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<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=Hwang%2C+S&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Hwang%2C+S&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Hwang%2C+S&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.15818">arXiv:2411.15818</a> <span> [<a href="https://arxiv.org/pdf/2411.15818">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Charge gain via solid-state gating of an oxide Mott system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Shoham%2C+L">Lishai Shoham</a>, <a href="/search/cond-mat?searchtype=author&query=Silber%2C+I">Itai Silber</a>, <a href="/search/cond-mat?searchtype=author&query=Tuvia%2C+G">Gal Tuvia</a>, <a href="/search/cond-mat?searchtype=author&query=Baskin%2C+M">Maria Baskin</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Soo-Yoon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Choi%2C+S">Si-Young Choi</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+M">Myung-Geun Han</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+Y">Yimei Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Yalon%2C+E">Eilam Yalon</a>, <a href="/search/cond-mat?searchtype=author&query=Rozenberg%2C+M+J">Marcelo J. Rozenberg</a>, <a href="/search/cond-mat?searchtype=author&query=Dagan%2C+Y">Yoram Dagan</a>, <a href="/search/cond-mat?searchtype=author&query=Trier%2C+F">Felix Trier</a>, <a href="/search/cond-mat?searchtype=author&query=Kornblum%2C+L">Lior Kornblum</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.15818v1-abstract-short" style="display: inline;"> The modulation of channel conductance in field-effect transistors (FETs) via metal-oxide-semiconductor (MOS) structures has revolutionized information processing and storage. However, the limitations of silicon-based FETs in electrical switching have driven the search for new materials capable of overcoming these constraints. Electrostatic gating of competing electronic phases in a Mott material n… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.15818v1-abstract-full').style.display = 'inline'; document.getElementById('2411.15818v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.15818v1-abstract-full" style="display: none;"> The modulation of channel conductance in field-effect transistors (FETs) via metal-oxide-semiconductor (MOS) structures has revolutionized information processing and storage. However, the limitations of silicon-based FETs in electrical switching have driven the search for new materials capable of overcoming these constraints. Electrostatic gating of competing electronic phases in a Mott material near its metal to insulator transition (MIT) offers prospects of substantial modulation of the free carriers and electrical resistivity through small changes in band filling. While electrostatic control of the MIT has been previously reported, the advancement of Mott materials towards novel Mott transistors requires the realization of their charge gain prospects in a solid-state device. In this study, we present gate-control of electron correlation using a solid-state device utilizing the oxide Mott system $La_{1-x}Sr_xVO_3$ as a correlated FET channel. We report on a gate resistance response that cannot be explained in a purely electrostatic framework, suggesting at least $\times100$ charge gain originating from the correlated behavior. These preliminary results pave the way towards the development of highly efficient, low-power electronic devices that could surpass the performance bottlenecks of conventional FETs by leveraging the electronic phase transitions of correlated electron systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.15818v1-abstract-full').style.display = 'none'; document.getElementById('2411.15818v1-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.11217">arXiv:2408.11217</a> <span> [<a href="https://arxiv.org/pdf/2408.11217">pdf</a>, <a href="https://arxiv.org/format/2408.11217">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</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"> Beyond skyrmion spin texture from quantum Kelvin-Helmholtz instability </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Huh%2C+S">SeungJung Huh</a>, <a href="/search/cond-mat?searchtype=author&query=Yun%2C+W">Wooyoung Yun</a>, <a href="/search/cond-mat?searchtype=author&query=Yun%2C+G">Gabin Yun</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Samgyu Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Kwon%2C+K">Kiryang Kwon</a>, <a href="/search/cond-mat?searchtype=author&query=Hur%2C+J">Junhyeok Hur</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+S">Seungho Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Takeuchi%2C+H">Hiromitsu Takeuchi</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+S+K">Se Kwon Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Choi%2C+J">Jae-yoon Choi</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="2408.11217v1-abstract-short" style="display: inline;"> Topology profoundly influences diverse fields of science, providing a powerful framework for classifying phases of matter and predicting nontrivial excitations, such as solitons, vortices, and skyrmions. These topological defects are typically characterized by integer numbers, called topological charges, representing the winding number in their order parameter field. The classification and predict… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.11217v1-abstract-full').style.display = 'inline'; document.getElementById('2408.11217v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.11217v1-abstract-full" style="display: none;"> Topology profoundly influences diverse fields of science, providing a powerful framework for classifying phases of matter and predicting nontrivial excitations, such as solitons, vortices, and skyrmions. These topological defects are typically characterized by integer numbers, called topological charges, representing the winding number in their order parameter field. The classification and prediction of topological defects, however, become challenging when singularities are included within the integration domain for calculating the topological charge. While such exotic nonlinear excitations have been proposed in the superfluid $^3$He-A phase and spinor Bose-Einstein condensate of atomic gases, experimental observation of these structures and studies of their stability have long been elusive. Here we report the observation of a singular skyrmion that goes beyond the framework of topology in a ferromagnetic superfluid. The exotic skyrmions are sustained by undergoing anomalous symmetry breaking associated with the eccentric spin singularity and carry half of the elementary charge, distinctive from conventional skyrmions or merons. By successfully realizing the universal regime of the quantum Kelvin-Helmholtz instability, we identified the eccentric fractional skyrmions, produced by emission from a magnetic domain wall and a spontaneous splitting of an integer skyrmion with spin singularities. The singular skyrmions are stable and can be observed after 2~s of hold time. Our results confirm the universality between classical and quantum Kelvin-Helmholtz instabilities and broaden our understanding on complex nonlinear dynamics of nontrivial texture beyond skyrmion in topological quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.11217v1-abstract-full').style.display = 'none'; document.getElementById('2408.11217v1-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">13 pages, 5 main figures and 7 supplemental figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.07557">arXiv:2408.07557</a> <span> [<a href="https://arxiv.org/pdf/2408.07557">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Band-selective simulation of photoelectron intensity and converging Berry phase in trilayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Im%2C+H">Hayoon Im</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S+H">Sue Hyeon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+M">Minhee Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+K">Kyoo Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+H">Haeyong Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+C">Choongyu Hwang</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="2408.07557v1-abstract-short" style="display: inline;"> Berry phase is one of the key elements to understand quantum-mechanical phenomena such as the Aharonov-Bohm effect and the unconventional Hall effect in graphene. The Berry phase in monolayer and bilayer graphene has been manifested by the anisotropic distribution of photoelectron intensity along a closed loop in the momentum space as well as its rotation by a characteristic angle upon rotating li… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.07557v1-abstract-full').style.display = 'inline'; document.getElementById('2408.07557v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.07557v1-abstract-full" style="display: none;"> Berry phase is one of the key elements to understand quantum-mechanical phenomena such as the Aharonov-Bohm effect and the unconventional Hall effect in graphene. The Berry phase in monolayer and bilayer graphene has been manifested by the anisotropic distribution of photoelectron intensity along a closed loop in the momentum space as well as its rotation by a characteristic angle upon rotating light polarization. Here we report the band-selective simulation of photoelectron intensity of trilayer graphene to understand its Berry phase within the tight-binding formalism. ABC- and ABA-stacked trilayer graphene show characteristic rotational angles of photoelectron intensity distribution, as predicted from their well-known Berry phases. Surprisingly, however, in ABA-stacked trilayer graphene, the rotational angle changes upon approaching toward the band touching point between the conduction and valence bands, which suggest that Berry phase changes as a function of binding energy. The binding energy-dependent Berry phase is attributed to the enhanced hybridization of the two electron bands of ABA-stacked trilayer graphene that converge at the band touching point, resulting in the converging Berry phase. These findings will provide an efficient way of tuning Berry phase and hence exotic phenomena stemming from the Berry phase. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.07557v1-abstract-full').style.display = 'none'; document.getElementById('2408.07557v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Sci. Converg. Technol. 33, 91 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.05930">arXiv:2408.05930</a> <span> [<a href="https://arxiv.org/pdf/2408.05930">pdf</a>, <a href="https://arxiv.org/ps/2408.05930">ps</a>, <a href="https://arxiv.org/format/2408.05930">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> <p class="title is-5 mathjax"> Evolution of the Fermi surface of 1T-VSe$_2$ across a structural phase transition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yilmaz%2C+T">Turgut Yilmaz</a>, <a href="/search/cond-mat?searchtype=author&query=Tong%2C+X">Xiao Tong</a>, <a href="/search/cond-mat?searchtype=author&query=Sadowski%2C+J+T">Jerzy T. Sadowski</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sooyeon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Evans-Lutterodt%2C+K">Kenneth Evans-Lutterodt</a>, <a href="/search/cond-mat?searchtype=author&query=Kisslinger%2C+K">Kim Kisslinger</a>, <a href="/search/cond-mat?searchtype=author&query=Vescovo%2C+E">Elio Vescovo</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="2408.05930v1-abstract-short" style="display: inline;"> The electronic origin of the structural transition in 1T-VSe$_2$ is re-evaluated through an extensive angle-resolved photoemission spectroscopy experiment. The components of the band structure, missing in previous reports, are revealed. Earlier observations, shown to be temperature independent and therefore not correlated with the phase transition, are explained in terms of the increased complexit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.05930v1-abstract-full').style.display = 'inline'; document.getElementById('2408.05930v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.05930v1-abstract-full" style="display: none;"> The electronic origin of the structural transition in 1T-VSe$_2$ is re-evaluated through an extensive angle-resolved photoemission spectroscopy experiment. The components of the band structure, missing in previous reports, are revealed. Earlier observations, shown to be temperature independent and therefore not correlated with the phase transition, are explained in terms of the increased complexity of the band structure close to the Fermi level. Only the overall size of the Fermi surface is found to be positively correlated with the phase transition at 110 K. These observations, quite distant from the charge density wave scenario commonly considered for 1T-VSe$_2$, bring fresh perspectives toward the correct description of structural transitions in dichalcogenides materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.05930v1-abstract-full').style.display = 'none'; document.getElementById('2408.05930v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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 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/2406.12543">arXiv:2406.12543</a> <span> [<a href="https://arxiv.org/pdf/2406.12543">pdf</a>, <a href="https://arxiv.org/format/2406.12543">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/PhysRevResearch.6.013215">10.1103/PhysRevResearch.6.013215 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phase-controlled heat modulation with Aharonov-Bohm interferometers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Sothmann%2C+B">Bj枚rn Sothmann</a>, <a href="/search/cond-mat?searchtype=author&query=L%C3%B3pez%2C+R">Rosa L贸pez</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.12543v1-abstract-short" style="display: inline;"> A heat modulator is proposed based on a voltage-biased Aharonov-Bohm interferometer. Once an electrical bias is applied, Peltier effects give rise to a flow of heat that can be modulated by a magnetic flux. We determine the corresponding temperature changes using a simple thermal model. Our calculations demonstrate that the modulated temperature difference can be as large as 80 mK at base temperat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.12543v1-abstract-full').style.display = 'inline'; document.getElementById('2406.12543v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.12543v1-abstract-full" style="display: none;"> A heat modulator is proposed based on a voltage-biased Aharonov-Bohm interferometer. Once an electrical bias is applied, Peltier effects give rise to a flow of heat that can be modulated by a magnetic flux. We determine the corresponding temperature changes using a simple thermal model. Our calculations demonstrate that the modulated temperature difference can be as large as 80 mK at base temperature about 600 mK with relative temperature variations reaching 10\%. Our model also predicts, quite generally, the emergence of spin-polarized heat flows without any ferromagnetic contacts, if Rashba spin-orbit interaction is combined with the applied magnetic flux, which potentially paves the way towards caloritronic information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.12543v1-abstract-full').style.display = 'none'; document.getElementById('2406.12543v1-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> 18 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 6, 013215 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.17373">arXiv:2405.17373</a> <span> [<a href="https://arxiv.org/pdf/2405.17373">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"> Probing the Relationship between Defects and Enhanced Mobility in MoS2 Monolayers Grown by Mo Foil </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Majumder%2C+S">Sudipta Majumder</a>, <a href="/search/cond-mat?searchtype=author&query=Walve%2C+V">Vaibhav Walve</a>, <a href="/search/cond-mat?searchtype=author&query=Chand%2C+R">Rahul Chand</a>, <a href="/search/cond-mat?searchtype=author&query=A.%2C+G+M">Gokul M. A.</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sooyeon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Kumar%2C+G+V+P">G. V. Pavan Kumar</a>, <a href="/search/cond-mat?searchtype=author&query=Deshpande%2C+A">Aparna Deshpande</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+A">Atikur Rahman</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.17373v1-abstract-short" style="display: inline;"> Atomic vacancies, such as chalcogen vacancies in 2D TMDs, are important in changing the host material's electronic structure and transport properties. We present a straightforward one-step method for growing monolayer MoS2 utilizing oxidized Molybdenum (Mo) foil using CVD and delve into the transport properties of as-grown samples. Devices fabricated from these MoS2 sheets exhibit excellent electr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.17373v1-abstract-full').style.display = 'inline'; document.getElementById('2405.17373v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.17373v1-abstract-full" style="display: none;"> Atomic vacancies, such as chalcogen vacancies in 2D TMDs, are important in changing the host material's electronic structure and transport properties. We present a straightforward one-step method for growing monolayer MoS2 utilizing oxidized Molybdenum (Mo) foil using CVD and delve into the transport properties of as-grown samples. Devices fabricated from these MoS2 sheets exhibit excellent electrical responses, with the standout device achieving mobility exceeding 100 cm2V-1s-1. Structural analysis and optical signatures unveiled the presence of chalcogen defects within these samples. To decipher the influence of inherent defects on the electronic transport properties, we measured low-temperature transport on two distinct sets of devices exhibiting relatively high or low mobilities. Combining the thermally activated transport model with quantum capacitance calculations, we have shown the existence of shallow states near the conduction band, likely attributed to sulfur vacancies within MoS2. These vacancies are responsible for the hopping conduction of electrons in the device channel. Furthermore, our claims were substantiated through low-temperature scanning tunnelling microscopy measurements, which revealed an abundance of isolated and lateral double sulfur vacancies in Mo foil-grown samples. We found that these vacancies increase the density of states near the conduction band, inducing intrinsic n-type doping in the MoS2 channel. Consequently, this elevated conductivity enhances the field-effect mobility of MoS2 transistors. Our study offers insights into chalcogen vacancies in CVD-grown monolayer MoS2 and highlights their beneficial impact on electronic transport properties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.17373v1-abstract-full').style.display = 'none'; document.getElementById('2405.17373v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.12250">arXiv:2404.12250</a> <span> [<a href="https://arxiv.org/pdf/2404.12250">pdf</a>, <a href="https://arxiv.org/format/2404.12250">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"> Effects of Reduced Interlayer Interactions on the K-point Excitons of MoS$_2$ Nanoscrolls </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chatterjee%2C+S">Sagnik Chatterjee</a>, <a href="/search/cond-mat?searchtype=author&query=Chowdhury%2C+T">Tamaghna Chowdhury</a>, <a href="/search/cond-mat?searchtype=author&query=N%C3%BA%C3%B1ez%2C+P+D">Pablo D铆az N煤帽ez</a>, <a href="/search/cond-mat?searchtype=author&query=Kay%2C+N">Nicholas Kay</a>, <a href="/search/cond-mat?searchtype=author&query=Rajput%2C+M">Manisha Rajput</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sooyeon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Timokhin%2C+I">Ivan Timokhin</a>, <a href="/search/cond-mat?searchtype=author&query=Mishchenko%2C+A">Artem Mishchenko</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+A">Atikur Rahman</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="2404.12250v1-abstract-short" style="display: inline;"> Transition metal dichalcogenide (TMD) nanoscrolls (NS) exhibit significant photoluminescence (PL) signals despite their multilayer structure, which cannot be explained by the strained multilayer description of NS. Here, we investigate the interlayer interactions in NS to address this discrepancy. The reduction of interlayer interactions in NS is attributed to two factors: (1) the symmetry-broken m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.12250v1-abstract-full').style.display = 'inline'; document.getElementById('2404.12250v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.12250v1-abstract-full" style="display: none;"> Transition metal dichalcogenide (TMD) nanoscrolls (NS) exhibit significant photoluminescence (PL) signals despite their multilayer structure, which cannot be explained by the strained multilayer description of NS. Here, we investigate the interlayer interactions in NS to address this discrepancy. The reduction of interlayer interactions in NS is attributed to two factors: (1) the symmetry-broken mixed stacking order between neighbouring layers due to misalignment, and (2) the high inhomogeneity in the strain landscape resulting from the unique Archimedean spiral-like geometry with positive eccentricity. These were confirmed through transmission electron microscopy, field emission scanning electron microscopy and atomic force microscopy. To probe the effect of reduction of interlayer interactions in multilayered MoS$_2$ nanoscrolls, low-temperature PL spectroscopy was employed investigating the behaviour of K-point excitons. The effects of reduced interlayer interactions on exciton-phonon coupling (EXPC), exciton energy, and exciton oscillator strength are discussed, providing insights into the unique properties of TMD nanoscrolls. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.12250v1-abstract-full').style.display = 'none'; document.getElementById('2404.12250v1-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> 18 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">S.C. and T.C. have contributed equally to this work</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.03789">arXiv:2402.03789</a> <span> [<a href="https://arxiv.org/pdf/2402.03789">pdf</a>, <a href="https://arxiv.org/format/2402.03789">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/10.1021/acs.jctc.4c00190">10.1021/acs.jctc.4c00190 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Scalable Parallel Algorithm for Graph Neural Network Interatomic Potentials in Molecular Dynamics Simulations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Park%2C+Y">Yutack Park</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J">Jaesun Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Seungwoo Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+S">Seungwu Han</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="2402.03789v1-abstract-short" style="display: inline;"> Message-passing graph neural network interatomic potentials (GNN-IPs), particularly those with equivariant representations such as NequIP, are attracting significant attention due to their data efficiency and high accuracy. However, parallelizing GNN-IPs poses challenges because multiple message-passing layers complicate data communication within the spatial decomposition method, which is preferre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.03789v1-abstract-full').style.display = 'inline'; document.getElementById('2402.03789v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.03789v1-abstract-full" style="display: none;"> Message-passing graph neural network interatomic potentials (GNN-IPs), particularly those with equivariant representations such as NequIP, are attracting significant attention due to their data efficiency and high accuracy. However, parallelizing GNN-IPs poses challenges because multiple message-passing layers complicate data communication within the spatial decomposition method, which is preferred by many molecular dynamics (MD) packages. In this article, we propose an efficient parallelization scheme compatible with GNN-IPs and develop a package, SevenNet (Scalable EquiVariance-Enabled Neural NETwork), based on the NequIP architecture. For MD simulations, SevenNet interfaces with the LAMMPS package. Through benchmark tests on a 32-GPU cluster with examples of SiO$_2$, SevenNet achieves over 80% parallel efficiency in weak-scaling scenarios and exhibits nearly ideal strong-scaling performance as long as GPUs are fully utilized. However, the strong-scaling performance significantly declines with suboptimal GPU utilization, particularly affecting parallel efficiency in cases involving lightweight models or simulations with small numbers of atoms. We also pre-train SevenNet with a vast dataset from the Materials Project (dubbed `SevenNet-0') and assess its performance on generating amorphous Si$_3$N$_4$ containing more than 100,000 atoms. By developing scalable GNN-IPs, this work aims to bridge the gap between advanced machine learning models and large-scale MD simulations, offering researchers a powerful tool to explore complex material systems with high accuracy and efficiency. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.03789v1-abstract-full').style.display = 'none'; document.getElementById('2402.03789v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">34 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Chemical Theory and Computation 20 (2024) 4857-4868 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.19350">arXiv:2310.19350</a> <span> [<a href="https://arxiv.org/pdf/2310.19350">pdf</a>, <a href="https://arxiv.org/format/2310.19350">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> <p class="title is-5 mathjax"> Disorder-dependent Li diffusion in $\mathrm{Li_6PS_5Cl}$ investigated by machine learning potential </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lee%2C+J">Jiho Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Ju%2C+S">Suyeon Ju</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Seungwoo Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=You%2C+J">Jinmu You</a>, <a href="/search/cond-mat?searchtype=author&query=Jung%2C+J">Jisu Jung</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+Y">Youngho Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+S">Seungwu Han</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="2310.19350v1-abstract-short" style="display: inline;"> Solid-state electrolytes with argyrodite structures, such as $\mathrm{Li_6PS_5Cl}$, have attracted considerable attention due to their superior safety compared to liquid electrolytes and higher ionic conductivity than other solid electrolytes. Although experimental efforts have been made to enhance conductivity by controlling the degree of disorder, the underlying diffusion mechanism is not yet fu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.19350v1-abstract-full').style.display = 'inline'; document.getElementById('2310.19350v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.19350v1-abstract-full" style="display: none;"> Solid-state electrolytes with argyrodite structures, such as $\mathrm{Li_6PS_5Cl}$, have attracted considerable attention due to their superior safety compared to liquid electrolytes and higher ionic conductivity than other solid electrolytes. Although experimental efforts have been made to enhance conductivity by controlling the degree of disorder, the underlying diffusion mechanism is not yet fully understood. Moreover, existing theoretical analyses based on ab initio MD simulations have limitations in addressing various types of disorder at room temperature. In this study, we directly investigate Li-ion diffusion in $\mathrm{Li_6PS_5Cl}$ at 300 K using large-scale, long-term MD simulations empowered by machine learning potentials (MLPs). To ensure the convergence of conductivity values within an error range of 10%, we employ a 25 ns simulation using a $5\times5\times5$ supercell containing 6500 atoms. The computed Li-ion conductivity, activation energies, and equilibrium site occupancies align well with experimental observations. Notably, Li-ion conductivity peaks when Cl ions occupy 25% of the 4c sites, rather than at 50% where the disorder is maximized. This phenomenon is explained by the interplay between inter-cage and intra-cage jumps. By elucidating the key factors affecting Li-ion diffusion in $\mathrm{Li_6PS_5Cl}$, this work paves the way for optimizing ionic conductivity in the argyrodite family. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.19350v1-abstract-full').style.display = 'none'; document.getElementById('2310.19350v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">34 pages, 6 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/2310.11424">arXiv:2310.11424</a> <span> [<a href="https://arxiv.org/pdf/2310.11424">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"> Theoretical investigation of delafossite-Cu2ZnSnO4 as a promising photovoltaic absorber </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kang%2C+S">Seoung-Hun Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+M">Myeongjun Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S+W">Sang Woon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Yeom%2C+S">Sinchul Yeom</a>, <a href="/search/cond-mat?searchtype=author&query=Yoon%2C+M">Mina Yoon</a>, <a href="/search/cond-mat?searchtype=author&query=Ok%2C+J+M">Jong Mok Ok</a>, <a href="/search/cond-mat?searchtype=author&query=Yoon%2C+S">Sangmoon Yoon</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="2310.11424v1-abstract-short" style="display: inline;"> In the quest for efficient and cost-effective photovoltaic absorber materials beyond silicon, considerable attention has been directed toward exploring alternatives. One such material, zincblende-derived Cu2ZnSnS4 (CZTS), has shown promise due to its ideal band-gap size and high absorption coefficient. However, challenges such as structural defects and secondary phase formation have hindered its d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.11424v1-abstract-full').style.display = 'inline'; document.getElementById('2310.11424v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.11424v1-abstract-full" style="display: none;"> In the quest for efficient and cost-effective photovoltaic absorber materials beyond silicon, considerable attention has been directed toward exploring alternatives. One such material, zincblende-derived Cu2ZnSnS4 (CZTS), has shown promise due to its ideal band-gap size and high absorption coefficient. However, challenges such as structural defects and secondary phase formation have hindered its development. In this study, we examine the potential of another compound Cu2ZnSnO4 (CZTO) with a similar composition to CZTS as a promising alternative. Employing ab initio density function theory (DFT) calculations in combination with an evolutionary structure prediction algorithm, we identify that the crystalline phase of the delafossite structure is the most stable among the 900 (meta)stable CZTO. Its thermodynamic stability at room temperature is also confirmed by the molecular dynamics study. Excitingly, this new phase of CZTO displays a direct band gap where the dipole-allowed transition occurs, making it a strong candidate for efficient light absorption. Furthermore, the estimation of spectroscopic limited maximum efficiency (SLME) directly demonstrates the high potential of delafossite-CZTO as a photovoltaic absorber. Our numerical results suggest that delafossite-CZTO holds another promise for future photovoltaic applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.11424v1-abstract-full').style.display = 'none'; document.getElementById('2310.11424v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.01872">arXiv:2305.01872</a> <span> [<a href="https://arxiv.org/pdf/2305.01872">pdf</a>, <a href="https://arxiv.org/format/2305.01872">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey 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="Applied Physics">physics.app-ph</span> </div> </div> <p class="title is-5 mathjax"> Microwave loss characterization using multi-mode superconducting resonators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lei%2C+C+U">Chan U Lei</a>, <a href="/search/cond-mat?searchtype=author&query=Ganjam%2C+S">Suhas Ganjam</a>, <a href="/search/cond-mat?searchtype=author&query=Krayzman%2C+L">Lev Krayzman</a>, <a href="/search/cond-mat?searchtype=author&query=Banerjee%2C+A">Archan Banerjee</a>, <a href="/search/cond-mat?searchtype=author&query=Kisslinger%2C+K">Kim Kisslinger</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sooyeon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Frunzio%2C+L">Luigi Frunzio</a>, <a href="/search/cond-mat?searchtype=author&query=Schoelkopf%2C+R+J">Robert J. Schoelkopf</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="2305.01872v1-abstract-short" style="display: inline;"> Measuring the losses arising from different materials and interfaces is crucial to improving the coherence of superconducting quantum circuits. Although this has been of interest for a long time, current studies can either only provide bounds to those losses, or require several devices for a complete characterization. In this work, we introduce a method to measure the microwave losses of materials… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.01872v1-abstract-full').style.display = 'inline'; document.getElementById('2305.01872v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.01872v1-abstract-full" style="display: none;"> Measuring the losses arising from different materials and interfaces is crucial to improving the coherence of superconducting quantum circuits. Although this has been of interest for a long time, current studies can either only provide bounds to those losses, or require several devices for a complete characterization. In this work, we introduce a method to measure the microwave losses of materials and interfaces with a single multi-mode superconducting resonator. We demonstrate a formalism for analyzing the loss sensitivity of multi-mode systems and discuss the design strategies of multi-mode resonators for material loss studies. We present two types of multi-mode superconducting resonators for the study of bulk superconductors: the forky whispering-gallery-mode resonator (FWGMR) and the ellipsoidal cavity. We use these resonators to measure the surface dielectric, conductor, and seam losses of high-purity (5N5) aluminum and aluminum alloy (6061), as well as how they are affected by chemical etching, diamond turning, and thin-film coating. We find that chemical etching and diamond turning reduce both the surface dielectric and conductive losses of high-purity aluminum, but provide no appreciable improvement to the seam. Coating the surfaces of diamond-turned aluminum alloys with e-beam evaporated or sputtered aluminum thin-films significantly reduces all three losses under study. In addition, we study the effect of chemical etching on the surface of high-purity aluminum using transmission electron microscopy (TEM) and find that the chemical etching process creates a thinner and more uniform oxide layer, consistent with the observed improvement in the surface dielectric loss. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.01872v1-abstract-full').style.display = 'none'; document.getElementById('2305.01872v1-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 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.14940">arXiv:2304.14940</a> <span> [<a href="https://arxiv.org/pdf/2304.14940">pdf</a>, <a href="https://arxiv.org/format/2304.14940">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</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.131.227101">10.1103/PhysRevLett.131.227101 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Heterogeneous Mean First-Passage Time Scaling in Fractal Media </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chun%2C+H">Hyun-Myung Chun</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sungmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Kahng%2C+B">Byungnam Kahng</a>, <a href="/search/cond-mat?searchtype=author&query=Rieger%2C+H">Heiko Rieger</a>, <a href="/search/cond-mat?searchtype=author&query=Noh%2C+J+D">Jae Dong Noh</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="2304.14940v2-abstract-short" style="display: inline;"> The mean first passage time~(MFPT) of random walks is a key quantity characterizing dynamic processes on disordered media. In a random fractal embedded in the Euclidean space, the MFPT is known to obey the power law scaling with the distance between a source and a target site with a universal exponent. We find that the scaling law for the MFPT is not determined solely by the distance between a sou… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.14940v2-abstract-full').style.display = 'inline'; document.getElementById('2304.14940v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.14940v2-abstract-full" style="display: none;"> The mean first passage time~(MFPT) of random walks is a key quantity characterizing dynamic processes on disordered media. In a random fractal embedded in the Euclidean space, the MFPT is known to obey the power law scaling with the distance between a source and a target site with a universal exponent. We find that the scaling law for the MFPT is not determined solely by the distance between a source and a target but also by their locations. The role of a site in the first passage processes is quantified by the random walk centrality. It turns out that the site of highest random walk centrality, dubbed as a hub, intervenes in first passage processes. We show that the MFPT from a departure site to a target site is determined by a competition between direct paths and indirect paths detouring via the hub. Consequently, the MFPT displays a crossover scaling between a short distance regime, where direct paths are dominant, and a long distance regime, where indirect paths are dominant. The two regimes are characterized by power laws with different scaling exponents. The crossover scaling behavior is confirmed by extensive numerical calculations of the MFPTs on the critical percolation cluster in two dimensional square lattices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.14940v2-abstract-full').style.display = 'none'; document.getElementById('2304.14940v2-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">revised version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 131, 227101 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.10826">arXiv:2301.10826</a> <span> [<a href="https://arxiv.org/pdf/2301.10826">pdf</a>, <a href="https://arxiv.org/format/2301.10826">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.107.245412">10.1103/PhysRevB.107.245412 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Superconductor-quantum dot hybrid coolers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Sothmann%2C+B">Bj枚rn Sothmann</a>, <a href="/search/cond-mat?searchtype=author&query=Sanchez%2C+D">David Sanchez</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="2301.10826v1-abstract-short" style="display: inline;"> We propose a refrigeration scheme in a mesoscopic superconductor-quantum dot hybrid device. The setup can significantly cool down a normal metal coupled to the device by applying a bias voltage across the system. We demonstrate that the cooling power can be as large as 0.05$螖_0^2/h$ where $螖_0$ is the absolute value of superconducting order parameter. In contrast to previous proposals, our device… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.10826v1-abstract-full').style.display = 'inline'; document.getElementById('2301.10826v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.10826v1-abstract-full" style="display: none;"> We propose a refrigeration scheme in a mesoscopic superconductor-quantum dot hybrid device. The setup can significantly cool down a normal metal coupled to the device by applying a bias voltage across the system. We demonstrate that the cooling power can be as large as 0.05$螖_0^2/h$ where $螖_0$ is the absolute value of superconducting order parameter. In contrast to previous proposals, our device operates without any magnetic elements such as ferromagnetic reservoirs or Zeeman splittings. The refrigeration scheme works over a broad parameter range and can be optimized by tuning system parameters such as level position and bias voltage. Our theory self-consistently determines the temperature drop of the normal reservoir in the nonlinear transport regime including electron-electron interactions at the mean field level. Finally, we evaluate the refrigeration performance and find efficiencies as large as half of the Carnot bound for realistic values of the coupling strength. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.10826v1-abstract-full').style.display = 'none'; document.getElementById('2301.10826v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 107, 245412 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.15233">arXiv:2209.15233</a> <span> [<a href="https://arxiv.org/pdf/2209.15233">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Advanced interfacial phase change material: structurally confined and interfacially extended superlattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lim%2C+H+w">Hyeon wook Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+Y+s">Young sam Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Jo%2C+K">Kyu-jin Jo</a>, <a href="/search/cond-mat?searchtype=author&query=Seok-Choi"> Seok-Choi</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+C+W">Chang Woo Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+D">Dasol Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Kwon%2C+K+h">Ki hyeon Kwon</a>, <a href="/search/cond-mat?searchtype=author&query=Kwon%2C+H+d">Hoe don Kwon</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S+b">Soo bin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Choi%2C+B">Byung-Joon Choi</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C">Cheol-Woong Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Sim%2C+E+J">Eun Ji Sim</a>, <a href="/search/cond-mat?searchtype=author&query=Cho%2C+M">Mann-Ho Cho</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2209.15233v2-abstract-short" style="display: inline;"> Interfacial Phase Change Memory (iPCM) retrench unnecessary power consumption due to wasted heat generated during phase change by reducing unnecessary entropic loss. In this study, an advanced iPCM (GeTe/Ti-Sb2Te3 Superlattice) is synthesized by doping Ti into Sb2Te3. Structural analysis and density functional theory (DFT) calculations confirm that bonding distortion and structurally well-confined… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.15233v2-abstract-full').style.display = 'inline'; document.getElementById('2209.15233v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.15233v2-abstract-full" style="display: none;"> Interfacial Phase Change Memory (iPCM) retrench unnecessary power consumption due to wasted heat generated during phase change by reducing unnecessary entropic loss. In this study, an advanced iPCM (GeTe/Ti-Sb2Te3 Superlattice) is synthesized by doping Ti into Sb2Te3. Structural analysis and density functional theory (DFT) calculations confirm that bonding distortion and structurally well-confined layers contribute to improve phase change properties in iPCM. Ti-Sb2Te3 acts as an effective thermal barrier to localize the generated heat inside active region, which leads to reduction of switching energy. Since Ge-Te bonds adjacent to short and strong Ti-Te bonds are more elongated than the bonds near Sb-Te, it is easier for Ge atoms to break the bond with Te due to strengthened Peierls distortions (Rlong/Rshort) during phase change process. Properties of advanced iPCM (cycling endurance, write speed/energy) exceed previous records. Moreover, well-confined multi-level states are obtained with advanced iPCM, showing potential as a neuromorphic memory. Our work paves the way for designing superlattice based PCM by controlling confinement layers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.15233v2-abstract-full').style.display = 'none'; document.getElementById('2209.15233v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 Figures and 2 table, 5 Supplementary figures, 27 pages There are problems with typos and quality degradation of figures during PDF conversion process, so we resubmit the updated one in which those issues are resolved. Under mutual agreement between our group(Prof.m.h.cho) and Prof. Robert E.Simpson group, each research content is submitted separately to arXiv.org on the same day. (2022. 9/30)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.10156">arXiv:2107.10156</a> <span> [<a href="https://arxiv.org/pdf/2107.10156">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.104.054406">10.1103/PhysRevB.104.054406 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spin orbit torque switching of antiferromagnet through the Neel reorientation in rare-earth ferrite </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kim%2C+T+H">T. H. Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">S. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Hamh%2C+S+Y">S. Y. Hamh</a>, <a href="/search/cond-mat?searchtype=author&query=Yoon%2C+S+H">S. H. Yoon</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+S+H">S. H. Han</a>, <a href="/search/cond-mat?searchtype=author&query=Cho%2C+B+K">B. K. Cho</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.10156v1-abstract-short" style="display: inline;"> We suggest coherent switching of canted antiferromagnetic (AFM) spins using spin-orbit torque (SOT) in small magnet. The magnetic system of orthoferrite features biaxial easy anisotropy and the Dzyaloshinskii Moriya interaction, which is perpendicular to the easy axes and therefore creates weak magnetization (m). A damping-like component of the SOT induces N茅el reorientation along one of the easy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.10156v1-abstract-full').style.display = 'inline'; document.getElementById('2107.10156v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.10156v1-abstract-full" style="display: none;"> We suggest coherent switching of canted antiferromagnetic (AFM) spins using spin-orbit torque (SOT) in small magnet. The magnetic system of orthoferrite features biaxial easy anisotropy and the Dzyaloshinskii Moriya interaction, which is perpendicular to the easy axes and therefore creates weak magnetization (m). A damping-like component of the SOT induces N茅el reorientation along one of the easy axes and then exerts torque on m, leading to tilting of the N茅el order l. The torque on the magnetization becomes stronger due to coupling with the induced Oersted field or the field-like component of the SOT, enhancing the tilting of l. Therefore, l is found to experience deterministic switching after the SOT is turned off. Based upon both numerical and analytical analysis of the coherent switching, XOR logic gates are also found to be implemented in a single magnetic layer. In addition, we investigate how magnetic parameters affect the critical reorientation angle and current density in a simple layered structure of platinum and a canted AFM. Our findings are expected to provide an alternative spin-switching mechanism for ultrafast applications such as spin logic and electronic devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.10156v1-abstract-full').style.display = 'none'; document.getElementById('2107.10156v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.02594">arXiv:2107.02594</a> <span> [<a href="https://arxiv.org/pdf/2107.02594">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41524-022-00792-w">10.1038/s41524-022-00792-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Accelerated identification of equilibrium structures of multicomponent inorganic crystals using machine learning potentials </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kang%2C+S">Sungwoo Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Jeong%2C+W">Wonseok Jeong</a>, <a href="/search/cond-mat?searchtype=author&query=Hong%2C+C">Changho Hong</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Seungwoo Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Yoon%2C+Y">Youngchae Yoon</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+S">Seungwu Han</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.02594v2-abstract-short" style="display: inline;"> The discovery of new multicomponent inorganic compounds can provide direct solutions to many scientific and engineering challenges, yet the vast size of the uncharted material space dwarfs current synthesis throughput. While the computational crystal structure prediction is expected to mitigate this frustration, the NP-hardness and steep costs of density functional theory (DFT) calculations prohib… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.02594v2-abstract-full').style.display = 'inline'; document.getElementById('2107.02594v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.02594v2-abstract-full" style="display: none;"> The discovery of new multicomponent inorganic compounds can provide direct solutions to many scientific and engineering challenges, yet the vast size of the uncharted material space dwarfs current synthesis throughput. While the computational crystal structure prediction is expected to mitigate this frustration, the NP-hardness and steep costs of density functional theory (DFT) calculations prohibit material exploration at scale. Herein, we introduce SPINNER, a highly efficient and reliable structure-prediction framework based on exhaustive random searches and evolutionary algorithms, which is completely free from empiricism. Empowered by accurate neural network potentials, the program can navigate the configuration space faster than DFT by more than 10$^{2}$-fold. In blind tests on 60 ternary compositions diversely selected from the experimental database, SPINNER successfully identifies experimental (or theoretically more stable) phases for ~80% of materials within 5000 generations, entailing up to half a million structure evaluations for each composition. When benchmarked against previous data mining or DFT-based evolutionary predictions, SPINNER identifies more stable phases in the majority of cases. By developing a reliable and fast structure-prediction framework, this work opens the door to large-scale, unbounded computational exploration of undiscovered inorganic crystals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.02594v2-abstract-full').style.display = 'none'; document.getElementById('2107.02594v2-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 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Comput. Mater. 8, 108 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.04198">arXiv:2012.04198</a> <span> [<a href="https://arxiv.org/pdf/2012.04198">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="Computational Physics">physics.comp-ph</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/10.1016/j.cpc.2021.108089">10.1016/j.cpc.2021.108089 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> InterPhon: Ab initio Interface Phonon Calculations within a 3D Electronic Structure Framework </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yeu%2C+I+W">In Won Yeu</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+G">Gyuseung Han</a>, <a href="/search/cond-mat?searchtype=author&query=Ye%2C+K+H">Kun Hee Ye</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+C+S">Cheol Seong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Choi%2C+J">Jung-Hae Choi</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="2012.04198v2-abstract-short" style="display: inline;"> This work provides the community with an easily executable open-source Python package designed to automize the evaluation of Interfacial Phonons (InterPhon). Its strategy of arbitrarily defining the interfacial region and periodicity alleviates the excessive computational cost in applying ab initio phonon calculations to interfaces and enables efficient extraction of interfacial phonons. InterPhon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.04198v2-abstract-full').style.display = 'inline'; document.getElementById('2012.04198v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.04198v2-abstract-full" style="display: none;"> This work provides the community with an easily executable open-source Python package designed to automize the evaluation of Interfacial Phonons (InterPhon). Its strategy of arbitrarily defining the interfacial region and periodicity alleviates the excessive computational cost in applying ab initio phonon calculations to interfaces and enables efficient extraction of interfacial phonons. InterPhon makes it possible to apply all of the phonon-based predictions that have been available for bulk systems, to interfacial systems. The first example, in which this package was applied to InAs surfaces, demonstrates a systematic structure search for unexplored surface reconstructions, navigated by the imaginary mode of surface phonons. It eventually explains the anisotropic surface vibrations of the polar crystal. The second example, involving oxygen adsorption on Cu, reveals adsorption-induced vibrational change and its contribution to energetic stability. The third example, on a Si/GaAs interface, shows distinct vibrational patterns depending on interfacial structures. It leads to a prediction regarding the structural transition of interfaces and unveils the processing conditions for spontaneous growth of GaAs nanowires on Si. High-level automation in InterPhon will be of great help in elucidating interfacial atomic dynamics and in implementing an automated computational workflow for diverse interfacial systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.04198v2-abstract-full').style.display = 'none'; document.getElementById('2012.04198v2-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 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">43 pages, 6 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/2006.13447">arXiv:2006.13447</a> <span> [<a href="https://arxiv.org/pdf/2006.13447">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"> Emergent of the flat band and superstructures in the VSe2 / Bi2Se3 system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yilmaz%2C+T">Turgut Yilmaz</a>, <a href="/search/cond-mat?searchtype=author&query=Tong%2C+X">Xiao Tong</a>, <a href="/search/cond-mat?searchtype=author&query=Dai%2C+Z">Zhongwei Dai</a>, <a href="/search/cond-mat?searchtype=author&query=Sadowski%2C+J+T">Jerzy T. Sadowski</a>, <a href="/search/cond-mat?searchtype=author&query=Schwier%2C+E+F">Eike F. Schwier</a>, <a href="/search/cond-mat?searchtype=author&query=Shimada%2C+K">Kenya Shimada</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sooyeon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Kisslinger%2C+K">Kim Kisslinger</a>, <a href="/search/cond-mat?searchtype=author&query=Kaznatcheev%2C+K">Konstantine Kaznatcheev</a>, <a href="/search/cond-mat?searchtype=author&query=Vescovo%2C+E">Elio Vescovo</a>, <a href="/search/cond-mat?searchtype=author&query=Sinkovic%2C+B">Boris Sinkovic</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="2006.13447v1-abstract-short" style="display: inline;"> Dispersionless flat bands are proposed to be a fundamental ingredient to achieve the various sought after quantum states of matter including high-temperature superconductivity1-4 and fractional quantum Hall effect5-6. Materials with such peculiar electronic states, however, are very rare and often exhibit very complex band structures. Here, we report on the emergence of a flat band with a possible… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.13447v1-abstract-full').style.display = 'inline'; document.getElementById('2006.13447v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.13447v1-abstract-full" style="display: none;"> Dispersionless flat bands are proposed to be a fundamental ingredient to achieve the various sought after quantum states of matter including high-temperature superconductivity1-4 and fractional quantum Hall effect5-6. Materials with such peculiar electronic states, however, are very rare and often exhibit very complex band structures. Here, we report on the emergence of a flat band with a possible insulating ground state in the sub-monolayer VSe2 / Bi2Se3 heterostructure by means of angle-resolved photoemission spectroscopy and scanning tunneling microscopy. The flat band is dispersionless along the kll and kz momenta, filling the entire Brillouin zone, and it exhibits a complex circular dichroism signal reversing the sign at several points of the Brillouin zone. These properties together with the presence of a Moir茅 patterns in VSe2 suggest that the flat band is not a trivial disorder or confinement effect and could even be topologically non-trivial. Another intriguing finding is that the flat band does not modify the Dirac cone of Bi2Se3 around the Dirac point. Furthermore, we found that the flat band and the Dirac surface states of Bi2Se3 have opposite energy shifts with electron doping. This opens a novel way of controlling the spin texture of photocurrents as well as the transport properties of the heterostructure. These features make this flat band remarkably distinguishable from previous findings and our methodology can be applied to other systems opening a promising pathway to realize strongly correlated quantum effects in topological materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.13447v1-abstract-full').style.display = 'none'; document.getElementById('2006.13447v1-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 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">25 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/2006.10669">arXiv:2006.10669</a> <span> [<a href="https://arxiv.org/pdf/2006.10669">pdf</a>, <a href="https://arxiv.org/format/2006.10669">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> <p class="title is-5 mathjax"> Influence of Ti/V Cation-Exchange in Na$_2$Ti$_3$O$_7$ on Na-Ion Negative Electrode Performance: an Insight from First-Principles Study </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yu%2C+C">Chol-Jun Yu</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Suk-Gyong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Pak%2C+Y">Yong-Chol Pak</a>, <a href="/search/cond-mat?searchtype=author&query=Choe%2C+S">Song-Hyok Choe</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J">Jin-Song Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Ri%2C+K">Kum-Chol Ri</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="2006.10669v1-abstract-short" style="display: inline;"> Sodium-titanate \ce{Na2Ti3O7} (NTO) is regarded as a highly promising anode material with a very low voltage for Na-ion batteries and capacitors, but suffered from relatively low specific capacity and poor electron conductivity. Here we report a first-principles study of electrochemical properties of NTO and its vanadium-modified compounds, \ce{Na2Ti2VO7} and \ce{Na2TiV2O7} (NTVO), offering an ins… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.10669v1-abstract-full').style.display = 'inline'; document.getElementById('2006.10669v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.10669v1-abstract-full" style="display: none;"> Sodium-titanate \ce{Na2Ti3O7} (NTO) is regarded as a highly promising anode material with a very low voltage for Na-ion batteries and capacitors, but suffered from relatively low specific capacity and poor electron conductivity. Here we report a first-principles study of electrochemical properties of NTO and its vanadium-modified compounds, \ce{Na2Ti2VO7} and \ce{Na2TiV2O7} (NTVO), offering an insight into their detailed working mechanism and an evidence of enhancing anode performance by Ti/V cation exchange. Our calculations reveal that the specific capacity can increase from 177 mAh g$^{-1}$ in NTO to over 280 mAh g$^{-1}$ in NTVO when using \ce{NaTi_{3-$x$}V_{$x$}O7} ($x$ = 1, 2) as a starting material for Na insertion due to higher oxidation state of \ce{V^{+5}}, together with lower voltages and small volume expansion rates below 3\%. With Ti/V exchange, we obtain slightly higher activation energies for Na ion migrations along the two different pathways, but find an obvious improvement of electronic transport in NTVO. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.10669v1-abstract-full').style.display = 'none'; document.getElementById('2006.10669v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2006.03273">arXiv:2006.03273</a> <span> [<a href="https://arxiv.org/pdf/2006.03273">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/5.0016414">10.1063/5.0016414 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Time-resolved resonant elastic soft X-ray scattering at Pohang Accelerator Laboratory X-ray Free Electron Laser </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Jang%2C+H">Hoyoung Jang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+H">Hyeong-Do Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+M">Minseok Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+S+H">Sang Han Park</a>, <a href="/search/cond-mat?searchtype=author&query=Kwon%2C+S">Soonnam Kwon</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+J+Y">Ju Yeop Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+S">Sang-Youn Park</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+G">Gisu Park</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+S">Seonghan Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Hyun%2C+H">HyoJung Hyun</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sunmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+C">Chae-Soon Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Lim%2C+C">Chae-Yong Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Gang%2C+W">Wonup Gang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+M">Myeongjin Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Heo%2C+S">Seongbeom Heo</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J">Jinhong Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Jung%2C+G">Gigun Jung</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+S">Seungnam Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+J">Jaeku Park</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J">Jihwa Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Shin%2C+H">Hocheol Shin</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+J">Jaehun Park</a>, <a href="/search/cond-mat?searchtype=author&query=Koo%2C+T">Tae-Yeong Koo</a>, <a href="/search/cond-mat?searchtype=author&query=Shin%2C+H">Hyun-Joon Shin</a> , et al. (9 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="2006.03273v2-abstract-short" style="display: inline;"> Resonant elastic X-ray scattering has been widely employed for exploring complex electronic ordering phenomena, like charge, spin, and orbital order, in particular in strongly correlated electronic systems. In addition, recent developments of pump-probe X-ray scattering allow us to expand the investigation of the temporal dynamics of such orders. Here, we introduce a new time-resolved Resonant Sof… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.03273v2-abstract-full').style.display = 'inline'; document.getElementById('2006.03273v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.03273v2-abstract-full" style="display: none;"> Resonant elastic X-ray scattering has been widely employed for exploring complex electronic ordering phenomena, like charge, spin, and orbital order, in particular in strongly correlated electronic systems. In addition, recent developments of pump-probe X-ray scattering allow us to expand the investigation of the temporal dynamics of such orders. Here, we introduce a new time-resolved Resonant Soft X-ray Scattering (tr-RSXS) endstation developed at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). This endstation has an optical laser (wavelength of 800 nm plus harmonics) as the pump source. Based on the commissioning results, the tr-RSXS at PAL-XFEL can deliver a soft X-ray probe (400-1300 eV) with a time resolution about ~100 fs without jitter correction. As an example, the temporal dynamics of a charge density wave on a high-temperature cuprate superconductor is demonstrated. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.03273v2-abstract-full').style.display = 'none'; document.getElementById('2006.03273v2-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 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 figures, 2 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Rev. Sci. Instrum. 91, 083904 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.12650">arXiv:2004.12650</a> <span> [<a href="https://arxiv.org/pdf/2004.12650">pdf</a>, <a href="https://arxiv.org/format/2004.12650">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"> Tailoring high-TN interlayer antiferromagnetism in a van der Waals itinerant magnet </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Seo%2C+J">Junho Seo</a>, <a href="/search/cond-mat?searchtype=author&query=An%2C+E+S">Eun Su An</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+T">Taesu Park</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Soo-Yoon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+G">Gi-Yeop Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+K">Kyung Song</a>, <a href="/search/cond-mat?searchtype=author&query=Oh%2C+E">Eunseok Oh</a>, <a href="/search/cond-mat?searchtype=author&query=Choi%2C+M">Minhyuk Choi</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=Jo%2C+Y+J">Youn Jung Jo</a>, <a href="/search/cond-mat?searchtype=author&query=Yeom%2C+H+W">Han Woong Yeom</a>, <a href="/search/cond-mat?searchtype=author&query=Choi%2C+S">Si-Young Choi</a>, <a href="/search/cond-mat?searchtype=author&query=Shim%2C+J+H">Ji Hoon Shim</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J+S">Jun Sung 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="2004.12650v1-abstract-short" style="display: inline;"> Antiferromagnetic (AFM) van der Waals (vdW) materials provide a novel platform for synthetic AFM spintronics, in which the spin-related functionalities are derived from manipulating spin configurations between the layers. Metallic vdW antiferromagnets are expected to have several advantages over the widely-studied insulating counterparts in switching and detecting the spin states through electrica… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.12650v1-abstract-full').style.display = 'inline'; document.getElementById('2004.12650v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.12650v1-abstract-full" style="display: none;"> Antiferromagnetic (AFM) van der Waals (vdW) materials provide a novel platform for synthetic AFM spintronics, in which the spin-related functionalities are derived from manipulating spin configurations between the layers. Metallic vdW antiferromagnets are expected to have several advantages over the widely-studied insulating counterparts in switching and detecting the spin states through electrical currents but have been much less explored due to the lack of suitable materials. Here, utilizing the extreme sensitivity of the vdW interlayer magnetism to material composition, we report the itinerant antiferromagnetism in Co-doped Fe4GeTe2 with TN ~ 210 K, an order of magnitude increased as compared to other known AFM vdW metals. The resulting spin configurations and orientations are sensitively controlled by doping, magnetic field, temperature, and thickness, which are effectively read out by electrical conduction. These findings manifest strong merits of metallic vdW magnets with tunable interlayer exchange interaction and magnetic anisotropy, suitable for AFM spintronic applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.12650v1-abstract-full').style.display = 'none'; document.getElementById('2004.12650v1-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 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 4 figures, submitted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.02908">arXiv:2004.02908</a> <span> [<a href="https://arxiv.org/pdf/2004.02908">pdf</a>, <a href="https://arxiv.org/format/2004.02908">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Microscopic Relaxation Channels in Materials for Superconducting Qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Premkumar%2C+A">Anjali Premkumar</a>, <a href="/search/cond-mat?searchtype=author&query=Weiland%2C+C">Conan Weiland</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sooyeon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Jaeck%2C+B">Berthold Jaeck</a>, <a href="/search/cond-mat?searchtype=author&query=Place%2C+A+P+M">Alexander P. M. Place</a>, <a href="/search/cond-mat?searchtype=author&query=Waluyo%2C+I">Iradwikanari Waluyo</a>, <a href="/search/cond-mat?searchtype=author&query=Hunt%2C+A">Adrian Hunt</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=Barbour%2C+A">Andi Barbour</a>, <a href="/search/cond-mat?searchtype=author&query=Miller%2C+M+S">Mike S. Miller</a>, <a href="/search/cond-mat?searchtype=author&query=Russo%2C+P">Paola Russo</a>, <a href="/search/cond-mat?searchtype=author&query=Camino%2C+F">Fernando Camino</a>, <a href="/search/cond-mat?searchtype=author&query=Kisslinger%2C+K">Kim Kisslinger</a>, <a href="/search/cond-mat?searchtype=author&query=Tong%2C+X">Xiao Tong</a>, <a href="/search/cond-mat?searchtype=author&query=Hybertsen%2C+M+S">Mark S. Hybertsen</a>, <a href="/search/cond-mat?searchtype=author&query=Houck%2C+A+A">Andrew A. Houck</a>, <a href="/search/cond-mat?searchtype=author&query=Jarrige%2C+I">Ignace Jarrige</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="2004.02908v1-abstract-short" style="display: inline;"> Despite mounting evidence that materials imperfections are a major obstacle to practical applications of superconducting qubits, connections between microscopic material properties and qubit coherence are poorly understood. Here, we perform measurements of transmon qubit relaxation times $T_1$ in parallel with spectroscopy and microscopy of the thin polycrystalline niobium films used in qubit fabr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.02908v1-abstract-full').style.display = 'inline'; document.getElementById('2004.02908v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.02908v1-abstract-full" style="display: none;"> Despite mounting evidence that materials imperfections are a major obstacle to practical applications of superconducting qubits, connections between microscopic material properties and qubit coherence are poorly understood. Here, we perform measurements of transmon qubit relaxation times $T_1$ in parallel with spectroscopy and microscopy of the thin polycrystalline niobium films used in qubit fabrication. By comparing results for films deposited using three techniques, we reveal correlations between $T_1$ and grain size, enhanced oxygen diffusion along grain boundaries, and the concentration of suboxides near the surface. Physical mechanisms connect these microscopic properties to residual surface resistance and $T_1$ through losses arising from the grain boundaries and from defects in the suboxides. Further, experiments show that the residual resistance ratio can be used as a figure of merit for qubit lifetime. This comprehensive approach to understanding qubit decoherence charts a pathway for materials-driven improvements of superconducting qubit performance. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.02908v1-abstract-full').style.display = 'none'; document.getElementById('2004.02908v1-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 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2002.10849">arXiv:2002.10849</a> <span> [<a href="https://arxiv.org/pdf/2002.10849">pdf</a>, <a href="https://arxiv.org/ps/2002.10849">ps</a>, <a href="https://arxiv.org/format/2002.10849">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1751-8121/ab9780">10.1088/1751-8121/ab9780 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Distribution of the number of fitness maxima in Fisher's Geometric Model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Park%2C+S">Su-Chan Park</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sungmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Krug%2C+J">Joachim Krug</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="2002.10849v2-abstract-short" style="display: inline;"> Fisher's geometric model describes biological fitness landscapes by combining a linear map from the discrete space of genotypes to an $n$-dimensional Euclidean phenotype space with a nonlinear, single-peaked phenotype-fitness map. Genotypes are represented by binary sequences of length $L$, and the phenotypic effects of mutations at different sites are represented by $L$ random vectors drawn from… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.10849v2-abstract-full').style.display = 'inline'; document.getElementById('2002.10849v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.10849v2-abstract-full" style="display: none;"> Fisher's geometric model describes biological fitness landscapes by combining a linear map from the discrete space of genotypes to an $n$-dimensional Euclidean phenotype space with a nonlinear, single-peaked phenotype-fitness map. Genotypes are represented by binary sequences of length $L$, and the phenotypic effects of mutations at different sites are represented by $L$ random vectors drawn from an isotropic Gaussian distribution. Recent work has shown that the interplay between the genotypic and phenotypic levels gives rise to a range of different landscape topographies that can be characterised by the number of local fitness maxima. Extending our previous study of the mean number of local maxima, here we focus on the distribution of the number of maxima when the limit $L \to \infty$ is taken at finite $n$. We identify the typical scale of the number of maxima for general $n$, and determine the full scaled probability density and two point correlation function of maxima for the one-dimensional case. We also elaborate on the close relation of the model to the anti-ferromagnetic Hopfield model with $n$ random continuous pattern vectors, and show that many of our results carry over to this setting. More generally, we expect that our analysis can help to elucidate the fluctuation structure of metastable states in various spin glass problems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.10849v2-abstract-full').style.display = 'none'; document.getElementById('2002.10849v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">36 pages, 5 figures. Minor corrections</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J. Phys. A: Math. Theor. 53, 385601 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.02057">arXiv:2001.02057</a> <span> [<a href="https://arxiv.org/pdf/2001.02057">pdf</a>, <a href="https://arxiv.org/format/2001.02057">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="Applied Physics">physics.app-ph</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.4.045402">10.1103/PhysRevMaterials.4.045402 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First-Principles Study on Material Properties and Stability of Inorganic Halide Perovskite Solid Solutions CsPb(I$_{1-x}$Br$_x$)$_3$ towards High Performance Perovskite Solar Cells </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yu%2C+C">Chol-Jun Yu</a>, <a href="/search/cond-mat?searchtype=author&query=Ko%2C+U">Un-Hyok Ko</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Suk-Gyong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+Y">Yun-Sim Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Jong%2C+U">Un-Gi Jong</a>, <a href="/search/cond-mat?searchtype=author&query=Kye%2C+Y">Yun-Hyok Kye</a>, <a href="/search/cond-mat?searchtype=author&query=Ri%2C+C">Chol-Hyok Ri</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="2001.02057v1-abstract-short" style="display: inline;"> All-inorganic halide perovskites have attracted a great interest as a promising light harvester of perovskite solar cells due to their enhanced chemical stability. In this work we investigate the material properties of solid solutions CsPb(I$_{1-x}$Br$_x$)$_3$ in cubic phase by applying the virtual crystal approximation approach within a density functional theory framework. First we check the vali… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.02057v1-abstract-full').style.display = 'inline'; document.getElementById('2001.02057v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.02057v1-abstract-full" style="display: none;"> All-inorganic halide perovskites have attracted a great interest as a promising light harvester of perovskite solar cells due to their enhanced chemical stability. In this work we investigate the material properties of solid solutions CsPb(I$_{1-x}$Br$_x$)$_3$ in cubic phase by applying the virtual crystal approximation approach within a density functional theory framework. First we check the validity of constructed pseudopotentials of the virtual atoms (X = I$_{1-x}$Br$_x$) by verifying that the lattice constants follow the linear function of mixing ratio. We then suggest an idea of using the hybrid HSE functional with linear increasing value of exact exchange term as increasing the Br content x, which produces the band gaps of CsPbX3 in good agreement with the available experimental data. The calculated light absorption coefficients and reflectivity show the systematic varying tendency to the Br content. We calculate the phonon dispersions of CsPbX3, CsX and PbX2 as slightly changing their volumes, revealing the phase instability of CsPbX3 and calculating the thermodynamic potential function differences. By projecting Gibbs free energy differences onto the plane of G = 0, we determine the P - T diagram for CsPbX3 to be stable against the chemical decomposition, highlighting that the area of being stable extends gradually as the Br content increases. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.02057v1-abstract-full').style.display = 'none'; document.getElementById('2001.02057v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Materials 4, 045402 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.00262">arXiv:2001.00262</a> <span> [<a href="https://arxiv.org/pdf/2001.00262">pdf</a>, <a href="https://arxiv.org/format/2001.00262">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10955-020-02664-3">10.1007/s10955-020-02664-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the number of limit cycles in diluted neural networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sungmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Lanza%2C+E">Enrico Lanza</a>, <a href="/search/cond-mat?searchtype=author&query=Parisi%2C+G">Giorgio Parisi</a>, <a href="/search/cond-mat?searchtype=author&query=Rocchi%2C+J">Jacopo Rocchi</a>, <a href="/search/cond-mat?searchtype=author&query=Ruocco%2C+G">Giancarlo Ruocco</a>, <a href="/search/cond-mat?searchtype=author&query=Zamponi%2C+F">Francesco Zamponi</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="2001.00262v1-abstract-short" style="display: inline;"> We consider the storage properties of temporal patterns, i.e. cycles of finite lengths, in neural networks represented by (generally asymmetric) spin glasses defined on random graphs. Inspired by the observation that dynamics on sparse systems have more basins of attractions than the dynamics of densely connected ones, we consider the attractors of a greedy dynamics in sparse topologies, considere… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.00262v1-abstract-full').style.display = 'inline'; document.getElementById('2001.00262v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.00262v1-abstract-full" style="display: none;"> We consider the storage properties of temporal patterns, i.e. cycles of finite lengths, in neural networks represented by (generally asymmetric) spin glasses defined on random graphs. Inspired by the observation that dynamics on sparse systems have more basins of attractions than the dynamics of densely connected ones, we consider the attractors of a greedy dynamics in sparse topologies, considered as proxy for the stored memories. We enumerate them using numerical simulation and extend the analysis to large systems sizes using belief propagation. We find that the logarithm of the number of such cycles is a non monotonic function of the mean connectivity and we discuss the similarities with biological neural networks describing the memory capacity of the hippocampus. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.00262v1-abstract-full').style.display = 'none'; document.getElementById('2001.00262v1-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> 1 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Statistical Physics 181, 2304-2321 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.07307">arXiv:1910.07307</a> <span> [<a href="https://arxiv.org/pdf/1910.07307">pdf</a>, <a href="https://arxiv.org/ps/1910.07307">ps</a>, <a href="https://arxiv.org/format/1910.07307">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</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/PhysRevE.101.052308">10.1103/PhysRevE.101.052308 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Force balance controls the relaxation time of the gradient descent algorithm in the satisfiable phase </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sungmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Ikeda%2C+H">Harukuni Ikeda</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1910.07307v3-abstract-short" style="display: inline;"> We numerically study the relaxation dynamics of the single layer perceptron with the spherical constraint. This is the simplest model of neural networks and serves a prototypical mean-field model of both convex and non-convex optimization problems. The relaxation time of the gradient descent algorithm rapidly increases near the SAT-UNSAT transition point. We numerically confirm that the first non-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.07307v3-abstract-full').style.display = 'inline'; document.getElementById('1910.07307v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.07307v3-abstract-full" style="display: none;"> We numerically study the relaxation dynamics of the single layer perceptron with the spherical constraint. This is the simplest model of neural networks and serves a prototypical mean-field model of both convex and non-convex optimization problems. The relaxation time of the gradient descent algorithm rapidly increases near the SAT-UNSAT transition point. We numerically confirm that the first non-zero eigenvalue of the Hessian controls the relaxation time. This first eigenvalue vanishes much faster upon approaching the SAT-UNSAT transition point than the prediction of Marchenko-Pastur law in random matrix theory derived under the assumption that the set of unsatisfied constraints are uncorrelated. This leads to a non-trivial critical exponent of the relaxation time in the SAT phase. Using a simple scaling analysis, we show that the isolation of this first eigenvalue from the bulk of spectrum is attributed to the force balance at the SAT-UNSAT transition point. Finally, we show that the estimated critical exponent of the relaxation time in the non-convex region agrees very well with that of frictionless spherical particles, which have been studied in the context of the jamming transition of granular materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.07307v3-abstract-full').style.display = 'none'; document.getElementById('1910.07307v3-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 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 12 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. E 101, 052308 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.02269">arXiv:1907.02269</a> <span> [<a href="https://arxiv.org/pdf/1907.02269">pdf</a>, <a href="https://arxiv.org/format/1907.02269">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/10.1021/acs.nanolett.0c01756">10.1021/acs.nanolett.0c01756 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Symmetry dictated grain boundary state in a two-dimensional topological insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kim%2C+H+W">Hyo Won Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+S">Seoung-Hun Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+H">Hyun-Jung Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Chae%2C+K">Kisung Chae</a>, <a href="/search/cond-mat?searchtype=author&query=Cho%2C+S">Suyeon Cho</a>, <a href="/search/cond-mat?searchtype=author&query=Ko%2C+W">Wonhee Ko</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+S+H">Se Hwang Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+H">Heejun Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+S+W">Sung Wng Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+S">Seongjun Park</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S+W">Sung Woo Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Kwon%2C+Y">Young-Kyun Kwon</a>, <a href="/search/cond-mat?searchtype=author&query=Son%2C+Y">Young-Woo Son</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1907.02269v2-abstract-short" style="display: inline;"> Structural imperfections such as grain boundaries (GBs) and dislocations are ubiquitous in solids and have been of central importance in understanding nature of polycrystals. In addition to their classical roles, advent of topological insulators (TIs) offers a chance to realize distinct topological states bound to them. Although dislocation inside three-dimensional TIs is one of the prime candidat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.02269v2-abstract-full').style.display = 'inline'; document.getElementById('1907.02269v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.02269v2-abstract-full" style="display: none;"> Structural imperfections such as grain boundaries (GBs) and dislocations are ubiquitous in solids and have been of central importance in understanding nature of polycrystals. In addition to their classical roles, advent of topological insulators (TIs) offers a chance to realize distinct topological states bound to them. Although dislocation inside three-dimensional TIs is one of the prime candidates to look for, its direct detection and characterization are challenging. Instead, in two-dimensional (2D) TIs, their creations and measurements are easier and, moreover, topological states at the GBs or dislocations intimately connect to their lattice symmetry. However, such roles of crystalline symmetries of GBs in 2D TIs have not been clearly measured yet. Here, we present the first direct evidence of a symmetry enforced Dirac type metallic state along a GB in 1T'-MoTe$_2$, a prototypical 2D TI. Using scanning tunneling microscope, we show a metallic state along a grain boundary with non-symmorphic lattice symmetry and its absence along the other boundary with symmorphic one. Our large scale atomistic simulations demonstrate hourglass like nodal-line semimetallic in-gap states for the former while the gap-opening for the latter, explaining our observation very well. The protected metallic state tightly linked to its crystal symmetry demonstrated here can be used to create stable metallic nanowire inside an insulator. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.02269v2-abstract-full').style.display = 'none'; document.getElementById('1907.02269v2-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 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nano Letters 20(8), 5837-5843 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.00965">arXiv:1907.00965</a> <span> [<a href="https://arxiv.org/pdf/1907.00965">pdf</a>, <a href="https://arxiv.org/format/1907.00965">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevResearch.2.022019">10.1103/PhysRevResearch.2.022019 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On-demand thermoelectric generation of equal-spin Cooper pairs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Keidel%2C+F">Felix Keidel</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Trauzettel%2C+B">Bj枚rn Trauzettel</a>, <a href="/search/cond-mat?searchtype=author&query=Sothmann%2C+B">Bj枚rn Sothmann</a>, <a href="/search/cond-mat?searchtype=author&query=Burset%2C+P">Pablo Burset</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1907.00965v3-abstract-short" style="display: inline;"> Superconducting spintronics is based on the creation of spin-triplet Cooper pairs in ferromagnet-superconductor (F-S) hybrid junctions. Previous proposals to manipulate spin-polarized supercurrents on-demand typically require the ability to carefully control magnetic materials. We, instead, propose a quantum heat engine that generates equal-spin Cooper pairs and drives supercurrents on-demand with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.00965v3-abstract-full').style.display = 'inline'; document.getElementById('1907.00965v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.00965v3-abstract-full" style="display: none;"> Superconducting spintronics is based on the creation of spin-triplet Cooper pairs in ferromagnet-superconductor (F-S) hybrid junctions. Previous proposals to manipulate spin-polarized supercurrents on-demand typically require the ability to carefully control magnetic materials. We, instead, propose a quantum heat engine that generates equal-spin Cooper pairs and drives supercurrents on-demand without manipulating magnetic components. We consider a S-F-S junction, connecting two leads at different temperatures, on top of the helical edge of a two-dimensional topological insulator. Heat and charge currents generated by the thermal bias are caused by different transport processes, where electron cotunneling is responsible for the heat flow to the cold lead and, strikingly, only crossed Andreev reflections contribute to the charge current. Such a purely nonlocal Andreev thermoelectric effect injects spin-polarized Cooper pairs at the superconductors, generating a supercurrent that can be switched on/off by tuning their relative phase. We further demonstrate that signatures of spin-triplet pairing are facilitated by rather low fluctuations of the thermoelectric current for temperature gradients smaller than the superconducting gap. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.00965v3-abstract-full').style.display = 'none'; document.getElementById('1907.00965v3-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, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7+11 pages, 3+6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 2, 022019 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.11988">arXiv:1906.11988</a> <span> [<a href="https://arxiv.org/pdf/1906.11988">pdf</a>, <a href="https://arxiv.org/format/1906.11988">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41598-021-99353-2">10.1038/s41598-021-99353-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Inverse problems for structured datasets using parallel TAP equations and RBM </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Decelle%2C+A">Aur茅lien Decelle</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sungmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Rocchi%2C+J">Jacopo Rocchi</a>, <a href="/search/cond-mat?searchtype=author&query=Tantari%2C+D">Daniele Tantari</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.11988v1-abstract-short" style="display: inline;"> We propose an efficient algorithm to solve inverse problems in the presence of binary clustered datasets. We consider the paradigmatic Hopfield model in a teacher student scenario, where this situation is found in the retrieval phase. This problem has been widely analyzed through various methods such as mean-field approaches or the pseudo-likelihood optimization. Our approach is based on the estim… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.11988v1-abstract-full').style.display = 'inline'; document.getElementById('1906.11988v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.11988v1-abstract-full" style="display: none;"> We propose an efficient algorithm to solve inverse problems in the presence of binary clustered datasets. We consider the paradigmatic Hopfield model in a teacher student scenario, where this situation is found in the retrieval phase. This problem has been widely analyzed through various methods such as mean-field approaches or the pseudo-likelihood optimization. Our approach is based on the estimation of the posterior using the Thouless-Anderson-Palmer (TAP) equations in a parallel updating scheme. At the difference with other methods, it allows to retrieve the exact patterns of the teacher and the parallel update makes it possible to apply it for large system sizes. We also observe that the Approximate Message Passing (AMP) equations do not reproduce the expected behavior in the direct problem, questioning the standard practice used to obtain time indexes coming from Belief Propagation (BP). We tackle the same problem using a Restricted Boltzmann Machine (RBM) and discuss the analogies between the two algorithms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.11988v1-abstract-full').style.display = 'none'; document.getElementById('1906.11988v1-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 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Sci Rep 11, 19990 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.10270">arXiv:1906.10270</a> <span> [<a href="https://arxiv.org/pdf/1906.10270">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</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="Other Condensed Matter">cond-mat.other</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.5108529">10.1063/1.5108529 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Compositionally graded contact layers for MOCVD grown high Al-content AlGaN transistors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Razzak%2C+T">Towhidur Razzak</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Seongmo Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Coleman%2C+A">Antwon Coleman</a>, <a href="/search/cond-mat?searchtype=author&query=Xue%2C+H">Hao Xue</a>, <a href="/search/cond-mat?searchtype=author&query=Sohel%2C+S+H">Shahadat Hasan Sohel</a>, <a href="/search/cond-mat?searchtype=author&query=Bajaj%2C+S">Sanyam Bajaj</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Y">Yuewei Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+W">Wu Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Khan%2C+A">Asif Khan</a>, <a href="/search/cond-mat?searchtype=author&query=Rajan%2C+S">Siddharth Rajan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.10270v2-abstract-short" style="display: inline;"> In this letter, we design and demonstrate an improved MOCVD grown reverse Al-composition graded contact layer to achieve low resistance contact to MOCVD grown ultra-wide bandgap (UWBG) Al0.70Ga0.30N channel metal semiconductor field-effect transistors (MESFETs). Increasing the thickness of the reverse graded layer was found to improve contact layer resistance significantly, leading to contact resi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.10270v2-abstract-full').style.display = 'inline'; document.getElementById('1906.10270v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.10270v2-abstract-full" style="display: none;"> In this letter, we design and demonstrate an improved MOCVD grown reverse Al-composition graded contact layer to achieve low resistance contact to MOCVD grown ultra-wide bandgap (UWBG) Al0.70Ga0.30N channel metal semiconductor field-effect transistors (MESFETs). Increasing the thickness of the reverse graded layer was found to improve contact layer resistance significantly, leading to contact resistance of 3.3x10^-5 Ohm.cm2. Devices with gate length, LG, of 0.6 microns and source-drain spacing, LSD, of 1.5 microns displayed a maximum current density, IDSMAX, of 635 mA/mm with an applied gate voltage, VGS, of +2 V. Breakdown measurements on transistors with gate to drain spacing, LGD, of 770 nm had breakdown voltage greater than 220 , corresponding to minimum breakdown field of 2.86 MV/cm. This work provides a framework for the design of low resistance contacts to MOCVD grown high Al-content AlxGa1-xN channel transistors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.10270v2-abstract-full').style.display = 'none'; document.getElementById('1906.10270v2-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 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 115, 043502 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.09262">arXiv:1905.09262</a> <span> [<a href="https://arxiv.org/pdf/1905.09262">pdf</a>, <a href="https://arxiv.org/format/1905.09262">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1140/epjst/e2019-900094-y">10.1140/epjst/e2019-900094-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phase-coherent caloritronics with ordinary and topological Josephson junctions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Sothmann%2C+B">Bj枚rn Sothmann</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.09262v2-abstract-short" style="display: inline;"> We provide a brief and comprehensive overview over recent developments in the field of phase-coherent caloritronics in ordinary and topological Josephson junctions. We start from the simple case of a short, one-dimensional superconductor-normal metal-superconductor (S-N-S) Josephson junction and derive the phase-dependent thermal conductance within the Bogoliubov-de Gennes formalism. Then, we revi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.09262v2-abstract-full').style.display = 'inline'; document.getElementById('1905.09262v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.09262v2-abstract-full" style="display: none;"> We provide a brief and comprehensive overview over recent developments in the field of phase-coherent caloritronics in ordinary and topological Josephson junctions. We start from the simple case of a short, one-dimensional superconductor-normal metal-superconductor (S-N-S) Josephson junction and derive the phase-dependent thermal conductance within the Bogoliubov-de Gennes formalism. Then, we review the key experimental breakthroughs that have triggered the recent growing interest into phase-coherent heat transport. They include the realization of thermal interferometers, diffractors, modulators and routers based on superconducting tunnel junctions. Finally, we discuss very recent theoretical findings based on superconductor-topological insulator-superconductor (S-TI-S) Josephson junctions that show interesting heat transport properties due to the interplay between topological band structures and superconductivity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.09262v2-abstract-full').style.display = 'none'; document.getElementById('1905.09262v2-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, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">A topical review invited from EPJ ST Special Issues; 23 pages, 8 figures, 120 references</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Eur. Phys. J. Special Topics 229, 683 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1810.09325">arXiv:1810.09325</a> <span> [<a href="https://arxiv.org/pdf/1810.09325">pdf</a>, <a href="https://arxiv.org/format/1810.09325">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1742-5468/ab11e3">10.1088/1742-5468/ab11e3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the number of limit cycles in asymmetric neural networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sungmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Folli%2C+V">Viola Folli</a>, <a href="/search/cond-mat?searchtype=author&query=Lanza%2C+E">Enrico Lanza</a>, <a href="/search/cond-mat?searchtype=author&query=Parisi%2C+G">Giorgio Parisi</a>, <a href="/search/cond-mat?searchtype=author&query=Ruocco%2C+G">Giancarlo Ruocco</a>, <a href="/search/cond-mat?searchtype=author&query=Zamponi%2C+F">Francesco Zamponi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1810.09325v3-abstract-short" style="display: inline;"> The comprehension of the mechanisms at the basis of the functioning of complexly interconnected networks represents one of the main goals of neuroscience. In this work, we investigate how the structure of recurrent connectivity influences the ability of a network to have storable patterns and in particular limit cycles, by modeling a recurrent neural network with McCulloch-Pitts neurons as a conte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.09325v3-abstract-full').style.display = 'inline'; document.getElementById('1810.09325v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.09325v3-abstract-full" style="display: none;"> The comprehension of the mechanisms at the basis of the functioning of complexly interconnected networks represents one of the main goals of neuroscience. In this work, we investigate how the structure of recurrent connectivity influences the ability of a network to have storable patterns and in particular limit cycles, by modeling a recurrent neural network with McCulloch-Pitts neurons as a content-addressable memory system. A key role in such models is played by the connectivity matrix, which, for neural networks, corresponds to a schematic representation of the "connectome": the set of chemical synapses and electrical junctions among neurons. The shape of the recurrent connectivity matrix plays a crucial role in the process of storing memories. This relation has already been exposed by the work of Tanaka and Edwards, which presents a theoretical approach to evaluate the mean number of fixed points in a fully connected model at thermodynamic limit. Interestingly, further studies on the same kind of model but with a finite number of nodes have shown how the symmetry parameter influences the types of attractors featured in the system. Our study extends the work of Tanaka and Edwards by providing a theoretical evaluation of the mean number of attractors of any given length $L$ for different degrees of symmetry in the connectivity matrices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.09325v3-abstract-full').style.display = 'none'; document.getElementById('1810.09325v3-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 January, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">35 pages, 12 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J. Stat. Mech. (2019) 053402 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1809.09945">arXiv:1809.09945</a> <span> [<a href="https://arxiv.org/pdf/1809.09945">pdf</a>, <a href="https://arxiv.org/format/1809.09945">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.123.160602">10.1103/PhysRevLett.123.160602 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Jamming in multilayer supervised learning models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Franz%2C+S">Silvio Franz</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sungmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Urbani%2C+P">Pierfrancesco Urbani</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1809.09945v3-abstract-short" style="display: inline;"> Critical jamming transitions are characterized by an astonishing degree of universality. Analytic and numerical evidence points to the existence of a large universality class that encompasses finite and infinite dimensional spheres and continuous constraint satisfaction problems (CCSP) such as the non-convex perceptron and related models. In this paper we investigate multilayer neural networks (ML… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.09945v3-abstract-full').style.display = 'inline'; document.getElementById('1809.09945v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1809.09945v3-abstract-full" style="display: none;"> Critical jamming transitions are characterized by an astonishing degree of universality. Analytic and numerical evidence points to the existence of a large universality class that encompasses finite and infinite dimensional spheres and continuous constraint satisfaction problems (CCSP) such as the non-convex perceptron and related models. In this paper we investigate multilayer neural networks (MLNN) learning random associations as models for CCSP which could potentially define different jamming universality classes. As opposed to simple perceptrons and infinite dimensional spheres, which are described by a single effective field in terms of which the constraints appear to be one-dimensional, the description of MLNN, involves multiple fields, and the constraints acquire a multidimensional character. We first study the models numerically and show that similarly to the perceptron, whenever jamming is isostatic, the sphere universality class is recovered, we then write the exact mean-field equations for the models and identify a dimensional reduction mechanism that leads to a scaling regime identical to one of the infinite dimensional spheres. We suggest that this mechanism could be general enough to explain finite dimensional universality. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.09945v3-abstract-full').style.display = 'none'; document.getElementById('1809.09945v3-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, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5+12 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 123, 160602 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.04606">arXiv:1808.04606</a> <span> [<a href="https://arxiv.org/pdf/1808.04606">pdf</a>, <a href="https://arxiv.org/format/1808.04606">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevApplied.10.044062">10.1103/PhysRevApplied.10.044062 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phase-coherent heat circulator based on multi-terminal Josephson junctions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Giazotto%2C+F">Francesco Giazotto</a>, <a href="/search/cond-mat?searchtype=author&query=Sothmann%2C+B">Bj枚rn Sothmann</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="1808.04606v2-abstract-short" style="display: inline;"> We theoretically propose a phase-coherent thermal circulator based on ballistic multiterminal Josephson junctions. The breaking of time-reversal symmetry by either a magnetic flux or a superconducting phase bias allows heat to flow preferentially in one direction from one terminal to the next while heat flow in the opposite direction is suppressed. We find that our device can achieve a high circul… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.04606v2-abstract-full').style.display = 'inline'; document.getElementById('1808.04606v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.04606v2-abstract-full" style="display: none;"> We theoretically propose a phase-coherent thermal circulator based on ballistic multiterminal Josephson junctions. The breaking of time-reversal symmetry by either a magnetic flux or a superconducting phase bias allows heat to flow preferentially in one direction from one terminal to the next while heat flow in the opposite direction is suppressed. We find that our device can achieve a high circulation efficiency over a wide range of parameters and that its performance is robust with respect to the presence of disorder. We provide estimates for the expected heat currents for realistic samples. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.04606v2-abstract-full').style.display = 'none'; document.getElementById('1808.04606v2-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 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 6 figures, published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Applied 10, 044062 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1802.02024">arXiv:1802.02024</a> <span> [<a href="https://arxiv.org/pdf/1802.02024">pdf</a>, <a href="https://arxiv.org/ps/1802.02024">ps</a>, <a href="https://arxiv.org/format/1802.02024">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1742-6596/969/1/012139">10.1088/1742-6596/969/1/012139 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nonlinear heat transport in ferromagnetic-quantum dot-superconducting systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Sanchez%2C+D">David Sanchez</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="1802.02024v1-abstract-short" style="display: inline;"> We analyze the heat current traversing a quantum dot sandwiched between a ferromagnetic and a superconducting electrode. The heat flow generated in response to a voltage bias presents rectification as a function of the gate potential applied to the quantum dot. Remarkably, in the thermally driven case the heat shows a strong diode effect with large asymmetry ratios that can be externally tuned wit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1802.02024v1-abstract-full').style.display = 'inline'; document.getElementById('1802.02024v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1802.02024v1-abstract-full" style="display: none;"> We analyze the heat current traversing a quantum dot sandwiched between a ferromagnetic and a superconducting electrode. The heat flow generated in response to a voltage bias presents rectification as a function of the gate potential applied to the quantum dot. Remarkably, in the thermally driven case the heat shows a strong diode effect with large asymmetry ratios that can be externally tuned with magnetic fields or spin-polarized tunneling. Our results thus demonstrate the importance of hybrid systems as promising candidates for thermal applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1802.02024v1-abstract-full').style.display = 'none'; document.getElementById('1802.02024v1-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, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 3 figures, A contribution paper to the proceedings of LT28 (Sweden, August 2017)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J. Phys.: Conf. Ser. 969, 012139 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1712.03067">arXiv:1712.03067</a> <span> [<a href="https://arxiv.org/pdf/1712.03067">pdf</a>, <a href="https://arxiv.org/format/1712.03067">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.98.161408">10.1103/PhysRevB.98.161408 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Odd-frequency Superconductivity Revealed by Thermopower </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Burset%2C+P">Pablo Burset</a>, <a href="/search/cond-mat?searchtype=author&query=Sothmann%2C+B">Bj枚rn Sothmann</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="1712.03067v2-abstract-short" style="display: inline;"> Superconductivity is characterized by a nonvanishing superconducting pair amplitude. It has a definite symmetry in spin, momentum and frequency (time). While the spin and momentum symmetry have been probed experimentally for different classes of superconductivity, the odd-frequency nature of certain superconducting correlations has not been demonstrated yet in a direct way. Here we propose the the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.03067v2-abstract-full').style.display = 'inline'; document.getElementById('1712.03067v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1712.03067v2-abstract-full" style="display: none;"> Superconductivity is characterized by a nonvanishing superconducting pair amplitude. It has a definite symmetry in spin, momentum and frequency (time). While the spin and momentum symmetry have been probed experimentally for different classes of superconductivity, the odd-frequency nature of certain superconducting correlations has not been demonstrated yet in a direct way. Here we propose the thermopower as an unambiguous way to assess odd-frequency superconductivity. This is possible since the thermoelectric coefficient given by Andreev-like processes is only finite in the presence of odd-frequency superconductivity. We illustrate our general findings with a simple example of a superconductor-quantum dot-ferromagnet hybrid. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.03067v2-abstract-full').style.display = 'none'; document.getElementById('1712.03067v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 December, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 2 figures + supplemental material, published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 98, 161408 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1711.04622">arXiv:1711.04622</a> <span> [<a href="https://arxiv.org/pdf/1711.04622">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1002/adma.201702001">10.1002/adma.201702001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electronic Reconstruction Enhanced Tunneling Conductance at Terrace Edges of Ultrathin Oxide Films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+L">Lingfei Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+R">Rokyeon Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+Y">Yoonkoo Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+C+H">Choong H. Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sangwoon Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Cho%2C+M+R">Myung Rae Cho</a>, <a href="/search/cond-mat?searchtype=author&query=Shin%2C+Y+J">Yeong Jae Shin</a>, <a href="/search/cond-mat?searchtype=author&query=Das%2C+S">Saikat Das</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J+R">Jeong Rae Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Kalinin%2C+S+V">Sergei V. Kalinin</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+M">Miyoung Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+S+M">Sang Mo Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Noh%2C+T+W">Tae Won Noh</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="1711.04622v1-abstract-short" style="display: inline;"> Quantum mechanical tunneling of electrons across ultrathin insulating oxide barriers has been studied extensively for decades due to its great potential in electronic device applications. In the few-nanometer-thick epitaxial oxide films, atomic-scale structural imperfections, such as the ubiquitously existed one-unit-cell-high terrace edges, can dramatically affect the tunneling probability and de… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1711.04622v1-abstract-full').style.display = 'inline'; document.getElementById('1711.04622v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1711.04622v1-abstract-full" style="display: none;"> Quantum mechanical tunneling of electrons across ultrathin insulating oxide barriers has been studied extensively for decades due to its great potential in electronic device applications. In the few-nanometer-thick epitaxial oxide films, atomic-scale structural imperfections, such as the ubiquitously existed one-unit-cell-high terrace edges, can dramatically affect the tunneling probability and device performance. However, the underlying physics has not been investigated adequately. Here, taking ultrathin BaTiO3 films as a model system, we report an intrinsic tunneling conductance enhancement near the terrace edges. Scanning probe microscopy results demonstrate the existence of highly-conductive regions (tens of nanometers-wide) near the terrace edges. First-principles calculations suggest that the terrace edge geometry can trigger an electronic reconstruction, which reduces the effective tunneling barrier width locally. Furthermore, such tunneling conductance enhancement can be discovered in other transition-metal-oxides and controlled by surface termination engineering. The controllable electronic reconstruction could facilitate the implementation of oxide electronic devices and discovery of exotic low-dimensional quantum phases. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1711.04622v1-abstract-full').style.display = 'none'; document.getElementById('1711.04622v1-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 November, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">53 pages, 4 figures, and supporting information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Advanced Materials 1702001, 2017 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1708.02451">arXiv:1708.02451</a> <span> [<a href="https://arxiv.org/pdf/1708.02451">pdf</a>, <a href="https://arxiv.org/ps/1708.02451">ps</a>, <a href="https://arxiv.org/format/1708.02451">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1140/epjb/e2017-80242-1">10.1140/epjb/e2017-80242-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nonlinear electric and thermoelectric Andreev transport through a hybrid quantum dot coupled to ferromagnetic and superconducting leads </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Sanchez%2C+D">David Sanchez</a>, <a href="/search/cond-mat?searchtype=author&query=Lopez%2C+R">Rosa Lopez</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="1708.02451v1-abstract-short" style="display: inline;"> We discuss the nonlinear Andreev current of an interacting quantum dot coupled to spin-polarized and superconducting reservoirs when voltage and temperature biases are applied across the nanostructure. Due to the particle-hole symmetry introduced by the superconducting (S) lead, the subgap spin current vanishes identically. Nevertheless, the Andreev charge current depends on the degree of polariza… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.02451v1-abstract-full').style.display = 'inline'; document.getElementById('1708.02451v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1708.02451v1-abstract-full" style="display: none;"> We discuss the nonlinear Andreev current of an interacting quantum dot coupled to spin-polarized and superconducting reservoirs when voltage and temperature biases are applied across the nanostructure. Due to the particle-hole symmetry introduced by the superconducting (S) lead, the subgap spin current vanishes identically. Nevertheless, the Andreev charge current depends on the degree of polarization in the ferromagnetic (F) contact since the shift of electrostatic internal potential of the conductor depends on spin orientation of the charge carrier. This spin-dependent potential shift characterizes nonlinear responses in our device. We show how the subgap current versus the bias voltage or temperature difference depends on the lead polarization in two cases, namely (i) S-dominant case, when the dot-superconductor tunneling rate ($螕_R$) is much higher than the ferromagnet-dot tunnel coupling ($螕_L$), and (ii) F-dominant case, when $螕_L\gg 螕_R$. For the ferromagnetic dominant case the spin-dependent potential shows a nonmonotonic behavior as the dot level is detuned. Thus the subgap current can also exhibit interesting behaviors such as current rectification and the maximization of thermocurrents with smaller thermal biases when the lead polarization and the quantum dot level are adjusted. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.02451v1-abstract-full').style.display = 'none'; document.getElementById('1708.02451v1-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 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Eur. Phys. J. B 90, 189 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.00651">arXiv:1705.00651</a> <span> [<a href="https://arxiv.org/pdf/1705.00651">pdf</a>, <a href="https://arxiv.org/format/1705.00651">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/10.1016/j.jcrysgro.2017.10.024">10.1016/j.jcrysgro.2017.10.024 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> MBE growth of 2H-MoTe2 and 1T'-MoTe2 on 3D substrates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Vishwanath%2C+S">Suresh Vishwanath</a>, <a href="/search/cond-mat?searchtype=author&query=Sundar%2C+A">Aditya Sundar</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+X">Xinyu Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Azcatl%2C+A">Angelica Azcatl</a>, <a href="/search/cond-mat?searchtype=author&query=Lochocki%2C+E">Edward Lochocki</a>, <a href="/search/cond-mat?searchtype=author&query=Woll%2C+A+R">Arthur R. Woll</a>, <a href="/search/cond-mat?searchtype=author&query=Rouvimov%2C+S">Sergei Rouvimov</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+W+S">Wan Sik Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+N">Ning Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Peng%2C+X">Xin Peng</a>, <a href="/search/cond-mat?searchtype=author&query=Lien%2C+H">Huai-Hsun Lien</a>, <a href="/search/cond-mat?searchtype=author&query=Weisenberger%2C+J">John Weisenberger</a>, <a href="/search/cond-mat?searchtype=author&query=McDonnell%2C+S">Stephen McDonnell</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+M+J">Moon J. Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Dobrowolska%2C+M">Margaret Dobrowolska</a>, <a href="/search/cond-mat?searchtype=author&query=Furdyna%2C+J+K">Jacek K Furdyna</a>, <a href="/search/cond-mat?searchtype=author&query=Shen%2C+K">Kyle Shen</a>, <a href="/search/cond-mat?searchtype=author&query=Wallace%2C+R+M">Robert M. Wallace</a>, <a href="/search/cond-mat?searchtype=author&query=Jena%2C+D">Debdeep Jena</a>, <a href="/search/cond-mat?searchtype=author&query=Xing%2C+H+G">Huili Grace Xing</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="1705.00651v1-abstract-short" style="display: inline;"> MoTe2 is the least explored material in the Molybdenum-chalcogen family, which crystallizes in thermodynamically stable semiconducting 2H phase at \textless 500 C and 1T' metallic phase at higher temperatures. Molecular beam epitaxy (MBE) provides an unique opportunity to tackle the small electronegativity difference between Mo and Te while growing layer by layer away from thermodynamic equilibriu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.00651v1-abstract-full').style.display = 'inline'; document.getElementById('1705.00651v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.00651v1-abstract-full" style="display: none;"> MoTe2 is the least explored material in the Molybdenum-chalcogen family, which crystallizes in thermodynamically stable semiconducting 2H phase at \textless 500 C and 1T' metallic phase at higher temperatures. Molecular beam epitaxy (MBE) provides an unique opportunity to tackle the small electronegativity difference between Mo and Te while growing layer by layer away from thermodynamic equilibrium. For a few-layer MoTe2 grown at a moderate rate of $\sim$6 mins per monolayer under varied Te:Mo flux ratio and substrate temperature, the boundary between the 2 phases in MBE grown MoTe2 on CaF2 is characterized using Reflection high-energy electron diffraction (RHEED), Raman spectroscopy and X-ray photoemission spectroscopy (XPS). Grazing incidence X-ray diffraction (GI-XRD) reveals a grain size of $\sim$90 脜 and presence of twinned grains. XRD, transmission electron miscroscopy, RHEED, low energy electron diffraction along with lack of electrical conductivity modulation by field effect in MBE 2H-MoTe2 on GaAs (111) B show likelihood of excess Te incorporation in the films. Finally, thermal stability and air sensitivity of MBE 2H-MoTe2 is investigated by temperature dependent XRD and XPS, respectively. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.00651v1-abstract-full').style.display = 'none'; document.getElementById('1705.00651v1-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> 1 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Six figure in main tex, 8 figures in SI and 4 tables in main text</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1612.08790">arXiv:1612.08790</a> <span> [<a href="https://arxiv.org/pdf/1612.08790">pdf</a>, <a href="https://arxiv.org/ps/1612.08790">ps</a>, <a href="https://arxiv.org/format/1612.08790">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1534/genetics.116.199497">10.1534/genetics.116.199497 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Genotypic complexity of Fisher's geometric model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sungmin Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+S">Su-Chan Park</a>, <a href="/search/cond-mat?searchtype=author&query=Krug%2C+J">Joachim Krug</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="1612.08790v3-abstract-short" style="display: inline;"> Fisher's geometric model was originally introduced to argue that complex adaptations must occur in small steps because of pleiotropic constraints. When supplemented with the assumption of additivity of mutational effects on phenotypic traits, it provides a simple mechanism for the emergence of genotypic epistasis from the nonlinear mapping of phenotypes to fitness. Of particular interest is the oc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.08790v3-abstract-full').style.display = 'inline'; document.getElementById('1612.08790v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1612.08790v3-abstract-full" style="display: none;"> Fisher's geometric model was originally introduced to argue that complex adaptations must occur in small steps because of pleiotropic constraints. When supplemented with the assumption of additivity of mutational effects on phenotypic traits, it provides a simple mechanism for the emergence of genotypic epistasis from the nonlinear mapping of phenotypes to fitness. Of particular interest is the occurrence of reciprocal sign epistasis, which is a necessary condition for multipeaked genotypic fitness landscapes. Here we compute the probability that a pair of randomly chosen mutations interacts sign epistatically, which is found to decrease with increasing phenotypic dimension $n$, and varies nonmonotonically with the distance from the phenotypic optimum. We then derive expressions for the mean number of fitness maxima in genotypic landscapes comprised of all combinations of $L$ random mutations. This number increases exponentially with $L$, and the corresponding growth rate is used as a measure of the complexity of the landscape. The dependence of the complexity on the model parameters is found to be surprisingly rich, and three distinct phases characterized by different landscape structures are identified. Our analysis shows that the phenotypic dimension, which is often referred to as phenotypic complexity, does not generally correlate with the complexity of fitness landscapes and that even organisms with a single phenotypic trait can have complex landscapes. Our results further inform the interpretation of experiments where the parameters of Fisher's model have been inferred from data, and help to elucidate which features of empirical fitness landscapes can be described by this model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.08790v3-abstract-full').style.display = 'none'; document.getElementById('1612.08790v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 June, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 December, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">27 pages, 14 figures, 2 tables, minor changes (published version)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Genetics 206, 1049 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1607.02626">arXiv:1607.02626</a> <span> [<a href="https://arxiv.org/pdf/1607.02626">pdf</a>, <a href="https://arxiv.org/ps/1607.02626">ps</a>, <a href="https://arxiv.org/format/1607.02626">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1367-2630/18/9/093024">10.1088/1367-2630/18/9/093024 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A hybrid superconducting quantum dot acting as an efficient charge and spin Seebeck diode </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Sanchez%2C+D">David Sanchez</a>, <a href="/search/cond-mat?searchtype=author&query=Lopez%2C+R">Rosa Lopez</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="1607.02626v2-abstract-short" style="display: inline;"> We propose a highly efficient thermoelectric diode device built from the coupling of a quantum dot with a normal or ferromagnetic electrode and a superconducting reservoir. The current shows a strongly nonlinear behavior in the forward direction (positive thermal gradients) while it almost vanishes in the backward direction (negative thermal gradients). Our discussion is supported by a gauge-invar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.02626v2-abstract-full').style.display = 'inline'; document.getElementById('1607.02626v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1607.02626v2-abstract-full" style="display: none;"> We propose a highly efficient thermoelectric diode device built from the coupling of a quantum dot with a normal or ferromagnetic electrode and a superconducting reservoir. The current shows a strongly nonlinear behavior in the forward direction (positive thermal gradients) while it almost vanishes in the backward direction (negative thermal gradients). Our discussion is supported by a gauge-invariant current-conserving transport theory accounting for electron-electron interactions inside the dot. We find that the diode behavior is greatly tuned with external gate potentials, Zeeman splittings or lead magnetizations. Our results are thus relevant for the search of novel thermoelectric devices with enhanced functionalities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.02626v2-abstract-full').style.display = 'none'; document.getElementById('1607.02626v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 July, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> New J. Phys. 18, 093024 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1605.07558">arXiv:1605.07558</a> <span> [<a href="https://arxiv.org/pdf/1605.07558">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="Chemical Physics">physics.chem-ph</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/10.3938/jkps.69.282">10.3938/jkps.69.282 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Reinforced magnetic properties of Ni-doped BiFeO3 ceramic </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J+S">J. S. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Yoo%2C+Y+J">Y. J. Yoo</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+J+-">J. -H. Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+K+H">K. H. Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+B+W">B. W. Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+S+Y">S. Y. Park</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+Y+P">Y. P. 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="1605.07558v1-abstract-short" style="display: inline;"> Multiferroic materials attract considerable interest because of the wide range of potential applications such as spintronic devices, data storage and sensors. As a strong candidate for the applications among the limited list of single-phase multiferroic materials, BiFeO3 (BFO) is a quite attractive material due to its multiferroic properties at room temperature (RT). However, BFO is widely known t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.07558v1-abstract-full').style.display = 'inline'; document.getElementById('1605.07558v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1605.07558v1-abstract-full" style="display: none;"> Multiferroic materials attract considerable interest because of the wide range of potential applications such as spintronic devices, data storage and sensors. As a strong candidate for the applications among the limited list of single-phase multiferroic materials, BiFeO3 (BFO) is a quite attractive material due to its multiferroic properties at room temperature (RT). However, BFO is widely known to have large leakage current and small spontaneous polarization due to the existence of crystalline defects such as oxygen vacancies. Furthermore, the magnetic moment of pure BFO is very weak owing to its antiferromagnetic nature. In this paper, the effects of Ni2+ substitution on the magnetic properties of bulk BFO have been investigated. BFO, and BiFe0.99Ni0.01O3, BiFe0.98Ni0.02O3 and BiFe0.97Ni0.03O3 (BFNO: Ni-doped BFO) ceramics were prepared by solid-state reaction and rapid sintering, and analyzed by structural and magnetic-property measurements. The leakage current density was measured at RT by using a standard ferroelectric tester. All the Ni-doped BFO exhibit the similar rhombohedral perovskite structure (R3c) to that of BFO. The magnetic properties of Ni-doped BFO are much enhanced with respect to BFO prepared at the same conditions, since the enhanced ferromagnetic interaction is caused by the Fe/Ni coupling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.07558v1-abstract-full').style.display = 'none'; document.getElementById('1605.07558v1-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 May, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2016. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1605.01680">arXiv:1605.01680</a> <span> [<a href="https://arxiv.org/pdf/1605.01680">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 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/10.1063/1.4948770">10.1063/1.4948770 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Large Electron Concentration Modulation using Capacitance Enhancement in SrTiO3/SmTiO3 FinFETs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Verma%2C+A">Amit Verma</a>, <a href="/search/cond-mat?searchtype=author&query=Nomoto%2C+K">Kazuki Nomoto</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+W+S">Wan Sik Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Raghavan%2C+S">Santosh Raghavan</a>, <a href="/search/cond-mat?searchtype=author&query=Stemmer%2C+S">Susanne Stemmer</a>, <a href="/search/cond-mat?searchtype=author&query=Jena%2C+D">Debdeep Jena</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="1605.01680v1-abstract-short" style="display: inline;"> Solid-state modulation of 2-dimensional electron gases (2DEGs) with extreme (~3.3 x 1014 cm-2) densities corresponding to 1/2 electron per interface unit cell at complex oxide heterointerfaces (such as SrTiO3/GdTiO3 or SrTiO3/SmTiO3) is challenging because it requires enormous gate capacitances. One way to achieve large gate capacitances is by geometrical capacitance enhancement in fin structures.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.01680v1-abstract-full').style.display = 'inline'; document.getElementById('1605.01680v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1605.01680v1-abstract-full" style="display: none;"> Solid-state modulation of 2-dimensional electron gases (2DEGs) with extreme (~3.3 x 1014 cm-2) densities corresponding to 1/2 electron per interface unit cell at complex oxide heterointerfaces (such as SrTiO3/GdTiO3 or SrTiO3/SmTiO3) is challenging because it requires enormous gate capacitances. One way to achieve large gate capacitances is by geometrical capacitance enhancement in fin structures. In this work, we fabricate both Au-gated planar field effect transistors (FETs) and Fin-FETs with varying fin-widths on 60nm SrTiO3/5nm SmTiO3 thin films grown by hybrid molecular beam epitaxy (hMBE). We find that the FinFETs exhibit higher gate capacitance compared to planar FETs. By scaling down the SrTiO3/SmTiO3 fin widths, we demonstrate further gate capacitance enhancement, almost twice compared to the planar FETs. In the FinFETs with narrowest fin-widths, we demonstrate a record 2DEG electron concentration modulation of ~2.4 x 1014 cm-2. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.01680v1-abstract-full').style.display = 'none'; document.getElementById('1605.01680v1-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 May, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 108, 183509 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1603.07599">arXiv:1603.07599</a> <span> [<a href="https://arxiv.org/pdf/1603.07599">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Soft Condensed Matter">cond-mat.soft</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/srep23245">10.1038/srep23245 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Chiral nematic self-assembly of minimally surface damaged chitin nanofibrils and its load bearing functions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Oh%2C+D+X">Dongyeop X. Oh</a>, <a href="/search/cond-mat?searchtype=author&query=Cha%2C+Y+J">Yun Jeong Cha</a>, <a href="/search/cond-mat?searchtype=author&query=Nguyen%2C+H">Hoang-Linh Nguyen</a>, <a href="/search/cond-mat?searchtype=author&query=Je%2C+H+H">Hwa Heon Je</a>, <a href="/search/cond-mat?searchtype=author&query=Jho%2C+Y+S">Yong Seok Jho</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+D+S">Dong Soo Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Yoon%2C+D+K">Dong Ki Yoon</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="1603.07599v1-abstract-short" style="display: inline;"> Chitin is one of the most abundant biomaterials in nature, with 10^10 tons produced annually as hierarchically organized nanofibril fillers to reinforce the exoskeletons of arthropods. This green and cheap biomaterial has attracted great attention due to its potential application to reinforce biomedical materials. Despite that, its practical use is limited since the extraction of chitin nanofibril… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.07599v1-abstract-full').style.display = 'inline'; document.getElementById('1603.07599v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1603.07599v1-abstract-full" style="display: none;"> Chitin is one of the most abundant biomaterials in nature, with 10^10 tons produced annually as hierarchically organized nanofibril fillers to reinforce the exoskeletons of arthropods. This green and cheap biomaterial has attracted great attention due to its potential application to reinforce biomedical materials. Despite that, its practical use is limited since the extraction of chitin nanofibrils requires surface modification involving harsh chemical treatments, leading to difficulties in reproducing their natural prototypal hierarchical structure, i.e. chiral nematic phase. Here, we develop a chemical etching-free approach using calcium ions, called natural way, to disintegrate the chitin nanofibrils while keeping the essential moiety for the self-assembly, ultimately resulting in the reproduction of chitins natural chiral structure in a polymeric matrix. This chiral chitin nanostructure exceptionally toughens the composite. Our resultant chiral nematic phase of chitin materials can contribute to the understanding and use of the reinforcing strategy in nature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.07599v1-abstract-full').style.display = 'none'; document.getElementById('1603.07599v1-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 March, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">29 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Sci. Rep., 2016, 6, 23245 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1601.01194">arXiv:1601.01194</a> <span> [<a href="https://arxiv.org/pdf/1601.01194">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Biological Physics">physics.bio-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Soft Condensed Matter">cond-mat.soft</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/10.1088/0957-4484">10.1088/0957-4484 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ternary and senary representations using DNA double-crossover tiles </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kim%2C+B">Byeonghoon Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Jo%2C+S">Soojin Jo</a>, <a href="/search/cond-mat?searchtype=author&query=Son%2C+J">Junyoung Son</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J">Junghoon Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S+U">Si Un Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Dugasani%2C+S+R">Sreekantha Reddy Dugasani</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+M+H">Min Hyeok Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+B">Byung-Dong Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Chang%2C+I">Iksoo Chang</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+W+K">Wing Kam Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+M+K">Moon Ki Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+S+H">Sung Ha Park</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="1601.01194v1-abstract-short" style="display: inline;"> The information capacity of double-crossover (DX) tiles was successfully increased beyond a binary representation to higher base representations. By controlling the length and the position of DNA hairpins on the DX tile, ternary and senary (base-3 and base-6) digit representations were realized and verified by atomic force microscopy (AFM). Also, normal mode analysis (NMA) was carried out to study… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.01194v1-abstract-full').style.display = 'inline'; document.getElementById('1601.01194v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1601.01194v1-abstract-full" style="display: none;"> The information capacity of double-crossover (DX) tiles was successfully increased beyond a binary representation to higher base representations. By controlling the length and the position of DNA hairpins on the DX tile, ternary and senary (base-3 and base-6) digit representations were realized and verified by atomic force microscopy (AFM). Also, normal mode analysis (NMA) was carried out to study the mechanical characteristics of each structure. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.01194v1-abstract-full').style.display = 'none'; document.getElementById('1601.01194v1-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, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages (including supplementary information), 3 main figures, First four authors contributed equally</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nanotechnology, Volume 25, Number 10, 105601 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1512.06242">arXiv:1512.06242</a> <span> [<a href="https://arxiv.org/pdf/1512.06242">pdf</a>, <a href="https://arxiv.org/ps/1512.06242">ps</a>, <a href="https://arxiv.org/format/1512.06242">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.94.054506">10.1103/PhysRevB.94.054506 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Large thermoelectric power and figure of merit in a ferromagnetic-quantum dot-superconducting device </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Lopez%2C+R">Rosa Lopez</a>, <a href="/search/cond-mat?searchtype=author&query=Sanchez%2C+D">David Sanchez</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="1512.06242v2-abstract-short" style="display: inline;"> We investigate the thermoelectric properties of a quantum dot coupled to ferromagnetic and superconducting electrodes. The combination of spin polarized tunneling at the ferromagnetic-quantum dot interface and the application of an external magnetic field that Zeeman splits the dot energy level leads to large values of the thermopower (Seebeck coefficient). Importantly, the thermopower can be tune… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.06242v2-abstract-full').style.display = 'inline'; document.getElementById('1512.06242v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1512.06242v2-abstract-full" style="display: none;"> We investigate the thermoelectric properties of a quantum dot coupled to ferromagnetic and superconducting electrodes. The combination of spin polarized tunneling at the ferromagnetic-quantum dot interface and the application of an external magnetic field that Zeeman splits the dot energy level leads to large values of the thermopower (Seebeck coefficient). Importantly, the thermopower can be tuned with an external gate voltage connected to the dot. We compute the figure of merit that measures the efficiency of thermoelectric conversion and find that it attains high values. We discuss the different contributions from Andreev reflection processes and quasiparticle tunneling into and out of the superconducting contact. Furthermore, we obtain dramatic variations of both the magnetothermopower and the spin Seebeck effect, which suggest that in our device spin currents can be controlled with temperature gradients only. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.06242v2-abstract-full').style.display = 'none'; document.getElementById('1512.06242v2-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 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 December, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 94, 054506 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1511.07325">arXiv:1511.07325</a> <span> [<a href="https://arxiv.org/pdf/1511.07325">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.nanolett.5b03575">10.1021/acs.nanolett.5b03575 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Thickness-dependent Dielectric Constant of Few-layer In2Se3 Nano-flakes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wu%2C+D">Di Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Pak%2C+A+J">Alexander J. Pak</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Y">Yingnan Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+Y">Yu Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+X">Xiaoyu Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+Y">Yihan Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+M">Min Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+Y">Yu Han</a>, <a href="/search/cond-mat?searchtype=author&query=Ren%2C+Y">Yuan Ren</a>, <a href="/search/cond-mat?searchtype=author&query=Peng%2C+H">Hailin Peng</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+Y">Yu-Hao Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+G+S">Gyeong S. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Lai%2C+K">Keji Lai</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="1511.07325v1-abstract-short" style="display: inline;"> The dielectric constant or relative permittivity of a dielectric material, which describes how the net electric field in the medium is reduced with respect to the external field, is a parameter of critical importance for charging and screening in electronic devices. Such a fundamental material property is intimately related to not only the polarizability of individual atoms, but also the specific… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.07325v1-abstract-full').style.display = 'inline'; document.getElementById('1511.07325v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1511.07325v1-abstract-full" style="display: none;"> The dielectric constant or relative permittivity of a dielectric material, which describes how the net electric field in the medium is reduced with respect to the external field, is a parameter of critical importance for charging and screening in electronic devices. Such a fundamental material property is intimately related to not only the polarizability of individual atoms, but also the specific atomic arrangement in the crystal lattice. In this letter, we present both experimental and theoretical investigations on the dielectric constant of few-layer In2Se3 nano-flakes grown on mica substrates by van der Waals epitaxy. A nondestructive microwave impedance microscope is employed to simultaneously quantify the number of layers and local electrical properties. The measured dielectric constant increases monotonically as a function of the thickness and saturates to the bulk value at around 6 ~ 8 quintuple layers. The same trend of layer-dependent dielectric constant is also revealed by first-principle calculations. Our results of the dielectric response, being ubiquitously applicable to layered 2D semiconductors, are expected to be significant for this vibrant research field. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.07325v1-abstract-full').style.display = 'none'; document.getElementById('1511.07325v1-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 November, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 4 figures, 1 table in Nano letters, 2015 ASAP</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1505.03483">arXiv:1505.03483</a> <span> [<a href="https://arxiv.org/pdf/1505.03483">pdf</a>, <a href="https://arxiv.org/ps/1505.03483">ps</a>, <a href="https://arxiv.org/format/1505.03483">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/10.1088/1742-6596/568/5/052016">10.1088/1742-6596/568/5/052016 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Thermoelectric effects in quantum Hall systems beyond linear response </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lopez%2C+R">Rosa Lopez</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Sanchez%2C+D">David Sanchez</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="1505.03483v1-abstract-short" style="display: inline;"> We consider a quantum Hall system with an antidot acting as an energy dependent scatterer. In the purely charge case, we find deviations from the Wiedemann-Franz law that take place in the nonlinear regime of transport. We also discuss Peltier effects beyond linear response and describe both effects using magnetic-field asymmetric transport coefficients. For the spin case such as that arising alon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1505.03483v1-abstract-full').style.display = 'inline'; document.getElementById('1505.03483v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1505.03483v1-abstract-full" style="display: none;"> We consider a quantum Hall system with an antidot acting as an energy dependent scatterer. In the purely charge case, we find deviations from the Wiedemann-Franz law that take place in the nonlinear regime of transport. We also discuss Peltier effects beyond linear response and describe both effects using magnetic-field asymmetric transport coefficients. For the spin case such as that arising along the helical edge states of a two-dimensional topological insulator, we investigate the generation of spin currents as a result of applied voltage and temperature differences in samples attached to ferromagnetic leads. We find that in the parallel configuration the spin current can be tuned with the leads' polarization even in the linear regime of transport. In contrast, for antiparallel magnetizations the spin currents has a strict nonlinear dependence on the applied fields. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1505.03483v1-abstract-full').style.display = 'none'; document.getElementById('1505.03483v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 May, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J. Phys.: Conf. Ser. 568, 052016 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1503.02297">arXiv:1503.02297</a> <span> [<a href="https://arxiv.org/pdf/1503.02297">pdf</a>, <a href="https://arxiv.org/ps/1503.02297">ps</a>, <a href="https://arxiv.org/format/1503.02297">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="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.91.104518">10.1103/PhysRevB.91.104518 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cross thermoelectric coupling in normal-superconductor quantum dots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+S">Sun-Yong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Lopez%2C+R">Rosa Lopez</a>, <a href="/search/cond-mat?searchtype=author&query=Sanchez%2C+D">David Sanchez</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="1503.02297v1-abstract-short" style="display: inline;"> We discuss the nonlinear current of an interacting quantum dot coupled to normal and superconducting reservoirs with applied voltage and temperature differences. Due to the particle-hole symmetry introduced by the superconducting lead, the pure (subgap) thermoelectric response vanishes. However, we show that the Andreev bound states shift as the thermal gradient increases. As a consequence, the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1503.02297v1-abstract-full').style.display = 'inline'; document.getElementById('1503.02297v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1503.02297v1-abstract-full" style="display: none;"> We discuss the nonlinear current of an interacting quantum dot coupled to normal and superconducting reservoirs with applied voltage and temperature differences. Due to the particle-hole symmetry introduced by the superconducting lead, the pure (subgap) thermoelectric response vanishes. However, we show that the Andreev bound states shift as the thermal gradient increases. As a consequence, the $I$--$V$ characteristic can be tuned with a temperature bias if the system is simultaneously voltage biased. This is a cross effect that occurs beyond linear response only. Furthermore, we emphasize the role of quasiparticle tunneling processes in the generation of high thermopower sensitivities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1503.02297v1-abstract-full').style.display = 'none'; document.getElementById('1503.02297v1-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 March, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> NSF-KITP-15-031 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 91, 104518 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1411.6000">arXiv:1411.6000</a> <span> [<a href="https://arxiv.org/pdf/1411.6000">pdf</a>, <a href="https://arxiv.org/format/1411.6000">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/10.1063/1.4906066">10.1063/1.4906066 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Synthesized multiwall MoS2 nanotube and nanoribbon field-effect transistors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Fathipour%2C+S">Sara Fathipour</a>, <a href="/search/cond-mat?searchtype=author&query=Remskar%2C+M">Maja Remskar</a>, <a href="/search/cond-mat?searchtype=author&query=Varlec%2C+A">Ana Varlec</a>, <a href="/search/cond-mat?searchtype=author&query=Ajoy%2C+A">Arvind Ajoy</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+R">Rusen Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Vishwanath%2C+S">Suresh Vishwanath</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+W+S">Wan Sik Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Huili"> Huili</a>, <a href="/search/cond-mat?searchtype=author&query=Xing"> Xing</a>, <a href="/search/cond-mat?searchtype=author&query=Jena%2C+D">Debdeep Jena</a>, <a href="/search/cond-mat?searchtype=author&query=Seabaugh%2C+A">Alan Seabaugh</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="1411.6000v1-abstract-short" style="display: inline;"> We report on the fabrication and characterization of synthesized multiwall MoS2 nanotube (NT) and nanoribbon (NR) field-effect transistors (FETs). The MoS2 NTs and NRs were grown by chemical transport, using iodine as a transport agent. Raman spectroscopy confirms the material as unambiguously MoS2 in NT, NR, and flake forms. Transmission electron microscopy was used to observe cross sections of t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.6000v1-abstract-full').style.display = 'inline'; document.getElementById('1411.6000v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1411.6000v1-abstract-full" style="display: none;"> We report on the fabrication and characterization of synthesized multiwall MoS2 nanotube (NT) and nanoribbon (NR) field-effect transistors (FETs). The MoS2 NTs and NRs were grown by chemical transport, using iodine as a transport agent. Raman spectroscopy confirms the material as unambiguously MoS2 in NT, NR, and flake forms. Transmission electron microscopy was used to observe cross sections of the devices after electrical measurements and these were used in the interpretation of the electrical measurements allowing estimation of the current density. The NT and NR FETs demonstrate n-type behavior, with ON/OFF current ratios exceeding 10^3, and with current densities of 1.02 渭A/渭m, and 0.79 渭A/渭m at VDS = 0.3 V and VBG = 1 V, respectively. Photocurrent measurements conducted on a MoS2 NT FET, revealed short-circuit photocurrent of tens of nanoamps under an excitation optical power of 78 渭W and 488 nm wavelength, which corresponds to a responsivity of 460 渭A/W. A long channel transistor model was used to model the common-source characteristics of MoS2 NT and NR FETs and was shown to be consistent with the measured data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.6000v1-abstract-full').style.display = 'none'; document.getElementById('1411.6000v1-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 November, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2014. </p> </li> </ol> <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=Hwang%2C+S&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a 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