v2-abstract-full').style.display = 'none'; document.getElementById('1912.12798v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 10 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 102, 115149 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.08246">arXiv:1912.08246</a> <span> [<a href="https://arxiv.org/pdf/1912.08246">pdf</a>, <a href="https://arxiv.org/format/1912.08246">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41535-020-00305-2">10.1038/s41535-020-00305-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Metal-to-insulator transition in Pt-doped TiSe$_2$ driven by emergent network of narrow transport channels </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lee%2C+K">Kyungmin Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Choe%2C+J">Jesse Choe</a>, <a href="/search/cond-mat?searchtype=author&query=Iaia%2C+D">Davide Iaia</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+J">Juqiang Li</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+J">Junjing Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Shi%2C+M">Ming Shi</a>, <a href="/search/cond-mat?searchtype=author&query=Ma%2C+J">Junzhang Ma</a>, <a href="/search/cond-mat?searchtype=author&query=Yao%2C+M">Mengyu Yao</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+C">Chien-Lung Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Ochi%2C+M">Masayuki Ochi</a>, <a href="/search/cond-mat?searchtype=author&query=Arita%2C+R">Ryotaro Arita</a>, <a href="/search/cond-mat?searchtype=author&query=Chatterjee%2C+U">Utpal Chatterjee</a>, <a href="/search/cond-mat?searchtype=author&query=Morosan%2C+E">Emilia Morosan</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Trivedi%2C+N">Nandini Trivedi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1912.08246v2-abstract-short" style="display: inline;"> Metal-to-insulator transitions (MIT) can be driven by a number of different mechanisms, each resulting in a different type of insulator -- Change in chemical potential can induce a transition from a metal to a band insulator; strong correlations can drive a metal into a Mott insulator with an energy gap; an Anderson transition, on the other hand, due to disorder leads to a localized insulator with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.08246v2-abstract-full').style.display = 'inline'; document.getElementById('1912.08246v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.08246v2-abstract-full" style="display: none;"> Metal-to-insulator transitions (MIT) can be driven by a number of different mechanisms, each resulting in a different type of insulator -- Change in chemical potential can induce a transition from a metal to a band insulator; strong correlations can drive a metal into a Mott insulator with an energy gap; an Anderson transition, on the other hand, due to disorder leads to a localized insulator without a gap in the spectrum. Here we report the discovery of an alternative route for MIT driven by the creation of a network of narrow channels. Transport data on Pt substituted for Ti in TiSe$_2$ shows a dramatic increase of resistivity by five orders of magnitude for few % of Pt substitution, with a power-law dependence of the temperature-dependent resistivity $蟻(T)$. Our scanning tunneling microscopy data show that Pt induces an irregular network of nanometer-thick domain walls (DWs) of charge density wave (CDW) order, which pull charge carriers out of the bulk and into the DWs. While the CDW domains are gapped, the charges confined to the narrow DWs interact strongly, with pseudogap-like suppression in the local density of states, even when they were weakly interacting in the bulk, and scatter at the DW network interconnects thereby generating the highly resistive state. Angle-resolved photoemission spectroscopy spectra exhibit pseudogap behavior corroborating the spatial coexistence of gapped domains and narrow domain walls with excess charge carriers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.08246v2-abstract-full').style.display = 'none'; document.getElementById('1912.08246v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Mater. 6, 8 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.02798">arXiv:1912.02798</a> <span> [<a href="https://arxiv.org/pdf/1912.02798">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1073/pnas.1916463117">10.1073/pnas.1916463117 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Momentum Resolved Superconducting Energy Gaps of Sr$_2$RuO$_4$ from Quasiparticle Interference Imaging </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sharma%2C+R">Rahul Sharma</a>, <a href="/search/cond-mat?searchtype=author&query=Edkins%2C+S+D">Stephen D. Edkins</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Kostin%2C+A">Andrey Kostin</a>, <a href="/search/cond-mat?searchtype=author&query=Sow%2C+C">Chanchal Sow</a>, <a href="/search/cond-mat?searchtype=author&query=Maeno%2C+Y">Yoshiteru Maeno</a>, <a href="/search/cond-mat?searchtype=author&query=Mackenzie%2C+A+P">Andrew P. Mackenzie</a>, <a href="/search/cond-mat?searchtype=author&query=Davis%2C+J+C+S">J. C. S茅amus Davis</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1912.02798v2-abstract-short" style="display: inline;"> Sr$_2$RuO$_4$ has long been the focus of intense research interest because of conjectures that it is a correlated topological superconductor. It is the momentum space (k-space) structure of the superconducting energy gap $螖_i(\mathbf{k})$ on each band $i$ that encodes its unknown superconducting order-parameter. But, because the energy scales are so low, it has never been possible to directly meas… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.02798v2-abstract-full').style.display = 'inline'; document.getElementById('1912.02798v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.02798v2-abstract-full" style="display: none;"> Sr$_2$RuO$_4$ has long been the focus of intense research interest because of conjectures that it is a correlated topological superconductor. It is the momentum space (k-space) structure of the superconducting energy gap $螖_i(\mathbf{k})$ on each band $i$ that encodes its unknown superconducting order-parameter. But, because the energy scales are so low, it has never been possible to directly measure the $螖_i(\mathbf{k})$ of Sr$_2$RuO$_4$. Here we implement Bogoliubov quasiparticle interference (BQPI) imaging, a technique capable of high-precision measurement of multiband $螖_i(\mathbf{k})$. At T=90 mK we visualize a set of Bogoliubov scattering interference wavevectors $q_j:j=1-5$ consistent with eight gap nodes/minima, that are all closely aligned to the $(\pm1,\pm1)$ crystal-lattice directions on both the $伪$-and $尾$-bands. Taking these observations in combination with other very recent advances in directional thermal conductivity (E. Hassinger et al. Phys. Rev. X 7, 011032 (2017)), temperature dependent Knight shift (A. Pustogow et al. Nature 574, 72 (2019)), time-reversal symmetry conservation (S. Kashiwaya et al. arXiv:1907.030939) and theory (A.T. Romer et al. Phys. Rev. Lett. 123, 247001 (2019); H. S. Roising et al. Phys. Rev. Research 1, 033108 (2019),O. Gingras et al. Phys. Rev. Lett. 123, 217005 (2019)), the BQPI signature of Sr$_2$RuO$_4$ appears most consistent with $螖_i(\mathbf{k})$ having $d_{x^2-y^2}$ $(B_{1g})$ symmetry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.02798v2-abstract-full').style.display = 'none'; document.getElementById('1912.02798v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">accepted in PNAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.11205">arXiv:1910.11205</a> <span> [<a href="https://arxiv.org/pdf/1910.11205">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Observation of linearly dispersive edge modes in a magnetic Weyl semimetal Co3Sn2S2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Howard%2C+S">Sean Howard</a>, <a href="/search/cond-mat?searchtype=author&query=Jiao%2C+L">Lin Jiao</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Vir%2C+P">Praveen Vir</a>, <a href="/search/cond-mat?searchtype=author&query=Shekhar%2C+C">Chandra Shekhar</a>, <a href="/search/cond-mat?searchtype=author&query=Felser%2C+C">Claudia Felser</a>, <a href="/search/cond-mat?searchtype=author&query=Hughes%2C+T">Taylor Hughes</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1910.11205v2-abstract-short" style="display: inline;"> The physical realization of Chern insulators is of fundamental and practical interest, as they are predicted to host the quantum anomalous Hall effect (QAHE) and topologically protected chiral edge states which can carry dissipationless current. The realization of the QAHE state has however been challenging because of the complex heterostructures and sub-Kelvin temperatures required. Time-reversal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.11205v2-abstract-full').style.display = 'inline'; document.getElementById('1910.11205v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.11205v2-abstract-full" style="display: none;"> The physical realization of Chern insulators is of fundamental and practical interest, as they are predicted to host the quantum anomalous Hall effect (QAHE) and topologically protected chiral edge states which can carry dissipationless current. The realization of the QAHE state has however been challenging because of the complex heterostructures and sub-Kelvin temperatures required. Time-reversal symmetry breaking Weyl semimetals, being essentially stacks of Chern insulators with inter-layer coupling, may provide a new platform for the higher temperature realization of robust QAHE edge states. In this work we present a combined scanning tunneling spectroscopy and theoretical investigation of a newly discovered magnetic Weyl semimetal, Co3Sn2S2. Using modeling and numerical simulations we find that chiral edge states can be localized on partially exposed Kagome planes on the surface of a Weyl semimetal. Correspondingly, our STM dI/dV maps on narrow kagome Co3Sn terraces show linearly dispersing quantum well like states, which can be attributed to hybridized chiral edge modes. Our experiment and theory results suggest a new paradigm for studying chiral edge modes in time-reversal breaking Weyl semimetals. More importantly, this work leads a practical route for realizing higher temperature QAHE. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.11205v2-abstract-full').style.display = 'none'; document.getElementById('1910.11205v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 9 figures including supplemental information</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.02846">arXiv:1908.02846</a> <span> [<a href="https://arxiv.org/pdf/1908.02846">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-020-2122-2">10.1038/s41586-020-2122-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Microscopic evidence for a chiral superconducting order parameter in the heavy fermion superconductor UTe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Jiao%2C+L">Lin Jiao</a>, <a href="/search/cond-mat?searchtype=author&query=Howard%2C+S">Sean Howard</a>, <a href="/search/cond-mat?searchtype=author&query=Ran%2C+S">Sheng Ran</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Rodriguez%2C+J+O">Jorge Olivares Rodriguez</a>, <a href="/search/cond-mat?searchtype=author&query=Sigrist%2C+M">Manfred Sigrist</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Butch%2C+N">Nicholas Butch</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1908.02846v2-abstract-short" style="display: inline;"> Spin-triplet superconductivity is a condensate of electron pairs with spin-1 and an odd-parity wavefunction. A particularly interesting manifestation of triplet pairing is a chiral p-wave state which is topologically non-trivial and a natural platform for realizing Majorana edge modes. Triplet pairing is however rare in solid state systems and so far, no unambiguous identification has been made in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.02846v2-abstract-full').style.display = 'inline'; document.getElementById('1908.02846v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.02846v2-abstract-full" style="display: none;"> Spin-triplet superconductivity is a condensate of electron pairs with spin-1 and an odd-parity wavefunction. A particularly interesting manifestation of triplet pairing is a chiral p-wave state which is topologically non-trivial and a natural platform for realizing Majorana edge modes. Triplet pairing is however rare in solid state systems and so far, no unambiguous identification has been made in any bulk compound. Since pairing is most naturally mediated by ferromagnetic spin fluctuations, uranium based heavy fermion systems containing f electron elements that can harbor both strong correlations and magnetism are considered ideal candidate spin-triplet superconductors. In this work we present scanning tunneling microscopy (STM) studies of the newly discovered heavy fermion superconductor, UTe2 with a T$_{SC}$ of 1.6 K. We find signatures of coexisting Kondo effect and superconductivity which show competing spatial modulations within one unit-cell. STM spectroscopy at step edges show signatures of chiral in-gap states, predicted to exist at the boundaries of a topological superconductor. Combined with existing data indicating triplet pairing, the presence of chiral edge states suggests that UTe2 is a strong candidate material for chiral-triplet topological superconductivity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.02846v2-abstract-full').style.display = 'none'; document.getElementById('1908.02846v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 4+8 figures, with Supplementary Material</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 579, 523 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.12660">arXiv:1907.12660</a> <span> [<a href="https://arxiv.org/pdf/1907.12660">pdf</a>, <a href="https://arxiv.org/format/1907.12660">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.124.137402">10.1103/PhysRevLett.124.137402 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Local Spectroscopies Reveal Percolative Metal in Disordered Mott Insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Szabo%2C+J+C">Joseph C. Szabo</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+K">Kyungmin Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Trivedi%2C+N">Nandini Trivedi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1907.12660v1-abstract-short" style="display: inline;"> We elucidate the mechanism by which a Mott insulator transforms into a non-Fermi liquid metal upon increasing disorder at half filling. By correlating maps of the local density of states, the local magnetization and the local bond conductivity, we find a collapse of the Mott gap toward a V-shape pseudogapped density of states that occurs concomitantly with the decrease of magnetism around the high… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.12660v1-abstract-full').style.display = 'inline'; document.getElementById('1907.12660v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.12660v1-abstract-full" style="display: none;"> We elucidate the mechanism by which a Mott insulator transforms into a non-Fermi liquid metal upon increasing disorder at half filling. By correlating maps of the local density of states, the local magnetization and the local bond conductivity, we find a collapse of the Mott gap toward a V-shape pseudogapped density of states that occurs concomitantly with the decrease of magnetism around the highly disordered sites but an increase of bond conductivity. These metallic regions percolate to form an emergent non-Fermi liquid phase with a conductivity that increases with temperature. Bond conductivity measured via local microwave impedance combined with charge and spin local spectroscopies are ideal tools to corroborate our predictions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.12660v1-abstract-full').style.display = 'none'; document.getElementById('1907.12660v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 124, 137402 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.11983">arXiv:1906.11983</a> <span>  </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Visualizing 1D zigzag Wigner crystallization at domain walls in the Mott insulator TaS$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Aishwarya%2C+A">Anuva Aishwarya</a>, <a href="/search/cond-mat?searchtype=author&query=Howard%2C+S">Sean Howard</a>, <a href="/search/cond-mat?searchtype=author&query=Padhi%2C+B">Bikash Padhi</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+L">Lihai Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Cheong%2C+S">Sang-Wook Cheong</a>, <a href="/search/cond-mat?searchtype=author&query=Phillips%2C+P+W">Philip W. Phillips</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.11983v2-abstract-short" style="display: inline;"> In a certain regime of low carrier densities and strong correlations, electrons can crystallize into a periodic arrangement of charge known as Wigner crystal. Such phases are particularly interesting in one dimension (1D) as they display a variety of charge and spin ground states which may be harnessed in quantum devices as high-fidelity transmitters of spin information. Recent theoretical studies… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.11983v2-abstract-full').style.display = 'inline'; document.getElementById('1906.11983v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.11983v2-abstract-full" style="display: none;"> In a certain regime of low carrier densities and strong correlations, electrons can crystallize into a periodic arrangement of charge known as Wigner crystal. Such phases are particularly interesting in one dimension (1D) as they display a variety of charge and spin ground states which may be harnessed in quantum devices as high-fidelity transmitters of spin information. Recent theoretical studies suggest that the strong Coulomb interactions in Mott insulators and other flat band systems, may provide an attractive higher temperature platform for Wigner crystallization, but due to materials and device constraints experimental realization has proven difficult. In this work we use scanning tunneling microscopy at liquid helium temperatures to directly image the formation of a 1D Wigner crystal in a Mott insulator, TaS$_2$. Charge density wave domain walls in TaS$_2$ create band bending and provide ideal conditions of low densities and strong interactions in 1D. STM spectroscopic maps show that once the lower Hubbard band crosses the Fermi energy, the charges rearrange to minimize Coulomb energy, forming zigzag patterns expected for a 1D Wigner crystal. The zigzag charge patterns show characteristic noise signatures signifying charge or spin fluctuations induced by the tunneling electrons, which is expected for this more fragile condensed state. The observation of a Wigner crystal at orders of magnitude higher temperatures enabled by the large Coulomb energy scales combined with the low density of electrons, makes TaS$_2$ a promising system for exploiting the charge and spin order in 1D Wigner crystals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.11983v2-abstract-full').style.display = 'none'; document.getElementById('1906.11983v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">We have written a new paper describing a different aspect of this data</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.06469">arXiv:1905.06469</a> <span> [<a href="https://arxiv.org/pdf/1905.06469">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Doping induced Mott collapse and the density wave instabilities in (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Maximenko%2C+Y">Yulia Maximenko</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Hogan%2C+T">Tom Hogan</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.06469v1-abstract-short" style="display: inline;"> The path from a Mott insulating phase to high temperature superconductivity encounters a rich set of unconventional phenomena involving the insulator-to-metal transition (IMT) such as emergent electronic orders and pseudogaps that ultimately affect the condensation of Cooper pairs. A huge hindrance to understanding the origin of these phenomena in the curates is the difficulty in accessing doping… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.06469v1-abstract-full').style.display = 'inline'; document.getElementById('1905.06469v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.06469v1-abstract-full" style="display: none;"> The path from a Mott insulating phase to high temperature superconductivity encounters a rich set of unconventional phenomena involving the insulator-to-metal transition (IMT) such as emergent electronic orders and pseudogaps that ultimately affect the condensation of Cooper pairs. A huge hindrance to understanding the origin of these phenomena in the curates is the difficulty in accessing doping levels near the parent state. Recently, the J$_{eff}$=1/2 Mott state of the perovskite strontium iridates has revealed intriguing parallels to the cuprates, with the advantage that it provides unique access to the Mott transition. Here, we exploit this accessibility to study the IMT and the possible nearby electronic orders in the electron-doped bilayer iridate (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$. Using spectroscopic imaging scanning tunneling microscopy, we image the La dopants in the top as well as the interlayer SrO planes. Surprisingly, we find a disproportionate distribution of La in these layers with the interlayer La being primarily responsible for the IMT, thereby revealing the distinct site-dependent effects of dopants on the electronic properties of bilayer systems. Furthermore, we discover the coexistence of two electronic orders generated by electron doping: a unidirectional electronic order with a concomitant structural distortion; and local resonant states forming a checkerboard-like pattern trapped by La. This provides evidence that multiple charge orders may exist simultaneously in Mott systems, even with only one band crossing the Fermi energy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.06469v1-abstract-full').style.display = 'none'; document.getElementById('1905.06469v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 5 figures; Supplementary information included</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.00515">arXiv:1903.00515</a> <span> [<a href="https://arxiv.org/pdf/1903.00515">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.aaw8419">10.1126/science.aaw8419 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Signature of Dispersing 1D Majorana Channels in an Iron-based Superconductor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Rodriguez%2C+J+O">Jorge Olivares Rodriguez</a>, <a href="/search/cond-mat?searchtype=author&query=Jiao%2C+L">Lin Jiao</a>, <a href="/search/cond-mat?searchtype=author&query=Howard%2C+S">Sean Howard</a>, <a href="/search/cond-mat?searchtype=author&query=Graham%2C+M">Martin Graham</a>, <a href="/search/cond-mat?searchtype=author&query=Gu%2C+G+D">G. D. Gu</a>, <a href="/search/cond-mat?searchtype=author&query=Hughes%2C+T">Taylor Hughes</a>, <a href="/search/cond-mat?searchtype=author&query=Morr%2C+D+K">Dirk K. Morr</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1903.00515v4-abstract-short" style="display: inline;"> The possible realization of Majorana fermions as quasiparticle excitations in condensed matter physics has created much excitement. Most recent studies have focused on Majorana bound states which can serve as topological qubits. More generally, akin to elementary particles, Majorana fermions can propagate and display linear dispersion. These excitations have not yet been directly observed, and can… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.00515v4-abstract-full').style.display = 'inline'; document.getElementById('1903.00515v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.00515v4-abstract-full" style="display: none;"> The possible realization of Majorana fermions as quasiparticle excitations in condensed matter physics has created much excitement. Most recent studies have focused on Majorana bound states which can serve as topological qubits. More generally, akin to elementary particles, Majorana fermions can propagate and display linear dispersion. These excitations have not yet been directly observed, and can also be used for quantum information processing. One route to realizing this is in a line junction between two phase-shifted superconductors coupled to topological surface states. Recent theory indicates that in iron-based superconductors, a particular type of crystalline defect, i.e., a domain wall (DW) between two regions with a half-unit cell shift between them, should create a $蟺$-phase shift in the superconducting order parameter. Combined with recent data showing topological surface states in FeSe$_x$Te$_{1-x}$ we find that this is the ideal system to realize helical 1D-dispersing Majorana modes. Here we report scanning tunneling spectroscopic (STS) measurements of crystalline DWs in FeSe$_{0.45}$Te$_{0.55}$. By analyzing large-area superconducting gap maps, we identify the gap in the topological surface state, demonstrating that our sample is an effective Fu-Kane proximitized topological system. We further locate DWs across which the atoms shift by half a unit cell. STS data on these DWs reveal a flat density of states inside the superconducting gap, a hallmark of linearly dispersing modes in 1D. This unique signature is absent in DWs in the related superconductor, FeSe which is not in the topological phase. Our combined data are consistent with the observation of dispersing Majorana states at a $蟺$-phase shift DW in a proximitized topological material. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.00515v4-abstract-full').style.display = 'none'; document.getElementById('1903.00515v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 4 figures; with supplementary information;added Acknowledgement</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.05690">arXiv:1811.05690</a> <span> [<a href="https://arxiv.org/pdf/1811.05690">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.121.196402">10.1103/PhysRevLett.121.196402 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unique gap structure and symmetry of the charge density wave in single-layer VSe$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chen%2C+P">P. Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Pai%2C+W+-">W. -W. Pai</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+Y+-">Y. -H. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">V. Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+M+Y">M. Y. Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Mo%2C+S+-">S. -K. Mo</a>, <a href="/search/cond-mat?searchtype=author&query=Fedorov%2C+A+-">A. -V. Fedorov</a>, <a href="/search/cond-mat?searchtype=author&query=Chiang%2C+T+-">T. -C. Chiang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1811.05690v1-abstract-short" style="display: inline;"> Single layers of transition metal dichalcogenides (TMDCs) are excellent candidates for electronic applications beyond the graphene platform; many of them exhibit novel properties including charge density waves (CDWs) and magnetic ordering. CDWs in these single layers are generally a planar projection of the corresponding bulk CDWs because of the quasi-two-dimensional nature of TMDCs; a different C… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.05690v1-abstract-full').style.display = 'inline'; document.getElementById('1811.05690v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.05690v1-abstract-full" style="display: none;"> Single layers of transition metal dichalcogenides (TMDCs) are excellent candidates for electronic applications beyond the graphene platform; many of them exhibit novel properties including charge density waves (CDWs) and magnetic ordering. CDWs in these single layers are generally a planar projection of the corresponding bulk CDWs because of the quasi-two-dimensional nature of TMDCs; a different CDW symmetry is unexpected. We report herein the successful creation of pristine single-layer VSe$_2$, which shows a ($\sqrt7 \times \sqrt3$) CDW in contrast to the (4 $\times$ 4) CDW for the layers in bulk VSe$_2$. Angle-resolved photoemission spectroscopy (ARPES) from the single layer shows a sizable ($\sqrt7 \times \sqrt3$) CDW gap of $\sim$100 meV at the zone boundary, a 220 K CDW transition temperature twice the bulk value, and no ferromagnetic exchange splitting as predicted by theory. This robust CDW with an exotic broken symmetry as the ground state is explained via a first-principles analysis. The results illustrate a unique CDW phenomenon in the two-dimensional limit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.05690v1-abstract-full').style.display = 'none'; document.getElementById('1811.05690v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 121, 196402 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1810.06688">arXiv:1810.06688</a> <span> [<a href="https://arxiv.org/pdf/1810.06688">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1073/pnas.1808056115">10.1073/pnas.1808056115 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Disorder induced power-law gaps in an insulator-metal Mott transition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=O%27Neal%2C+J">Jared O'Neal</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Dhital%2C+C">Chetan Dhital</a>, <a href="/search/cond-mat?searchtype=author&query=Hogan%2C+T">Tom Hogan</a>, <a href="/search/cond-mat?searchtype=author&query=Clancy%2C+P">Patrick Clancy</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+Y">Young-June Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+Y+F">Y. F. Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Santos%2C+L+H">Luiz H. Santos</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Trivedi%2C+N">Nandini Trivedi</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1810.06688v1-abstract-short" style="display: inline;"> A correlated material in the vicinity of an insulator-metal transition (IMT) exhibits rich phenomenology and variety of interesting phases. A common avenue to induce IMTs in Mott insulators is doping, which inevitably leads to disorder. While disorder is well known to create electronic inhomogeneity, recent theoretical studies have indicated that it may play an unexpected and much more profound ro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.06688v1-abstract-full').style.display = 'inline'; document.getElementById('1810.06688v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.06688v1-abstract-full" style="display: none;"> A correlated material in the vicinity of an insulator-metal transition (IMT) exhibits rich phenomenology and variety of interesting phases. A common avenue to induce IMTs in Mott insulators is doping, which inevitably leads to disorder. While disorder is well known to create electronic inhomogeneity, recent theoretical studies have indicated that it may play an unexpected and much more profound role in controlling the properties of Mott systems. Theory predicts that disorder might play a role in driving a Mott insulator across an IMT, with the emergent metallic state hosting a power law suppression of the density of states (with exponent close to 1; V-shaped gap) centered at the Fermi energy. Such V-shaped gaps have been observed in Mott systems but their origins are as yet unknown. To investigate this, we use scanning tunneling microscopy and spectroscopy to study isovalent Ru substitutions in Sr$_3$(Ir$_{1-x}$Ru$_x$)$_2$O$_7$ which drives the system into an antiferromagnetic, metallic state. Our experiments reveal that many core features of the IMT such as power law density of states, pinning of the Fermi energy with increasing disorder, and persistence of antiferromagnetism can be understood as universal features of a disordered Mott system near an IMT and suggest that V-shaped gaps may be an inevitable consequence of disorder in doped Mott insulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.06688v1-abstract-full').style.display = 'none'; document.getElementById('1810.06688v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 4 figures; A new version can be find in PNAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1809.10689">arXiv:1809.10689</a> <span> [<a href="https://arxiv.org/pdf/1809.10689">pdf</a>, <a href="https://arxiv.org/format/1809.10689">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.99.155116">10.1103/PhysRevB.99.155116 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Topological nature of step edge states on the surface of topological crystalline insulator Pb$_{0.7}$Sn$_{0.3}$Se </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Iaia%2C+D">Davide Iaia</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+C">Chang-Yan Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Maximenko%2C+Y">Yulia Maximenko</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">R. Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+F">Fangcheng Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+Y">Yuan-Ming Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1809.10689v3-abstract-short" style="display: inline;"> In addition to novel surface states, topological insulators can also exhibit robust gapless states at crystalline defects. Step edges constitute a class of common defects on the surface of crystals. In this work we establish the topological nature of one-dimensional (1D) bound states localized at step edges of the [001] surface of a topological crystalline insulator (TCI) Pb$_{0.7}$Sn$_{0.3}$Se, b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.10689v3-abstract-full').style.display = 'inline'; document.getElementById('1809.10689v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1809.10689v3-abstract-full" style="display: none;"> In addition to novel surface states, topological insulators can also exhibit robust gapless states at crystalline defects. Step edges constitute a class of common defects on the surface of crystals. In this work we establish the topological nature of one-dimensional (1D) bound states localized at step edges of the [001] surface of a topological crystalline insulator (TCI) Pb$_{0.7}$Sn$_{0.3}$Se, both theoretically and experimentally. We show that the topological stability of the step edge states arises from an emergent particle-hole symmetry of the surface low-energy physics, and demonstrate the experimental signatures of the particle-hole symmetry breaking. We also reveal the effects of an external magnetic field on the 1D bound states. Our work suggests the possibility of similar topological step edge modes in other topological materials with a rocks-salt structure. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.10689v3-abstract-full').style.display = 'none'; document.getElementById('1809.10689v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 January, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8+6 pages, 6 figures, references and acknowledgements updated</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 99, 155116 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1804.00244">arXiv:1804.00244</a> <span> [<a href="https://arxiv.org/pdf/1804.00244">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41535-018-0112-5">10.1038/s41535-018-0112-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Searching for topological Fermi arcs via quasiparticle interference on a type-II Weyl semimetal MoTe$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Iaia%2C+D">Davide Iaia</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+G">Guoqing Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+T">Tay-Rong Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+J">Jin Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Mao%2C+Z">Zhiqiang Mao</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+S">Shichao Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1804.00244v2-abstract-short" style="display: inline;"> Weyl semimetals display a novel topological phase of matter where the Weyl nodes emerge in pairs of opposite chirality and can be seen as either a source or a sink of Berry curvature. The exotic effects in Weyl semimetals, such as surface Fermi arcs and the chiral anomaly, make them a new playground for exploring novel functionalities. Further exploiting their potential applications requires clear… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1804.00244v2-abstract-full').style.display = 'inline'; document.getElementById('1804.00244v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1804.00244v2-abstract-full" style="display: none;"> Weyl semimetals display a novel topological phase of matter where the Weyl nodes emerge in pairs of opposite chirality and can be seen as either a source or a sink of Berry curvature. The exotic effects in Weyl semimetals, such as surface Fermi arcs and the chiral anomaly, make them a new playground for exploring novel functionalities. Further exploiting their potential applications requires clear understanding of their topological electronic properties, such as Weyl points and Fermi arcs. Here we report a Fourier transform scanning tunneling spectroscopy (FT-STS) study on a type-II Weyl semimetal candidate MoTe$_2$ whose Weyl points are predicated to be located above Fermi level. Although its electronic structure below the Fermi level have been identified by angle resolved photo emission spectroscopy (ARPES), by comparing our experimental data with first-principles calculations, we are able to identify the origins of the multiple scattering channels at energies both below and above Fermi level. Our calculations also show the existence of both trivial and topological arc like states above the Fermi energy. In the FT-STS experiments, we have observed strong signals from intra-arc scatterings as well as from the scattering between the arc-like surface states and the projected bulk states. A detailed comparison between our experimental observations and calculated results reveals the trivial and non-trivial scattering channels are difficult to distinguish in this compound. Interestingly, we find that the broken inversion symmetry changes the terminating states on the two inequivalent surfaces, which in turn changes the relative strength of the scattering channels observed in the FT-STS images on the two surfaces. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1804.00244v2-abstract-full').style.display = 'none'; document.getElementById('1804.00244v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Materials 3, 38 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1709.09133">arXiv:1709.09133</a> <span> [<a href="https://arxiv.org/pdf/1709.09133">pdf</a>, <a href="https://arxiv.org/format/1709.09133">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.97.125150">10.1103/PhysRevB.97.125150 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Defect Role in the Carrier Tunable Topological Insulator (Bi$_{1-x}$Sb$_x$)$_2$Te$_3$ Thin Films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Scipioni%2C+K+L">Kane L Scipioni</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Maximenko%2C+Y">Yulia Maximenko</a>, <a href="/search/cond-mat?searchtype=author&query=Katmis%2C+F">Ferhat Katmis</a>, <a href="/search/cond-mat?searchtype=author&query=Steiner%2C+C">Charlie Steiner</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1709.09133v1-abstract-short" style="display: inline;"> Alloys of Bi$_2$Te$_3$ and Sb$_2$Te$_3$ ((Bi$_{1-x}$Sb$_x$)$_2$Te$_3$) have played an essential role in the exploration of topological surface states, allowing us to study phenomena that would otherwise be obscured by bulk contributions to conductivity. Thin films of these alloys have been particularly important for tuning the energy of the Fermi level, a key step in observing spin-polarized surfa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.09133v1-abstract-full').style.display = 'inline'; document.getElementById('1709.09133v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1709.09133v1-abstract-full" style="display: none;"> Alloys of Bi$_2$Te$_3$ and Sb$_2$Te$_3$ ((Bi$_{1-x}$Sb$_x$)$_2$Te$_3$) have played an essential role in the exploration of topological surface states, allowing us to study phenomena that would otherwise be obscured by bulk contributions to conductivity. Thin films of these alloys have been particularly important for tuning the energy of the Fermi level, a key step in observing spin-polarized surface currents and the quantum anomalous Hall effect. Previous studies reported the chemical tuning of the Fermi level to the Dirac point by controlling the Sb:Bi composition ratio, but the optimum ratio varies widely across various studies with no consensus. In this work, we use scanning tunneling microscopy and Landau level spectroscopy, in combination with X-ray photoemission spectroscopy to isolate the effects of growth factors such as temperature and composition, and to provide a microscopic picture of the role that disorder and composition play in determining the carrier density of epitaxially grown (Bi,Sb)$_2$Te$_3$ thin films. Using Landau level spectroscopy, we determine that the ideal Sb concentration to place the Fermi energy to within a few meV of the Dirac point is $x\sim 0.7$. However, we find that the post- growth annealing temperature can have a drastic impact on microscopic structure as well as carrier density. In particular, we find that when films are post-growth annealed at high temperature, better crystallinity and surface roughness are achieved; but this also produces a larger Te defect density, adding n-type carriers. This work provides key information necessary for optimizing thin film quality in this fundamentally and technologically important class of materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.09133v1-abstract-full').style.display = 'none'; document.getElementById('1709.09133v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 September, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 figures, 6 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 97, 125150 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1701.02773">arXiv:1701.02773</a> <span> [<a href="https://arxiv.org/pdf/1701.02773">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nphys4107">10.1038/nphys4107 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quasiparticle Interference and Strong Electron-Mode Coupling in the Quasi-One-Dimensional Bands of Sr$_2$RuO$_4$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Derry%2C+P">Philip Derry</a>, <a href="/search/cond-mat?searchtype=author&query=Scaffidi%2C+T">Thomas Scaffidi</a>, <a href="/search/cond-mat?searchtype=author&query=Rak%2C+M">Melinda Rak</a>, <a href="/search/cond-mat?searchtype=author&query=Vig%2C+S">Sean Vig</a>, <a href="/search/cond-mat?searchtype=author&query=Kogar%2C+A">Anshul Kogar</a>, <a href="/search/cond-mat?searchtype=author&query=Zeljkovic%2C+I">Ilija Zeljkovic</a>, <a href="/search/cond-mat?searchtype=author&query=Husain%2C+A">Ali Husain</a>, <a href="/search/cond-mat?searchtype=author&query=Santos%2C+L+H">Luiz H. Santos</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y">Yuxuan Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Damascelli%2C+A">Andrea Damascelli</a>, <a href="/search/cond-mat?searchtype=author&query=Maeno%2C+Y">Yoshiteru Maeno</a>, <a href="/search/cond-mat?searchtype=author&query=Abbamonte%2C+P">Peter Abbamonte</a>, <a href="/search/cond-mat?searchtype=author&query=Fradkin%2C+E">Eduardo Fradkin</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1701.02773v1-abstract-short" style="display: inline;"> The single-layered ruthenate Sr$_2$RuO$_4$ has attracted a great deal of interest as a spin-triplet superconductor with an order parameter that may potentially break time reversal invariance and host half-quantized vortices with Majorana zero modes. While the actual nature of the superconducting state is still a matter of controversy, it has long been believed that it condenses from a metallic sta… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.02773v1-abstract-full').style.display = 'inline'; document.getElementById('1701.02773v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1701.02773v1-abstract-full" style="display: none;"> The single-layered ruthenate Sr$_2$RuO$_4$ has attracted a great deal of interest as a spin-triplet superconductor with an order parameter that may potentially break time reversal invariance and host half-quantized vortices with Majorana zero modes. While the actual nature of the superconducting state is still a matter of controversy, it has long been believed that it condenses from a metallic state that is well described by a conventional Fermi liquid. In this work we use a combination of Fourier transform scanning tunneling spectroscopy (FT-STS) and momentum resolved electron energy loss spectroscopy (M-EELS) to probe interaction effects in the normal state of Sr$_2$RuO$_4$. Our high-resolution FT-STS data show signatures of the 尾-band with a distinctly quasi-one-dimensional (1D) character. The band dispersion reveals surprisingly strong interaction effects that dramatically renormalize the Fermi velocity, suggesting that the normal state of Sr$_2$RuO$_4$ is that of a 'correlated metal' where correlations are strengthened by the quasi 1D nature of the bands. In addition, kinks at energies of approximately 10meV, 38meV and 70meV are observed. By comparing STM and M-EELS data we show that the two higher energy features arise from coupling with collective modes. The strong correlation effects and the kinks in the quasi 1D bands may provide important information for understanding the superconducting state. This work opens up a unique approach to revealing the superconducting order parameter in this compound. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.02773v1-abstract-full').style.display = 'none'; document.getElementById('1701.02773v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 January, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 13 (2017) 799-805 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1610.09337">arXiv:1610.09337</a> <span> [<a href="https://arxiv.org/pdf/1610.09337">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-018-03887-5">10.1038/s41467-018-03887-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Interplay of orbital effects and nanoscale strain in topological crystalline insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Assaf%2C+B">Badih Assaf</a>, <a href="/search/cond-mat?searchtype=author&query=Scipioni%2C+K+L">Kane L Scipioni</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">R. Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+F">Fangcheng Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+G">Guoqing Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Zeljkovic%2C+I">Ilija Zeljkovic</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1610.09337v2-abstract-short" style="display: inline;"> Orbital degrees of freedom can have pronounced effects on the fundamental properties of electrons in solids. In addition to influencing bandwidths, gaps, correlation strength and dispersion, orbital effects have also been implicated in generating novel electronic and structural phases, such as Jahn-Teller effect and colossal magnetoresistance. In this work, we show for the first time how the orbit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.09337v2-abstract-full').style.display = 'inline'; document.getElementById('1610.09337v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1610.09337v2-abstract-full" style="display: none;"> Orbital degrees of freedom can have pronounced effects on the fundamental properties of electrons in solids. In addition to influencing bandwidths, gaps, correlation strength and dispersion, orbital effects have also been implicated in generating novel electronic and structural phases, such as Jahn-Teller effect and colossal magnetoresistance. In this work, we show for the first time how the orbital nature of bands can result in non-trivial effects of strain on the band structure. We use scanning tunneling microscopy and quasiparticle interference imaging to study the effects of strain on the electronic structure of a heteroepitaxial thin film of a topological crystalline insulator, SnTe. We find a surprising effect where strain applied in one direction affects the band structure in the perpendicular direction. Our theoretical calculations indicate that this effect directly arises from the orbital nature of the conduction and valance bands. Our results imply that a microscopic model capturing strain effects on the band structure must include a consideration of the orbital nature of the bands. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.09337v2-abstract-full').style.display = 'none'; document.getElementById('1610.09337v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 9, 1550 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.08249">arXiv:1609.08249</a> <span> [<a href="https://arxiv.org/pdf/1609.08249">pdf</a>, <a href="https://arxiv.org/format/1609.08249">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.118.106405">10.1103/PhysRevLett.118.106405 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Influence of domain walls in the incommensurate charge density wave state of Cu intercalated 1$T$-TiSe$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yan%2C+S">Shichao Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Iaia%2C+D">Davide Iaia</a>, <a href="/search/cond-mat?searchtype=author&query=Morosan%2C+E">Emilia Morosan</a>, <a href="/search/cond-mat?searchtype=author&query=Fradkin%2C+E">Eduardo Fradkin</a>, <a href="/search/cond-mat?searchtype=author&query=Abbamonte%2C+P">Peter Abbamonte</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1609.08249v3-abstract-short" style="display: inline;"> We report a low-temperature scanning tunneling microscopy study of the charge density wave (CDW) order in 1$T$-TiSe$_2$ and Cu$_{0.08}$TiSe$_2$. In pristine 1$T$-TiSe$_2$ we observe a long-range coherent commensurate CDW (C-CDW) order. In contrast, Cu$_{0.08}$TiSe$_{2}$ displays an incommensurate CDW (I-CDW) phase with localized C-CDW domains separated by domain walls. Density of states measuremen… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.08249v3-abstract-full').style.display = 'inline'; document.getElementById('1609.08249v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.08249v3-abstract-full" style="display: none;"> We report a low-temperature scanning tunneling microscopy study of the charge density wave (CDW) order in 1$T$-TiSe$_2$ and Cu$_{0.08}$TiSe$_2$. In pristine 1$T$-TiSe$_2$ we observe a long-range coherent commensurate CDW (C-CDW) order. In contrast, Cu$_{0.08}$TiSe$_{2}$ displays an incommensurate CDW (I-CDW) phase with localized C-CDW domains separated by domain walls. Density of states measurements indicate that the domain walls host an extra population of fermions near the Fermi level which may play a role in the emergence of superconductivity in this system. Fourier transform scanning tunneling spectroscopy studies suggest that the dominant mechanism for CDW formation in the I-CDW phase may be electron-phonon coupling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.08249v3-abstract-full').style.display = 'none'; document.getElementById('1609.08249v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures, Supplemental materials not included</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 118, 106405 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1506.07574">arXiv:1506.07574</a> <span> [<a href="https://arxiv.org/pdf/1506.07574">pdf</a>, <a href="https://arxiv.org/format/1506.07574">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.92.075125">10.1103/PhysRevB.92.075125 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The influence of electron-doping on the ground state of (Sr{1-x}La{x})2IrO4 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chen%2C+X">Xiang Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Hogan%2C+T">Tom Hogan</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">D. Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Pokharel%2C+M">M. Pokharel</a>, <a href="/search/cond-mat?searchtype=author&query=Yao%2C+M">Mengliang Yao</a>, <a href="/search/cond-mat?searchtype=author&query=Tian%2C+W">Wei Tian</a>, <a href="/search/cond-mat?searchtype=author&query=Ward%2C+T+Z">Thomas Z. Ward</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+Y">Y. Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Parshall%2C+D">D. Parshall</a>, <a href="/search/cond-mat?searchtype=author&query=Opeil%2C+C">C. Opeil</a>, <a href="/search/cond-mat?searchtype=author&query=Lynn%2C+J+W">J. W. Lynn</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1506.07574v2-abstract-short" style="display: inline;"> The evolution of the electronic properties of electron-doped (Sr{1-x}La{x})2IrO4 is experimentally explored as the doping limit of La is approached. As electrons are introduced, the electronic ground state transitions from a spin-orbit Mott phase into an electronically phase separated state, where long-range magnetic order vanishes beyond x = 0.02 and charge transport remains percolative up to the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.07574v2-abstract-full').style.display = 'inline'; document.getElementById('1506.07574v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1506.07574v2-abstract-full" style="display: none;"> The evolution of the electronic properties of electron-doped (Sr{1-x}La{x})2IrO4 is experimentally explored as the doping limit of La is approached. As electrons are introduced, the electronic ground state transitions from a spin-orbit Mott phase into an electronically phase separated state, where long-range magnetic order vanishes beyond x = 0.02 and charge transport remains percolative up to the limit of La substitution (x~0.06). In particular, the electronic ground state remains inhomogeneous even beyond the collapse of the parent state's long-range antiferromagnetic order, while persistent short-range magnetism survives up to the highest La-substitution levels. Furthermore, as electrons are doped into Sr2IrO4, we observe the appearance of a low temperature magnetic glass-like state intermediate to the complete suppression of antiferromagnetic order. Universalities and differences in the electron-doped phase diagrams of single layer and bilayer Ruddlesden-Popper strontium iridates are discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.07574v2-abstract-full').style.display = 'none'; document.getElementById('1506.07574v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 August, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 12 figures. New version has revised text, added references, and updated figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 92, 075125 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1506.00041">arXiv:1506.00041</a> <span> [<a href="https://arxiv.org/pdf/1506.00041">pdf</a>, <a href="https://arxiv.org/format/1506.00041">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.114.257203">10.1103/PhysRevLett.114.257203 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First-order melting of a weak spin-orbit Mott insulator into a correlated metal </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hogan%2C+T">Tom Hogan</a>, <a href="/search/cond-mat?searchtype=author&query=Yamani%2C+Z">Z. Yamani</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">D. Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+X">Xiang Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Dally%2C+R">Rebecca Dally</a>, <a href="/search/cond-mat?searchtype=author&query=Ward%2C+T+Z">Thomas Z. Ward</a>, <a href="/search/cond-mat?searchtype=author&query=Hill%2C+J">John Hill</a>, <a href="/search/cond-mat?searchtype=author&query=Islam%2C+Z">Z. Islam</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1506.00041v1-abstract-short" style="display: inline;"> The electronic phase diagram of the weak spin-orbit Mott insulator (Sr(1-x)Lax)3Ir2O7 is determined via an exhaustive experimental study. Upon doping electrons via La substitution, an immediate collapse in resistivity occurs along with a narrow regime of nanoscale phase separation comprised of antiferromagnetic, insulating regions and paramagnetic, metallic puddles persisting until x~0.04. Continu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.00041v1-abstract-full').style.display = 'inline'; document.getElementById('1506.00041v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1506.00041v1-abstract-full" style="display: none;"> The electronic phase diagram of the weak spin-orbit Mott insulator (Sr(1-x)Lax)3Ir2O7 is determined via an exhaustive experimental study. Upon doping electrons via La substitution, an immediate collapse in resistivity occurs along with a narrow regime of nanoscale phase separation comprised of antiferromagnetic, insulating regions and paramagnetic, metallic puddles persisting until x~0.04. Continued electron doping results in an abrupt, first-order phase boundary where the Neel state is suppressed and a homogenous, correlated, metallic state appears with an enhanced spin susceptibility and local moments. As the metallic state is stabilized, a weak structural distortion develops and suggests a competing instability with the parent spin-orbit Mott state. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.00041v1-abstract-full').style.display = 'none'; document.getElementById('1506.00041v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 May, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physical Review Letters 114, 257203 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1502.04694">arXiv:1502.04694</a> <span> [<a href="https://arxiv.org/pdf/1502.04694">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/ncomms7559">10.1038/ncomms7559 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nanoscale Determination of the Mass Enhancement Factor in the Lightly-Doped Bulk Insulator Lead Selenide </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zeljkovic%2C+I">Ilija Zeljkovic</a>, <a href="/search/cond-mat?searchtype=author&query=Scipioni%2C+K+L">Kane L Scipioni</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">Raman Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+G">Guoqing Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y+J">Yung Jui Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Bansil%2C+A">Arun Bansil</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+F">Fangcheng Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1502.04694v1-abstract-short" style="display: inline;"> Bismuth chalcogenides and lead telluride/selenide alloys exhibit exceptional thermoelectric properties which could be harnessed for power generation and device applications. Since phonons play a significant role in achieving these desired properties, quantifying the interaction between phonons and electrons, which is encoded in the Eliashberg function of a material, is of immense importance. Howev… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.04694v1-abstract-full').style.display = 'inline'; document.getElementById('1502.04694v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1502.04694v1-abstract-full" style="display: none;"> Bismuth chalcogenides and lead telluride/selenide alloys exhibit exceptional thermoelectric properties which could be harnessed for power generation and device applications. Since phonons play a significant role in achieving these desired properties, quantifying the interaction between phonons and electrons, which is encoded in the Eliashberg function of a material, is of immense importance. However, its precise extraction has in part been limited due to the lack of local experimental probes. Here we construct a method to directly extract the Eliashberg function using Landau level spectroscopy, and demonstrate its applicability to lightly-doped thermoelectric bulk insulator PbSe. In addition to its high energy resolution only limited by thermal broadening, this novel experimental method could be used to detect variations in mass enhancement factor at the nanoscale. As such, it opens up a new pathway for investigating the effects of chemical defects, surface doping and strain on the mass enhancement factor. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.04694v1-abstract-full').style.display = 'none'; document.getElementById('1502.04694v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 February, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">to appear in Nature Communications (2015)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Commun. 6, 6559 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1501.01299">arXiv:1501.01299</a> <span> [<a href="https://arxiv.org/pdf/1501.01299">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nnano.2015.177">10.1038/nnano.2015.177 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Strain engineering Dirac surface states in heteroepitaxial topological crystalline insulator thin films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zeljkovic%2C+I">Ilija Zeljkovic</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Assaf%2C+B">Badih Assaf</a>, <a href="/search/cond-mat?searchtype=author&query=Scipioni%2C+K+L">Kane L Scipioni</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">R. Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+F">Fangcheng Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1501.01299v1-abstract-short" style="display: inline;"> In newly discovered topological crystalline insulators (TCIs), the unique crystalline protection of the surface state (SS) band structure has led to a series of intriguing predictions of strain generated phenomena, from the appearance of pseudo-magnetic fields and helical flat bands, to the tunability of the Dirac SS by strain that may be used to construct "straintronic" nanoswitches. However, pra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.01299v1-abstract-full').style.display = 'inline'; document.getElementById('1501.01299v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1501.01299v1-abstract-full" style="display: none;"> In newly discovered topological crystalline insulators (TCIs), the unique crystalline protection of the surface state (SS) band structure has led to a series of intriguing predictions of strain generated phenomena, from the appearance of pseudo-magnetic fields and helical flat bands, to the tunability of the Dirac SS by strain that may be used to construct "straintronic" nanoswitches. However, practical realization of this exotic phenomenology via strain engineering is experimentally challenging and is yet to be achieved. In this work, we have designed an experiment to not only generate and measure strain locally, but to also directly measure the resulting effects on the Dirac SS. We grow heteroepitaxial thin films of TCI SnTe in-situ and measure them by using high-resolution scanning tunneling microscopy (STM). Large STM images were analyzed to determine picoscale changes in the atomic positions which reveal regions of both tensile and compressive strain. Simultaneous Fourier-transform STM was then used to determine the effects of strain on the Dirac electrons. We find that strain continuously tunes the momentum space position of the Dirac points, consistent with theoretical predictions. Our work demonstrates the fundamental mechanism necessary for using TCIs in strain-based applications, and establishes these systems as highly tunable platforms for nanodevices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.01299v1-abstract-full').style.display = 'none'; document.getElementById('1501.01299v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Nanotechnology 10, 849 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1403.4906">arXiv:1403.4906</a> <span> [<a href="https://arxiv.org/pdf/1403.4906">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nmat4215">10.1038/nmat4215 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dirac mass generation from crystal symmetry breaking on the surfaces of topological crystalline insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zeljkovic%2C+I">Ilija Zeljkovic</a>, <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Serbyn%2C+M">Maksym Serbyn</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">R. Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+J">Junwei Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+G">Guoqing Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y+J">Yung Jui Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Hasan%2C+M+Z">M. Zahid Hasan</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+F">Fangcheng Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Bansil%2C+A">Arun Bansil</a>, <a href="/search/cond-mat?searchtype=author&query=Fu%2C+L">Liang Fu</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1403.4906v2-abstract-short" style="display: inline;"> The tunability of topological surface states (SS) and controllable opening of the Dirac gap are of fundamental and practical interest in the field of topological materials. In topological crystalline insulators (TCIs), a spontaneously generated Dirac gap was recently observed, which was ascribed to broken cubic crystal symmetry. However, this structural distortion has not been directly observed so… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.4906v2-abstract-full').style.display = 'inline'; document.getElementById('1403.4906v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1403.4906v2-abstract-full" style="display: none;"> The tunability of topological surface states (SS) and controllable opening of the Dirac gap are of fundamental and practical interest in the field of topological materials. In topological crystalline insulators (TCIs), a spontaneously generated Dirac gap was recently observed, which was ascribed to broken cubic crystal symmetry. However, this structural distortion has not been directly observed so far, and the microscopic mechanism of Dirac gap opening via crystal symmetry breaking remains elusive. In this work, we present scanning tunneling microscopy (STM) measurements of a TCI Pb$_{1-x}$Sn$_x$Se for a wide range of alloy compositions spanning the topological and non-topological regimes. STM topographies directly reveal a symmetry-breaking distortion on the surface, which imparts mass to the otherwise massless Dirac electrons - a mechanism analogous to the long sought-after Higgs mechanism in particle physics. Remarkably, our measurements show that the Dirac gap scales with alloy composition, while the magnitude of the distortion remains nearly constant. Based on theoretical calculations, we find the Dirac mass is controlled by the composition-dependent SS penetration depth, which determines the weight of SS in the distorted region that is confined to the surface. Finally, we discover the existence of SS in the non-topological regime, which have the characteristics of gapped, double-branched Dirac fermions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.4906v2-abstract-full').style.display = 'none'; document.getElementById('1403.4906v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 August, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 March, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Materials 14, 318 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1312.0164">arXiv:1312.0164</a> <span> [<a href="https://arxiv.org/pdf/1312.0164">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nphys3012">10.1038/nphys3012 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mapping the unconventional orbital texture in topological crystalline insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zeljkovic%2C+I">Ilija Zeljkovic</a>, <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+C">Cheng-Yi Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">R. Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Serbyn%2C+M">Maksym Serbyn</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+F">Fangcheng Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+W">Wei-Feng Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Bansil%2C+A">Arun Bansil</a>, <a href="/search/cond-mat?searchtype=author&query=Fu%2C+L">Liang Fu</a>, <a href="/search/cond-mat?searchtype=author&query=Hasan%2C+M+Z">M. Zahid Hasan</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1312.0164v2-abstract-short" style="display: inline;"> The newly discovered topological crystalline insulators (TCIs) harbor a complex band structure involving multiple Dirac cones. These materials are potentially highly tunable by external electric field, temperature or strain and could find future applications in field-effect transistors, photodetectors, and nano-mechanical systems. Theoretically, it has been predicted that different Dirac cones, of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.0164v2-abstract-full').style.display = 'inline'; document.getElementById('1312.0164v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1312.0164v2-abstract-full" style="display: none;"> The newly discovered topological crystalline insulators (TCIs) harbor a complex band structure involving multiple Dirac cones. These materials are potentially highly tunable by external electric field, temperature or strain and could find future applications in field-effect transistors, photodetectors, and nano-mechanical systems. Theoretically, it has been predicted that different Dirac cones, offset in energy and momentum-space, might harbor vastly different orbital character, a unique property which if experimentally realized, would present an ideal platform for accomplishing new spintronic devices. However, the orbital texture of the Dirac cones, which is of immense importance in determining a variety of materials properties, still remains elusive in TCIs. Here, we unveil the orbital texture in a prototypical TCI Pb$_{1-x}$Sn$_x$Se. By using Fourier-transform (FT) scanning tunneling spectroscopy (STS) we measure the interference patterns produced by the scattering of surface state electrons. We discover that the intensity and energy dependences of FTs show distinct characteristics, which can directly be attributed to orbital effects. Our experiments reveal the complex band topology involving two Lifshitz transitions and establish the orbital nature of the Dirac bands in this new class of topological materials, which could provide a different pathway towards future quantum applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.0164v2-abstract-full').style.display = 'none'; document.getElementById('1312.0164v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 December, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 November, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 10, 572-577 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1311.0783">arXiv:1311.0783</a> <span> [<a href="https://arxiv.org/pdf/1311.0783">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/ncomms4377">10.1038/ncomms4377 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Carrier localization and electronic phase separation in a doped spin-orbit driven Mott phase in Sr3(Ir1-xRux)2O7 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Dhital%2C+C">Chetan Dhital</a>, <a href="/search/cond-mat?searchtype=author&query=Hogan%2C+T">Tom Hogan</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+X">Xiang Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Ren%2C+Z">Zhensong Ren</a>, <a href="/search/cond-mat?searchtype=author&query=Pokharel%2C+M">Mani Pokharel</a>, <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Heine%2C+M">M. Heine</a>, <a href="/search/cond-mat?searchtype=author&query=Tian%2C+W">Wei Tian</a>, <a href="/search/cond-mat?searchtype=author&query=Yamani%2C+Z">Z. Yamani</a>, <a href="/search/cond-mat?searchtype=author&query=Opeil%2C+C">C. Opeil</a>, <a href="/search/cond-mat?searchtype=author&query=Helton%2C+J+S">J. S. Helton</a>, <a href="/search/cond-mat?searchtype=author&query=Lynn%2C+J+W">J. W. Lynn</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1311.0783v2-abstract-short" style="display: inline;"> Interest in many strongly spin-orbit coupled 5d-transition metal oxide insulators stems from mapping their electronic structures to a J=1/2 Mott phase. One of the hopes is to establish their Mott parent states and explore these systems' potential of realizing novel electronic states upon carrier doping. However, once doped, little is understood regarding the role of their reduced Coulomb interacti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.0783v2-abstract-full').style.display = 'inline'; document.getElementById('1311.0783v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1311.0783v2-abstract-full" style="display: none;"> Interest in many strongly spin-orbit coupled 5d-transition metal oxide insulators stems from mapping their electronic structures to a J=1/2 Mott phase. One of the hopes is to establish their Mott parent states and explore these systems' potential of realizing novel electronic states upon carrier doping. However, once doped, little is understood regarding the role of their reduced Coulomb interaction U relative to their strongly correlated 3d-electron cousins. Here we show that, upon hole-doping a candidate J=1/2 Mott insulator, carriers remain localized within a nanoscale phase separated ground state. A percolative metal-insulator transition occurs with interplay between localized and itinerant regions, stabilizing an antiferromagnetic metallic phase beyond the critical region. Our results demonstrate a surprising parallel between doped 5d- and 3d-electron Mott systems and suggest either through the near degeneracy of nearby electronic phases or direct carrier localization that U is essential to the carrier response of this doped spin-orbit Mott insulator. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.0783v2-abstract-full').style.display = 'none'; document.getElementById('1311.0783v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 March, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 November, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">25 pages, 4 figures in main text, 4 figures in supplemental text</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 5, 3377 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1305.2823">arXiv:1305.2823</a> <span> [<a href="https://arxiv.org/pdf/1305.2823">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.1239451">10.1126/science.1239451 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of Dirac node formation and mass acquisition in a topological crystalline insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Serbyn%2C+M">Maksym Serbyn</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Dhital%2C+C">Chetan Dhital</a>, <a href="/search/cond-mat?searchtype=author&query=Neupane%2C+M">Madhab Neupane</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+S">Suyang Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y+J">Yung Jui Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">R. Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+F">Fangcheng Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Bansil%2C+A">Arun Bansil</a>, <a href="/search/cond-mat?searchtype=author&query=Hasan%2C+M+Z">M. Zahid Hasan</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Fu%2C+L">Liang Fu</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1305.2823v1-abstract-short" style="display: inline;"> In the recently discovered topological crystalline insulators (TCIs), topology and crystal symmetry intertwine to create surface states with a unique set of characteristics. Among the theoretical predictions for TCIs is the possibility of imparting mass to the massless Dirac fermions by breaking crystal symmetry, as well as a Lifshitz transition with a change of Fermi surface topology. Here we rep… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1305.2823v1-abstract-full').style.display = 'inline'; document.getElementById('1305.2823v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1305.2823v1-abstract-full" style="display: none;"> In the recently discovered topological crystalline insulators (TCIs), topology and crystal symmetry intertwine to create surface states with a unique set of characteristics. Among the theoretical predictions for TCIs is the possibility of imparting mass to the massless Dirac fermions by breaking crystal symmetry, as well as a Lifshitz transition with a change of Fermi surface topology. Here we report high resolution scanning tunneling microscopy studies of a TCI, Pb1-xSnxSe. We demonstrate the formation of zero mass Dirac fermions protected by crystal symmetry and the mechanism of mass generation via symmetry breaking, which constitute the defining characteristics of TCIs. In addition, we show two distinct regimes of fermiology separated by a Van-Hove singularity at the Lifshitz transition point. Our work paves the way for engineering the Dirac band gap and realizing interaction-driven topological quantum phenomena in TCIs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1305.2823v1-abstract-full').style.display = 'none'; document.getElementById('1305.2823v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 May, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 341, 6153 (2013) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1303.6027">arXiv:1303.6027</a> <span> [<a href="https://arxiv.org/pdf/1303.6027">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nmat3653">10.1038/nmat3653 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Imaging the evolution of metallic states in a spin-orbit interaction driven correlated iridate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">Daniel Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Dhital%2C+C">Chetan Dhital</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+T">Tay-Rong Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Khadka%2C+S">Sovit Khadka</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Jeng%2C+H">Horng-Tay Jeng</a>, <a href="/search/cond-mat?searchtype=author&query=Bansil%2C+A">Arun Bansil</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S">Stephen Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">Vidya Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1303.6027v1-abstract-short" style="display: inline;"> The Ruddlesden-Popper (RP) series of iridates (Srn+1IrnO3n+1) have been the subject of much recent attention due to the anticipation of emergent physics arising from the cooperative action of spin-orbit (SO) driven band splitting and Coulomb interactions[1-3]. However an ongoing debate over the role of correlations in the formation of the charge gap and a lack of understanding of the effects of do… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1303.6027v1-abstract-full').style.display = 'inline'; document.getElementById('1303.6027v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1303.6027v1-abstract-full" style="display: none;"> The Ruddlesden-Popper (RP) series of iridates (Srn+1IrnO3n+1) have been the subject of much recent attention due to the anticipation of emergent physics arising from the cooperative action of spin-orbit (SO) driven band splitting and Coulomb interactions[1-3]. However an ongoing debate over the role of correlations in the formation of the charge gap and a lack of understanding of the effects of doping on the low energy electronic structure have hindered experimental progress in realizing many of the predicted states[4-8] including possible high-Tc superconductivity[7,9]. Using scanning tunneling spectroscopy we map out the spatially resolved density of states in the n=2 RP member, Sr3Ir2O7 (Ir327). We show that the Ir327 parent compound, argued to exist only as a weakly correlated band insulator in fact possesses a substantial ~130meV charge excitation gap driven by an interplay between structure, SO coupling and correlations. A critical component in distinguishing the intrinsic electronic character within the inhomogeneous textured electronic structure is our identification of the signature of missing apical oxygen defects, which play a critical role in many of the layered oxides. Our measurements combined with insights from calculations reveal how apical oxygen vacancies transfer spectral weight from higher energies to the gap energies thereby revealing a path toward obtaining metallic electronic states from the parent-insulating states in the iridates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1303.6027v1-abstract-full').style.display = 'none'; document.getElementById('1303.6027v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 March, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Materials 12, 707 (2013) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1207.4468">arXiv:1207.4468</a> <span> [<a href="https://arxiv.org/pdf/1207.4468">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/ncomms2150">10.1038/ncomms2150 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ripple modulated electronic structure of a 3D topological insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">D. Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Dhital%2C+C">Chetan Dhital</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">S. D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">V. Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1207.4468v2-abstract-short" style="display: inline;"> 3D topological insulators, similar to the Dirac material graphene, host linearly dispersing states with unique properties and a strong potential for applications. A key, missing element in realizing some of the more exotic states in topological insulators is the ability to manipulate local electronic properties. Analogy with graphene suggests a possible avenue via a topographic route by the format… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1207.4468v2-abstract-full').style.display = 'inline'; document.getElementById('1207.4468v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1207.4468v2-abstract-full" style="display: none;"> 3D topological insulators, similar to the Dirac material graphene, host linearly dispersing states with unique properties and a strong potential for applications. A key, missing element in realizing some of the more exotic states in topological insulators is the ability to manipulate local electronic properties. Analogy with graphene suggests a possible avenue via a topographic route by the formation of superlattice structures such as a moir茅 patterns or ripples, which can induce controlled potential variations. However, while the charge and lattice degrees of freedom are intimately coupled in graphene, it is not clear a priori how a physical buckling or ripples might influence the electronic structure of topological insulators. Here we use Fourier transform scanning tunneling spectroscopy to determine the effects of a one-dimensional periodic buckling on the electronic properties of Bi2Te3. By tracking the spatial variations of the scattering vector of the interference patterns as well as features associated with bulk density of states, we show that the buckling creates a periodic potential modulation, which in turn modulates the surface and the bulk states. The strong correlation between the topographic ripples and electronic structure indicates that while doping alone is insufficient to create predetermined potential landscapes, creating ripples provides a path to controlling the potential seen by the Dirac electrons on a local scale. Such rippled features may be engineered by strain in thin films and may find use in future applications of topological insulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1207.4468v2-abstract-full').style.display = 'none'; document.getElementById('1207.4468v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 September, 2012; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 July, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Nature Communications (accepted)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 3, 1158 (2012) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1205.6230">arXiv:1205.6230</a> <span> [<a href="https://arxiv.org/pdf/1205.6230">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.109.166407">10.1103/PhysRevLett.109.166407 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Visualizing Landau levels of Dirac electrons in a one dimensional potential </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Dhital%2C+C">Chetan. Dhital</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">D. Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Ran%2C+Y">Ying Ran</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Z. Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">V. Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1205.6230v2-abstract-short" style="display: inline;"> Using scanning tunneling spectroscopy we have measured the response of Dirac electrons in a magnetic field to the presence of a well-defined smoothly varying 1D periodic potential. We find that the lower index Landau level energies reliably trace the potential variations, while the higher index levels appear surprisingly homogeneous. Modeling the effects of the periodic potential on the Landau lev… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1205.6230v2-abstract-full').style.display = 'inline'; document.getElementById('1205.6230v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1205.6230v2-abstract-full" style="display: none;"> Using scanning tunneling spectroscopy we have measured the response of Dirac electrons in a magnetic field to the presence of a well-defined smoothly varying 1D periodic potential. We find that the lower index Landau level energies reliably trace the potential variations, while the higher index levels appear surprisingly homogeneous. Modeling the effects of the periodic potential on the Landau level spectra, we show that the Landau level behavior encodes information on the spatial extent of the wavefunctions. The lower index maps reveal Landau level stripes, which would act as traps for chiral one-dimensional modes. Our findings have important implications for transport and magneto-resistance measurements in Dirac materials with engineered potential landscapes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1205.6230v2-abstract-full').style.display = 'none'; document.getElementById('1205.6230v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 September, 2012; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 May, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Phys. Rev. Lett. (accepted)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 109, 166407 (2012) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1203.0020">arXiv:1203.0020</a> <span>  </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> One-dimensional channel for Dirac electrons in a 3D topological insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Yoshinori Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wenwen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Dhital%2C+C">Chetan. Dhital</a>, <a href="/search/cond-mat?searchtype=author&query=Walkup%2C+D">D. Walkup</a>, <a href="/search/cond-mat?searchtype=author&query=Ran%2C+Y">Ying Ran</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Z. Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">V. Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1203.0020v3-abstract-short" style="display: inline;"> Topological insulators represent a new state of matter where the topological nature of the bulk bands dictates the existence of a surface state with unique properties. These materials are predicted to host exotic states such as Majorana Fermions and 1D chiral modes, many of which require a delicate tuning of the surface state properties near the Dirac point. Using scanning tunneling microscopy (ST… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1203.0020v3-abstract-full').style.display = 'inline'; document.getElementById('1203.0020v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1203.0020v3-abstract-full" style="display: none;"> Topological insulators represent a new state of matter where the topological nature of the bulk bands dictates the existence of a surface state with unique properties. These materials are predicted to host exotic states such as Majorana Fermions and 1D chiral modes, many of which require a delicate tuning of the surface state properties near the Dirac point. Using scanning tunneling microscopy (STM) on the prototypical topological insulator Bi2Te3, we have discovered one-dimensional topographic stripes which induce spatially modulated changes in the electronic structure. Direct magnetic field measurements reveal a striped pattern of Landau level energies, which can be used to realize spatial regions with alternating filling fractions. When the chemical potential is properly tuned, the observed modulation would dictate the existence of topological 1D chiral modes at the boundaries between the stripes, and provide a platform for the experimental realization of 1D dissipationless quantum wires in topological insulators. Our discovery that the surface state dispersion is modulated over nanometer length scales by an intrinsic topographic route represents a new paradigm for controlling the properties of Dirac electrons. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1203.0020v3-abstract-full').style.display = 'none'; document.getElementById('1203.0020v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 May, 2012; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 February, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">This paper has been withdrawn due to major changes. The improved version would be submitted elsewhere</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1105.3987">arXiv:1105.3987</a> <span> [<a href="https://arxiv.org/pdf/1105.3987">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/NPHYS2006">10.1038/NPHYS2006 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electron-Spin Excitation Coupling in an Electron Doped Copper Oxide Superconductor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+J">Jun Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Niestemski%2C+F+C">F. C. Niestemski</a>, <a href="/search/cond-mat?searchtype=author&query=Kunwar%2C+S">Shankar Kunwar</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+S">Shiliang Li</a>, <a href="/search/cond-mat?searchtype=author&query=Steffens%2C+P">P. Steffens</a>, <a href="/search/cond-mat?searchtype=author&query=Hiess%2C+A">A. Hiess</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+H+J">H. J. Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Dai%2C+P">Pengcheng Dai</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">V. Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1105.3987v1-abstract-short" style="display: inline;"> High-temperature (high-Tc) superconductivity in the copper oxides arises from electron or hole doping of their antiferromagnetic (AF) insulating parent compounds. The evolution of the AF phase with doping and its spatial coexistence with superconductivity are governed by the nature of charge and spin correlations and provide clues to the mechanism of high-Tc superconductivity. Here we use a combin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1105.3987v1-abstract-full').style.display = 'inline'; document.getElementById('1105.3987v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1105.3987v1-abstract-full" style="display: none;"> High-temperature (high-Tc) superconductivity in the copper oxides arises from electron or hole doping of their antiferromagnetic (AF) insulating parent compounds. The evolution of the AF phase with doping and its spatial coexistence with superconductivity are governed by the nature of charge and spin correlations and provide clues to the mechanism of high-Tc superconductivity. Here we use a combined neutron scattering and scanning tunneling spectroscopy (STS) to study the Tc evolution of electron-doped superconducting Pr0.88LaCe0.12CuO4-delta obtained through the oxygen annealing process. We find that spin excitations detected by neutron scattering have two distinct modes that evolve with Tc in a remarkably similar fashion to the electron tunneling modes in STS. These results demonstrate that antiferromagnetism and superconductivity compete locally and coexist spatially on nanometer length scales, and the dominant electron-boson coupling at low energies originates from the electron-spin excitations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1105.3987v1-abstract-full').style.display = 'none'; document.getElementById('1105.3987v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 May, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 12 figures, supplementary information included</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 7, 719-724 (2011) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1011.4913">arXiv:1011.4913</a> <span> [<a href="https://arxiv.org/pdf/1011.4913">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Observation of novel interference patterns in Bi2-xFexTe3+d by Fourier transform scanning tunneling spectroscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Okada%2C+Y">Y. Okada</a>, <a href="/search/cond-mat?searchtype=author&query=Dhital%2C+C">C. Dhital</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+W">Wen-Wen Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+H">Hsin Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Basak%2C+S">S. Basak</a>, <a href="/search/cond-mat?searchtype=author&query=Bansil%2C+A">A. Bansil</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+Y+-">Y. -B. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Ding%2C+H">H. Ding</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Z. Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Wilson%2C+S+D">Stephen D. Wilson</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">V. Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1011.4913v1-abstract-short" style="display: inline;"> In topological insulators (TI), strong spin-orbit coupling results in non-trivial scattering processes of the surface states, whose effects include suppressed back scattering1, 2, 3, 4 weak anti-localization5, 6 and the possibility of an exotic Kondo effect that mimics graphene7. Introducing time reversal breaking perturbations and establishing long-range magnetic order has been theorized to lead… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1011.4913v1-abstract-full').style.display = 'inline'; document.getElementById('1011.4913v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1011.4913v1-abstract-full" style="display: none;"> In topological insulators (TI), strong spin-orbit coupling results in non-trivial scattering processes of the surface states, whose effects include suppressed back scattering1, 2, 3, 4 weak anti-localization5, 6 and the possibility of an exotic Kondo effect that mimics graphene7. Introducing time reversal breaking perturbations and establishing long-range magnetic order has been theorized to lead to the formation of quantized magnetoelectric phenomena8, fractionalized charge excitations, and the appearance of quantum wire states9. A key, elusive, step in exploring these and other novel electronic phases is the experimental observation of charge backscattering due to spin-flip processes at the surface of a magnetically-doped TI. Here we utilize Fourier transform scanning tunneling spectroscopy (FT-STS) to probe the surface of a magnetically doped TI, Bi2-xFexTe3+d. Our measurements show the appearance of a hitherto unobserved channel of electronic backscattering along surface q-vector 螕魏. By combining FT-STS with angle-resolved photoemission data, we identify the momentum space origins of the observed q-vectors, which on comparison to a model calculation are enhanced by spin-flip scattering. Our findings present compelling evidence for the first spatial and momentum resolved measurements of magnetic impurity induced backscattering in a prototypical TI. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1011.4913v1-abstract-full').style.display = 'none'; document.getElementById('1011.4913v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 November, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physical Review Letters 106 206805 (2011) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0906.2761">arXiv:0906.2761</a> <span> [<a href="https://arxiv.org/pdf/0906.2761">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Unveiling the Atomic and Electronic Structure at the Surface of the Parent Pnictide SrFe2As2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Niestemski%2C+F+C">F. C. Niestemski</a>, <a href="/search/cond-mat?searchtype=author&query=Nascimento%2C+V+B">Von Braun Nascimento</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+B">Biao Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Plummer%2C+W">Ward Plummer</a>, <a href="/search/cond-mat?searchtype=author&query=Gillett%2C+J">J. Gillett</a>, <a href="/search/cond-mat?searchtype=author&query=Sebastian%2C+S">Suchitra Sebastian</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">V. Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0906.2761v1-abstract-short" style="display: inline;"> The parent compounds of the recently discovered iron-arsenic (pnictide) high temperature superconductors transition into an intriguing spin density wave (SDW) phase at low temperatures. Progress in understanding this SDW state has been complicated by a complex band structure and by the fact that the spin, electronic, and structural degrees of freedom are closely intertwined in these compounds. S… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0906.2761v1-abstract-full').style.display = 'inline'; document.getElementById('0906.2761v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0906.2761v1-abstract-full" style="display: none;"> The parent compounds of the recently discovered iron-arsenic (pnictide) high temperature superconductors transition into an intriguing spin density wave (SDW) phase at low temperatures. Progress in understanding this SDW state has been complicated by a complex band structure and by the fact that the spin, electronic, and structural degrees of freedom are closely intertwined in these compounds. Scanning tunneling microscopy (STM) measurements have added to this complexity by revealing different topographies with no consensus on the surface structure. In this paper, we use a combination of high-resolution STM imaging and spectroscopy, and low energy electron diffraction (LEED) to determine the atomic and electronic structure of the parent pnictide SrFe2As2. Our data present a compelling picture of the existence of two coexisting homotopic structures on the surface. Based on this, we construct a simple model for the surface, which offers an explanation of the two classes of topographies seen by STM. STM spectroscopy shows that while the high energy density of states (DOS) profile is consistent with the Fe 3d and As 4p-electrons predicted by LDA it is in better agreement with calculations that include electron correlations beyond LDA. Importantly, we find a gap of ~15 meV in the low energy density of states on both structures which may be linked with the SDW or the observed surface reconstruction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0906.2761v1-abstract-full').style.display = 'none'; document.getElementById('0906.2761v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 June, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2009. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0807.3294">arXiv:0807.3294</a> <span> [<a href="https://arxiv.org/pdf/0807.3294">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.101.207002">10.1103/PhysRevLett.101.207002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coexistence of competing orders with two energy gaps in real and momentum space in high-Tc superconductor Bi2Sr2-xLaxCuO6+delta </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ma%2C+J+-">J. -H. Ma</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+Z+-">Z. -H. Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Niestemski%2C+F+C">F. C. Niestemski</a>, <a href="/search/cond-mat?searchtype=author&query=Neupane%2C+M">M. Neupane</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+Y+-">Y. -M. Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Richard%2C+P">P. Richard</a>, <a href="/search/cond-mat?searchtype=author&query=Nakayama%2C+K">K. Nakayama</a>, <a href="/search/cond-mat?searchtype=author&query=Sato%2C+T">T. Sato</a>, <a href="/search/cond-mat?searchtype=author&query=Takahashi%2C+T">T. Takahashi</a>, <a href="/search/cond-mat?searchtype=author&query=Luo%2C+H+-">H. -Q. Luo</a>, <a href="/search/cond-mat?searchtype=author&query=Fang%2C+L">L. Fang</a>, <a href="/search/cond-mat?searchtype=author&query=Wen%2C+H+-">H. -H. Wen</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziqiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Ding%2C+H">H. Ding</a>, <a href="/search/cond-mat?searchtype=author&query=Madhavan%2C+V">V. Madhavan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0807.3294v1-abstract-short" style="display: inline;"> The superconducting phase of the high-Tc cuprates has been thought to be described by a single d-wave pairing order parameter. Recently, there has been growing evidence suggesting that another form of order, possibly inherited from the pseudogap phase above Tc, may coexist with superconductivity in the underdoped regime. Through a combined study of scanning tunneling microscopy and angle-resolve… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0807.3294v1-abstract-full').style.display = 'inline'; document.getElementById('0807.3294v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0807.3294v1-abstract-full" style="display: none;"> The superconducting phase of the high-Tc cuprates has been thought to be described by a single d-wave pairing order parameter. Recently, there has been growing evidence suggesting that another form of order, possibly inherited from the pseudogap phase above Tc, may coexist with superconductivity in the underdoped regime. Through a combined study of scanning tunneling microscopy and angle-resolved photoemission spectroscopy, we report the observation of two distinct gaps (a small-gap and a large-gap) that coexist both in real space and in the anti-nodal region of momentum space in the superconducting phase of Bi2Sr2-xLaxCuO6+delta. We show that the small-gap is associated with superconductivity. The large-gap persists to temperatures above the transition temperature Tc and is found to be linked to short-range charge ordering. Remarkably, we find a strong, short-ranged correlation between the local small- and large- gap magnitudes suggesting that the superconductivity and charge ordering are affected by similar physical processes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0807.3294v1-abstract-full').style.display = 'none'; document.getElementById('0807.3294v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 July, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PRL 101, 207002 (2008) </p> </li> </ol> <nav 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