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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=Taniguchi%2C+T&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Taniguchi%2C+T&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Taniguchi%2C+T&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Taniguchi%2C+T&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Taniguchi%2C+T&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> <li> <a href="/search/?searchtype=author&query=Taniguchi%2C+T&start=200" class="pagination-link " aria-label="Page 5" aria-current="page">5 </a> </li> <li><span class="pagination-ellipsis">…</span></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/2502.17314">arXiv:2502.17314</a> <span> [<a href="https://arxiv.org/pdf/2502.17314">pdf</a>, <a href="https://arxiv.org/format/2502.17314">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"> Photoluminescence efficiency of MBE-grown MoSe$_2$ monolayers featuring sharp excitonic lines and diverse grain structures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Raczy%C5%84ski%2C+M">Mateusz Raczy艅ski</a>, <a href="/search/cond-mat?searchtype=author&query=Kucharek%2C+J">Julia Kucharek</a>, <a href="/search/cond-mat?searchtype=author&query=Oreszczuk%2C+K">Kacper Oreszczuk</a>, <a href="/search/cond-mat?searchtype=author&query=Rodek%2C+A">Aleksander Rodek</a>, <a href="/search/cond-mat?searchtype=author&query=Kazimierczuk%2C+T">Tomasz Kazimierczuk</a>, <a href="/search/cond-mat?searchtype=author&query=Bo%C5%BCek%2C+R">Rafa艂 Bo偶ek</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Pacuski%2C+W">Wojciech Pacuski</a>, <a href="/search/cond-mat?searchtype=author&query=Kossacki%2C+P">Piotr Kossacki</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="2502.17314v1-abstract-short" style="display: inline;"> Recent studies have demonstrated that using h-BN as a substrate for the growth of transition metal dichalcogenides can significantly reduce excitonic linewidths. However, many other optical parameters still require optimization. In this work, we present a detailed study of the low-temperature photoluminescence efficiency of MBE-grown MoSe$_2$ monolayers on h-BN substrates, comparing them to state-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.17314v1-abstract-full').style.display = 'inline'; document.getElementById('2502.17314v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.17314v1-abstract-full" style="display: none;"> Recent studies have demonstrated that using h-BN as a substrate for the growth of transition metal dichalcogenides can significantly reduce excitonic linewidths. However, many other optical parameters still require optimization. In this work, we present a detailed study of the low-temperature photoluminescence efficiency of MBE-grown MoSe$_2$ monolayers on h-BN substrates, comparing them to state-of-the-art exfoliated monolayers encapsulated in h-BN. We demonstrate that a quantitative comparison between samples requires accounting for interference effects and Purcell enhancement or suppression of the emission. By accounting for these effects in both photoluminescence and Raman signals, we show that the overall intrinsic luminescence efficiency is proportional to the sample coverage. Consequently, we find that exciton diffusion and edge effects are negligible in spectroscopy of MBE-grown samples, even for nanometer-sized crystals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.17314v1-abstract-full').style.display = 'none'; document.getElementById('2502.17314v1-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> 24 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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">9 pages, 9 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/2502.16700">arXiv:2502.16700</a> <span> [<a href="https://arxiv.org/pdf/2502.16700">pdf</a>, <a href="https://arxiv.org/format/2502.16700">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> <p class="title is-5 mathjax"> Modulation of superconductivity across a Lifshitz transition in alternating-angle twisted quadrilayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Phinney%2C+I+Y">Isabelle Y. Phinney</a>, <a href="/search/cond-mat?searchtype=author&query=Zimmerman%2C+A">Andrew Zimmerman</a>, <a href="/search/cond-mat?searchtype=author&query=Hao%2C+Z">Zeyu Hao</a>, <a href="/search/cond-mat?searchtype=author&query=Ledwith%2C+P+J">Patrick J. Ledwith</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Vishwanath%2C+A">Ashvin Vishwanath</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+P">Philip Kim</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="2502.16700v1-abstract-short" style="display: inline;"> We report electric field-controlled modulation of the Fermi surface topology and explore its effects on the superconducting state in alternating-angle twisted quadrilayer graphene (TQG). The unique combination of flat and dispersive bands in TQG allows us to simultaneously tune the band structure through carrier density, $n$, and displacement field, $D$. From density-dependent Shubnikov-de Haas qu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.16700v1-abstract-full').style.display = 'inline'; document.getElementById('2502.16700v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.16700v1-abstract-full" style="display: none;"> We report electric field-controlled modulation of the Fermi surface topology and explore its effects on the superconducting state in alternating-angle twisted quadrilayer graphene (TQG). The unique combination of flat and dispersive bands in TQG allows us to simultaneously tune the band structure through carrier density, $n$, and displacement field, $D$. From density-dependent Shubnikov-de Haas quantum oscillations and Hall measurements, we quantify the $D$-dependent bandwidth of the flat and dispersive bands and their hybridization. In the high $|D|$ regime, the increased bandwidth favors the single particle bands, which coincides exactly with the vanishing of the superconducting transition temperature $T_c$, showing that superconductivity in TQG is strongly bound to the symmetry-broken state. For a range of lower $|D|$ values, a Lifshitz transition occurs when the flat and dispersive band Fermi surfaces merge within the $谓=+2$ symmetry-broken state. The superconducting state correspondingly shows an enhanced $T_c$, suggesting that the superconducting condensate is strongly dependent on the Fermi surface topology and density of states within this symmetry-broken state. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.16700v1-abstract-full').style.display = 'none'; document.getElementById('2502.16700v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.15557">arXiv:2502.15557</a> <span> [<a href="https://arxiv.org/pdf/2502.15557">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> </div> </div> <p class="title is-5 mathjax"> Quantifying hydrogen bonding using electrically tunable nanoconfined water </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Ziwei Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Bhattacharya%2C+A">Anupam Bhattacharya</a>, <a href="/search/cond-mat?searchtype=author&query=Yagmurcukardes%2C+M">Mehmet Yagmurcukardes</a>, <a href="/search/cond-mat?searchtype=author&query=Kravets%2C+V">Vasyl Kravets</a>, <a href="/search/cond-mat?searchtype=author&query=D%C3%ADaz-N%C3%BA%C3%B1ez%2C+P">Pablo D铆az-N煤帽ez</a>, <a href="/search/cond-mat?searchtype=author&query=Mullan%2C+C">Ciaran Mullan</a>, <a href="/search/cond-mat?searchtype=author&query=Timokhin%2C+I">Ivan Timokhin</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Grigorenko%2C+A+N">Alexander N. Grigorenko</a>, <a href="/search/cond-mat?searchtype=author&query=Peeters%2C+F">Francois Peeters</a>, <a href="/search/cond-mat?searchtype=author&query=Novoselov%2C+K+S">Kostya S. Novoselov</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+Q">Qian Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Mishchenko%2C+A">Artem Mishchenko</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="2502.15557v1-abstract-short" style="display: inline;"> Hydrogen bonding plays a crucial role in biology and technology, yet it remains poorly understood and quantified despite its fundamental importance. Traditional models, which describe hydrogen bonds as electrostatic interactions between electropositive hydrogen and electronegative acceptors, fail to quantitatively capture bond strength, directionality, or cooperativity, and cannot predict the prop… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.15557v1-abstract-full').style.display = 'inline'; document.getElementById('2502.15557v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.15557v1-abstract-full" style="display: none;"> Hydrogen bonding plays a crucial role in biology and technology, yet it remains poorly understood and quantified despite its fundamental importance. Traditional models, which describe hydrogen bonds as electrostatic interactions between electropositive hydrogen and electronegative acceptors, fail to quantitatively capture bond strength, directionality, or cooperativity, and cannot predict the properties of complex hydrogen-bonded materials. Here, we introduce a novel approach that conceptualizes the effect of hydrogen bonds as elastic dipoles in an electric field, which captures a wide range of hydrogen bonding phenomena in various water systems. Using gypsum, a hydrogen bond heterostructure with two-dimensional structural crystalline water, we calibrate the hydrogen bond strength through an externally applied electric field. We show that our approach quantifies the strength of hydrogen bonds directly from spectroscopic measurements and reproduces a wide range of key properties of confined water reported in the literature. Using only the stretching vibration frequency of confined water, we can predict hydrogen bond strength, local electric field, O-H bond length, and dipole moment. Our work also introduces hydrogen bond heterostructures - a new class of electrically and chemically tunable materials that offer stronger, more directional bonding compared to van der Waals heterostructures, with potential applications in areas such as catalysis, separation, and energy storage. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.15557v1-abstract-full').style.display = 'none'; document.getElementById('2502.15557v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.15232">arXiv:2502.15232</a> <span> [<a href="https://arxiv.org/pdf/2502.15232">pdf</a>, <a href="https://arxiv.org/format/2502.15232">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"> Gate tunable Dirac mass and Berry phase in Trilayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mann%2C+H+K">Harsimran Kaur Mann</a>, <a href="/search/cond-mat?searchtype=author&query=Kaur%2C+S">Simrandeep Kaur</a>, <a href="/search/cond-mat?searchtype=author&query=Mullick%2C+S">Safil Mullick</a>, <a href="/search/cond-mat?searchtype=author&query=Tiwari%2C+P">Priya Tiwari</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Bid%2C+A">Aveek Bid</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="2502.15232v1-abstract-short" style="display: inline;"> In-situ control over band mass inversion is crucial for developing materials with topologically protected edge modes. In this Letter, we report the direct observation of displacement field $D$ control of band mass and Berry phase in Bernal stacked trilayer graphene (TLG) in the region where trigonal warping distorts the quadratic band into off-center Dirac points, referred to as `Dirac Gullies.' U… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.15232v1-abstract-full').style.display = 'inline'; document.getElementById('2502.15232v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.15232v1-abstract-full" style="display: none;"> In-situ control over band mass inversion is crucial for developing materials with topologically protected edge modes. In this Letter, we report the direct observation of displacement field $D$ control of band mass and Berry phase in Bernal stacked trilayer graphene (TLG) in the region where trigonal warping distorts the quadratic band into off-center Dirac points, referred to as `Dirac Gullies.' Using Shubnikov-de-Haas (SdH) oscillations, we map the Fermi surface contours of the Dirac gullies and the $D$-dependent band structure. With increasing $D$-field, the Berry phase undergoes multiple transitions from $桅_B=2蟺$ $\rightarrow$ $蟺$ $\rightarrow$ $2蟺$ as $D$ is varied. Concurrently, measurement of the effective mass reveals a series of transitions between massless and massive bands, signaling the closure and reopening (accompanied by a possible band inversion) of the band gap at a critical value of $D$. Interestingly, the expected Dirac-like behavior of the Dirac gullies ($桅_B=蟺$) persists only over a narrow range of $D$. Our study directly confirms recent predictions of $ D$-field-induced band inversion in the low-energy regions of TLG. It is a significant step towards achieving control over pure valley transport in multilayer graphene. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.15232v1-abstract-full').style.display = 'none'; document.getElementById('2502.15232v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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">16 pages, comments and suggestions most welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.14588">arXiv:2502.14588</a> <span> [<a href="https://arxiv.org/pdf/2502.14588">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> <p class="title is-5 mathjax"> Superlative spin transport of holes in ultra-thin black phosphorus </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Liu%2C+J">Jiawei Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Fu%2C+D">Deyi Fu</a>, <a href="/search/cond-mat?searchtype=author&query=Qu%2C+T">Tingyu Qu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+D">Deqiang Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Avsar%2C+A">Ahmet Avsar</a>, <a href="/search/cond-mat?searchtype=author&query=Ozyilmaz%2C+B">Barbaros Ozyilmaz</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="2502.14588v1-abstract-short" style="display: inline;"> The development of energy-efficient spin-based hybrid devices that can perform functions such as logic, communication, and storage requires the ability to control and transport highly polarized spin currents over long distances in semiconductors. While traditional semiconductors such as silicon support spin transport, the effects of carrier type and concentration on important spin parameters are n… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.14588v1-abstract-full').style.display = 'inline'; document.getElementById('2502.14588v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.14588v1-abstract-full" style="display: none;"> The development of energy-efficient spin-based hybrid devices that can perform functions such as logic, communication, and storage requires the ability to control and transport highly polarized spin currents over long distances in semiconductors. While traditional semiconductors such as silicon support spin transport, the effects of carrier type and concentration on important spin parameters are not well understood due to the need for extrinsic doping, which can cause additional momentum and hence spin scattering. Two-dimensional semiconductors, on the other hand, offer the ability to tune carrier type and concentration through field effect gating and inherently have long intrinsic spin lifetimes, making them a desirable platform for spin transport. Here, we study gate-tunable spin transport across narrow band-gap black phosphorus-based spin valves which enable us to systematically investigate spin transport with varying hole and electron concentrations under non-local geometry. Our findings demonstrate exceptional pure spin transport that approaches intrinsic limit, particularly in the low hole doping range. We achieved record non-local signals reaching 350 惟 and spin lifetimes exceeding 16 ns. Contrary to the behaviour seen in typical semiconductors, we find that the spin transport performance of holes in black phosphorus is significantly better than that of electrons, with the Elliott-Yafet process being the primary spin scattering mechanism. The observation of gate-tunable nanosecond spin lifetimes and colossal pure spin signals in both p- and n-type black phosphorus offers promising prospects for the development of novel semiconducting spintronics devices requiring sharp p-n interfaces. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.14588v1-abstract-full').style.display = 'none'; document.getElementById('2502.14588v1-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> 20 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.10972">arXiv:2502.10972</a> <span> [<a href="https://arxiv.org/pdf/2502.10972">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> <p class="title is-5 mathjax"> Density-dependent spin susceptibility and effective mass in monolayer MoSe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Liu%2C+C">Chang Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+T">Tongtong Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zheng Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Gu%2C+Y">Yu Gu</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+F">Fan Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+J">Jinfeng Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+S">Shiyong Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+X">Xiaoxue Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+T">Tingxin Li</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="2502.10972v1-abstract-short" style="display: inline;"> Atomically thin MoSe2 is a promising platform for investigating quantum phenomena due to its large effective mass, high crystal quality, and strong spin-orbit coupling. In this work, we demonstrate a triple-gate device design with bismuth contacts, enabling reliable ohmic contact down to low electron densities, with a maximum Hall mobility of approximately 22,000 cm2/Vs. Low-temperature transport… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.10972v1-abstract-full').style.display = 'inline'; document.getElementById('2502.10972v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.10972v1-abstract-full" style="display: none;"> Atomically thin MoSe2 is a promising platform for investigating quantum phenomena due to its large effective mass, high crystal quality, and strong spin-orbit coupling. In this work, we demonstrate a triple-gate device design with bismuth contacts, enabling reliable ohmic contact down to low electron densities, with a maximum Hall mobility of approximately 22,000 cm2/Vs. Low-temperature transport measurements illustrate metal-insulator transitions, and density-dependent quantum oscillation sequences. Enhanced spin susceptibility and density-dependent effective mass are observed, attributed to interaction effects and valley polarization. These findings establish monolayer MoSe2 as a versatile platform for further exploring interaction-driven quantum states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.10972v1-abstract-full').style.display = 'none'; document.getElementById('2502.10972v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.09868">arXiv:2502.09868</a> <span> [<a href="https://arxiv.org/pdf/2502.09868">pdf</a>, <a href="https://arxiv.org/format/2502.09868">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="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/PhysRevLett.134.066002">10.1103/PhysRevLett.134.066002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unveiling resilient superconducting fluctuations in atomically thin NbSe$_2$ through Higgs mode spectroscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Du%2C+Y">Yu Du</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+G">Gan Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Ruan%2C+W">Wei Ruan</a>, <a href="/search/cond-mat?searchtype=author&query=Fang%2C+Z">Zhi Fang</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+R">Ronghua Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+J">Jian-Xin Li</a>, <a href="/search/cond-mat?searchtype=author&query=Xi%2C+X">Xiaoxiang Xi</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="2502.09868v1-abstract-short" style="display: inline;"> We report a combined electrical transport and optical study of the superconductivity in atomically thin NbSe$_2$. When subjected to an out-of-plane magnetic field, an anomalous metallic state emerges, characterized by a finite longitudinal resistance and a vanishing Hall resistance, suggesting the presence of particle-hole symmetry. We establish a superconducting Higgs mode in atomically thin samp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.09868v1-abstract-full').style.display = 'inline'; document.getElementById('2502.09868v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.09868v1-abstract-full" style="display: none;"> We report a combined electrical transport and optical study of the superconductivity in atomically thin NbSe$_2$. When subjected to an out-of-plane magnetic field, an anomalous metallic state emerges, characterized by a finite longitudinal resistance and a vanishing Hall resistance, suggesting the presence of particle-hole symmetry. We establish a superconducting Higgs mode in atomically thin samples, which reveals enduring superconducting fluctuations that withstand unexpectedly high reduced magnetic fields. These findings provide evidence of robust locally paired electrons in the anomalous metallic state, affirming its bosonic nature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.09868v1-abstract-full').style.display = 'none'; document.getElementById('2502.09868v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 134, 066002 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.08527">arXiv:2502.08527</a> <span> [<a href="https://arxiv.org/pdf/2502.08527">pdf</a>, <a href="https://arxiv.org/format/2502.08527">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="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Non-Reciprocal Current-Phase Relation and Superconducting Diode Effect in Topological-Insulator-Based Josephson Junctions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kudriashov%2C+A">A. Kudriashov</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+X">X. Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Hovhannisyan%2C+R+A">R. A. Hovhannisyan</a>, <a href="/search/cond-mat?searchtype=author&query=Frolov%2C+A">A. Frolov</a>, <a href="/search/cond-mat?searchtype=author&query=Elesin%2C+L">L. Elesin</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y">Y. Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Zharkova%2C+E+V">E. V. Zharkova</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">T. Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">K. Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Yashina%2C+L+A">L. A. Yashina</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Z">Z. Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+X">Xin Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Novoselov%2C+K+S">K. S. Novoselov</a>, <a href="/search/cond-mat?searchtype=author&query=Bandurin%2C+D+A">D. A. Bandurin</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="2502.08527v1-abstract-short" style="display: inline;"> Josephson junctions (JJ) are essential for superconducting quantum technologies and searches of self-conjugate quasiparticles, pivotal for fault-tolerant quantum computing. Measuring the current-phase relation (CPR) in JJ based on topological insulators (TI) can provide critical insights into unconventional phenomena in these systems, such as the presence of Majorana bound states (MBS) and the nat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.08527v1-abstract-full').style.display = 'inline'; document.getElementById('2502.08527v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.08527v1-abstract-full" style="display: none;"> Josephson junctions (JJ) are essential for superconducting quantum technologies and searches of self-conjugate quasiparticles, pivotal for fault-tolerant quantum computing. Measuring the current-phase relation (CPR) in JJ based on topological insulators (TI) can provide critical insights into unconventional phenomena in these systems, such as the presence of Majorana bound states (MBS) and the nature of non-reciprocal transport. However, reconstructing CPR as a function of magnetic field in such JJs has remained experimentally challenging. Here, we introduce a platform for precise CPR measurements in planar JJs composed of NbSe$_2$ and few layer thick Bi$_2$Se$_3$ (TI) as a function of magnetic field. When a single flux quantum $桅_\mathrm{0}$ threads the junction, we observe anomalous peak-dip-shaped CPR behaviour and non-reciprocal supercurrent flow. We demonstrate that these anomalies stem from the edge-amplified sloped supercurrent profile rather than MBS signatures often invoked to explain puzzles emerging near $桅_\mathrm{0}$ in TI-based JJ. Furthermore, we show that such a supercurrent profile gives rise to a previously overlooked, robust and tunable Josephson diode effect. These findings establish field-dependent CPR measurements as a critical tool for exploring topological superconducting devices and offer new design principles for non-reciprocal superconducting electronics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.08527v1-abstract-full').style.display = 'none'; document.getElementById('2502.08527v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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">10 pages, 5 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/2502.06245">arXiv:2502.06245</a> <span> [<a href="https://arxiv.org/pdf/2502.06245">pdf</a>, <a href="https://arxiv.org/format/2502.06245">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> <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"> Even denominator fractional quantum Hall states in the zeroth Landau level of monolayer-like band of ABA trilayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chanda%2C+T">Tanima Chanda</a>, <a href="/search/cond-mat?searchtype=author&query=Kaur%2C+S">Simrandeep Kaur</a>, <a href="/search/cond-mat?searchtype=author&query=Singh%2C+H">Harsimran Singh</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Jain%2C+M">Manish Jain</a>, <a href="/search/cond-mat?searchtype=author&query=Khanna%2C+U">Udit Khanna</a>, <a href="/search/cond-mat?searchtype=author&query=Balram%2C+A+C">Ajit C. Balram</a>, <a href="/search/cond-mat?searchtype=author&query=Bid%2C+A">Aveek Bid</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="2502.06245v1-abstract-short" style="display: inline;"> The fractional quantum Hall (FQH) effect is a macroscopic manifestation of strong electron-electron interactions. Even denominator FQH states (FQHSs) at half-filling are particularly interesting as they are predicted to host non-Abelian excitations with non-trivial braiding statistics. Such states are predominantly observed in the $N=1$ Landau level (LL) of semiconductors such as GaAs. In this Let… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.06245v1-abstract-full').style.display = 'inline'; document.getElementById('2502.06245v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.06245v1-abstract-full" style="display: none;"> The fractional quantum Hall (FQH) effect is a macroscopic manifestation of strong electron-electron interactions. Even denominator FQH states (FQHSs) at half-filling are particularly interesting as they are predicted to host non-Abelian excitations with non-trivial braiding statistics. Such states are predominantly observed in the $N=1$ Landau level (LL) of semiconductors such as GaAs. In this Letter, we report the unanticipated observation of even-denominator FQHSs in the $N=0$ LL of ABA trilayer graphene (TLG), a system characterized by tunable LL mixing and the absence of inversion symmetry. Notably, we find robust FQHSs at $谓=5/2$ and $谓=7/2$ when two LLs, originating from a monolayer-like band of TLG with different isospin indices, cross each other. These are flanked by the Levin-Halperin daughter states at $谓=7/13$ and $谓=9/17$, respectively, and further away, the standard series of Jain-sequence of composite fermions (CFs) is observed. The even-denominator FQHSs and their accompanying daughter states become stronger with increasing magnetic fields, while concomitantly, a weakening of the CF states is observed. We posit that the absence of inversion symmetry in the system gives rise to additional isospin interactions, which enhance LL mixing and soften the short-range part of the Coulomb repulsion, stabilizing the even-denominator FQHSs. In addition, we demonstrate that these states, along with their daughter states, can be finely tuned with an external displacement field that serves as an important tool to control the LL mixing in the system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.06245v1-abstract-full').style.display = 'none'; document.getElementById('2502.06245v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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, comments and suggestions are very welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.05527">arXiv:2502.05527</a> <span> [<a href="https://arxiv.org/pdf/2502.05527">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> <p class="title is-5 mathjax"> Preserving Twist-Angle in Marginally Twisted Double-Bilayer Graphene Devices During Fabrication </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Jeong%2C+H">Hyeon-Woo Jeong</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J">Jiho Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Chae%2C+B">Boknam Chae</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+G">Gil-Ho Lee</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="2502.05527v1-abstract-short" style="display: inline;"> Twisted van der Waals heterostructures provide a platform for studying a wide range of electron correlation phenomena, including unconventional superconductivity and correlated insulating states. However, fabricating such devices is challenging due to the difficulty in achieving and maintaining homogeneous twist-angles. Here, we present a fabrication method to preserve the twist-angle with minimal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.05527v1-abstract-full').style.display = 'inline'; document.getElementById('2502.05527v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.05527v1-abstract-full" style="display: none;"> Twisted van der Waals heterostructures provide a platform for studying a wide range of electron correlation phenomena, including unconventional superconductivity and correlated insulating states. However, fabricating such devices is challenging due to the difficulty in achieving and maintaining homogeneous twist-angles. Here, we present a fabrication method to preserve the twist-angle with minimal deformation. We fabricated marginally twisted double-bilayer graphene (mTDBG) stacks and directly imaged the resulting triangular superlattice periodicity via scattering-type scanning near-field optical microscopy (s-SNOM). This technique enabled us to monitor twist-angle deformation at each fabrication step, paving the way for more reliable device fabrication and facilitating the exploration of twist-angle-dependent physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.05527v1-abstract-full').style.display = 'none'; document.getElementById('2502.05527v1-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> 8 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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, 4 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/2502.04911">arXiv:2502.04911</a> <span> [<a href="https://arxiv.org/pdf/2502.04911">pdf</a>, <a href="https://arxiv.org/format/2502.04911">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"> Kerr non-linearity enhances the response of a graphene Josephson bolometer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sarkar%2C+J">Joydip Sarkar</a>, <a href="/search/cond-mat?searchtype=author&query=Maji%2C+K">Krishnendu Maji</a>, <a href="/search/cond-mat?searchtype=author&query=Sunamudi%2C+A">Abhishek Sunamudi</a>, <a href="/search/cond-mat?searchtype=author&query=Agarwal%2C+H">Heena Agarwal</a>, <a href="/search/cond-mat?searchtype=author&query=Samanta%2C+P">Priyanka Samanta</a>, <a href="/search/cond-mat?searchtype=author&query=Bhattacharjee%2C+A">Anirban Bhattacharjee</a>, <a href="/search/cond-mat?searchtype=author&query=Rajkhowa%2C+R">Rishiraj Rajkhowa</a>, <a href="/search/cond-mat?searchtype=author&query=Patankar%2C+M+P">Meghan P. Patankar</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Deshmukh%2C+M+M">Mandar M. Deshmukh</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="2502.04911v1-abstract-short" style="display: inline;"> Highly sensitive, broadband bolometers are of great interest because of their versatile usage in wide areas starting from dark matter search, radio astronomy, material science, and qubit readouts in cQED experiments. There have been different realizations of bolometers using superconducting thin films, nanowires, quantum dots, and various 2D materials in the recent past. The challenge is to have a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04911v1-abstract-full').style.display = 'inline'; document.getElementById('2502.04911v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.04911v1-abstract-full" style="display: none;"> Highly sensitive, broadband bolometers are of great interest because of their versatile usage in wide areas starting from dark matter search, radio astronomy, material science, and qubit readouts in cQED experiments. There have been different realizations of bolometers using superconducting thin films, nanowires, quantum dots, and various 2D materials in the recent past. The challenge is to have a single device that combines high sensitivity, broad bandwidth, a fast readout mechanism, and low noise. Here we demonstrate the first usage of a Josephson parametric amplifier (JPA) as a highly sensitive bolometer. Our key finding is the Kerr non-linearity of the JPA boosts the device's sensitivity. When the bolometer is biased in the non-linear regime, it enhances the sideband signals (~100 times), resulting in an order of magnitude improvement in sensitivity compared to the linear regime. In the non-linear biasing of the device, we achieve a NEP~500 aW/sqrt(Hz). Our bolometer offers a fast detection scheme with a thermal time constant of 4.26 us and an intrinsic JPA time constant of 70 ns. Our device's broadband and fast operation are key and new compared to previously studied graphene-based bolometers. In our device, the gate voltage tunability and the possibility of multiplexing combined with the sensitive bolometric performance offer an opportunity for integrated quantum sensor arrays. Our work demonstrates a way forward to enhance the performance of quantum sensors based on 2D materials by leveraging the inherent non-linear response. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04911v1-abstract-full').style.display = 'none'; document.getElementById('2502.04911v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.04785">arXiv:2502.04785</a> <span> [<a href="https://arxiv.org/pdf/2502.04785">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"> Probing the flat-band limit of the superconducting proximity effect in Twisted Bilayer Graphene Josephson junctions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Diez-Carlon%2C+A">A. Diez-Carlon</a>, <a href="/search/cond-mat?searchtype=author&query=Diez-Merida%2C+J">J. Diez-Merida</a>, <a href="/search/cond-mat?searchtype=author&query=Rout%2C+P">P. Rout</a>, <a href="/search/cond-mat?searchtype=author&query=Sedov%2C+D">D. Sedov</a>, <a href="/search/cond-mat?searchtype=author&query=Virtanen%2C+P">P. Virtanen</a>, <a href="/search/cond-mat?searchtype=author&query=Banerjee%2C+S">S. Banerjee</a>, <a href="/search/cond-mat?searchtype=author&query=Penttila%2C+R+P+S">R. P. S. Penttila</a>, <a href="/search/cond-mat?searchtype=author&query=Altpeter%2C+P">P. Altpeter</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">K. Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">T. Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+S+-">S. -Y. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Law%2C+K+T">K. T. Law</a>, <a href="/search/cond-mat?searchtype=author&query=Heikkila%2C+T+T">T. T. Heikkila</a>, <a href="/search/cond-mat?searchtype=author&query=Torma%2C+P">P. Torma</a>, <a href="/search/cond-mat?searchtype=author&query=Scheurer%2C+M+S">M. S. Scheurer</a>, <a href="/search/cond-mat?searchtype=author&query=Efetov%2C+D+K">D. K. Efetov</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="2502.04785v1-abstract-short" style="display: inline;"> While extensively studied in normal metals, semimetals and semiconductors, the superconducting (SC) proximity effect remains elusive in the emerging field of flat-band systems. In this study we probe proximity-induced superconductivity in Josephson junctions (JJs) formed between superconducting NbTiN electrodes and twisted bilayer graphene (TBG) weak links. Here the TBG acts as a highly tunable to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04785v1-abstract-full').style.display = 'inline'; document.getElementById('2502.04785v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.04785v1-abstract-full" style="display: none;"> While extensively studied in normal metals, semimetals and semiconductors, the superconducting (SC) proximity effect remains elusive in the emerging field of flat-band systems. In this study we probe proximity-induced superconductivity in Josephson junctions (JJs) formed between superconducting NbTiN electrodes and twisted bilayer graphene (TBG) weak links. Here the TBG acts as a highly tunable topological flat-band system, which due to its twist-angle dependent bandwidth, allows to probe the SC proximity effect at the crossover from the dispersive to the flat-band limit. Contrary to our original expectations, we find that the SC remains strong even in the flat-band limit, and gives rise to broad, dome shaped SC regions, in the filling dependent phase diagram. In addition, we find that unlike in conventional JJs, the critical current Ic strongly deviates from a scaling with the normal state conductance GN. We attribute these findings to the onset of strong electron interactions, which can give rise to an excess critical current, and also work out the potential importance of quantum geometric terms as well as multiband pairing mechanisms. Our results present the first detailed study of the SC proximity effect in the flat-band limit and shed new light on the mechanisms that drive the formation of SC domes in flat-band systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04785v1-abstract-full').style.display = 'none'; document.getElementById('2502.04785v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.03925">arXiv:2502.03925</a> <span> [<a href="https://arxiv.org/pdf/2502.03925">pdf</a>, <a href="https://arxiv.org/format/2502.03925">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 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.110.235414">10.1103/PhysRevB.110.235414 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electric field tunable bands in doubly aligned bilayer graphene hBN moire superlattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tiwari%2C+P">Priya Tiwari</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Bid%2C+A">Aveek Bid</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="2502.03925v1-abstract-short" style="display: inline;"> In this letter, we demonstrate electric field-induced band modification of an asymmetrically twisted hBN/BLG/hBN supermoire lattice. Distinct from unaligned BLG/hBN systems, we observe regions in the density-displacement field (n-D) plane where the device conductance is independent of n and decreases as |D| increases. This distinction arises due to the angle asymmetry between the layers, which ind… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.03925v1-abstract-full').style.display = 'inline'; document.getElementById('2502.03925v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.03925v1-abstract-full" style="display: none;"> In this letter, we demonstrate electric field-induced band modification of an asymmetrically twisted hBN/BLG/hBN supermoire lattice. Distinct from unaligned BLG/hBN systems, we observe regions in the density-displacement field (n-D) plane where the device conductance is independent of n and decreases as |D| increases. This distinction arises due to the angle asymmetry between the layers, which induces field-controlled layer polarization. We identify D-dependent additional band gaps near the charge neutrality point that appear in the conduction (valence) band for negative (positive) D values. In the quantum Hall regime, new 6-fold degenerate Landau levels are observed. Our findings establish that in an asymmetric supermoire heterostructure, an external vertical displacement field affects the valence and conduction bands very differently and sheds light on the asymmetric conductance patterns noted in previous studies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.03925v1-abstract-full').style.display = 'none'; document.getElementById('2502.03925v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 110, 235414 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.03049">arXiv:2502.03049</a> <span> [<a href="https://arxiv.org/pdf/2502.03049">pdf</a>, <a href="https://arxiv.org/format/2502.03049">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> <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"> Spin-valley polarization control in WSe$_2$ monolayers using photochemical doping </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Katsipoulaki%2C+E">E. Katsipoulaki</a>, <a href="/search/cond-mat?searchtype=author&query=Mourzidis%2C+K">K. Mourzidis</a>, <a href="/search/cond-mat?searchtype=author&query=Jindal%2C+V">V. Jindal</a>, <a href="/search/cond-mat?searchtype=author&query=Lagarde%2C+D">D. Lagarde</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">T. Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">K. Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Kopidakis%2C+G">G. Kopidakis</a>, <a href="/search/cond-mat?searchtype=author&query=Marie%2C+X">X. Marie</a>, <a href="/search/cond-mat?searchtype=author&query=Glazov%2C+M+M">M. M. Glazov</a>, <a href="/search/cond-mat?searchtype=author&query=Stratakis%2C+E">E. Stratakis</a>, <a href="/search/cond-mat?searchtype=author&query=Kioseoglou%2C+G">G. Kioseoglou</a>, <a href="/search/cond-mat?searchtype=author&query=Paradisanos%2C+I">I. Paradisanos</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="2502.03049v1-abstract-short" style="display: inline;"> We report on the influence of a photochemical doping method on the spin-valley polarization degree ($P_{c}$) of excitons in WSe$_2$ monolayers. By varying the carrier density and transitioning from an excess of electrons (n-type) to an excess of holes (p-type), we observe a non-monotonic dependence of $P_{c}$ on the doping level. Using controlled, single-shot photochlorination steps, we unveil thi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.03049v1-abstract-full').style.display = 'inline'; document.getElementById('2502.03049v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.03049v1-abstract-full" style="display: none;"> We report on the influence of a photochemical doping method on the spin-valley polarization degree ($P_{c}$) of excitons in WSe$_2$ monolayers. By varying the carrier density and transitioning from an excess of electrons (n-type) to an excess of holes (p-type), we observe a non-monotonic dependence of $P_{c}$ on the doping level. Using controlled, single-shot photochlorination steps, we unveil this non-monotonic behavior, with $P_{c}$ reaching a minimum value of less than 10$\%$ at 78 K near the charge neutrality point, while increasing by a factor of three at a hole density of $5 \times 10^{11} \,\mathrm{cm^{-2}}$. The impact of the doping on $P_{c}$ is explained using a phenomenological model that accounts for various mechanisms influencing exciton polarization dynamics, including exciton-carrier scattering processes and exciton-to-trion conversion rates. Among these, exciton-carrier collisions emerge as the dominant mechanism driving the observed variations in $P_{c}$, while the exciton effective lifetime remains nearly independent of doping. These findings highlight the potential of photochemical methods for investigating valley physics and for effectively tuning the exciton polarization degree in transition metal dichalcogenide monolayers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.03049v1-abstract-full').style.display = 'none'; document.getElementById('2502.03049v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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 pages, 4 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/2501.18206">arXiv:2501.18206</a> <span> [<a href="https://arxiv.org/pdf/2501.18206">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Charge state tuning of spin defects in hexagonal boron nitride </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Frauni%C3%A9%2C+J">Jules Frauni茅</a>, <a href="/search/cond-mat?searchtype=author&query=Clua-Provost%2C+T">Tristan Clua-Provost</a>, <a href="/search/cond-mat?searchtype=author&query=Roux%2C+S">S茅bastien Roux</a>, <a href="/search/cond-mat?searchtype=author&query=Mu%2C+Z">Zhao Mu</a>, <a href="/search/cond-mat?searchtype=author&query=Delpoux%2C+A">Adrien Delpoux</a>, <a href="/search/cond-mat?searchtype=author&query=Seine%2C+G">Gr茅gory Seine</a>, <a href="/search/cond-mat?searchtype=author&query=Lagarde%2C+D">Delphine Lagarde</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Marie%2C+X">Xavier Marie</a>, <a href="/search/cond-mat?searchtype=author&query=Poirier%2C+T">Thomas Poirier</a>, <a href="/search/cond-mat?searchtype=author&query=Edgar%2C+J+H">James H. Edgar</a>, <a href="/search/cond-mat?searchtype=author&query=Grisolia%2C+J">Jeremie Grisolia</a>, <a href="/search/cond-mat?searchtype=author&query=Lassagne%2C+B">Benjamin Lassagne</a>, <a href="/search/cond-mat?searchtype=author&query=Claverie%2C+A">Alain Claverie</a>, <a href="/search/cond-mat?searchtype=author&query=Jacques%2C+V">Vincent Jacques</a>, <a href="/search/cond-mat?searchtype=author&query=Robert%2C+C">Cedric Robert</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="2501.18206v1-abstract-short" style="display: inline;"> Boron vacancies in hexagonal boron nitride (hBN) are among the most extensively studied optically active spin defects in van der Waals crystals, due to their promising potential to develop two-dimensional (2D) quantum sensors. In this letter, we demonstrate the tunability of the charge state of boron vacancies in ultrathin hBN layers, revealing a transition from the optically active singly negativ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.18206v1-abstract-full').style.display = 'inline'; document.getElementById('2501.18206v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.18206v1-abstract-full" style="display: none;"> Boron vacancies in hexagonal boron nitride (hBN) are among the most extensively studied optically active spin defects in van der Waals crystals, due to their promising potential to develop two-dimensional (2D) quantum sensors. In this letter, we demonstrate the tunability of the charge state of boron vacancies in ultrathin hBN layers, revealing a transition from the optically active singly negatively charged state to the optically inactive doubly negatively charged state when sandwiched between graphene electrodes. Notably, there is a photoluminescence quenching of a few percent upon the application of a bias voltage between the electrodes. Our findings emphasize the critical importance of considering the charge state of optically active defects in 2D materials, while also showing that the negatively charged boron vacancy remains robust against external perpendicular electric fields. This stability makes it a promising candidate for integration into various van der Waals heterostructures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.18206v1-abstract-full').style.display = 'none'; document.getElementById('2501.18206v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.18168">arXiv:2501.18168</a> <span> [<a href="https://arxiv.org/pdf/2501.18168">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="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Competition between excitonic insulators and quantum Hall states in correlated electron-hole bilayers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Qi%2C+R">Ruishi Qi</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+Q">Qize Li</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Z">Zuocheng Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Cui%2C+Z">Zhiyuan Cui</a>, <a href="/search/cond-mat?searchtype=author&query=Zou%2C+B">Bo Zou</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+H">Haleem Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Sanborn%2C+C">Collin Sanborn</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+S">Sudi Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Xie%2C+J">Jingxu Xie</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=MacDonald%2C+A+H">Allan H. MacDonald</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</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="2501.18168v1-abstract-short" style="display: inline;"> Excitonic insulators represent a unique quantum phase of matter, providing a rich ground for studying exotic quantum bosonic states. Strongly coupled electron-hole bilayers, which host stable dipolar exciton fluids with an exciton density that can be adjusted electrostatically, offer an ideal platform to investigate correlated excitonic insulators. Based on electron-hole bilayers made of MoSe2/hBN… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.18168v1-abstract-full').style.display = 'inline'; document.getElementById('2501.18168v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.18168v1-abstract-full" style="display: none;"> Excitonic insulators represent a unique quantum phase of matter, providing a rich ground for studying exotic quantum bosonic states. Strongly coupled electron-hole bilayers, which host stable dipolar exciton fluids with an exciton density that can be adjusted electrostatically, offer an ideal platform to investigate correlated excitonic insulators. Based on electron-hole bilayers made of MoSe2/hBN/WSe2 heterostructures, here we study the behavior of excitonic insulators in a perpendicular magnetic field. We report the observation of excitonic quantum oscillations in both Coulomb drag signals and electrical resistance at low to medium magnetic fields. Under a strong magnetic field, we identify multiple quantum phase transitions between the excitonic insulator phase and the bilayer quantum Hall insulator phase. These findings underscore the interplay between the electron-hole interactions and Landau level quantization that opens new possibilities for exploring quantum phenomena in composite bosonic insulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.18168v1-abstract-full').style.display = 'none'; document.getElementById('2501.18168v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.17829">arXiv:2501.17829</a> <span> [<a href="https://arxiv.org/pdf/2501.17829">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="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Quantum oscillations in a dipolar excitonic insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Nguyen%2C+P+X">Phuong X. Nguyen</a>, <a href="/search/cond-mat?searchtype=author&query=Chaturvedi%2C+R">Raghav Chaturvedi</a>, <a href="/search/cond-mat?searchtype=author&query=Zou%2C+B">Bo Zou</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=MacDonald%2C+A+H">Allan H. MacDonald</a>, <a href="/search/cond-mat?searchtype=author&query=Mak%2C+K+F">Kin Fai Mak</a>, <a href="/search/cond-mat?searchtype=author&query=Shan%2C+J">Jie Shan</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="2501.17829v1-abstract-short" style="display: inline;"> Quantum oscillations in magnetization or resistivity are a defining feature of metals subject to an external magnetic field. The phenomenon is generally not expected in insulators without a Fermi surface. The observations of quantum oscillations in Kondo insulating materials have provided a rare counterexample and attracted much theoretical interest. However, the magnetic oscillations in correlate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.17829v1-abstract-full').style.display = 'inline'; document.getElementById('2501.17829v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.17829v1-abstract-full" style="display: none;"> Quantum oscillations in magnetization or resistivity are a defining feature of metals subject to an external magnetic field. The phenomenon is generally not expected in insulators without a Fermi surface. The observations of quantum oscillations in Kondo insulating materials have provided a rare counterexample and attracted much theoretical interest. However, the magnetic oscillations in correlated insulators remain poorly understood. Here we report the observations of resistivity quantum oscillations in an excitonic insulator realized in Coulomb-coupled electron-hole double layers with gate-tunability that allows the phenomenon to be explored in a more controllable fashion than in bulk materials. When the cyclotron energy of the electrons or holes is tuned to be comparable to or larger than the exciton binding energy, recurring transitions between excitonic insulators and electron-hole decoupled quantum Hall states are observed. Compressibility measurements show an oscillatory exciton binding energy as a function of magnetic field and electron-hole pair density. Coulomb drag measurements further reveal the formation of excitons with finite angular momentum. Our results are qualitatively captured by mean-field theory calculations. The study demonstrates a new platform for studying quantum oscillations in correlated insulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.17829v1-abstract-full').style.display = 'none'; document.getElementById('2501.17829v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.17417">arXiv:2501.17417</a> <span> [<a href="https://arxiv.org/pdf/2501.17417">pdf</a>, <a href="https://arxiv.org/format/2501.17417">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> </div> </div> <p class="title is-5 mathjax"> Spin-forbidden excitations in the magneto-optical spectra of CrI$_3$ tuned by covalency </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Occhialini%2C+C+A">Connor A. Occhialini</a>, <a href="/search/cond-mat?searchtype=author&query=Nessi%2C+L">Luca Nessi</a>, <a href="/search/cond-mat?searchtype=author&query=Martins%2C+L+G+P">Luiz G. P. Martins</a>, <a href="/search/cond-mat?searchtype=author&query=Demir%2C+A+K">Ahmet Kemal Demir</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+Q">Qian Song</a>, <a href="/search/cond-mat?searchtype=author&query=Hasse%2C+V">Vicky Hasse</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=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Bisogni%2C+V">Valentina Bisogni</a>, <a href="/search/cond-mat?searchtype=author&query=Pelliciari%2C+J">Jonathan Pelliciari</a>, <a href="/search/cond-mat?searchtype=author&query=Comin%2C+R">Riccardo Comin</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="2501.17417v1-abstract-short" style="display: inline;"> Spin-forbidden ($螖S \neq 0$) multiplet excitations and their coupling to magnetic properties are of increasing importance for magneto-optical studies of correlated materials. Nonetheless, the mechanisms for optically brightening these transitions and their generality remain poorly understood. Here, we report magnetic circular dichroism (MCD) spectroscopy on the van der Waals (vdW) ferromagnet (FM)… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.17417v1-abstract-full').style.display = 'inline'; document.getElementById('2501.17417v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.17417v1-abstract-full" style="display: none;"> Spin-forbidden ($螖S \neq 0$) multiplet excitations and their coupling to magnetic properties are of increasing importance for magneto-optical studies of correlated materials. Nonetheless, the mechanisms for optically brightening these transitions and their generality remain poorly understood. Here, we report magnetic circular dichroism (MCD) spectroscopy on the van der Waals (vdW) ferromagnet (FM) CrI$_3$. Previously unreported spin-forbidden ($螖S = 1$) ${}^4A_{2\mathrm{g}} \to{}^2E_\mathrm{g}/{}^2T_{1\mathrm{g}}$ Cr${}^{3+}$ $dd$ excitations are observed near the ligand-to-metal charge transfer (LMCT) excitation threshold. The assignment of these excitations and their Cr$^{3+}$ multiplet character is established through complementary Cr $L_3$-edge resonant inelastic X-ray scattering (RIXS) measurements along with charge transfer multiplet (CTM) calculations and chemical trends in the chromium trihalide series (CrX$_3$, X = Cl, Br, I). We utilize the high sensitivity of MCD spectroscopy to study the thickness dependent optical response. The spin-forbidden excitations remain robust down to the monolayer limit and exhibit a significant magnetic field tunability across the antiferromagnetic to FM transition in few-layer samples. This behavior is associated to changes in the metal-ligand covalency with magnetic state, as supported by our CTM analysis. Our results clarify the magneto-optical response of CrI$_3$ and identify covalency as a central mechanism for the brightening and field-tunability of spin-forbidden multiplet excitations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.17417v1-abstract-full').style.display = 'none'; document.getElementById('2501.17417v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.16736">arXiv:2501.16736</a> <span> [<a href="https://arxiv.org/pdf/2501.16736">pdf</a>, <a href="https://arxiv.org/format/2501.16736">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> </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.9.024001">10.1103/PhysRevMaterials.9.024001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Laser patterning of the room temperature van der Waals ferromagnet 1$T$-CrTe$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Riccardi%2C+T">Tristan Riccardi</a>, <a href="/search/cond-mat?searchtype=author&query=Sarkar%2C+S">Suman Sarkar</a>, <a href="/search/cond-mat?searchtype=author&query=Purbawati%2C+A">Anike Purbawati</a>, <a href="/search/cond-mat?searchtype=author&query=Arrighi%2C+A">Alo茂s Arrighi</a>, <a href="/search/cond-mat?searchtype=author&query=Kostka%2C+M">Marek Kostka</a>, <a href="/search/cond-mat?searchtype=author&query=Hadj-Azzem%2C+A">Abdellali Hadj-Azzem</a>, <a href="/search/cond-mat?searchtype=author&query=Vogel%2C+J">Jan Vogel</a>, <a href="/search/cond-mat?searchtype=author&query=Renard%2C+J">Julien Renard</a>, <a href="/search/cond-mat?searchtype=author&query=Marty%2C+L">La毛titia Marty</a>, <a href="/search/cond-mat?searchtype=author&query=Pawbake%2C+A">Amit Pawbake</a>, <a href="/search/cond-mat?searchtype=author&query=Faugeras%2C+C">Cl茅ment Faugeras</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Finco%2C+A">Aurore Finco</a>, <a href="/search/cond-mat?searchtype=author&query=Jacques%2C+V">Vincent Jacques</a>, <a href="/search/cond-mat?searchtype=author&query=Ren%2C+L">Lei Ren</a>, <a href="/search/cond-mat?searchtype=author&query=Marie%2C+X">Xavier Marie</a>, <a href="/search/cond-mat?searchtype=author&query=Robert%2C+C">Cedric Robert</a>, <a href="/search/cond-mat?searchtype=author&query=Nu%C3%B1ez-Regueiro%2C+M">Manuel Nu帽ez-Regueiro</a>, <a href="/search/cond-mat?searchtype=author&query=Rougemaille%2C+N">Nicolas Rougemaille</a>, <a href="/search/cond-mat?searchtype=author&query=Bendiab%2C+N">Nedjma Bendiab</a>, <a href="/search/cond-mat?searchtype=author&query=Coraux%2C+J">Johann Coraux</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="2501.16736v1-abstract-short" style="display: inline;"> Lamellar crystalline materials, whose layers are bond by van der Waals forces, can be stacked to form ultrathin artificial heterostructures, and in particular vertical magnetic junctions when some of the stacked materials are (ferro)magnetic. Here, using the room temperature van der Waals ferromagnet 1$T$-CrTe$_2$, we report a method for patterning lateral magnetic junctions. Exploiting the heat-i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.16736v1-abstract-full').style.display = 'inline'; document.getElementById('2501.16736v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.16736v1-abstract-full" style="display: none;"> Lamellar crystalline materials, whose layers are bond by van der Waals forces, can be stacked to form ultrathin artificial heterostructures, and in particular vertical magnetic junctions when some of the stacked materials are (ferro)magnetic. Here, using the room temperature van der Waals ferromagnet 1$T$-CrTe$_2$, we report a method for patterning lateral magnetic junctions. Exploiting the heat-induced phase transformation of the material into Cr$_x$Te$_y$ compounds ($x/y>1/2$), we use local laser heating to imprint patterns at the micron-scale. Optimizing laser heat dissipation, we further demonstrate the crucial role of the substrate to control the phase transformation. If plain, unstructured poorly heat-conducting substrates allow for direct writing of magnetic patterns, structured $h$-BN layers can serve as heat stencils to draw potentially thinner patterns. Besides, $h$-BN encapsulation turns out to be heat-protective (in addition from protecting against oxidation as it is generally used for), allowing the demonstration of room temperature ferromagnetism in $<$7~nm-thick 1$T$-CrTe$_2$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.16736v1-abstract-full').style.display = 'none'; document.getElementById('2501.16736v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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 Physical Review Materials, 5 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/2501.16715">arXiv:2501.16715</a> <span> [<a href="https://arxiv.org/pdf/2501.16715">pdf</a>, <a href="https://arxiv.org/format/2501.16715">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"> Systematic investigation of dynamic nuclear polarization with boron vacancy in hexagonal boron nitride </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Nakamura%2C+Y">Yuki Nakamura</a>, <a href="/search/cond-mat?searchtype=author&query=Nishimura%2C+S">Shunsuke Nishimura</a>, <a href="/search/cond-mat?searchtype=author&query=Iwasaki%2C+T">Takuya Iwasaki</a>, <a href="/search/cond-mat?searchtype=author&query=Nakaharai%2C+S">Shu Nakaharai</a>, <a href="/search/cond-mat?searchtype=author&query=Ogawa%2C+S">Shinichi Ogawa</a>, <a href="/search/cond-mat?searchtype=author&query=Morita%2C+Y">Yukinori Morita</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Sasaki%2C+K">Kento Sasaki</a>, <a href="/search/cond-mat?searchtype=author&query=Kobayashi%2C+K">Kensuke Kobayashi</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="2501.16715v1-abstract-short" style="display: inline;"> Dynamic nuclear polarization (DNP) using the boron vacancy ($\mathrm{V_B^-}$) in hexagonal boron nitride (hBN) has gained increasing attention. Understanding this DNP requires systematically investigating the optically detected magnetic resonance (ODMR) spectra and developing a model that quantitatively describes its behavior. Here, we measure the ODMR spectra of $\mathrm{V_B^-}$ in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.16715v1-abstract-full').style.display = 'inline'; document.getElementById('2501.16715v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.16715v1-abstract-full" style="display: none;"> Dynamic nuclear polarization (DNP) using the boron vacancy ($\mathrm{V_B^-}$) in hexagonal boron nitride (hBN) has gained increasing attention. Understanding this DNP requires systematically investigating the optically detected magnetic resonance (ODMR) spectra and developing a model that quantitatively describes its behavior. Here, we measure the ODMR spectra of $\mathrm{V_B^-}$ in $\mathrm{h}^{10}\mathrm{B}^{15}\mathrm{N}$ over a wide magnetic field range, including the ground state level anti-crossing (GSLAC), and compare them with the results of the Lindblad-based simulation that considers a single electron spin and three neighboring $^{15}\mathrm{N}$ nuclear spins. Our simulation successfully reproduces the experimental spectra, including the vicinity of GSLAC. It can explain the overall behavior of the magnetic field dependence of the nuclear spin polarization estimated using the Lorentzian fitting of the spectra. Despite such qualitative agreement, we also demonstrate that the fitting methods cannot give accurate polarizations. Finally, we discuss that symmetry-induced mechanisms of $\mathrm{V_B^-}$ limit the maximum polarization. Our study is an essential step toward a quantitative understanding of DNP using defects in hBN and its quantum applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.16715v1-abstract-full').style.display = 'none'; document.getElementById('2501.16715v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.16699">arXiv:2501.16699</a> <span> [<a href="https://arxiv.org/pdf/2501.16699">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="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> <p class="title is-5 mathjax"> Unconventional Superconducting Phase Diagram of Monolayer WTe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Song%2C+T">Tiancheng Song</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+Y">Yanyu Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Yu%2C+G">Guo Yu</a>, <a href="/search/cond-mat?searchtype=author&query=Tang%2C+Y">Yue Tang</a>, <a href="/search/cond-mat?searchtype=author&query=Uzan%2C+A+J">Ayelet J. Uzan</a>, <a href="/search/cond-mat?searchtype=author&query=Zheng%2C+Z+J">Zhaoyi Joy Zheng</a>, <a href="/search/cond-mat?searchtype=author&query=Guan%2C+H">Haosen Guan</a>, <a href="/search/cond-mat?searchtype=author&query=Onyszczak%2C+M">Michael Onyszczak</a>, <a href="/search/cond-mat?searchtype=author&query=Singha%2C+R">Ratnadwip Singha</a>, <a href="/search/cond-mat?searchtype=author&query=Gui%2C+X">Xin Gui</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Cava%2C+R+J">Robert J. Cava</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=Ong%2C+N+P">N. P. Ong</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+S">Sanfeng Wu</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="2501.16699v1-abstract-short" style="display: inline;"> The existence of a quantum critical point (QCP) and fluctuations around it are believed to be important for understanding the phase diagram in unconventional superconductors such as cuprates, iron pnictides, and heavy fermion superconductors. However, the QCP is usually buried deep within the superconducting dome and is difficult to investigate. The connection between quantum critical fluctuations… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.16699v1-abstract-full').style.display = 'inline'; document.getElementById('2501.16699v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.16699v1-abstract-full" style="display: none;"> The existence of a quantum critical point (QCP) and fluctuations around it are believed to be important for understanding the phase diagram in unconventional superconductors such as cuprates, iron pnictides, and heavy fermion superconductors. However, the QCP is usually buried deep within the superconducting dome and is difficult to investigate. The connection between quantum critical fluctuations and superconductivity remains an outstanding problem in condensed matter. Here combining both electrical transport and Nernst experiments, we explicitly demonstrate the onset of superconductivity at an unconventional QCP in gate-tuned monolayer tungsten ditelluride (WTe2), with features incompatible with the conventional Bardeen-Cooper-Schrieffer (BCS) scenario. The results lead to a novel superconducting phase diagram that is distinguished from other known superconductors. Two distinct gate-tuned quantum phase transitions are observed at the ends of the superconducting dome. We find that quantum fluctuations around the QCP of the underdoped regime are essential for understanding how the monolayer superconductivity is established. The unconventional phase diagram we report here illustrates a previously unknown relation between superconductivity and QCP. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.16699v1-abstract-full').style.display = 'none'; document.getElementById('2501.16699v1-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> 27 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.14969">arXiv:2501.14969</a> <span> [<a href="https://arxiv.org/pdf/2501.14969">pdf</a>, <a href="https://arxiv.org/format/2501.14969">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Crystalline superconductor-semiconductor Josephson junctions for compact superconducting qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Balgley%2C+J">Jesse Balgley</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+J">Jinho Park</a>, <a href="/search/cond-mat?searchtype=author&query=Chu%2C+X">Xuanjing Chu</a>, <a href="/search/cond-mat?searchtype=author&query=Arnault%2C+E+G">Ethan G. Arnault</a>, <a href="/search/cond-mat?searchtype=author&query=Gustafsson%2C+M+V">Martin V. Gustafsson</a>, <a href="/search/cond-mat?searchtype=author&query=Ranzani%2C+L">Leonardo Ranzani</a>, <a href="/search/cond-mat?searchtype=author&query=Holbrook%2C+M">Madisen Holbrook</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Perebeinos%2C+V">Vasili Perebeinos</a>, <a href="/search/cond-mat?searchtype=author&query=Hone%2C+J">James Hone</a>, <a href="/search/cond-mat?searchtype=author&query=Fong%2C+K+C">Kin Chung Fong</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="2501.14969v1-abstract-short" style="display: inline;"> The narrow bandgap of semiconductors allows for thick, uniform Josephson junction barriers, potentially enabling reproducible, stable, and compact superconducting qubits. We study vertically stacked van der Waals Josephson junctions with semiconducting weak links, whose crystalline structures and clean interfaces offer a promising platform for quantum devices. We observe robust Josephson coupling… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.14969v1-abstract-full').style.display = 'inline'; document.getElementById('2501.14969v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.14969v1-abstract-full" style="display: none;"> The narrow bandgap of semiconductors allows for thick, uniform Josephson junction barriers, potentially enabling reproducible, stable, and compact superconducting qubits. We study vertically stacked van der Waals Josephson junctions with semiconducting weak links, whose crystalline structures and clean interfaces offer a promising platform for quantum devices. We observe robust Josephson coupling across 2--12 nm (3--18 atomic layers) of semiconducting WSe$_2$ and, notably, a crossover from proximity- to tunneling-type behavior with increasing weak link thickness. Building on these results, we fabricate a prototype all-crystalline merged-element transmon qubit with transmon frequency and anharmonicity closely matching design parameters. We demonstrate dispersive coupling between this transmon and a microwave resonator, highlighting the potential of crystalline superconductor-semiconductor structures for compact, tailored superconducting quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.14969v1-abstract-full').style.display = 'none'; document.getElementById('2501.14969v1-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> 24 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.12029">arXiv:2501.12029</a> <span> [<a href="https://arxiv.org/pdf/2501.12029">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> </div> </div> <p class="title is-5 mathjax"> Nanoscale functionalization of MoS$_2$ monolayers with DNA origami </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+S">Shen Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+Z">Zhijie Li</a>, <a href="/search/cond-mat?searchtype=author&query=Meggyesi%2C+Z">Zs贸fia Meggyesi</a>, <a href="/search/cond-mat?searchtype=author&query=Erber%2C+E">Elisabeth Erber</a>, <a href="/search/cond-mat?searchtype=author&query=Sikeler%2C+C">Christoph Sikeler</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Baimuratov%2C+A+S">Anvar S. Baimuratov</a>, <a href="/search/cond-mat?searchtype=author&query=Liedl%2C+T">Tim Liedl</a>, <a href="/search/cond-mat?searchtype=author&query=H%C3%B6gele%2C+A">Alexander H枚gele</a>, <a href="/search/cond-mat?searchtype=author&query=Martynenko%2C+I+V">Irina V. Martynenko</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="2501.12029v1-abstract-short" style="display: inline;"> The functionalization of two-dimensional (2D) materials with organic molecules is a promising approach for realizing nanoscale optoelectronic devices with tailored functionalities, such as quantum light generation and p-n junctions. However, achieving control over the molecules' precise positioning on the 2D material remains a significant challenge. Here, we overcome the limitations of solution- a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.12029v1-abstract-full').style.display = 'inline'; document.getElementById('2501.12029v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.12029v1-abstract-full" style="display: none;"> The functionalization of two-dimensional (2D) materials with organic molecules is a promising approach for realizing nanoscale optoelectronic devices with tailored functionalities, such as quantum light generation and p-n junctions. However, achieving control over the molecules' precise positioning on the 2D material remains a significant challenge. Here, we overcome the limitations of solution- and vapor deposition methods and use a DNA origami placement technique to spatially arrange various organic molecules on a chip surface at the single-molecule level with high assembly yields. This versatile method allows for precise patterning of transition metal dichalcogenides (TMDs) with organic molecules, including thiols and fluorescent dyes. We successfully integrated MoS$_2$ monolayers with micron-scale molecule-origami patterns achieving both single photon emission from thiol-induced localized excitons in MoS$_2$ and photoexcitation energy transfer with patterned fluorescent dyes. Our approach offers a pathway for producing complex, tailored 2D inorganic-organic heterostructures with molecular-level control, opening up new possibilities for advanced materials and device design. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.12029v1-abstract-full').style.display = 'none'; document.getElementById('2501.12029v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.11713">arXiv:2501.11713</a> <span> [<a href="https://arxiv.org/pdf/2501.11713">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="Other Condensed Matter">cond-mat.other</span> </div> </div> <p class="title is-5 mathjax"> Quantum confining excitons with electrostatic moir茅 superlattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Gu%2C+L">Liuxin Gu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+L">Lifu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Felsenfeld%2C+S">Sam Felsenfeld</a>, <a href="/search/cond-mat?searchtype=author&query=Ma%2C+R">Rundong Ma</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+S">Suji Park</a>, <a href="/search/cond-mat?searchtype=author&query=Jang%2C+H">Houk Jang</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+Y">You Zhou</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="2501.11713v1-abstract-short" style="display: inline;"> Quantum confining excitons has been a persistent challenge in the pursuit of strong exciton interactions and quantum light generation. Unlike electrons, which can be readily controlled via electric fields, imposing strong nanoscale potentials on excitons to enable quantum confinement has proven challenging. In this study, we utilize piezoresponse force microscopy to image the domain structures of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.11713v1-abstract-full').style.display = 'inline'; document.getElementById('2501.11713v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.11713v1-abstract-full" style="display: none;"> Quantum confining excitons has been a persistent challenge in the pursuit of strong exciton interactions and quantum light generation. Unlike electrons, which can be readily controlled via electric fields, imposing strong nanoscale potentials on excitons to enable quantum confinement has proven challenging. In this study, we utilize piezoresponse force microscopy to image the domain structures of twisted hexagonal boron nitride (hBN), revealing evidence of strong in-plane electric fields at the domain boundaries. By placing a monolayer MoSe2 only one to two nanometers away from the twisted hBN interface, we observe energy splitting of neutral excitons and Fermi polarons by several millielectronvolts at the moir茅 domain boundaries. By directly correlating local structural and optical properties, we attribute such observations to excitons confined in a nanoscale one-dimensional electrostatic potential created by the strong in-plane electric fields at the moir茅 domain boundaries. Intriguingly, this 1D quantum confinement results in pronounced polarization anisotropy in the excitons' reflection and emission, persistent to temperatures as high as ~80 Kelvins. These findings open new avenues for exploring and controlling strongly interacting excitons for classical and quantum optoelectronics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.11713v1-abstract-full').style.display = 'none'; document.getElementById('2501.11713v1-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> 20 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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, 11 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/2501.09124">arXiv:2501.09124</a> <span> [<a href="https://arxiv.org/pdf/2501.09124">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> <p class="title is-5 mathjax"> Landauer resistivity dipole at one dimensional defect revealed via near-field photocurrent nanoscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Falorsi%2C+F">Francesca Falorsi</a>, <a href="/search/cond-mat?searchtype=author&query=Dembecki%2C+M">Marco Dembecki</a>, <a href="/search/cond-mat?searchtype=author&query=Eckel%2C+C">Christian Eckel</a>, <a href="/search/cond-mat?searchtype=author&query=de+Azagra%2C+M+K+M">Monica Kolek Martinez de Azagra</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Statz%2C+M">Martin Statz</a>, <a href="/search/cond-mat?searchtype=author&query=Weitz%2C+R+T">R. Thomas Weitz</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="2501.09124v1-abstract-short" style="display: inline;"> The fundamental question how to describe Ohmic resistance at the nanoscale has been answered by Landauer in his seminal picture of the so-called Landauer resistivity dipole. This picture has been theoretically well understood, however experimentally there are only few studies due to the need for a non-invasive local probe. Here we use the nanometer lateral resolution of near-field photocurrent ima… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.09124v1-abstract-full').style.display = 'inline'; document.getElementById('2501.09124v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.09124v1-abstract-full" style="display: none;"> The fundamental question how to describe Ohmic resistance at the nanoscale has been answered by Landauer in his seminal picture of the so-called Landauer resistivity dipole. This picture has been theoretically well understood, however experimentally there are only few studies due to the need for a non-invasive local probe. Here we use the nanometer lateral resolution of near-field photocurrent imaging to thoroughly characterize a buried monolayer - bilayer graphene interface as an ideal one dimensional defect for the Landauer resistivity dipole. Via systematic tuning of the overall charge carrier density and the current flow we are able to detect the formation of Landauer resistivity dipoles due to charge carrier accumulation around the one dimensional defects. We found that, for Fermi energy values near the charge neutrality point (i.e. at low hole or electron doping), the photocurrent exhibits the same polarity as the applied source-drain voltage, which is consistent with changes in carrier concentration induced by the Landauer resistivity dipoles. This signature is no longer evident at higher charge carrier density in agreement with the performed numerical calculations. Photocurrent nanoscopy can thus serve as non-invasive technique to study local dissipation at hidden interfaces. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.09124v1-abstract-full').style.display = 'none'; document.getElementById('2501.09124v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.06852">arXiv:2501.06852</a> <span> [<a href="https://arxiv.org/pdf/2501.06852">pdf</a>, <a href="https://arxiv.org/ps/2501.06852">ps</a>, <a href="https://arxiv.org/format/2501.06852">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"> Flat Band and Many-body Gap in Chirally Twisted Triple Bilayer Graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lin%2C+W">Wenlu Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+W">Wenxuan Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Cao%2C+S">Shimin Cao</a>, <a href="/search/cond-mat?searchtype=author&query=Liang%2C+M">Miao Liang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+L">Lili Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Gao%2C+J">Jinhua Gao</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+J">Jianhao Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+X">Xiaobo Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Y">Yang Liu</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="2501.06852v1-abstract-short" style="display: inline;"> We experimentally investigate the band structures of chirally twisted triple bilayer graphene. The new kind of moir茅 structure, formed by three pieces of helically stacked Bernal bilayer graphene, has flat bands at charge neutral point based on the continuum approximation. We experimentally confirm the existence of flat bands and directly acquire the gap in-between flat bands as well as between th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06852v1-abstract-full').style.display = 'inline'; document.getElementById('2501.06852v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.06852v1-abstract-full" style="display: none;"> We experimentally investigate the band structures of chirally twisted triple bilayer graphene. The new kind of moir茅 structure, formed by three pieces of helically stacked Bernal bilayer graphene, has flat bands at charge neutral point based on the continuum approximation. We experimentally confirm the existence of flat bands and directly acquire the gap in-between flat bands as well as between the flat bands and dispersive bands from the capacitance measurements. We discover a finite gap even at zero perpendicular electric field, possibly induced by the Coulomb interaction and ferromagnetism. Our quantitative study not only provides solid evidence for the flat-band and interesting physics, but also introduces a quantitative approach to explore phenomena of similar moir茅 systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06852v1-abstract-full').style.display = 'none'; document.getElementById('2501.06852v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.06817">arXiv:2501.06817</a> <span> [<a href="https://arxiv.org/pdf/2501.06817">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> <p class="title is-5 mathjax"> Switching Graphitic Polytypes in Elastically Coupled Islands </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Roy%2C+N">Nirmal Roy</a>, <a href="/search/cond-mat?searchtype=author&query=Atri%2C+S+S">Simon Salleh Atri</a>, <a href="/search/cond-mat?searchtype=author&query=Sharaby%2C+Y">Yoav Sharaby</a>, <a href="/search/cond-mat?searchtype=author&query=Raab%2C+N">Noam Raab</a>, <a href="/search/cond-mat?searchtype=author&query=Yeo%2C+Y">Youngki Yeo</a>, <a href="/search/cond-mat?searchtype=author&query=Kenji%2C+W">Watanabe Kenji</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Shalom%2C+M+B">Moshe Ben Shalom</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="2501.06817v1-abstract-short" style="display: inline;"> Van der Waals polytypes are commensurate configurations of two-dimensional layers with discrete crystalline symmetries and distinct stacking-dependent properties. In graphitic polytypes, the different stacking arrangements of graphene sheets exhibit rich electronic phases, such as intrinsic electric polarizations, orbital magnetizations, superconductivity, and anomalous fractional Hall states. Swi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06817v1-abstract-full').style.display = 'inline'; document.getElementById('2501.06817v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.06817v1-abstract-full" style="display: none;"> Van der Waals polytypes are commensurate configurations of two-dimensional layers with discrete crystalline symmetries and distinct stacking-dependent properties. In graphitic polytypes, the different stacking arrangements of graphene sheets exhibit rich electronic phases, such as intrinsic electric polarizations, orbital magnetizations, superconductivity, and anomalous fractional Hall states. Switching between these metastable periodic configurations by controlling interlayer shifts unlocks intriguing multiferroic responses. Here, we report super-lubricant arrays of polytypes (SLAP) devices, with nanometer-scale islands of Bernal polytypes that switch into Rhombohedral crystals and vice versa under a shear force as low as 6 nano-Newtons. We assemble these four-layer SLAP structures by aligning a pair of graphene bilayers above and under circular cavities in a misaligned spacer layer. Using local current measurements, we detect the shifts between the active bilayers and reveal long-range elastic relaxations outside the cavities that enable efficient nucleation and spontaneous sliding of stacking dislocation inside the islands. We demonstrate configurable, deterministic, and robust polytype switching by confining these boundary strips in narrow cavity channels that connect the islands. Such controlled switching between elastically-coupled single-crystalline islands is appealing for novel multiferroic SlideTronic applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06817v1-abstract-full').style.display = 'none'; document.getElementById('2501.06817v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.06671">arXiv:2501.06671</a> <span> [<a href="https://arxiv.org/pdf/2501.06671">pdf</a>, <a href="https://arxiv.org/format/2501.06671">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> The role of antisymmetric orbitals and electron-electron interactions on the two-particle spin and valley blockade in graphene double quantum dots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=M%C3%B6ller%2C+S">Samuel M枚ller</a>, <a href="/search/cond-mat?searchtype=author&query=Banszerus%2C+L">Luca Banszerus</a>, <a href="/search/cond-mat?searchtype=author&query=Hecker%2C+K">Katrin Hecker</a>, <a href="/search/cond-mat?searchtype=author&query=Dulisch%2C+H">Hubert Dulisch</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Volk%2C+C">Christian Volk</a>, <a href="/search/cond-mat?searchtype=author&query=Stampfer%2C+C">Christoph Stampfer</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="2501.06671v1-abstract-short" style="display: inline;"> We report on an experimental study of spin and valley blockade in two-electron bilayer graphene (BLG) double quantum dots (DQDs) and explore the limits set by asymmetric orbitals and electronelectron interactions. The results obtained from magnetotransport measurements on two-electron BLG DQDs, where the resonant tunneling transport involves both orbital symmetric and antisymmetric two-particle st… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06671v1-abstract-full').style.display = 'inline'; document.getElementById('2501.06671v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.06671v1-abstract-full" style="display: none;"> We report on an experimental study of spin and valley blockade in two-electron bilayer graphene (BLG) double quantum dots (DQDs) and explore the limits set by asymmetric orbitals and electronelectron interactions. The results obtained from magnetotransport measurements on two-electron BLG DQDs, where the resonant tunneling transport involves both orbital symmetric and antisymmetric two-particle states, show a rich level spectrum. We observe a magnetic field tunable spin and valley blockade, which is limited by the orbital splitting, the strength of the electron-electron interaction and the difference in the valley g-factors between the symmetric and antisymmetric twoparticle orbital states. Our conclusions are supported by simulations based on rate equations, which allow the identification of prominent interdot transitions associated with the transition from single to two-particle states observed in the experiment. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06671v1-abstract-full').style.display = 'none'; document.getElementById('2501.06671v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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">16 pages, 11 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/2501.06460">arXiv:2501.06460</a> <span> [<a href="https://arxiv.org/pdf/2501.06460">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> <p class="title is-5 mathjax"> Probing electric field tunable multiband superconductivity in alternating twisted quadralayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Liu%2C+L">Le Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Hong%2C+Y">Yu Hong</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+C">Chengping Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+J">Jundong Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Dong%2C+J">Jingwei Dong</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Du%2C+L">Luojun Du</a>, <a href="/search/cond-mat?searchtype=author&query=Shi%2C+D">Dongxia Shi</a>, <a href="/search/cond-mat?searchtype=author&query=Law%2C+K+T">Kam Tuen Law</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+W">Wei Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+G">Guangyu Zhang</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="2501.06460v1-abstract-short" style="display: inline;"> Alternating twisted multilayer graphene presents a compelling multiband system for exploring superconductivity. Here we investigate robust superconductivity in alternating twisted quadralayer graphene, elucidating carrier contributions from both flat and dispersive bands. The superconductivity is robust, with a strong electrical field tunability, a maximum BKT transition temperature of 1.6 K, and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06460v1-abstract-full').style.display = 'inline'; document.getElementById('2501.06460v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.06460v1-abstract-full" style="display: none;"> Alternating twisted multilayer graphene presents a compelling multiband system for exploring superconductivity. Here we investigate robust superconductivity in alternating twisted quadralayer graphene, elucidating carrier contributions from both flat and dispersive bands. The superconductivity is robust, with a strong electrical field tunability, a maximum BKT transition temperature of 1.6 K, and high critical magnetic fields beyond the Pauli limit. We disentangle the carrier density of Dirac bands and flat bands from the Landau fan diagram. Moreover, we could estimate the flatband Fermi velocity from the obtained high critical current near half filling when superconductivity is killed at finite magnetic fields, and further quantify the superfluid stiffness from the low critical current in the superconducting regime. Our results exhibit the electric field tunable coupling strength within the superconducting phase, revealing unconventional properties with vanishing Fermi velocity and large superfluid stiffness. These phenomena, attributed to substantial quantum metric contributions, offer new insights into the mechanisms underlying unconventional superconductivity in moire systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06460v1-abstract-full').style.display = 'none'; document.getElementById('2501.06460v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.05980">arXiv:2501.05980</a> <span> [<a href="https://arxiv.org/pdf/2501.05980">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="Applied Physics">physics.app-ph</span> </div> </div> <p class="title is-5 mathjax"> Tunable superconductivity coexisting with the anomalous Hall effect in 1T'-WS2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hossain%2C+M+S">Md Shafayat Hossain</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Q">Qi Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Graf%2C+D">David Graf</a>, <a href="/search/cond-mat?searchtype=author&query=Iraola%2C+M">Mikel Iraola</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%BCller%2C+T">Tobias M眉ller</a>, <a href="/search/cond-mat?searchtype=author&query=Mardanya%2C+S">Sougata Mardanya</a>, <a href="/search/cond-mat?searchtype=author&query=Tu%2C+Y">Yi-Hsin Tu</a>, <a href="/search/cond-mat?searchtype=author&query=Lai%2C+Z">Zhuangchai Lai</a>, <a href="/search/cond-mat?searchtype=author&query=Soldini%2C+M+O">Martina O. Soldini</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+S">Siyuan Li</a>, <a href="/search/cond-mat?searchtype=author&query=Yao%2C+Y">Yao Yao</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+Y">Yu-Xiao Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+Z">Zi-Jia Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Litskevich%2C+M">Maksim Litskevich</a>, <a href="/search/cond-mat?searchtype=author&query=Casas%2C+B">Brian Casas</a>, <a href="/search/cond-mat?searchtype=author&query=Cochran%2C+T+A">Tyler A. Cochran</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+X+P">Xian P. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+B">Byunghoon Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Chowdhury%2C+S">Sugata Chowdhury</a>, <a href="/search/cond-mat?searchtype=author&query=Bansil%2C+A">Arun Bansil</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+H">Hua Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+T">Tay-Rong Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Fischer%2C+M">Mark Fischer</a> , et al. (3 additional authors not shown) </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="2501.05980v1-abstract-short" style="display: inline;"> Transition metal dichalcogenides are a family of quasi-two-dimensional materials that display a high technological potential due to their wide range of electronic ground states, e.g., from superconducting to semiconducting, depending on the chemical composition, crystal structure, or electrostatic doping. Here, we unveil that by tuning a single parameter, the hydrostatic pressure P, a cascade of e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.05980v1-abstract-full').style.display = 'inline'; document.getElementById('2501.05980v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.05980v1-abstract-full" style="display: none;"> Transition metal dichalcogenides are a family of quasi-two-dimensional materials that display a high technological potential due to their wide range of electronic ground states, e.g., from superconducting to semiconducting, depending on the chemical composition, crystal structure, or electrostatic doping. Here, we unveil that by tuning a single parameter, the hydrostatic pressure P, a cascade of electronic phase transitions can be induced in the few-layer transition metal dichalcogenide 1T'-WS2, including superconducting, topological, and anomalous Hall effect phases. Specifically, as P increases, we observe a dual phase transition: the suppression of superconductivity with the concomitant emergence of an anomalous Hall effect at P=1.15 GPa. Remarkably, upon further increasing the pressure above 1.6 GPa, we uncover a reentrant superconducting state that emerges out of a state still exhibiting an anomalous Hall effect. This superconducting state shows a marked increase in superconducting anisotropy with respect to the phase observed at ambient pressure, suggesting a different superconducting state with a distinct pairing symmetry. Via first-principles calculations, we demonstrate that the system concomitantly transitions into a strong topological phase with markedly different band orbital characters and Fermi surfaces contributing to the superconductivity. These findings position 1T'-WS2 as a unique, tunable superconductor, wherein superconductivity, anomalous transport, and band features can be tuned through the application of moderate pressures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.05980v1-abstract-full').style.display = 'none'; document.getElementById('2501.05980v1-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, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.04840">arXiv:2501.04840</a> <span> [<a href="https://arxiv.org/pdf/2501.04840">pdf</a>, <a href="https://arxiv.org/format/2501.04840">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="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Direct measurement of the longitudinal exciton dispersion in hBN by resonant inelastic x-ray scattering </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Nicolaou%2C+A">Alessandro Nicolaou</a>, <a href="/search/cond-mat?searchtype=author&query=Ruotsalainen%2C+K">Kari Ruotsalainen</a>, <a href="/search/cond-mat?searchtype=author&query=Susana%2C+L">Laura Susana</a>, <a href="/search/cond-mat?searchtype=author&query=Por%C3%A9e%2C+V">Victor Por茅e</a>, <a href="/search/cond-mat?searchtype=author&query=Tizei%2C+L+G">Luiz Galvao Tizei</a>, <a href="/search/cond-mat?searchtype=author&query=Koskelo%2C+J">Jaakko Koskelo</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Zobelli%2C+A">Alberto Zobelli</a>, <a href="/search/cond-mat?searchtype=author&query=Gatti%2C+M">Matteo Gatti</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="2501.04840v2-abstract-short" style="display: inline;"> We report resonant inelastic X-ray scattering (RIXS) measurements on the prototypical hexagonal boron nitride hBN layered compound. The RIXS results at the B and N K edges have been combined with electron energy loss spectroscopy (EELS) experiments and ab initio calculations within the framework of the Bethe-Salpeter equation of many-body perturbation theory. By means of this tight interplay of di… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04840v2-abstract-full').style.display = 'inline'; document.getElementById('2501.04840v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.04840v2-abstract-full" style="display: none;"> We report resonant inelastic X-ray scattering (RIXS) measurements on the prototypical hexagonal boron nitride hBN layered compound. The RIXS results at the B and N K edges have been combined with electron energy loss spectroscopy (EELS) experiments and ab initio calculations within the framework of the Bethe-Salpeter equation of many-body perturbation theory. By means of this tight interplay of different spectroscopies, the lowest longitudinal exciton of hBN has been identified. Moreover, its qualitatively different dispersions along the $螕$K and the $螕$M directions of the Brillouin zone have been determined. Our study advocates soft X-ray RIXS and EELS to be a promising combination to investigate electronic excitations in materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04840v2-abstract-full').style.display = 'none'; document.getElementById('2501.04840v2-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.04777">arXiv:2501.04777</a> <span> [<a href="https://arxiv.org/pdf/2501.04777">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="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Spectroscopy of the Fractal Hofstadter Energy Spectrum </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Nuckolls%2C+K+P">Kevin P. Nuckolls</a>, <a href="/search/cond-mat?searchtype=author&query=Scheer%2C+M+G">Michael G. Scheer</a>, <a href="/search/cond-mat?searchtype=author&query=Wong%2C+D">Dillon Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Oh%2C+M">Myungchul Oh</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+R+L">Ryan L. Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Herzog-Arbeitman%2C+J">Jonah Herzog-Arbeitman</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Lian%2C+B">Biao Lian</a>, <a href="/search/cond-mat?searchtype=author&query=Yazdani%2C+A">Ali Yazdani</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="2501.04777v1-abstract-short" style="display: inline;"> Hofstadter's butterfly, the predicted energy spectrum for non-interacting electrons confined to a two-dimensional lattice in a magnetic field, is one of the most remarkable fractal structures in nature. At rational ratios of magnetic flux quanta per lattice unit cell, this spectrum shows self-similar distributions of energy levels that reflect its recursive construction. For most materials, Hofsta… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04777v1-abstract-full').style.display = 'inline'; document.getElementById('2501.04777v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.04777v1-abstract-full" style="display: none;"> Hofstadter's butterfly, the predicted energy spectrum for non-interacting electrons confined to a two-dimensional lattice in a magnetic field, is one of the most remarkable fractal structures in nature. At rational ratios of magnetic flux quanta per lattice unit cell, this spectrum shows self-similar distributions of energy levels that reflect its recursive construction. For most materials, Hofstadter's butterfly is predicted under experimental conditions that are unachievable using laboratory-scale magnetic fields. More recently, electrical transport studies have provided evidence for Hofstadter's butterfly in materials engineered to have artificially large lattice constants, such as those with moir茅 superlattices. Yet to-date, direct spectroscopy of the fractal energy spectrum predicted by Hofstadter nearly 50 years ago has remained out of reach. Here we use high-resolution scanning tunneling microscopy / spectroscopy (STM / STS) to probe the flat electronic bands in twisted bilayer graphene near the predicted second magic angle, an ideal setting for spectroscopic studies of Hofstadter's spectrum. Our study shows the fractionalization of flat moir茅 bands into discrete Hofstadter subbands and discerns experimental signatures of self-similarity of this spectrum. Moreover, our measurements uncover a spectrum that evolves dynamically with electron density, displaying phenomena beyond that of Hofstadter's original model due to the combined effects of strong correlations, Coulomb interactions, and the quantum degeneracy of electrons in twisted bilayer graphene. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04777v1-abstract-full').style.display = 'none'; document.getElementById('2501.04777v1-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> 8 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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">20 pages, 5 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/2501.03193">arXiv:2501.03193</a> <span> [<a href="https://arxiv.org/pdf/2501.03193">pdf</a>, <a href="https://arxiv.org/format/2501.03193">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> <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"> Universality in quantum critical flow of charge and heat in ultra-clean graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Majumdar%2C+A">Aniket Majumdar</a>, <a href="/search/cond-mat?searchtype=author&query=Chadha%2C+N">Nisarg Chadha</a>, <a href="/search/cond-mat?searchtype=author&query=Pal%2C+P">Pritam Pal</a>, <a href="/search/cond-mat?searchtype=author&query=Gugnani%2C+A">Akash Gugnani</a>, <a href="/search/cond-mat?searchtype=author&query=Ghawri%2C+B">Bhaskar Ghawri</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Mukerjee%2C+S">Subroto Mukerjee</a>, <a href="/search/cond-mat?searchtype=author&query=Ghosh%2C+A">Arindam Ghosh</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="2501.03193v1-abstract-short" style="display: inline;"> Close to the Dirac point, graphene is expected to exist in quantum critical Dirac fluid state, where the flow of both charge and heat can be described with a dc electrical conductivity $蟽_\mathrm{Q}$, and thermodynamic variables such as the entropy and enthalpy densities. Although the fluid-like viscous flow of charge is frequently reported in state-of-the-art graphene devices, the value of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.03193v1-abstract-full').style.display = 'inline'; document.getElementById('2501.03193v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.03193v1-abstract-full" style="display: none;"> Close to the Dirac point, graphene is expected to exist in quantum critical Dirac fluid state, where the flow of both charge and heat can be described with a dc electrical conductivity $蟽_\mathrm{Q}$, and thermodynamic variables such as the entropy and enthalpy densities. Although the fluid-like viscous flow of charge is frequently reported in state-of-the-art graphene devices, the value of $蟽_\mathrm{Q}$, predicted to be quantized and determined only by the universality class of the critical point, has not been established experimentally so far. Here we have discerned the quantum critical universality in graphene transport by combining the electrical ($蟽$) and thermal ($魏_\mathrm{e}$) conductivities in very high-quality devices close to the Dirac point. We find that $蟽$ and $魏_\mathrm{e}$ are inversely related, as expected from relativistic hydrodynamics, and $蟽_\mathrm{Q}$ converges to $\approx (4\pm 1)\times e^2/h$ for multiple devices, where $e$ and $h$ are the electronic charge and the Planck's constant, respectively. We also observe, (1) a giant violation of the Wiedemann-Franz law where the effective Lorentz number exceeds the semiclassical value by more than 200 times close to the Dirac point at low temperatures, and (2) the effective dynamic viscosity ($畏_\mathrm{th}$) in the thermal regime approaches the holographic limit $畏_\mathrm{th}/s_\mathrm{th} \rightarrow \hbar/4蟺k_\mathrm{B}$ within a factor of four in the cleanest devices close to the room temperature, where $s_\mathrm{th}$ and $k_\mathrm{B}$ are the thermal entropy density and the Boltzmann constant, respectively. Our experiment addresses the missing piece in the potential of high-quality graphene as a testing bed for some of the unifying concepts in physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.03193v1-abstract-full').style.display = 'none'; document.getElementById('2501.03193v1-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, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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">6 pages, 10 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/2501.02525">arXiv:2501.02525</a> <span> [<a href="https://arxiv.org/pdf/2501.02525">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="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Time-reversal symmetry breaking fractional quantum spin Hall insulator in moir茅 MoTe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kang%2C+K">Kaifei Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Qiu%2C+Y">Yichen Qiu</a>, <a href="/search/cond-mat?searchtype=author&query=Shen%2C+B">Bowen Shen</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+K">Kihong Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Xia%2C+Z">Zhengchao Xia</a>, <a href="/search/cond-mat?searchtype=author&query=Zeng%2C+Y">Yihang Zeng</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Shan%2C+J">Jie Shan</a>, <a href="/search/cond-mat?searchtype=author&query=Mak%2C+K+F">Kin Fai Mak</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="2501.02525v3-abstract-short" style="display: inline;"> Twisted bilayer transition metal dichalcogenide semiconductors, which support flat Chern bands with enhanced interaction effects, realize a platform for fractional Chern insulators and fractional quantum spin Hall (FQSH) insulators. A recent experiment has reported the emergence of a FQSH insulator protected by spin-Sz conservation at a moir茅 lattice filling factor 谓=3 in 2.1-degree twisted bilaye… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.02525v3-abstract-full').style.display = 'inline'; document.getElementById('2501.02525v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.02525v3-abstract-full" style="display: none;"> Twisted bilayer transition metal dichalcogenide semiconductors, which support flat Chern bands with enhanced interaction effects, realize a platform for fractional Chern insulators and fractional quantum spin Hall (FQSH) insulators. A recent experiment has reported the emergence of a FQSH insulator protected by spin-Sz conservation at a moir茅 lattice filling factor 谓=3 in 2.1-degree twisted bilayer MoTe2. Theoretical studies have proposed both time-reversal symmetric and asymmetric ground states as possible candidates for the observed FQSH insulator, but the nature of the state remains unexplored. Here we report the observation of spontaneous time-reversal symmetry breaking at generic fillings in 2.1-degree twisted bilayer MoTe2 from 谓<1 all the way to 谓>6 except at 谓=2, 4, and 6. Although zero Hall response is observed at 谓=3 for magnetic fields higher than 20 mT, a finite anomalous Hall response accompanied by a magnetic hysteresis is observed at lower magnetic fields, demonstrating spontaneous time-reversal symmetry breaking. Our work shows the tendency towards ferromagnetism by doping the first three pairs of conjugate Chern bands in the material; it also sheds light on the nature of the FQSH insulator at 谓=3. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.02525v3-abstract-full').style.display = 'none'; document.getElementById('2501.02525v3-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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">In Supplemental Figure 4, we contrast a 2.6-degree device with a 2.1-degree device</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.02372">arXiv:2501.02372</a> <span> [<a href="https://arxiv.org/pdf/2501.02372">pdf</a>, <a href="https://arxiv.org/format/2501.02372">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 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.134.036901">10.1103/PhysRevLett.134.036901 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Valley-mediated singlet- and triplet-polaron interactions and quantum dynamics in a doped WSe$_2$ monolayer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ni%2C+Y">Yue Ni</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+D">Di Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Liang%2C+D">Danfu Liang</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+A">Albert Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+X">Xiaohui Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Sampson%2C+K">Kevin Sampson</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Z">Zhida Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Quan%2C+J">Jianmin Quan</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Efimkin%2C+D+K">Dmitry K. Efimkin</a>, <a href="/search/cond-mat?searchtype=author&query=Levinsen%2C+J">Jesper Levinsen</a>, <a href="/search/cond-mat?searchtype=author&query=Parish%2C+M+M">Meera M. Parish</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+X">Xiaoqin Li</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="2501.02372v1-abstract-short" style="display: inline;"> In doped transition metal dichalcogenides, optically created excitons (bound electron-hole pairs) can strongly interact with a Fermi sea of electrons to form Fermi polaron quasiparticles. When there are two distinct Fermi seas, as is the case in WSe$_2$, there are two flavors of lowest-energy (attractive) polarons -- singlet and triplet -- where the exciton is coupled to the Fermi sea in the same… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.02372v1-abstract-full').style.display = 'inline'; document.getElementById('2501.02372v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.02372v1-abstract-full" style="display: none;"> In doped transition metal dichalcogenides, optically created excitons (bound electron-hole pairs) can strongly interact with a Fermi sea of electrons to form Fermi polaron quasiparticles. When there are two distinct Fermi seas, as is the case in WSe$_2$, there are two flavors of lowest-energy (attractive) polarons -- singlet and triplet -- where the exciton is coupled to the Fermi sea in the same or opposite valley, respectively. Using two-dimensional coherent electronic spectroscopy, we analyze how their quantum decoherence evolves with doping density and determine the condition under which stable Fermi polarons form. Because of the large oscillator strength associated with these resonances, intrinsic quantum dynamics of polarons as well as valley coherence between coupled singlet- and triplet polarons occur on sub-picosecond time scales. Surprisingly, we find that a dark-to-bright state conversion process leads to a particularly long-lived singlet polaron valley polarization, persisting up to 200-800 ps. Valley coherence between the singlet- and triplet polaron is correlated with their energy fluctuations. Our finding provides valuable guidance for the electrical and optical control of spin and valley indexes in atomically thin semiconductors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.02372v1-abstract-full').style.display = 'none'; document.getElementById('2501.02372v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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">4 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 134.3 (2025): 036901 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.01319">arXiv:2501.01319</a> <span> [<a href="https://arxiv.org/pdf/2501.01319">pdf</a>, <a href="https://arxiv.org/format/2501.01319">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"> Launching Focused and Spatially Confined Phonon-Polaritons in Hexagonal Boron Nitride </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Borodin%2C+B">Bogdan Borodin</a>, <a href="/search/cond-mat?searchtype=author&query=Lepeshov%2C+S">Sergey Lepeshov</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Stepanov%2C+P">Petr Stepanov</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="2501.01319v1-abstract-short" style="display: inline;"> Launching and focusing phonon-polaritons present novel opportunities for low-loss guiding of subdiffractionally confined light at the nanoscale. Despite significant efforts to improve control in polaritonic media, focused and spatially confined phonon-polariton waves have only been achieved in the in-plane anisotropic crystals (such as MoO$_3$) and remain elusive in the in-plane isotropic crystals… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.01319v1-abstract-full').style.display = 'inline'; document.getElementById('2501.01319v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.01319v1-abstract-full" style="display: none;"> Launching and focusing phonon-polaritons present novel opportunities for low-loss guiding of subdiffractionally confined light at the nanoscale. Despite significant efforts to improve control in polaritonic media, focused and spatially confined phonon-polariton waves have only been achieved in the in-plane anisotropic crystals (such as MoO$_3$) and remain elusive in the in-plane isotropic crystals (such as hexagonal boron nitride). In this study, we present a previously unexplored approach to launching phonon-polaritons by employing hBN subwavelength resonators coupled to gold nanoantennas. The integration of gold nanoantennas enables efficient coupling to the far-field component of mid-infrared light, while the geometry of the resonators defines the wavefront curvature, spatial confinement, and focusing of the launched polaritons. Using standard lithographic protocols, we achieve strong field enhancement and resonant mode localization, generating phonon-polaritons with precise spatial definition. Scattering-type scanning near-field optical microscopy reveals the real-space optical contrast of these modes. This innovative and practical approach introduces a new paradigm for fabricating nanoresonators that actively launch and focus phonon-polaritons, opening avenues for advanced nanophotonic devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.01319v1-abstract-full').style.display = 'none'; document.getElementById('2501.01319v1-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, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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 pages, 4 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/2412.20334">arXiv:2412.20334</a> <span> [<a href="https://arxiv.org/pdf/2412.20334">pdf</a>, <a href="https://arxiv.org/format/2412.20334">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"> Magnetic Hofstadter cascade in a twisted semiconductor homobilayer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Foutty%2C+B+A">Benjamin A. Foutty</a>, <a href="/search/cond-mat?searchtype=author&query=Reddy%2C+A+P">Aidan P. Reddy</a>, <a href="/search/cond-mat?searchtype=author&query=Kometter%2C+C+R">Carlos R. Kometter</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Devakul%2C+T">Trithep Devakul</a>, <a href="/search/cond-mat?searchtype=author&query=Feldman%2C+B+E">Benjamin E. Feldman</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="2412.20334v1-abstract-short" style="display: inline;"> Transition metal dichalcogenide moir茅 homobilayers have emerged as a platform in which magnetism, strong correlations, and topology are intertwined. In a large magnetic field, the energetic alignment of states with different spin in these systems is dictated by both strong Zeeman splitting and the structure of the Hofstadter's butterfly spectrum, yet the latter has been difficult to probe experime… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.20334v1-abstract-full').style.display = 'inline'; document.getElementById('2412.20334v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.20334v1-abstract-full" style="display: none;"> Transition metal dichalcogenide moir茅 homobilayers have emerged as a platform in which magnetism, strong correlations, and topology are intertwined. In a large magnetic field, the energetic alignment of states with different spin in these systems is dictated by both strong Zeeman splitting and the structure of the Hofstadter's butterfly spectrum, yet the latter has been difficult to probe experimentally. Here we conduct local thermodynamic measurements of twisted WSe$_2$ homobilayers that reveal a cascade of magnetic phase transitions. We understand these transitions as the filling of individual Hofstadter subbands, allowing us to extract the structure and connectivity of the Hofstadter spectrum of a single spin. The onset of magnetic transitions is independent of twist angle, indicating that the exchange interactions of the component layers are only weakly modified by the moir茅 potential. In contrast, the magnetic transitions are associated with stark changes in the insulating states at commensurate filling. Our work achieves a spin-resolved measurement of Hofstadter's butterfly despite overlapping states, and it disentangles the role of material and moir茅 effects on the nature of the correlated ground states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.20334v1-abstract-full').style.display = 'none'; document.getElementById('2412.20334v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.19886">arXiv:2412.19886</a> <span> [<a href="https://arxiv.org/pdf/2412.19886">pdf</a>, <a href="https://arxiv.org/format/2412.19886">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> <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"> Aharonov-Bohm Interference in Even-Denominator Fractional Quantum Hall States </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J">Jehyun Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Dev%2C+H">Himanshu Dev</a>, <a href="/search/cond-mat?searchtype=author&query=Shaer%2C+A">Amit Shaer</a>, <a href="/search/cond-mat?searchtype=author&query=Kumar%2C+R">Ravi Kumar</a>, <a href="/search/cond-mat?searchtype=author&query=Ilin%2C+A">Alexey Ilin</a>, <a href="/search/cond-mat?searchtype=author&query=Haug%2C+A">Andr茅 Haug</a>, <a href="/search/cond-mat?searchtype=author&query=Iskoz%2C+S">Shelly Iskoz</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Mross%2C+D+F">David F. Mross</a>, <a href="/search/cond-mat?searchtype=author&query=Stern%2C+A">Ady Stern</a>, <a href="/search/cond-mat?searchtype=author&query=Ronen%2C+Y">Yuval Ronen</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="2412.19886v1-abstract-short" style="display: inline;"> Position exchange of non-Abelian anyons affects the quantum state of their system in a topologically-protected way. Their expected manifestations in even-denominator fractional quantum Hall (FQH) systems offer the opportunity to directly study their unique statistical properties in interference experiments. In this work, we present the observation of coherent Aharonov-Bohm interference at two even… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.19886v1-abstract-full').style.display = 'inline'; document.getElementById('2412.19886v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.19886v1-abstract-full" style="display: none;"> Position exchange of non-Abelian anyons affects the quantum state of their system in a topologically-protected way. Their expected manifestations in even-denominator fractional quantum Hall (FQH) systems offer the opportunity to directly study their unique statistical properties in interference experiments. In this work, we present the observation of coherent Aharonov-Bohm interference at two even-denominator states in high-mobility bilayer graphene-based van der Waals heterostructures by employing the Fabry-P茅rot interferometry (FPI) technique. Operating the interferometer at a constant filling factor, we observe an oscillation period corresponding to two flux quanta inside the interference loop, $螖桅=2桅_0$, at which the interference does not carry signatures of non-Abelian statistics. The absence of the expected periodicity of $螖桅=4桅_0$ may indicate that the interfering quasiparticles carry the charge $e^* = \frac{1}{2}e$ or that interference of $e^* = \frac{1}{4}e$ quasiparticles is thermally smeared. Interestingly, at two hole-conjugate states, we also observe oscillation periods of half the expected value, indicating interference of $e^* = \frac{2}{3}e$ quasiparticles instead of $e^* = \frac{1}{3}e$. To probe statistical phase contributions, we operated the FPI with controlled deviations of the filling factor, thereby introducing fractional quasiparticles inside the interference loop. The resulting changes to the interference patterns at both half-filled states indicate that the additional bulk quasiparticles carry the fundamental charge $e^*=\frac{1}{4}e$, as expected for non-Abelian anyons. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.19886v1-abstract-full').style.display = 'none'; document.getElementById('2412.19886v1-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> 27 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.18763">arXiv:2412.18763</a> <span> [<a href="https://arxiv.org/pdf/2412.18763">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"> Unusual topological polar texture in moir茅 ferroelectrics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Li%2C+Y">Yuhao Li</a>, <a href="/search/cond-mat?searchtype=author&query=Wei%2C+Y">Yuanhao Wei</a>, <a href="/search/cond-mat?searchtype=author&query=Guo%2C+R">Ruiping Guo</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y">Yifei Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+H">Hanhao Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Shi%2C+Y">Yan Shi</a>, <a href="/search/cond-mat?searchtype=author&query=Shi%2C+Y">Yi Shi</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+C">Chong Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Fei%2C+Z">Zaiyao Fei</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="2412.18763v1-abstract-short" style="display: inline;"> Topological polar textures in ferroelectrics have attracted significant interest for their potential for energy-efficient and high-density data storage and processing. Among these, polar merons and antimerons are predicted in strained and twisted bilayers of inversion symmetry broken systems. However, experimental observation of these polar textures within twisted two-dimensional van der Waals (2D… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.18763v1-abstract-full').style.display = 'inline'; document.getElementById('2412.18763v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.18763v1-abstract-full" style="display: none;"> Topological polar textures in ferroelectrics have attracted significant interest for their potential for energy-efficient and high-density data storage and processing. Among these, polar merons and antimerons are predicted in strained and twisted bilayers of inversion symmetry broken systems. However, experimental observation of these polar textures within twisted two-dimensional van der Waals (2D vdW) materials remains challenging. Here, we utilize vector piezoresponse force microscopy (PFM) to reconstruct the polarization fields in R-type marginally twisted hexagonal boron nitride (hBN). We observe alternating out-of-plane (OOP) polarizations at domain regions and in-plane (IP) vortex-like polarization patterns along domain walls (DWs), indicative of a network of polar merons and antimerons. Notably, the OOP polarization exhibits three polarity reversals across a DW. Similar polar textures are identified in marginally twisted MoSe2 and WSe2 homobilayers. Our theoretical simulations attribute these unusual polarization reversals near the DWs to the competition between moir茅 ferroelectricity and piezoelectricity. These results provide experimental evidence of complex polar textures in moir茅 ferroelectrics, offering new insights into the electronic band topology in twisted transition metal dichalcogenides (TMDCs). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.18763v1-abstract-full').style.display = 'none'; document.getElementById('2412.18763v1-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> 24 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.18000">arXiv:2412.18000</a> <span> [<a href="https://arxiv.org/pdf/2412.18000">pdf</a>, <a href="https://arxiv.org/format/2412.18000">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"> Entropy spectroscopy of a bilayer graphene quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Adam%2C+C">Christoph Adam</a>, <a href="/search/cond-mat?searchtype=author&query=Duprez%2C+H">Hadrien Duprez</a>, <a href="/search/cond-mat?searchtype=author&query=Lehmann%2C+N">Natalie Lehmann</a>, <a href="/search/cond-mat?searchtype=author&query=Yglesias%2C+A">Antoni Yglesias</a>, <a href="/search/cond-mat?searchtype=author&query=Cances%2C+S">Solenn Cances</a>, <a href="/search/cond-mat?searchtype=author&query=Ruckriegel%2C+M+J">Max Josef Ruckriegel</a>, <a href="/search/cond-mat?searchtype=author&query=Masseroni%2C+M">Michele Masseroni</a>, <a href="/search/cond-mat?searchtype=author&query=Tong%2C+C">Chuyao Tong</a>, <a href="/search/cond-mat?searchtype=author&query=Denisov%2C+A+O">Artem Olegovich Denisov</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W+W">Wei Wister Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Kealhofer%2C+D">David Kealhofer</a>, <a href="/search/cond-mat?searchtype=author&query=Garreis%2C+R">Rebekka Garreis</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Ensslin%2C+K">Klaus Ensslin</a>, <a href="/search/cond-mat?searchtype=author&query=Ihn%2C+T">Thomas Ihn</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="2412.18000v1-abstract-short" style="display: inline;"> We measure the entropy change of charge transitions in an electrostatically defined quantum dot in bilayer graphene. Entropy provides insights into the equilibrium thermodynamic properties of both ground and excited states beyond transport measurements. For the one-carrier regime, the obtained entropy shows that the ground state has a two-fold degeneracy lifted by an out-of-plane magnetic field. T… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.18000v1-abstract-full').style.display = 'inline'; document.getElementById('2412.18000v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.18000v1-abstract-full" style="display: none;"> We measure the entropy change of charge transitions in an electrostatically defined quantum dot in bilayer graphene. Entropy provides insights into the equilibrium thermodynamic properties of both ground and excited states beyond transport measurements. For the one-carrier regime, the obtained entropy shows that the ground state has a two-fold degeneracy lifted by an out-of-plane magnetic field. This observation is in agreement with previous direct transport measurements and confirms the applicability of this novel method. For the two-carrier regime, the extracted entropy indicates a non-degenerate ground state at zero magnetic field, contrary to previous studies suggesting a three-fold degeneracy. We attribute the degeneracy lifting to the effect of Kane-Mele type spin-orbit interaction on the two-carrier ground state, which has not been observed before. Our work demonstrates the validity and efficacy of entropy measurements as a unique, supplementary experimental tool to investigate the degeneracy of the ground state in quantum devices build in materials such as graphene. This technique, applied to exotic systems with fractional ground state entropies, will be a powerful tool in the study of quantum matter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.18000v1-abstract-full').style.display = 'none'; document.getElementById('2412.18000v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">17 pages, 9 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/2412.12703">arXiv:2412.12703</a> <span> [<a href="https://arxiv.org/pdf/2412.12703">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/10.1021/acs.nanolett.4c05062">10.1021/acs.nanolett.4c05062 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optical detection of the sliding ferroelectric switching in hBN with a WSe2 monolayer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Roux%2C+S">S茅bastien Roux</a>, <a href="/search/cond-mat?searchtype=author&query=Frauni%C3%A9%2C+J">Jules Frauni茅</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Lassagne%2C+B">Benjamin Lassagne</a>, <a href="/search/cond-mat?searchtype=author&query=Robert%2C+C">Cedric Robert</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="2412.12703v1-abstract-short" style="display: inline;"> When two BN layers are stacked in parallel in an AB or BA arrangement, a spontaneous out-of-plane electric polarization arises due to charge transfer in the out-of-plane B-N bonds. The ferroelectric switching from AB to BA (or BA to AB) can be achieved with a relatively small out-of-plane electric field through the in-plane sliding of one atomic layer over the other. However, the optical detection… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12703v1-abstract-full').style.display = 'inline'; document.getElementById('2412.12703v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.12703v1-abstract-full" style="display: none;"> When two BN layers are stacked in parallel in an AB or BA arrangement, a spontaneous out-of-plane electric polarization arises due to charge transfer in the out-of-plane B-N bonds. The ferroelectric switching from AB to BA (or BA to AB) can be achieved with a relatively small out-of-plane electric field through the in-plane sliding of one atomic layer over the other. However, the optical detection of such ferroelectric switching in hBN has not yet been demonstrated. In this study, we utilize an adjacent WSe2 monolayer to detect the ferroelectric switching in BN. This dynamic coupling between a 2D ferroelectric and a 2D semiconductor allows for the fundamental investigation of the ferroelectric material using a non-destructive, local optical probe, offering promising applications for compact and non-volatile memory devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12703v1-abstract-full').style.display = 'none'; document.getElementById('2412.12703v1-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> 17 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.12344">arXiv:2412.12344</a> <span> [<a href="https://arxiv.org/pdf/2412.12344">pdf</a>, <a href="https://arxiv.org/format/2412.12344">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="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"> Field-Resilient Supercurrent Diode in a Multiferroic Josephson Junction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yang%2C+H">Hung-Yu Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Cuozzo%2C+J+J">Joseph J. Cuozzo</a>, <a href="/search/cond-mat?searchtype=author&query=Bokka%2C+A+J">Anand Johnson Bokka</a>, <a href="/search/cond-mat?searchtype=author&query=Qiu%2C+G">Gang Qiu</a>, <a href="/search/cond-mat?searchtype=author&query=Eckberg%2C+C">Christopher Eckberg</a>, <a href="/search/cond-mat?searchtype=author&query=Lyu%2C+Y">Yanfeng Lyu</a>, <a href="/search/cond-mat?searchtype=author&query=Huyan%2C+S">Shuyuan Huyan</a>, <a href="/search/cond-mat?searchtype=author&query=Chu%2C+C">Ching-Wu Chu</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+K+L">Kang L. Wang</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="2412.12344v1-abstract-short" style="display: inline;"> The research on supercurrent diodes has surged rapidly due to their potential applications in electronic circuits at cryogenic temperatures. To unlock this functionality, it is essential to find supercurrent diodes that can work consistently at zero magnetic field and under ubiquitous stray fields generated in electronic circuits. However, a supercurrent diode with robust field tolerance is curren… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12344v1-abstract-full').style.display = 'inline'; document.getElementById('2412.12344v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.12344v1-abstract-full" style="display: none;"> The research on supercurrent diodes has surged rapidly due to their potential applications in electronic circuits at cryogenic temperatures. To unlock this functionality, it is essential to find supercurrent diodes that can work consistently at zero magnetic field and under ubiquitous stray fields generated in electronic circuits. However, a supercurrent diode with robust field tolerance is currently lacking. Here, we demonstrate a field-resilient supercurrent diode by incorporating a multiferroic material into a Josephson junction. We first observed a pronounced supercurrent diode effect at zero magnetic field. More importantly, the supercurrent rectification persists over a wide and bipolar magnetic field range beyond industrial standards for field tolerance. By theoretically modeling a multiferroic Josephson junction, we unveil that the interplay between spin-orbit coupling and multiferroicity underlies the unusual field resilience of the observed diode effect. This work introduces multiferroic Josephson junctions as a new field-resilient superconducting device for cryogenic electronics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12344v1-abstract-full').style.display = 'none'; document.getElementById('2412.12344v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">Preprint, 33 pages, 4 main figures, 10 extended data 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/2412.11135">arXiv:2412.11135</a> <span> [<a href="https://arxiv.org/pdf/2412.11135">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> </div> </div> <p class="title is-5 mathjax"> Competing Orbital Magnetism and Superconductivity in electrostatically defined Josephson Junctions of Alternating Twisted Trilayer Graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bhardwaj%2C+V">Vishal Bhardwaj</a>, <a href="/search/cond-mat?searchtype=author&query=Rajagopal%2C+L">Lekshmi Rajagopal</a>, <a href="/search/cond-mat?searchtype=author&query=Arici%2C+L">Lorenzo Arici</a>, <a href="/search/cond-mat?searchtype=author&query=Bocarsly%2C+M">Matan Bocarsly</a>, <a href="/search/cond-mat?searchtype=author&query=Ilin%2C+A">Alexey Ilin</a>, <a href="/search/cond-mat?searchtype=author&query=Shavit%2C+G">Gal Shavit</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Oreg%2C+Y">Yuval Oreg</a>, <a href="/search/cond-mat?searchtype=author&query=Holder%2C+T">Tobias Holder</a>, <a href="/search/cond-mat?searchtype=author&query=Ronen%2C+Y">Yuval Ronen</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="2412.11135v2-abstract-short" style="display: inline;"> The coexistence of superconductivity and magnetism within a single material system represents a long-standing goal in condensed matter physics. Van der Waals-based moir茅 superlattices provide an exceptional platform for exploring competing and coexisting broken symmetry states. Alternating twisted trilayer graphene (TTG) exhibits robust superconductivity at the magic angle of 1.57掳 and 1.3掳, with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.11135v2-abstract-full').style.display = 'inline'; document.getElementById('2412.11135v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.11135v2-abstract-full" style="display: none;"> The coexistence of superconductivity and magnetism within a single material system represents a long-standing goal in condensed matter physics. Van der Waals-based moir茅 superlattices provide an exceptional platform for exploring competing and coexisting broken symmetry states. Alternating twisted trilayer graphene (TTG) exhibits robust superconductivity at the magic angle of 1.57掳 and 1.3掳, with suppression at intermediate twist angles. In this study, we investigate the intermediate regime and uncover evidence of orbital magnetism. As previously reported, superconductivity is suppressed near the charge neutrality point (CNP) and emerges at larger moir茅 fillings. Conversely, we find orbital magnetism most substantial near the CNP, diminishing as superconductivity develops. This complementary behavior is similarly observed in the displacement field phase space, highlighting a competitive interplay between the two phases. Utilizing gate-defined Josephson junctions, we probe orbital magnetism by electrostatically tuning the weak links into the magnetic phase, revealing an asymmetric Fraunhofer interference pattern. The estimated orbital ferromagnetic ordering temperature is approximately half the superconducting critical temperature, coinciding with the onset of Fraunhofer asymmetry. Our findings suggest that the observed orbital magnetism is driven by valley polarization and is distinct from the anomalous Hall effect reported at integer fillings in twisted graphene systems. These results offer insights into the interplay between superconductivity and magnetism in moir茅 superlattices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.11135v2-abstract-full').style.display = 'none'; document.getElementById('2412.11135v2-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> 27 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">28 pages, 4 main figures, 5 extended figures, 11 supplementary 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/2412.10640">arXiv:2412.10640</a> <span> [<a href="https://arxiv.org/pdf/2412.10640">pdf</a>, <a href="https://arxiv.org/format/2412.10640">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Fermi Velocity Dependent Critical Current in Ballistic Bilayer Graphene Josephson Junctions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sharma%2C+A">Amis Sharma</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+C">Chun-Chia Chen</a>, <a href="/search/cond-mat?searchtype=author&query=McCourt%2C+J">Jordan McCourt</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Amet%2C+F">Francois Amet</a>, <a href="/search/cond-mat?searchtype=author&query=Finkelstein%2C+G">Gleb Finkelstein</a>, <a href="/search/cond-mat?searchtype=author&query=Borzenets%2C+I">Ivan Borzenets</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="2412.10640v1-abstract-short" style="display: inline;"> We perform transport measurements on proximitized, ballistic, bilayer graphene Josephson junctions (BGJJs) in the intermediate-to-long junction regime ($L>尉$). We measure the device's differential resistance as a function of bias current and gate voltage for a range of different temperatures. The extracted critical current $I_{C}$ follows an exponential trend with temperature:… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.10640v1-abstract-full').style.display = 'inline'; document.getElementById('2412.10640v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.10640v1-abstract-full" style="display: none;"> We perform transport measurements on proximitized, ballistic, bilayer graphene Josephson junctions (BGJJs) in the intermediate-to-long junction regime ($L>尉$). We measure the device's differential resistance as a function of bias current and gate voltage for a range of different temperatures. The extracted critical current $I_{C}$ follows an exponential trend with temperature: $ \exp(-k_{B} T/ 未E)$. Here $未E = \hbar 谓_F /2蟺L $: an expected trend for intermediate-to-long junctions. From $未E$, we determine the Fermi velocity of the bilayer graphene, which is found to increase with gate voltage. Simultaneously, we show the carrier density dependence of $未E$, which is attributed to the quadratic dispersion of bilayer graphene. This is in contrast to single layer graphene Josephson junctions, where $未E$ and the Fermi velocity are independent of the carrier density. The carrier density dependence in BGJJs allows for additional tuning parameters in graphene-based Josephson Junction devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.10640v1-abstract-full').style.display = 'none'; document.getElementById('2412.10640v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.10114">arXiv:2412.10114</a> <span> [<a href="https://arxiv.org/pdf/2412.10114">pdf</a>, <a href="https://arxiv.org/ps/2412.10114">ps</a>, <a href="https://arxiv.org/format/2412.10114">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> <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="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Large trion binding energy in monolayer WS$_2$ via strain-enhanced electron-phonon coupling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Waheed%2C+Y">Yunus Waheed</a>, <a href="/search/cond-mat?searchtype=author&query=Shit%2C+S">Sumitra Shit</a>, <a href="/search/cond-mat?searchtype=author&query=Surendran%2C+J+T">Jithin T Surendran</a>, <a href="/search/cond-mat?searchtype=author&query=Prasad%2C+I+D">Indrajeet D Prasad</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Kumar%2C+S">Santosh Kumar</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="2412.10114v1-abstract-short" style="display: inline;"> Transition metal dichalcogenides and related layered materials in their monolayer and a few layers thicknesses regime provide a promising optoelectronic platform for exploring the excitonic- and many-body physics. Strain engineering has emerged as a potent technique for tuning the excitonic properties favorable for exciton-based devices. We have investigated the effects of nanoparticle-induced loc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.10114v1-abstract-full').style.display = 'inline'; document.getElementById('2412.10114v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.10114v1-abstract-full" style="display: none;"> Transition metal dichalcogenides and related layered materials in their monolayer and a few layers thicknesses regime provide a promising optoelectronic platform for exploring the excitonic- and many-body physics. Strain engineering has emerged as a potent technique for tuning the excitonic properties favorable for exciton-based devices. We have investigated the effects of nanoparticle-induced local strain on the optical properties of exciton, $X^0$, and trion, $X^\text{-}$, in monolayer WS$_2$. Biaxial tensile strain up to 2.0% was quantified and verified by monitoring the changes in three prominent Raman modes of WS$_2$: E${^1_{2g}}$($螕$), A$_{1g}$, and 2LA(M). We obtained a remarkable increase of 34 meV in $X^\text{-}$ binding energy with an average tuning rate of 17.5 $\pm$ 2.5 meV/% strain across all the samples irrespective of the surrounding dielectric environment of monolayer WS$_2$ and the sample preparation conditions. At the highest tensile strain of $\approx$2%, we have achieved the largest binding energy $\approx$100 meV for $X^\text{-}$, leading to its enhanced emission intensity and thermal stability. By investigating strain-induced linewidth broadening and deformation potentials of both $X^0$ and $X^\text{-}$ emission, we elucidate that the increase in $X^\text{-}$ binding energy is due to strain-enhanced electron-phonon coupling. This work holds relevance for future $X^\text{-}$-based nano-opto-electro-mechanical systems and devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.10114v1-abstract-full').style.display = 'none'; document.getElementById('2412.10114v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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 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/2412.09985">arXiv:2412.09985</a> <span> [<a href="https://arxiv.org/pdf/2412.09985">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"> Switchable Chern insulator, isospin competitions and charge density waves in rhombohedral graphene moire superlattices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zheng%2C+J">Jian Zheng</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+S">Size Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+K">Kai Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Lyu%2C+B">Bosai Lyu</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+S">Shuhan Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Sha%2C+Y">Yating Sha</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+Z">Zhengxian Li</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+J">Jinfeng Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Shi%2C+Z">Zhiwen Shi</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+G">Guorui Chen</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="2412.09985v1-abstract-short" style="display: inline;"> Graphene-based moire superlattices provide a versatile platform for exploring novel correlated and topological electronic states, driven by enhanced Coulomb interactions within flat bands. The intrinsic tunability of graphene s multiple degrees of freedom enables precise control over these complex quantum phases. In this study, we observe a range of competing phases and their transitions in rhombo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09985v1-abstract-full').style.display = 'inline'; document.getElementById('2412.09985v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.09985v1-abstract-full" style="display: none;"> Graphene-based moire superlattices provide a versatile platform for exploring novel correlated and topological electronic states, driven by enhanced Coulomb interactions within flat bands. The intrinsic tunability of graphene s multiple degrees of freedom enables precise control over these complex quantum phases. In this study, we observe a range of competing phases and their transitions in rhombohedrally stacked hexalayer graphene on hexagonal boron nitride (r-6G/hBN) moire superlattices. When electrons are polarized away from the moire superlattice, we firstly identify a Chern insulator with reversible Chern numbers at v = 1 (one electron per moire cell), attributed to the competition between bulk and edge magnetizations.Then, we detect transitions between three distinct insulating states at v = 2, driven by vertical displacement field D and vertical magnetic field B. These insulating phases are distinguished as spin-antiferromagnetic, spin-polarized, and valley-polarized insulators, based on their responses to parallel and perpendicular magnetic fields. When electrons are polarized toward the moire superlattice, in a device with large twist angle, insulating states appear at v = 1/3 and 2/3 at zero magnetic field, and v = 1/2 in a magnetic field. Our findings reveal a rich interplay of charge, isospin, topology and magnetic field in rhombohedral graphene moire superlattices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09985v1-abstract-full').style.display = 'none'; document.getElementById('2412.09985v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">24 pages, 10 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/2412.09918">arXiv:2412.09918</a> <span> [<a href="https://arxiv.org/pdf/2412.09918">pdf</a>, <a href="https://arxiv.org/format/2412.09918">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 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.adf9887">10.1126/science.adf9887 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Emission and Coherent Control of Levitons in Graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Assouline%2C+A">A. Assouline</a>, <a href="/search/cond-mat?searchtype=author&query=Pugliese%2C+L">L. Pugliese</a>, <a href="/search/cond-mat?searchtype=author&query=Chakraborti%2C+H">H. Chakraborti</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+S">Seunghun Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Bernabeu%2C+L">L. Bernabeu</a>, <a href="/search/cond-mat?searchtype=author&query=Jo%2C+M">M. Jo</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">K. Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">T. Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Glattli%2C+D+C">D. C. Glattli</a>, <a href="/search/cond-mat?searchtype=author&query=Kumada%2C+N">N. Kumada</a>, <a href="/search/cond-mat?searchtype=author&query=Sim%2C+H+-">H. -S. Sim</a>, <a href="/search/cond-mat?searchtype=author&query=Parmentier%2C+F+D">F. D. Parmentier</a>, <a href="/search/cond-mat?searchtype=author&query=Roulleau%2C+P">P. Roulleau</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="2412.09918v1-abstract-short" style="display: inline;"> Flying qubits encode quantum information in propagating modes instead of stationary discrete states. Although photonic flying qubits are available, the weak interaction between photons limits the efficiency of conditional quantum gates. Conversely, electronic flying qubits can use Coulomb interactions, but the weaker quantum coherence in conventional semiconductors has hindered their realization.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09918v1-abstract-full').style.display = 'inline'; document.getElementById('2412.09918v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.09918v1-abstract-full" style="display: none;"> Flying qubits encode quantum information in propagating modes instead of stationary discrete states. Although photonic flying qubits are available, the weak interaction between photons limits the efficiency of conditional quantum gates. Conversely, electronic flying qubits can use Coulomb interactions, but the weaker quantum coherence in conventional semiconductors has hindered their realization. In this work, we engineered on-demand injection of a single electronic flying qubit state and its manipulation over the Bloch sphere. The flying qubit is a Leviton propagating in quantum Hall edge channels of a high-mobility graphene monolayer. Although single-shot qubit readout and two-qubit operations are still needed for a viable manipulation of flying qubits, the coherent manipulation of an itinerant electronic state at the single-electron level presents a highly promising alternative to conventional qubits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09918v1-abstract-full').style.display = 'none'; document.getElementById('2412.09918v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">5 Figures, Comments are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 382, 1260, 2023 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.09654">arXiv:2412.09654</a> <span> [<a href="https://arxiv.org/pdf/2412.09654">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> </div> </div> <p class="title is-5 mathjax"> Moir茅 Periodic and Quasiperiodic Crystals in Heterostructures of Twisted Bilayer Graphene and Hexagonal Boron Nitride </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lai%2C+X">Xinyuan Lai</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+G">Guohong Li</a>, <a href="/search/cond-mat?searchtype=author&query=Coe%2C+A+M">Angela M. Coe</a>, <a href="/search/cond-mat?searchtype=author&query=Pixley%2C+J+H">Jedediah H. Pixley</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Andrei%2C+E+Y">Eva Y. Andrei</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="2412.09654v1-abstract-short" style="display: inline;"> Stacking two atomic crystals with a twist between their crystal axes produces moir茅 potentials that modify the electronic properties. Here we show that double moir茅 potentials generated by superposing three atomic crystals create a new class of tunable quasiperiodic structures that alter the symmetry and spatial distribution of the electronic wavefunctions. By using scanning tunneling microscopy a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09654v1-abstract-full').style.display = 'inline'; document.getElementById('2412.09654v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.09654v1-abstract-full" style="display: none;"> Stacking two atomic crystals with a twist between their crystal axes produces moir茅 potentials that modify the electronic properties. Here we show that double moir茅 potentials generated by superposing three atomic crystals create a new class of tunable quasiperiodic structures that alter the symmetry and spatial distribution of the electronic wavefunctions. By using scanning tunneling microscopy and spectroscopy to study twisted bilayer graphene on hexagonal boron nitride (hBN), we unveil a moir茅 phase diagram defined by the lattice constants of the two moir茅 lattices (graphene-on-graphene and graphene-on-hBN), comprising both commensurate periodic and incommensurate quasiperiodic crystals. Remarkably, the 1:1 commensurate crystal, which should theoretically exist at only one point on this phase diagram, is observed over a wide range, demonstrating an unexpected self-alignment mechanism. The incommensurate crystals include quasicrystals, which are quasiperiodic and feature a Bravais-forbidden dodecagonal symmetry, and intercrystals, which are also quasiperiodic but lack forbidden symmetries. This rich variety of tunable double moir茅 structures offers a synthetic platform for exploring the unique electronic properties of quasiperiodic crystals, which are rarely found in nature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09654v1-abstract-full').style.display = 'none'; document.getElementById('2412.09654v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">This paper is completely different from 2311.07819. While some description of sample and technique are similar, the rest is new. 2311.07819 focuses on domains, and their boundaries, using both experiments and simulations. This paper focuses on structures emerging by superposing two moire patterns, and in particular the new physics arising from electrons in a quasiperiodic potential. arXiv admin note: substantial text overlap with arXiv:2311.07819</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.09210">arXiv:2412.09210</a> <span> [<a href="https://arxiv.org/pdf/2412.09210">pdf</a>, <a href="https://arxiv.org/format/2412.09210">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> <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/s41467-024-55486-2">10.1038/s41467-024-55486-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of 1/3 fractional quantum Hall physics in balanced large angle twisted bilayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kim%2C+D">Dohun Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Jin%2C+S">Seyoung Jin</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Smet%2C+J+H">Jurgen H. Smet</a>, <a href="/search/cond-mat?searchtype=author&query=Cho%2C+G+Y">Gil Young Cho</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+Y">Youngwook Kim</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="2412.09210v1-abstract-short" style="display: inline;"> Magnetotransport of conventional semiconductor based double layer systems with barrier suppressed interlayer tunneling has been a rewarding subject due to the emergence of an interlayer coherent state that behaves as an excitonic superfluid. Large angle twisted bilayer graphene offers unprecedented strong interlayer Coulomb interaction, since both layer thickness and layer spacing are of atomic sc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09210v1-abstract-full').style.display = 'inline'; document.getElementById('2412.09210v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.09210v1-abstract-full" style="display: none;"> Magnetotransport of conventional semiconductor based double layer systems with barrier suppressed interlayer tunneling has been a rewarding subject due to the emergence of an interlayer coherent state that behaves as an excitonic superfluid. Large angle twisted bilayer graphene offers unprecedented strong interlayer Coulomb interaction, since both layer thickness and layer spacing are of atomic scale and a barrier is no more needed as the twist induced momentum mismatch suppresses tunneling. The extra valley degree of freedom also adds richness. Here we report the observation of fractional quantum Hall physics at 1/3 total filling for balanced layer population in this system. Monte Carlo simulations support that the ground state is also an excitonic superfluid but the excitons are composed of fractional rather than elementary charges. The observed phase transitions with an applied displacement field at this and other fractional fillings are also addressed with simulations. They reveal ground states with different topology and symmetry properties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09210v1-abstract-full').style.display = 'none'; document.getElementById('2412.09210v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">accepted to Nature communications</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat Commun 16, 179 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.08758">arXiv:2412.08758</a> <span> [<a href="https://arxiv.org/pdf/2412.08758">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> </div> </div> <p class="title is-5 mathjax"> Electron transport in bilayer graphene nano constrictions patterned using AFM nanolithography </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Rienstra%2C+R+W">Robert W. Rienstra</a>, <a href="/search/cond-mat?searchtype=author&query=Sultana%2C+N">Nishat Sultana</a>, <a href="/search/cond-mat?searchtype=author&query=Shih%2C+E">En-Min Shih</a>, <a href="/search/cond-mat?searchtype=author&query=Stocker%2C+E">Evan Stocker</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Richter%2C+C+A">Curt A. Richter</a>, <a href="/search/cond-mat?searchtype=author&query=Stroscio%2C+J">Joseph Stroscio</a>, <a href="/search/cond-mat?searchtype=author&query=Zhitenev%2C+N">Nikolai Zhitenev</a>, <a href="/search/cond-mat?searchtype=author&query=Ghahari%2C+F">Fereshte Ghahari</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="2412.08758v1-abstract-short" style="display: inline;"> Here we report on low temperature transport measurements of encapsulated bilayer graphene nano constrictions fabricated employing electrode-free AFM-based local anodic oxidation (LAO) nanolithography. This technique allows for the creation of constrictions as narrow as 20 nm much smaller than previous studies. In wider constrictions, we observe bulk transport characteristics. However, as the const… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.08758v1-abstract-full').style.display = 'inline'; document.getElementById('2412.08758v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.08758v1-abstract-full" style="display: none;"> Here we report on low temperature transport measurements of encapsulated bilayer graphene nano constrictions fabricated employing electrode-free AFM-based local anodic oxidation (LAO) nanolithography. This technique allows for the creation of constrictions as narrow as 20 nm much smaller than previous studies. In wider constrictions, we observe bulk transport characteristics. However, as the constriction's width is reduced, a transport gap appears. Single quantum dot (QD) formation is observed within the narrowest constriction with addition energies exceeding 100 meV, which surpass previous experiments on patterned QDs. Our results suggest that transport through these narrow constrictions is governed by edge disorder combined with quantum confinement effects. Our findings introduce electrode-free AFM-LAO lithography as an easy and flexible method for creating nanostructures with tunable electronic properties without relying on patterning techniques such as e-beam lithography. The excellent control and reproducibility provided by this technique opens exciting opportunities for carbon-based quantum electronics and spintronics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.08758v1-abstract-full').style.display = 'none'; document.getElementById('2412.08758v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">25 Pages, 4 main figures, 5 supplementary figures</span> </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous 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