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name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author ID</option><option value="help">Help pages</option><option value="full_text">Full text</option></select> <input id="query" name="query" type="text" value="Pan, G"> <ul id="abstracts"><li><input checked id="abstracts-0" name="abstracts" type="radio" value="show"> <label for="abstracts-0">Show abstracts</label></li><li><input id="abstracts-1" name="abstracts" type="radio" value="hide"> <label for="abstracts-1">Hide abstracts</label></li></ul> </div> <div class="box field is-grouped is-grouped-multiline level-item"> <div class="control"> <span class="select is-small"> <select id="size" name="size"><option value="25">25</option><option selected value="50">50</option><option value="100">100</option><option value="200">200</option></select> </span> <label for="size">results per page</label>. </div> <div class="control"> <label for="order">Sort results by</label> <span class="select is-small"> <select id="order" name="order"><option selected value="-announced_date_first">Announcement date (newest first)</option><option value="announced_date_first">Announcement date (oldest first)</option><option value="-submitted_date">Submission date (newest first)</option><option value="submitted_date">Submission date (oldest first)</option><option value="">Relevance</option></select> </span> </div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <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/2409.20009">arXiv:2409.20009</a> <span> [<a href="https://arxiv.org/pdf/2409.20009">pdf</a>, <a href="https://arxiv.org/format/2409.20009">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> High-efficiency quantum Monte Carlo algorithm for extracting entanglement entropy in interacting fermion systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+W">Weilun Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhe Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Mao%2C+B">Bin-Bin Mao</a>, <a href="/search/cond-mat?searchtype=author&query=Shen%2C+H">Heng Shen</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+Z">Zheng Yan</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="2409.20009v2-abstract-short" style="display: inline;"> The entanglement entropy probing novel phases and phase transitions numerically via quantum Monte Carlo has made great achievements in large-scale interacting spin/boson systems. In contrast, the numerical exploration in interacting fermion systems is rare, even though fermion systems attract more attentions in condensed matter. The fundamental restrictions is that the computational cost of fermio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.20009v2-abstract-full').style.display = 'inline'; document.getElementById('2409.20009v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.20009v2-abstract-full" style="display: none;"> The entanglement entropy probing novel phases and phase transitions numerically via quantum Monte Carlo has made great achievements in large-scale interacting spin/boson systems. In contrast, the numerical exploration in interacting fermion systems is rare, even though fermion systems attract more attentions in condensed matter. The fundamental restrictions is that the computational cost of fermion quantum Monte Carlo ($\sim 尾N^3$) is much higher than that of spin/boson ($\sim 尾N$). To tackle the problem cumbersome existent methods of eantanglement entropy calculation, we propose a fermionic quantum Monte Carlo algorithm based on the incremental technique along physical parameters, which greatly improves the efficiency of extracting entanglement entropy. Taking a two-dimensional square lattice Hubbard model as an example, we demonstrate the effectiveness of the algorithm and show the high computation precision. In this simulation, the calculated scaling behavior of the entanglement entropy elucidates the different phases of the Fermi surface and Goldstone modes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.20009v2-abstract-full').style.display = 'none'; document.getElementById('2409.20009v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">Main text: 7 pages, 4 figures. Supplementary Material: 6 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/2403.08642">arXiv:2403.08642</a> <span> [<a href="https://arxiv.org/pdf/2403.08642">pdf</a>, <a href="https://arxiv.org/format/2403.08642">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-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/PhysRevB.110.165152">10.1103/PhysRevB.110.165152 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Reweight-annealing method for evaluating the partition function via quantum Monte Carlo calculations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ding%2C+Y">Yi-Ming Ding</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+J">Jun-Song Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Ma%2C+N">Nvsen Ma</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+C">Chen Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+Z">Zheng Yan</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="2403.08642v5-abstract-short" style="display: inline;"> Efficient and accurate algorithm for partition function, free energy and thermal entropy calculations is of great significance in statistical physics and quantum many-body physics. Here we present an unbiased but low-technical-barrier algorithm within the quantum Monte Carlo framework, which has exceptionally high accuracy and no systemic error. Compared with the conventional specific heat integra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.08642v5-abstract-full').style.display = 'inline'; document.getElementById('2403.08642v5-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.08642v5-abstract-full" style="display: none;"> Efficient and accurate algorithm for partition function, free energy and thermal entropy calculations is of great significance in statistical physics and quantum many-body physics. Here we present an unbiased but low-technical-barrier algorithm within the quantum Monte Carlo framework, which has exceptionally high accuracy and no systemic error. Compared with the conventional specific heat integral method and Wang-Landau sampling algorithm, our method can obtain a much more accurate result of the sub-leading coefficient of the entropy. This method can be widely used in both classical and quantum Monte Carlo simulations and is easy to be parallelized on computer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.08642v5-abstract-full').style.display = 'none'; document.getElementById('2403.08642v5-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">10 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 110.165152 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.01796">arXiv:2403.01796</a> <span> [<a href="https://arxiv.org/pdf/2403.01796">pdf</a>, <a href="https://arxiv.org/format/2403.01796">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Hydrogen is not necessary for superconductivity in topotactically reduced nickelates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Balakrishnan%2C+P+P">Purnima P. Balakrishnan</a>, <a href="/search/cond-mat?searchtype=author&query=Segedin%2C+D+F">Dan Ferenc Segedin</a>, <a href="/search/cond-mat?searchtype=author&query=Chow%2C+L+E">Lin Er Chow</a>, <a href="/search/cond-mat?searchtype=author&query=Quarterman%2C+P">P. Quarterman</a>, <a href="/search/cond-mat?searchtype=author&query=Muramoto%2C+S">Shin Muramoto</a>, <a href="/search/cond-mat?searchtype=author&query=Surendran%2C+M">Mythili Surendran</a>, <a href="/search/cond-mat?searchtype=author&query=Patel%2C+R+K">Ranjan K. Patel</a>, <a href="/search/cond-mat?searchtype=author&query=LaBollita%2C+H">Harrison LaBollita</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G+A">Grace A. Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+Q">Qi Song</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Y">Yang Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Baggari%2C+I+E">Ismail El Baggari</a>, <a href="/search/cond-mat?searchtype=author&query=Jagadish%2C+K">Koushik Jagadish</a>, <a href="/search/cond-mat?searchtype=author&query=Shao%2C+Y">Yu-Tsun Shao</a>, <a href="/search/cond-mat?searchtype=author&query=Goodge%2C+B+H">Berit H. Goodge</a>, <a href="/search/cond-mat?searchtype=author&query=Kourkoutis%2C+L+F">Lena F. Kourkoutis</a>, <a href="/search/cond-mat?searchtype=author&query=Middey%2C+S">Srimanta Middey</a>, <a href="/search/cond-mat?searchtype=author&query=Botana%2C+A+S">Antia S. Botana</a>, <a href="/search/cond-mat?searchtype=author&query=Ravichandran%2C+J">Jayakanth Ravichandran</a>, <a href="/search/cond-mat?searchtype=author&query=Ariando%2C+A">A. Ariando</a>, <a href="/search/cond-mat?searchtype=author&query=Mundy%2C+J+A">Julia A. Mundy</a>, <a href="/search/cond-mat?searchtype=author&query=Grutter%2C+A+J">Alexander J. Grutter</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="2403.01796v1-abstract-short" style="display: inline;"> A key open question in the study of layered superconducting nickelate films is the role that hydrogen incorporation into the lattice plays in the appearance of the superconducting state. Due to the challenges of stabilizing highly crystalline square planar nickelate films, films are prepared by the deposition of a more stable parent compound which is then transformed into the target phase via a to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.01796v1-abstract-full').style.display = 'inline'; document.getElementById('2403.01796v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.01796v1-abstract-full" style="display: none;"> A key open question in the study of layered superconducting nickelate films is the role that hydrogen incorporation into the lattice plays in the appearance of the superconducting state. Due to the challenges of stabilizing highly crystalline square planar nickelate films, films are prepared by the deposition of a more stable parent compound which is then transformed into the target phase via a topotactic reaction with a strongly reducing agent such as CaH$_2$. Recent studies, both experimental and theoretical, have introduced the possibility that the incorporation of hydrogen from the reducing agent into the nickelate lattice may be critical for the superconductivity. In this work, we use secondary ion mass spectrometry to examine superconducting La$_{1-x}$X$_x$NiO$_2$ / SrTiO$_3$ (X = Ca and Sr) and Nd$_6$Ni$_5$O$_{12}$ / NdGaO$_3$ films, along with non-superconducting NdNiO$_2$ / SrTiO$_3$ and (Nd,Sr)NiO$_2$ / SrTiO$_3$. We find no evidence for extensive hydrogen incorporation across a broad range of samples, including both superconducting and non-superconducting films. Theoretical calculations indicate that hydrogen incorporation is broadly energetically unfavorable in these systems, supporting our conclusion that hydrogen incorporation is not generally required to achieve a superconducting state in layered square-planar nickelates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.01796v1-abstract-full').style.display = 'none'; document.getElementById('2403.01796v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">23 pages, 21 figures (including supplemental information)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.14358">arXiv:2401.14358</a> <span> [<a href="https://arxiv.org/pdf/2401.14358">pdf</a>, <a href="https://arxiv.org/format/2401.14358">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Universal collective Larmor-Silin mode emerging in magnetized correlated Dirac fermions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chen%2C+C">Chuang Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Da+Liao%2C+Y">Yuan Da Liao</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+C">Chengkang Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</a>, <a href="/search/cond-mat?searchtype=author&query=Qi%2C+Y">Yang Qi</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="2401.14358v4-abstract-short" style="display: inline;"> Employing large-scale quantum Monte Carlo simulations, we find that in the magnetized interacting Dirac fermion model there emerges a universal collective Larmor-Silin spin wave mode in the transverse dynamical spin susceptibility. Such mode purely originates from the interaction among Dirac fermions and distinguishes itself from the usual particle-hole continuum with finite lifetime and clear dis… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.14358v4-abstract-full').style.display = 'inline'; document.getElementById('2401.14358v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.14358v4-abstract-full" style="display: none;"> Employing large-scale quantum Monte Carlo simulations, we find that in the magnetized interacting Dirac fermion model there emerges a universal collective Larmor-Silin spin wave mode in the transverse dynamical spin susceptibility. Such mode purely originates from the interaction among Dirac fermions and distinguishes itself from the usual particle-hole continuum with finite lifetime and clear dispersion, both at small and large momenta in a large portion of the Brillouin zone. Our unbiased numerical results offer the dynamic signature of this collective excitation in interacting Dirac fermion systems, and provide experimental guidance for inelastic neutron scattering, electron spin resonance, and other spectroscopic approaches in the investigation of such universal collective modes in quantum Moire materials, topological insulators, and quantum spin liquid materials under magnetic field, with quintessential interaction nature beyond the commonly assumed noninteracting Dirac fermion or spinon approximations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.14358v4-abstract-full').style.display = 'none'; document.getElementById('2401.14358v4-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">12 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/2311.03448">arXiv:2311.03448</a> <span> [<a href="https://arxiv.org/pdf/2311.03448">pdf</a>, <a href="https://arxiv.org/format/2311.03448">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-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/PhysRevB.109.205147">10.1103/PhysRevB.109.205147 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An integral algorithm of exponential observables for interacting fermions in quantum Monte Carlo simulation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+B">Bin-Bin Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2311.03448v2-abstract-short" style="display: inline;"> Exponential observables, formulated as $\log \langle e^{\hat{X}}\rangle$ where $\hat{X}$ is an extensive quantity, play a critical role in study of quantum many-body systems, examples of which include the free-energy and entanglement entropy. Given that $e^{X}$ becomes exponentially large (or small) in the thermodynamic limit, accurately computing the expectation value of this exponential quantity… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.03448v2-abstract-full').style.display = 'inline'; document.getElementById('2311.03448v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.03448v2-abstract-full" style="display: none;"> Exponential observables, formulated as $\log \langle e^{\hat{X}}\rangle$ where $\hat{X}$ is an extensive quantity, play a critical role in study of quantum many-body systems, examples of which include the free-energy and entanglement entropy. Given that $e^{X}$ becomes exponentially large (or small) in the thermodynamic limit, accurately computing the expectation value of this exponential quantity presents a significant challenge. In this Letter, we propose a comprehensive algorithm for quantifying these observables in interacting fermion systems, utilizing the determinant quantum Monte Carlo (DQMC) method. We have applied this novel algorithm to the 2D half-filled Hubbard model. At the strong coupling limit, our method showcases a significant accuracy improvement compared to conventional methods that are derived from the internal energy. We also illustrate that this novel approach delivers highly efficient and precise measurements of the nth R茅nyi entanglement entropy. Even more noteworthy is that this improvement comes without incurring increases in computational complexity. This algorithm effectively suppresses exponential fluctuations and can be easily generalized to other models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.03448v2-abstract-full').style.display = 'none'; document.getElementById('2311.03448v2-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">v1</span> submitted 6 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">5 pages, 2 figure</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 109, 205147 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.07380">arXiv:2308.07380</a> <span> [<a href="https://arxiv.org/pdf/2308.07380">pdf</a>, <a href="https://arxiv.org/format/2308.07380">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.132.156503">10.1103/PhysRevLett.132.156503 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Disorder Operator and R茅nyi Entanglement Entropy of Symmetric Mass Generation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Z+H">Zi Hong Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Da+Liao%2C+Y">Yuan Da Liao</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+M">Menghan Song</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+J">Jiarui Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+W">Weilun Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Jian%2C+C">Chao-Ming Jian</a>, <a href="/search/cond-mat?searchtype=author&query=You%2C+Y">Yi-Zhuang You</a>, <a href="/search/cond-mat?searchtype=author&query=Assaad%2C+F+F">Fakher F. Assaad</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+C">Cenke Xu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.07380v5-abstract-short" style="display: inline;"> In recent years a consensus has gradually been reached that the previously proposed deconfined quantum critical point (DQCP) for spin-1/2 systems, an archetypal example of quantum phase transition beyond the classic Landau's paradigm, actually does not correspond to a true unitary conformal field theory (CFT). In this work we carefully investigate another type of quantum phase transition supposedl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.07380v5-abstract-full').style.display = 'inline'; document.getElementById('2308.07380v5-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.07380v5-abstract-full" style="display: none;"> In recent years a consensus has gradually been reached that the previously proposed deconfined quantum critical point (DQCP) for spin-1/2 systems, an archetypal example of quantum phase transition beyond the classic Landau's paradigm, actually does not correspond to a true unitary conformal field theory (CFT). In this work we carefully investigate another type of quantum phase transition supposedly beyond the similar classic paradigm, the so called ``symmetric mass generation" (SMG) transition proposed in recent years. We employ the sharp diagnosis including the scaling of disorder operator and R茅nyi entanglement entropy in large-scale lattice model quantum Monte Carlo simulations. Our results strongly suggest that the SMG transition is indeed an unconventional quantum phase transition and it should correspond to a true $(2+1)d$ unitary CFT. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.07380v5-abstract-full').style.display = 'none'; document.getElementById('2308.07380v5-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 12 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PhysRevLett.132.156503(2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.14064">arXiv:2304.14064</a> <span> [<a href="https://arxiv.org/pdf/2304.14064">pdf</a>, <a href="https://arxiv.org/format/2304.14064">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div 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.109.125404">10.1103/PhysRevB.109.125404 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evolution from quantum anomalous Hall insulator to heavy-fermion semimetal in magic-angle twisted bilayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Huang%2C+C">Cheng Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Heqiu Li</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Dai%2C+X">Xi Dai</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z">Ziyang Meng</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="2304.14064v4-abstract-short" style="display: inline;"> The ground states of twisted bilayer graphene (TBG) at chiral and flat-band limit with integer fillings are known from exact solutions, while their dynamical and thermodynamical properties are revealed by unbiased quantum Monte Carlo (QMC) simulations. However, to elucidate experimental observations of correlated metallic, insulating and superconducting states and their transitions, investigations… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.14064v4-abstract-full').style.display = 'inline'; document.getElementById('2304.14064v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.14064v4-abstract-full" style="display: none;"> The ground states of twisted bilayer graphene (TBG) at chiral and flat-band limit with integer fillings are known from exact solutions, while their dynamical and thermodynamical properties are revealed by unbiased quantum Monte Carlo (QMC) simulations. However, to elucidate experimental observations of correlated metallic, insulating and superconducting states and their transitions, investigations on realistic, or non-chiral cases are vital. Here we employ momentum-space QMC method to investigate the evolution of correlated states in magic-angle TBG away from chiral limit at charge neutrality with polarized spin/valley, which approximates to an experimental case with filling factor $谓=-3$. We find that the ground state evolves from quantum anomalous Hall insulator into an intriguing correlated semimetallic state possessing heavy-fermion features as AA hopping strength reaches experimental values. Such a state resembles the recently proposed heavy-fermion representations with localized electrons residing at AA stacking regions and delocalized electrons itinerating via AB/BA stacking regions. The spectral signatures of the localized and itinerant electrons in the heavy-fermion semimetal phase are revealed, with the connection to experimental results being discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.14064v4-abstract-full').style.display = 'none'; document.getElementById('2304.14064v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 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">11 pages, 12 figures with appendixes</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.14326">arXiv:2303.14326</a> <span> [<a href="https://arxiv.org/pdf/2303.14326">pdf</a>, <a href="https://arxiv.org/format/2303.14326">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey 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="Quantum Physics">quant-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/PhysRevB.108.L081123">10.1103/PhysRevB.108.L081123 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Stable computation of entanglement entropy for 2D interacting fermion systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Da+Liao%2C+Y">Yuan Da Liao</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+W">Weilun Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=D%27Emidio%2C+J">Jonathan D'Emidio</a>, <a href="/search/cond-mat?searchtype=author&query=Qi%2C+Y">Yang Qi</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2303.14326v3-abstract-short" style="display: inline;"> There is no doubt that the information hidden in entanglement entropy (EE), for example, the $n$-th order R茅nyi EE, i.e., $S^{A}_n=\frac{1}{1-n}\ln \Tr (蟻_A^n)$ where $蟻_A=\mathrm{Tr}_{\overline{A}}蟻$ is the reduced density matrix, can be used to infer the organizing principle of 2D interacting fermion systems, ranging from spontaneous symmetry breaking phases, quantum critical points to topologic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.14326v3-abstract-full').style.display = 'inline'; document.getElementById('2303.14326v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.14326v3-abstract-full" style="display: none;"> There is no doubt that the information hidden in entanglement entropy (EE), for example, the $n$-th order R茅nyi EE, i.e., $S^{A}_n=\frac{1}{1-n}\ln \Tr (蟻_A^n)$ where $蟻_A=\mathrm{Tr}_{\overline{A}}蟻$ is the reduced density matrix, can be used to infer the organizing principle of 2D interacting fermion systems, ranging from spontaneous symmetry breaking phases, quantum critical points to topologically ordered states. It is far from clear, however, whether the EE can actually be obtained with the precision required to observe these fundamental features -- usually in the form of universal finite size scaling behavior. Even for the prototypical 2D interacting fermion model -- the Hubbard model, to all existing numerical algorithms, the computation of the EE has not been succeeded with reliable data that the universal scaling regime can be accessed. Here we explain the reason for these unsuccessful attempts in EE computations in quantum Monte Carlo simulations in the past decades and more importantly, show how to overcome the conceptual and computational barrier with the incremental algorithm, such that the stable computation of the EE in 2D interacting fermion systems can be achieved and universal scaling information can be extracted. Relevance towards the experimental 2D interacting fermion systems is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.14326v3-abstract-full').style.display = 'none'; document.getElementById('2303.14326v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">6+4 pages, 4+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. B 108, L081123 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.14283">arXiv:2302.14283</a> <span> [<a href="https://arxiv.org/pdf/2302.14283">pdf</a>, <a href="https://arxiv.org/format/2302.14283">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-023-37117-4">10.1038/s41467-023-37117-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Limits to the strain engineering of layered square-planar nickelate thin films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Segedin%2C+D+F">Dan Ferenc Segedin</a>, <a href="/search/cond-mat?searchtype=author&query=Goodge%2C+B+H">Berit H. Goodge</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G+A">Grace A. Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+Q">Qi Song</a>, <a href="/search/cond-mat?searchtype=author&query=LaBollita%2C+H">Harrison LaBollita</a>, <a href="/search/cond-mat?searchtype=author&query=Jung%2C+M">Myung-Chul Jung</a>, <a href="/search/cond-mat?searchtype=author&query=El-Sherif%2C+H">Hesham El-Sherif</a>, <a href="/search/cond-mat?searchtype=author&query=Doyle%2C+S">Spencer Doyle</a>, <a href="/search/cond-mat?searchtype=author&query=Turkiewicz%2C+A">Ari Turkiewicz</a>, <a href="/search/cond-mat?searchtype=author&query=Taylor%2C+N+K">Nicole K. Taylor</a>, <a href="/search/cond-mat?searchtype=author&query=Mason%2C+J+A">Jarad A. Mason</a>, <a href="/search/cond-mat?searchtype=author&query=N%27Diaye%2C+A+T">Alpha T. N'Diaye</a>, <a href="/search/cond-mat?searchtype=author&query=Paik%2C+H">Hanjong Paik</a>, <a href="/search/cond-mat?searchtype=author&query=Baggari%2C+I+E">Ismail El Baggari</a>, <a href="/search/cond-mat?searchtype=author&query=Botana%2C+A+S">Antia S. Botana</a>, <a href="/search/cond-mat?searchtype=author&query=Kourkoutis%2C+L+F">Lena F. Kourkoutis</a>, <a href="/search/cond-mat?searchtype=author&query=Brooks%2C+C+M">Charles M. Brooks</a>, <a href="/search/cond-mat?searchtype=author&query=Mundy%2C+J+A">Julia A. Mundy</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="2302.14283v1-abstract-short" style="display: inline;"> The layered square-planar nickelates, Nd$_{n+1}$Ni$_{n}$O$_{2n+2}$, are an appealing system to tune the electronic properties of square-planar nickelates via dimensionality; indeed, superconductivity was recently observed in Nd$_{6}$Ni$_{5}$O$_{12}$ thin films. Here, we investigate the role of epitaxial strain in the competing requirements for the synthesis of the $n=3$ Ruddlesden-Popper compound,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.14283v1-abstract-full').style.display = 'inline'; document.getElementById('2302.14283v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.14283v1-abstract-full" style="display: none;"> The layered square-planar nickelates, Nd$_{n+1}$Ni$_{n}$O$_{2n+2}$, are an appealing system to tune the electronic properties of square-planar nickelates via dimensionality; indeed, superconductivity was recently observed in Nd$_{6}$Ni$_{5}$O$_{12}$ thin films. Here, we investigate the role of epitaxial strain in the competing requirements for the synthesis of the $n=3$ Ruddlesden-Popper compound, Nd$_{4}$Ni$_{3}$O$_{10}$, and subsequent reduction to the square-planar phase, Nd$_{4}$Ni$_{3}$O$_{8}$. We synthesize our highest quality Nd$_{4}$Ni$_{3}$O$_{10}$ films under compressive strain on LaAlO$_{3}$ (001), while Nd$_{4}$Ni$_{3}$O$_{10}$ on NdGaO$_{3}$ (110) exhibits tensile strain-induced rock salt faults but retains bulk-like transport properties. A high density of extended defects forms in Nd$_{4}$Ni$_{3}$O$_{10}$ on SrTiO$_{3}$ (001). Films reduced on LaAlO$_{3}$ become insulating and form compressive strain-induced $c$-axis canting defects, while Nd$_{4}$Ni$_{3}$O$_{8}$ films on NdGaO$_{3}$ are metallic. This work provides a pathway to the synthesis of Nd$_{n+1}$Ni$_{n}$O$_{2n+2}$ thin films and sets limits on the ability to strain engineer these compounds via epitaxy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.14283v1-abstract-full').style.display = 'none'; document.getElementById('2302.14283v1-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 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat Commun 14, 1468 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.11742">arXiv:2302.11742</a> <span> [<a href="https://arxiv.org/pdf/2302.11742">pdf</a>, <a href="https://arxiv.org/format/2302.11742">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey 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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> The teaching from entanglement: 2D SU(2) antiferromagnet to valence bond solid deconfined quantum critical points are not conformal </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Da+Liao%2C+Y">Yuan Da Liao</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+W">Weilun Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Qi%2C+Y">Yang Qi</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2302.11742v2-abstract-short" style="display: inline;"> The deconfined quantum critical point (DQCP) -- the enigmatic incarnation of the quantum phase transition beyond the Landau-Ginzburg-Wilson paradigm of symmetries and their spontaneous breaking -- has been proposed and actively pursued for more than two decades. Various 2D quantum many-body lattice models, both in spin/boson and fermion representations have been tested with the state-of-the-art nu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.11742v2-abstract-full').style.display = 'inline'; document.getElementById('2302.11742v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.11742v2-abstract-full" style="display: none;"> The deconfined quantum critical point (DQCP) -- the enigmatic incarnation of the quantum phase transition beyond the Landau-Ginzburg-Wilson paradigm of symmetries and their spontaneous breaking -- has been proposed and actively pursued for more than two decades. Various 2D quantum many-body lattice models, both in spin/boson and fermion representations have been tested with the state-of-the-art numerical techniques and field-theoretical analyses, and yet, the conclusion is still controversial. Experimental realizations of DQCP in the quantum magnet SrCu$_2$(BO$_3$)$_2$ and superconducting quantum criticality in 2D material have either shown first order transition or intermediate phase. The tension between the lattice scale details and the requirement from continuum limit, manifested in the form of the inconsistent critical scaling behavior and violations of generic conformal bootstrap bound, has not been resolved. Here we solve these decades-long controversies from the new and fundamental perspective of the quantum entanglement. We develop the incremental algorithm to compute the entanglement entropy at a fermionic DQCP with unprecedentedly accurate data and reveal the universal coefficient of the logarithmic correction therein is negative and at odds with positivity requirement of the conformal field theory. Together with results in other 2D DQCP lattice models (both in fermion and spin systems), our discoveries clearly demonstrate the 2D SU(2) antiferromagnet to valence bond solid DQCPs are not conformal fixed point and naturally explain the experimental difficulties in finding them. This marks the end of the beginning of unambiguous finding of the quantum phase transitions truely beyond the Landau-Ginzburg-Wilson paradigm, since its suggestion two decades ago. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.11742v2-abstract-full').style.display = 'none'; document.getElementById('2302.11742v2-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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+5 pages, 3+1 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/2301.12438">arXiv:2301.12438</a> <span> [<a href="https://arxiv.org/pdf/2301.12438">pdf</a>, <a href="https://arxiv.org/format/2301.12438">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-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/PhysRevB.110.125141">10.1103/PhysRevB.110.125141 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Defining a universal sign to strictly probe a phase transition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ma%2C+N">Nvsen Ma</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+J">Jun-Song Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+C">Chen Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+Z">Zheng Yan</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="2301.12438v4-abstract-short" style="display: inline;"> The mystery of the infamous sign problem in quantum Monte Carlo simulations mightily restricts applications of the method in fermionic and frustrated systems. A recent work [Science 375, 418 (2022)] made a remarkable breakthrough in the sign problem by pointing out that the sign can be used to probe phase transition. In this work, we proposed a general argument based on the definition of the sign… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.12438v4-abstract-full').style.display = 'inline'; document.getElementById('2301.12438v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.12438v4-abstract-full" style="display: none;"> The mystery of the infamous sign problem in quantum Monte Carlo simulations mightily restricts applications of the method in fermionic and frustrated systems. A recent work [Science 375, 418 (2022)] made a remarkable breakthrough in the sign problem by pointing out that the sign can be used to probe phase transition. In this work, we proposed a general argument based on the definition of the sign that is related to the difference in free energy between the original and reference systems to clarify that the sign problem and phase transition cannot always be strictly related. The sign can exactly probe phase transition only if the free energy in the reference system is flat under variable parameters, which is almost impossible to design. Generally speaking, the conclusion that the sign can probe phase transition is survivorship bias without universality. To solve this problem, we define a modified sign that excludes the influence of the reference system, which can probe the phase transition strictly. The work gives an unbiased solution for detecting phase transition by the new modified sign. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.12438v4-abstract-full').style.display = 'none'; document.getElementById('2301.12438v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 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">Journal ref:</span> Phys. Rev. B 110, 125141 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.07525">arXiv:2211.07525</a> <span> [<a href="https://arxiv.org/pdf/2211.07525">pdf</a>, <a href="https://arxiv.org/ps/2211.07525">ps</a>, <a href="https://arxiv.org/format/2211.07525">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </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/s41567-022-01907-2">10.1038/s41567-022-01907-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Antiferromagnetic metal phase in an electron-doped rare-earth nickelate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Song%2C+Q">Qi Song</a>, <a href="/search/cond-mat?searchtype=author&query=Doyle%2C+S">Spencer Doyle</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G+A">Grace A. Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Baggari%2C+I+E">Ismail El Baggari</a>, <a href="/search/cond-mat?searchtype=author&query=Segedin%2C+D+F">Dan Ferenc Segedin</a>, <a href="/search/cond-mat?searchtype=author&query=Carrizales%2C+D+C">Denisse Cordova Carrizales</a>, <a href="/search/cond-mat?searchtype=author&query=Nordlander%2C+J">Johanna Nordlander</a>, <a href="/search/cond-mat?searchtype=author&query=Tzschaschel%2C+C">Christian Tzschaschel</a>, <a href="/search/cond-mat?searchtype=author&query=Ehrets%2C+J+R">James R. Ehrets</a>, <a href="/search/cond-mat?searchtype=author&query=Hasan%2C+Z">Zubia Hasan</a>, <a href="/search/cond-mat?searchtype=author&query=El-Sherif%2C+H">Hesham El-Sherif</a>, <a href="/search/cond-mat?searchtype=author&query=Krishna%2C+J">Jyoti Krishna</a>, <a href="/search/cond-mat?searchtype=author&query=Hanson%2C+C">Chase Hanson</a>, <a href="/search/cond-mat?searchtype=author&query=LaBollita%2C+H">Harrison LaBollita</a>, <a href="/search/cond-mat?searchtype=author&query=Bostwick%2C+A">Aaron Bostwick</a>, <a href="/search/cond-mat?searchtype=author&query=Jozwiak%2C+C">Chris Jozwiak</a>, <a href="/search/cond-mat?searchtype=author&query=Rotenberg%2C+E">Eli Rotenberg</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+S">Su-Yang Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Lanzara%2C+A">Alessandra Lanzara</a>, <a href="/search/cond-mat?searchtype=author&query=N%27Diaye%2C+A+T">Alpha T. N'Diaye</a>, <a href="/search/cond-mat?searchtype=author&query=Heikes%2C+C+A">Colin A. Heikes</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Y">Yaohua Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Paik%2C+H">Hanjong Paik</a>, <a href="/search/cond-mat?searchtype=author&query=Brooks%2C+C+M">Charles M. Brooks</a>, <a href="/search/cond-mat?searchtype=author&query=Pamuk%2C+B">Betul Pamuk</a> , et al. (6 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="2211.07525v1-abstract-short" style="display: inline;"> Long viewed as passive elements, antiferromagnetic materials have emerged as promising candidates for spintronic devices due to their insensitivity to external fields and potential for high-speed switching. Recent work exploiting spin and orbital effects has identified ways to electrically control and probe the spins in metallic antiferromagnets, especially in noncollinear or noncentrosymmetric sp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.07525v1-abstract-full').style.display = 'inline'; document.getElementById('2211.07525v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.07525v1-abstract-full" style="display: none;"> Long viewed as passive elements, antiferromagnetic materials have emerged as promising candidates for spintronic devices due to their insensitivity to external fields and potential for high-speed switching. Recent work exploiting spin and orbital effects has identified ways to electrically control and probe the spins in metallic antiferromagnets, especially in noncollinear or noncentrosymmetric spin structures. The rare earth nickelate NdNiO3 is known to be a noncollinear antiferromagnet where the onset of antiferromagnetic ordering is concomitant with a transition to an insulating state. Here, we find that for low electron doping, the magnetic order on the nickel site is preserved while electronically a new metallic phase is induced. We show that this metallic phase has a Fermi surface that is mostly gapped by an electronic reconstruction driven by the bond disproportionation. Furthermore, we demonstrate the ability to write to and read from the spin structure via a large zero-field planar Hall effect. Our results expand the already rich phase diagram of the rare-earth nickelates and may enable spintronics applications in this family of correlated oxides. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.07525v1-abstract-full').style.display = 'none'; document.getElementById('2211.07525v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">25 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/2210.11733">arXiv:2210.11733</a> <span> [<a href="https://arxiv.org/pdf/2210.11733">pdf</a>, <a href="https://arxiv.org/format/2210.11733">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.107.L241105">10.1103/PhysRevB.107.L241105 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum Monte Carlo sign bounds, topological Mott insulator and thermodynamic transitions in twisted bilayer graphene model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+B">Bin-Bin Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Heqiu Li</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2210.11733v1-abstract-short" style="display: inline;"> We show that for magic-angle twisted bilayer graphene (TBG) away from charge neutrality, although quantum Monte Carlo (QMC) simulations suffer from the sign problem, the computational complexity is at most polynomial at certain integer fillings. For even integer fillings, this polynomial complexity survives even if an extra inter-valley attractive interaction is introduced, on top of Coulomb repul… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.11733v1-abstract-full').style.display = 'inline'; document.getElementById('2210.11733v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.11733v1-abstract-full" style="display: none;"> We show that for magic-angle twisted bilayer graphene (TBG) away from charge neutrality, although quantum Monte Carlo (QMC) simulations suffer from the sign problem, the computational complexity is at most polynomial at certain integer fillings. For even integer fillings, this polynomial complexity survives even if an extra inter-valley attractive interaction is introduced, on top of Coulomb repulsions. This observation allows us to simulate magic-angle twisted bilayer graphene and to obtain accurate phase diagram and dynamical properties. At the chiral limit and filling $谓=1$, the simulations reveal a thermodynamic transition separating metallic state and a $C=1$ correlated Chern insulator -- topological Mott insulator (TMI) -- and the pseudogap spectrum slightly above the transition temperature. The ground state excitation spectra of the TMI exhibit a spin-valley U(4) Goldstone mode and a time reversal restoring excitonic gap smaller than the single particle gap. These results are qualitatively consistent with the recent experimental findings at zero-field and $谓=1$ filling in $h$-BN nonaligned TBG. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.11733v1-abstract-full').style.display = 'none'; document.getElementById('2210.11733v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.10987">arXiv:2210.10987</a> <span> [<a href="https://arxiv.org/pdf/2210.10987">pdf</a>, <a href="https://arxiv.org/format/2210.10987">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Electronic band structure of a superconducting nickelate probed by the Seebeck coefficient in the disordered limit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Grissonnanche%2C+G">G. Grissonnanche</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G+A">G. A. Pan</a>, <a href="/search/cond-mat?searchtype=author&query=LaBollita%2C+H">H. LaBollita</a>, <a href="/search/cond-mat?searchtype=author&query=Segedin%2C+D+F">D. Ferenc Segedin</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+Q">Q. Song</a>, <a href="/search/cond-mat?searchtype=author&query=Paik%2C+H">H. Paik</a>, <a href="/search/cond-mat?searchtype=author&query=Brooks%2C+C+M">C. M. Brooks</a>, <a href="/search/cond-mat?searchtype=author&query=Beauchesne-Blanchet%2C+E">E. Beauchesne-Blanchet</a>, <a href="/search/cond-mat?searchtype=author&query=Gonz%C3%A1lez%2C+J+L+S">J. L. Santana Gonz谩lez</a>, <a href="/search/cond-mat?searchtype=author&query=Botana%2C+A+S">A. S. Botana</a>, <a href="/search/cond-mat?searchtype=author&query=Mundy%2C+J+A">J. A. Mundy</a>, <a href="/search/cond-mat?searchtype=author&query=Ramshaw%2C+B+J">B. J. Ramshaw</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="2210.10987v3-abstract-short" style="display: inline;"> Superconducting nickelates are a new family of strongly correlated electron materials with a phase diagram closely resembling that of superconducting cuprates. While analogy with the cuprates is natural, very little is known about the metallic state of the nickelates, making these comparisons difficult. We probe the electronic dispersion of thin-film superconducting 5-layer ($n=5$) and metallic 3-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.10987v3-abstract-full').style.display = 'inline'; document.getElementById('2210.10987v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.10987v3-abstract-full" style="display: none;"> Superconducting nickelates are a new family of strongly correlated electron materials with a phase diagram closely resembling that of superconducting cuprates. While analogy with the cuprates is natural, very little is known about the metallic state of the nickelates, making these comparisons difficult. We probe the electronic dispersion of thin-film superconducting 5-layer ($n=5$) and metallic 3-layer ($n=3$) nickelates by measuring the Seebeck coefficient, $S$. We find a temperature-independent and negative $S/T$ for both $n=5$ and $n=3$ nickelates. These results are in stark contrast to the strongly temperature-dependent $S/T$ measured at similar electron filling in the cuprate La$_{1.36}$Nd$_{0.4}$Sr$_{0.24}$CuO$_4$. The electronic structure calculated from density functional theory can reproduce the temperature dependence, sign, and amplitude of $S/T$ in the nickelates using Boltzmann transport theory. This demonstrates that the electronic structure obtained from first-principles calculations provides a reliable description of the Fermiology of superconducting nickelates, and suggests that, despite indications of strong electronic correlations, there are well-defined quasiparticles in the metallic state. Finally, we explain the differences in the Seebeck coefficient between nickelates and cuprates as originating in strong dissimilarities in impurity concentrations. Our study demonstrates that the high elastic scattering limit of the Seebeck coefficient reflects only the underlying band structure of a metal, analogous to the high magnetic field limit of the Hall coefficient. This opens a new avenue for Seebeck measurements to probe the electronic band structures of relatively disordered quantum materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.10987v3-abstract-full').style.display = 'none'; document.getElementById('2210.10987v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">13 pages, 10 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.07133">arXiv:2207.07133</a> <span> [<a href="https://arxiv.org/pdf/2207.07133">pdf</a>, <a href="https://arxiv.org/format/2207.07133">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.130.016401">10.1103/PhysRevLett.130.016401 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Thermodynamic characteristic for correlated flat-band system with quantum anomalous Hall ground state </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+H">Hongyu Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Heqiu Li</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+B">Bin-Bin Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.07133v2-abstract-short" style="display: inline;"> While the ground state phase diagram of the correlated flat-band systems have been intensively investigated, the dynamic and thermodynamic properties of such lattice models are less explored, but it is the latter which is most relevant to the experimental probes (transport, quantum capacitance and spectroscopy) of the quantum moir茅 materials such as twisted bilayer graphene and transition metal di… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.07133v2-abstract-full').style.display = 'inline'; document.getElementById('2207.07133v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.07133v2-abstract-full" style="display: none;"> While the ground state phase diagram of the correlated flat-band systems have been intensively investigated, the dynamic and thermodynamic properties of such lattice models are less explored, but it is the latter which is most relevant to the experimental probes (transport, quantum capacitance and spectroscopy) of the quantum moir茅 materials such as twisted bilayer graphene and transition metal dichalcogenides. Here we show, by means of momentum-space quantum Monte Carlo and exact diagonalization, there exists a unique thermodynamic characteristic for the correlated flat-band models with interaction-driven quantum anomalous Hall (QAH) ground state, namely, the transition from the QAH insulator to the metallic state takes place at a much lower temperature compared with the zero-temperature single-particle gap generated by the long-range Coulomb interaction. Such low transition temperature comes from the proliferation of excitonic particle-hole excitations, which "quantum teleport" the electrons across the gap between different topological bands to restore the broken time-reversal symmetry and give rise to a pronounced enhancement in the charge compressibility. Future experiments, to verify such generic thermodynamic characteristics, are proposed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.07133v2-abstract-full').style.display = 'none'; document.getElementById('2207.07133v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 3 figures with supplemental material</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 130, 016401 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.02123">arXiv:2207.02123</a> <span> [<a href="https://arxiv.org/pdf/2207.02123">pdf</a>, <a href="https://arxiv.org/format/2207.02123">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1674-1056/aca083">10.1088/1674-1056/aca083 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Sport and a Pastime: Model Design and Computation in Quantum Many-Body Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+W">Weilun Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.02123v2-abstract-short" style="display: inline;"> We summarize the recent developments in the model design and computation for a few representative quantum many-body systems, encompassing quantum critical metals beyond the Hertz-Millis-Moriya framework with pseudogap and superconductivity, SYK non-Fermi-liquid with self-tuned quantum criticality and fluctuation induced superconductivity, and the flat-band quantum Moir茅 lattice models in continuum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.02123v2-abstract-full').style.display = 'inline'; document.getElementById('2207.02123v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.02123v2-abstract-full" style="display: none;"> We summarize the recent developments in the model design and computation for a few representative quantum many-body systems, encompassing quantum critical metals beyond the Hertz-Millis-Moriya framework with pseudogap and superconductivity, SYK non-Fermi-liquid with self-tuned quantum criticality and fluctuation induced superconductivity, and the flat-band quantum Moir茅 lattice models in continuum where the interplay of quantum geometry of flat-band wave function and the long-range Coulomb interactions gives rise to novel insulating phases at integer fillings and superconductivity away from them. Although the narrative choreography seems simple, we show how important the appropriate model design and their tailor-made algorithmic developments -- in other words, the scientific imagination inspired by the corresponding fast experimental developments in the aforementioned systems -- compel us to invent and discover new knowledge and insights in the sport and pastime of quantum many-body research. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.02123v2-abstract-full').style.display = 'none'; document.getElementById('2207.02123v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Invited review article on quantum many-body model design and computation. 29 pages + 27 figures. Comments and missing references are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chinese Phys. B 31 127101 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.09173">arXiv:2205.09173</a> <span> [<a href="https://arxiv.org/pdf/2205.09173">pdf</a>, <a href="https://arxiv.org/format/2205.09173">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 class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevMaterials.6.055003">10.1103/PhysRevMaterials.6.055003 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Synthesis and electronic properties of Nd$_{n+1}$Ni$_{n}$O$_{3n+1}$ Ruddlesden-Popper nickelate thin films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G+A">Grace A. Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+Q">Qi Song</a>, <a href="/search/cond-mat?searchtype=author&query=Segedin%2C+D+F">Dan Ferenc Segedin</a>, <a href="/search/cond-mat?searchtype=author&query=Jung%2C+M">Myung-Chul Jung</a>, <a href="/search/cond-mat?searchtype=author&query=El-Sherif%2C+H">Hesham El-Sherif</a>, <a href="/search/cond-mat?searchtype=author&query=Fleck%2C+E+E">Erin E. Fleck</a>, <a href="/search/cond-mat?searchtype=author&query=Goodge%2C+B+H">Berit H. Goodge</a>, <a href="/search/cond-mat?searchtype=author&query=Doyle%2C+S">Spencer Doyle</a>, <a href="/search/cond-mat?searchtype=author&query=Carrizales%2C+D+C">Denisse C贸rdova Carrizales</a>, <a href="/search/cond-mat?searchtype=author&query=N%27Diaye%2C+A+T">Alpha T. N'Diaye</a>, <a href="/search/cond-mat?searchtype=author&query=Shafer%2C+P">Padraic Shafer</a>, <a href="/search/cond-mat?searchtype=author&query=Paik%2C+H">Hanjong Paik</a>, <a href="/search/cond-mat?searchtype=author&query=Kourkoutis%2C+L+F">Lena F. Kourkoutis</a>, <a href="/search/cond-mat?searchtype=author&query=Baggari%2C+I+E">Ismail El Baggari</a>, <a href="/search/cond-mat?searchtype=author&query=Botana%2C+A+S">Antia S. Botana</a>, <a href="/search/cond-mat?searchtype=author&query=Brooks%2C+C+M">Charles M. Brooks</a>, <a href="/search/cond-mat?searchtype=author&query=Mundy%2C+J+A">Julia A. Mundy</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="2205.09173v1-abstract-short" style="display: inline;"> The rare-earth nickelates possess a diverse set of collective phenomena including metal-to-insulator transitions, magnetic phase transitions, and, upon chemical reduction, superconductivity. Here, we demonstrate epitaxial stabilization of layered nickelates in the Ruddlesden-Popper form, Nd$_{n+1}$Ni$_n$O$_{3n+1}$, using molecular beam epitaxy. By optimizing the stoichiometry of the parent perovsk… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.09173v1-abstract-full').style.display = 'inline'; document.getElementById('2205.09173v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.09173v1-abstract-full" style="display: none;"> The rare-earth nickelates possess a diverse set of collective phenomena including metal-to-insulator transitions, magnetic phase transitions, and, upon chemical reduction, superconductivity. Here, we demonstrate epitaxial stabilization of layered nickelates in the Ruddlesden-Popper form, Nd$_{n+1}$Ni$_n$O$_{3n+1}$, using molecular beam epitaxy. By optimizing the stoichiometry of the parent perovskite NdNiO$_3$, we can reproducibly synthesize the $n = 1 - 5$ member compounds. X-ray absorption spectroscopy at the O $K$ and Ni $L$ edges indicate systematic changes in both the nickel-oxygen hybridization level and nominal nickel filling from 3$d^8$ to 3$d^7$ as we move across the series from $n = 1$ to $n = \infty$. The $n = 3 - 5$ compounds exhibit weakly hysteretic metal-to-insulator transitions with transition temperatures that depress with increasing order toward NdNiO$_3$ ($n = \infty)$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.09173v1-abstract-full').style.display = 'none'; document.getElementById('2205.09173v1-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 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">11 pages, 4 figures with Supplemental Information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Materials 6, 055003 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.08777">arXiv:2204.08777</a> <span> [<a href="https://arxiv.org/pdf/2204.08777">pdf</a>, <a href="https://arxiv.org/format/2204.08777">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Lattice">hep-lat</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/B978-0-323-90800-9.00095-0">10.1016/B978-0-323-90800-9.00095-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Sign Problem in Quantum Monte Carlo Simulation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2204.08777v2-abstract-short" style="display: inline;"> Sign problem in quantum Monte Carlo (QMC) simulation appears to be an extremely hard yet interesting problem. In this article, we present a pedagogical overview on the origin of the sign problem in various quantum Monte Carlo simulation techniques, ranging from the world-line and stochastic series expansion Monte Carlo for boson and spin systems to the determinant and momentum-space quantum Monte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.08777v2-abstract-full').style.display = 'inline'; document.getElementById('2204.08777v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.08777v2-abstract-full" style="display: none;"> Sign problem in quantum Monte Carlo (QMC) simulation appears to be an extremely hard yet interesting problem. In this article, we present a pedagogical overview on the origin of the sign problem in various quantum Monte Carlo simulation techniques, ranging from the world-line and stochastic series expansion Monte Carlo for boson and spin systems to the determinant and momentum-space quantum Monte Carlo for interacting fermions. We point out the basis dependency of the sign problem and summarize the progresses to cure, ease and even make use of the sign problem over the years, such as symmetry analysis of the underlying Hamiltonian, basis optimization in writting down the partition functions and many others. Moreover, we state that although traditional lore saying that in case of sign problem, the average sign in QMC simulation approaches zero exponentially fast with the space-time volume of the configurational space, there are recent breakthroughs showing this is not always the case and based on the properties of the partition function for finite size systems, one could distinguish when the average sign has the usual exponential scaling and when it is bestowed with an algebraic scaling at the low temperature limit. Fermionic QMC simulations with such algebraic sign problems have been successfully carried out for extended Hubbard-type and quantum Moir茅 lattice models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.08777v2-abstract-full').style.display = 'none'; document.getElementById('2204.08777v2-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 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">Book chapter for Elsevier Encyclopedia of Condensed Matter Physics. Comments and missing references are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Encyclopedia of Condensed Matter Physics, 2nd edition, Volume 1, Pages 879-893 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2112.06139">arXiv:2112.06139</a> <span> [<a href="https://arxiv.org/pdf/2112.06139">pdf</a>, <a href="https://arxiv.org/format/2112.06139">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Lattice">hep-lat</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</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.106.035121">10.1103/PhysRevB.106.035121 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fermion sign bounds theory in quantum Monte Carlo simulation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+X+Y">Xiao Yan Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2112.06139v2-abstract-short" style="display: inline;"> Sign problem in fermion quantum Monte Carlo (QMC) simulation appears to be an extremely hard problem. Traditional lore passing around for years tells people that when there is a sign problem, the average sign in QMC simulation approaches zero exponentially fast with the space-time volume of the configurational space. We, however, analytically show this is not always the case and manage to find phy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.06139v2-abstract-full').style.display = 'inline'; document.getElementById('2112.06139v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2112.06139v2-abstract-full" style="display: none;"> Sign problem in fermion quantum Monte Carlo (QMC) simulation appears to be an extremely hard problem. Traditional lore passing around for years tells people that when there is a sign problem, the average sign in QMC simulation approaches zero exponentially fast with the space-time volume of the configurational space. We, however, analytically show this is not always the case and manage to find physical bounds for the average sign. Our understanding is based on a direct connection between the sign bounds and a well-defined partition function of reference system and could distinguish when the bounds have the usual exponential scaling, and when they are bestowed on an algebraic scaling at low temperature limit. We analytically explain such algebraic sign problems found in flat band moir茅 lattice models at low temperature limit. At finite temperature, a domain size argument based on sign bounds also explains the connection between sign behavior and finite temperature phase transition. Sign bounds, as a well-defined observable, may have ability to ease or even make use of the sign problem. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.06139v2-abstract-full').style.display = 'none'; document.getElementById('2112.06139v2-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 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 December, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">11 pages, 3 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/2111.10018">arXiv:2111.10018</a> <span> [<a href="https://arxiv.org/pdf/2111.10018">pdf</a>, <a href="https://arxiv.org/format/2111.10018">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.106.184517">10.1103/PhysRevB.106.184517 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Superconductivity and bosonic fluid emerging from Moir茅 flat bands </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Heqiu Li</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2111.10018v4-abstract-short" style="display: inline;"> Although evidence of inter-valley attraction-mediated by phonon or topological fluctuations is accumulating, the origin of superconductivity in the flat-band quantum moir茅 materials remains an open question. Here, instead of attempting to pinpoint the origin of the superconductivity, we aim at identifying universal properties of moir茅 flat bands that shall emerge in the presence of inter-valley at… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.10018v4-abstract-full').style.display = 'inline'; document.getElementById('2111.10018v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.10018v4-abstract-full" style="display: none;"> Although evidence of inter-valley attraction-mediated by phonon or topological fluctuations is accumulating, the origin of superconductivity in the flat-band quantum moir茅 materials remains an open question. Here, instead of attempting to pinpoint the origin of the superconductivity, we aim at identifying universal properties of moir茅 flat bands that shall emerge in the presence of inter-valley attractions. We show that by matching the interaction strength of inter-valley attraction with intra-valley repulsion, the flat-band limit becomes exactly solvable. Away from the flat-band limit, the system can be simulated via quantum Monte Carlo (QMC) methods without sign problem for any fillings. Combining analytic solutions with large-scale numerical simulations, we show that upon increasing temperature, the superconducting phase melts into a bosonic fluid of Cooper pairs with large/diverging compressibility. In contrast to flat-band attractive Hubbard models, where similar effects arise only for on-site interactions, our study indicates this physics is a universal property of moir茅 flat bands, regardless of microscopic details such as the range of interactions and/or spin-oribt couplings. At higher temperature, the boson fluid phase gives its way to a pseudo gap phase, where some Cooper pairs are torn apart by thermal fluctuations, resulting in fermion density of states inside the gap. Unlike the superconducting transition temperature, which is very sensitive to doping and twisting angles, the gap and the temperature scale of the boson fluid phase and the pseudo gap phase are found to be nearly independent of doping level and/or flat-band bandwidth. The relevance of these phases with experimental discoveries in the flat band quantum moir茅 materials is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.10018v4-abstract-full').style.display = 'none'; document.getElementById('2111.10018v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.09726">arXiv:2109.09726</a> <span> [<a href="https://arxiv.org/pdf/2109.09726">pdf</a>, <a href="https://arxiv.org/format/2109.09726">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41563-021-01142-9">10.1038/s41563-021-01142-9 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Superconductivity in a quintuple-layer square-planar nickelate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G+A">Grace A. Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Segedin%2C+D+F">Dan Ferenc Segedin</a>, <a href="/search/cond-mat?searchtype=author&query=LaBollita%2C+H">Harrison LaBollita</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+Q">Qi Song</a>, <a href="/search/cond-mat?searchtype=author&query=Nica%2C+E+M">Emilian M. Nica</a>, <a href="/search/cond-mat?searchtype=author&query=Goodge%2C+B+H">Berit H. Goodge</a>, <a href="/search/cond-mat?searchtype=author&query=Pierce%2C+A+T">Andrew T. Pierce</a>, <a href="/search/cond-mat?searchtype=author&query=Doyle%2C+S">Spencer Doyle</a>, <a href="/search/cond-mat?searchtype=author&query=Novakov%2C+S">Steve Novakov</a>, <a href="/search/cond-mat?searchtype=author&query=Carrizales%2C+D+C">Denisse C贸rdova Carrizales</a>, <a href="/search/cond-mat?searchtype=author&query=N%27Diaye%2C+A+T">Alpha T. N'Diaye</a>, <a href="/search/cond-mat?searchtype=author&query=Shafer%2C+P">Padraic Shafer</a>, <a href="/search/cond-mat?searchtype=author&query=Paik%2C+H">Hanjong Paik</a>, <a href="/search/cond-mat?searchtype=author&query=Heron%2C+J+T">John T. Heron</a>, <a href="/search/cond-mat?searchtype=author&query=Mason%2C+J+A">Jarad A. Mason</a>, <a href="/search/cond-mat?searchtype=author&query=Yacoby%2C+A">Amir Yacoby</a>, <a href="/search/cond-mat?searchtype=author&query=Kourkoutis%2C+L+F">Lena F. Kourkoutis</a>, <a href="/search/cond-mat?searchtype=author&query=Erten%2C+O">Onur Erten</a>, <a href="/search/cond-mat?searchtype=author&query=Brooks%2C+C+M">Charles M. Brooks</a>, <a href="/search/cond-mat?searchtype=author&query=Botana%2C+A+S">Antia S. Botana</a>, <a href="/search/cond-mat?searchtype=author&query=Mundy%2C+J+A">Julia A. Mundy</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="2109.09726v1-abstract-short" style="display: inline;"> Since the discovery of high-temperature superconductivity in the copper oxide materials, there have been sustained efforts to both understand the origins of this phase and discover new cuprate-like superconducting materials. One prime materials platform has been the rare-earth nickelates and indeed superconductivity was recently discovered in the doped compound Nd$_{0.8}$Sr$_{0.2}$NiO$_2$. Undoped… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.09726v1-abstract-full').style.display = 'inline'; document.getElementById('2109.09726v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.09726v1-abstract-full" style="display: none;"> Since the discovery of high-temperature superconductivity in the copper oxide materials, there have been sustained efforts to both understand the origins of this phase and discover new cuprate-like superconducting materials. One prime materials platform has been the rare-earth nickelates and indeed superconductivity was recently discovered in the doped compound Nd$_{0.8}$Sr$_{0.2}$NiO$_2$. Undoped NdNiO$_2$ belongs to a series of layered square-planar nickelates with chemical formula Nd$_{n+1}$Ni$_n$O$_{2n+2}$ and is known as the 'infinite-layer' ($n = \infty$) nickelate. Here, we report the synthesis of the quintuple-layer ($n = 5$) member of this series, Nd$_6$Ni$_5$O$_{12}$, in which optimal cuprate-like electron filling ($d^{8.8}$) is achieved without chemical doping. We observe a superconducting transition beginning at $\sim$13 K. Electronic structure calculations, in tandem with magnetoresistive and spectroscopic measurements, suggest that Nd$_6$Ni$_5$O$_{12}$ interpolates between cuprate-like and infinite-layer nickelate-like behavior. In engineering a distinct superconducting nickelate, we identify the square-planar nickelates as a new family of superconductors which can be tuned via both doping and dimensionality. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.09726v1-abstract-full').style.display = 'none'; document.getElementById('2109.09726v1-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 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">21 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Materials (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.12559">arXiv:2108.12559</a> <span> [<a href="https://arxiv.org/pdf/2108.12559">pdf</a>, <a href="https://arxiv.org/format/2108.12559">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.105.L121110">10.1103/PhysRevB.105.L121110 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dynamical properties of collective excitations in twisted bilayer Graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Heqiu Li</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2108.12559v4-abstract-short" style="display: inline;"> Employing the recently developed momentum-space quantum Monte Carlo scheme, we study the dynamic response of single-particle and collective excitations in realistic continuum models of twisted bilayer graphene. At charge neutrality, this unbiased numerical method reveals strong competition between different symmetry breaking channels with a leading instability towards the intervalley coherent stat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.12559v4-abstract-full').style.display = 'inline'; document.getElementById('2108.12559v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.12559v4-abstract-full" style="display: none;"> Employing the recently developed momentum-space quantum Monte Carlo scheme, we study the dynamic response of single-particle and collective excitations in realistic continuum models of twisted bilayer graphene. At charge neutrality, this unbiased numerical method reveals strong competition between different symmetry breaking channels with a leading instability towards the intervalley coherent state. Single-particle spectra indicate that repulsive interactions push the fermion spectral weight away from the Fermi energy and open up an insulating gap. The spectra of collective excitations suggest an approximate valley $SU(2)$ symmetry. At low-energy, long-lived valley waves are observed, which resemble spin waves of Heisenberg ferromagnetism. At high-energy, these sharp modes quickly become over-damped, when their energy reaches the fermion particle-hole continuum. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.12559v4-abstract-full').style.display = 'none'; document.getElementById('2108.12559v4-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 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">4 pages, 2 figures with supplemental material</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 105, L121110 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2105.07010">arXiv:2105.07010</a> <span> [<a href="https://arxiv.org/pdf/2105.07010">pdf</a>, <a href="https://arxiv.org/format/2105.07010">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0256-307X/38/7/077305">10.1088/0256-307X/38/7/077305 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Momentum space quantum Monte Carlo on twisted bilayer Graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Y">Yi Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Kang%2C+J">Jian Kang</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2105.07010v3-abstract-short" style="display: inline;"> We report an implementation of the momentum space quantum Monte Carlo (QMC) method on the interaction model for the twisted bilayer graphene (TBG) at integer fillings. The long-range Coulomb repulsion is treated exactly with the flat bands, spin and valley degrees of freedom of electrons taking into account. We prove the absence of the minus sign problem for QMC simulation at integer fillings when… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.07010v3-abstract-full').style.display = 'inline'; document.getElementById('2105.07010v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2105.07010v3-abstract-full" style="display: none;"> We report an implementation of the momentum space quantum Monte Carlo (QMC) method on the interaction model for the twisted bilayer graphene (TBG) at integer fillings. The long-range Coulomb repulsion is treated exactly with the flat bands, spin and valley degrees of freedom of electrons taking into account. We prove the absence of the minus sign problem for QMC simulation at integer fillings when either the two valley or the two spin degrees of freedom are considered. By taking the realistic parameters of the twist angle and interlayer tunnelings into the simulation, we benchmark the QMC data with the exact band gap obtained at the chiral limit, to reveal the insulating ground states at the charge neutrality point (CNP). Then, with the exact Green's functions from QMC, we perform stochastic analytic continuation to obtain the first set of single-particle spectral function for the TBG model at CNP. Our momentum space QMC scheme therefore offers the controlled computation pathway for systematic investigation of the electronic states in realistic TBG model at various electron fillings. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.07010v3-abstract-full').style.display = 'none'; document.getElementById('2105.07010v3-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 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">4 pages, 2 figures with supplemental material</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. Lett. 38 077305 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.10755">arXiv:2102.10755</a> <span> [<a href="https://arxiv.org/pdf/2102.10755">pdf</a>, <a href="https://arxiv.org/format/2102.10755">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.103.195108">10.1103/PhysRevB.103.195108 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phase diagram of the spin-1/2 Yukawa-SYK model: Non-Fermi liquid, insulator, and superconductor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+W">Wei Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Davis%2C+A">Andrew Davis</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y">Yuxuan Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2102.10755v3-abstract-short" style="display: inline;"> We analyze the phase diagram of the Yukawa-Sachdev-Ye-Kitaev model, which describes complex fermions randomly interacting with real bosons via a Yukawa coupling, at finite temperatures and varying fermion density. In a recent work [Phys. Rev. Research 2, 033084 (2020)] it has been shown that, upon varying filling or chemical potential, there exists a first-order quantum phase transition between a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.10755v3-abstract-full').style.display = 'inline'; document.getElementById('2102.10755v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.10755v3-abstract-full" style="display: none;"> We analyze the phase diagram of the Yukawa-Sachdev-Ye-Kitaev model, which describes complex fermions randomly interacting with real bosons via a Yukawa coupling, at finite temperatures and varying fermion density. In a recent work [Phys. Rev. Research 2, 033084 (2020)] it has been shown that, upon varying filling or chemical potential, there exists a first-order quantum phase transition between a non-Fermi liquid (nFL) phase and an insulating phase. Here we show that in such a model with time-reversal symmetry this quantum phase transition is preempted by a pairing phase that develops as a low-temperature instability. As a remnant of the would-be nFL-insulator transition, the superconducting critical temperature rapidly decreases beyond a certain chemical potential. On the other hand, depending on parameters the first-order quantum phase transition extend to finite-temperatures and terminate at a thermal critical point, beyond which the nFL and the insulator become the same phase, similar to that of the liquid-gas and metal-insulator transition in real materials. We determine the pairing phase boundary and the location of the thermal critical point via combined analytic and quantum Monte Carlo numeric efforts. Our results provide the model realization of the transition of nFL's towards superconductivity and insulating states, therefore offer a controlled platform for future investigations of the generic phase diagram that hosts nFL, insulator and superconductor and their phase transitions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.10755v3-abstract-full').style.display = 'none'; document.getElementById('2102.10755v3-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 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">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 103, 195108 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.06586">arXiv:2001.06586</a> <span> [<a href="https://arxiv.org/pdf/2001.06586">pdf</a>, <a href="https://arxiv.org/format/2001.06586">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevResearch.3.013250">10.1103/PhysRevResearch.3.013250 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Yukawa-SYK model and Self-tuned Quantum Criticality </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+W">Wei Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Davis%2C+A">Andrew Davis</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y">Yuxuan Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="2001.06586v2-abstract-short" style="display: inline;"> Non-Fermi liquids (NFL) are a class of strongly interacting gapless fermionic systems without long-lived quasiparticle excitations. An important group of NFL model features itinerant fermions coupled to soft bosonic fluctuations near a quantum-critical point (QCP), and are widely believed to capture the essential physics of many unconventional superconductors. However numerically the direct observ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.06586v2-abstract-full').style.display = 'inline'; document.getElementById('2001.06586v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.06586v2-abstract-full" style="display: none;"> Non-Fermi liquids (NFL) are a class of strongly interacting gapless fermionic systems without long-lived quasiparticle excitations. An important group of NFL model features itinerant fermions coupled to soft bosonic fluctuations near a quantum-critical point (QCP), and are widely believed to capture the essential physics of many unconventional superconductors. However numerically the direct observation of a canonical NFL behavior in such systems, characterized by a power-law form in the Green's function, has been elusive. Here we consider a Sachdev-Ye-Kitaev (SYK)-like model with random Yukawa interaction between critical bosons and fermions (dubbed Yukawa-SYK model). We show it is immune from minus-sign problem and hence can be solved exactly via large-scale quantum Monte Carlo simulation beyond the large-$N$ limit accessible to analytical approaches. Our simulation demonstrates the Yukawa-SYK model features "self-tuned quantum criticality", namely the system is critical independent of the bosonic bare mass. We put these results to test at finite $N$, and our unbiased numerics reveal clear evidence of these exotic quantum-critical NFL properties -- the power-law behavior in Green's function of fermions and bosons -- which propels the theoretical understanding of critical Planckian metals and unconventional superconductors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.06586v2-abstract-full').style.display = 'none'; document.getElementById('2001.06586v2-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 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 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">13 pages, 8 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 3, 013250 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.08229">arXiv:1912.08229</a> <span> [<a href="https://arxiv.org/pdf/1912.08229">pdf</a>, <a href="https://arxiv.org/format/1912.08229">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Lattice">hep-lat</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/10.1088/1674-1056/ac4f52">10.1088/1674-1056/ac4f52 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Solving quantum rotor model with different Monte Carlo techniques </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+W">Weilun Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Y">Yuzhi Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1912.08229v4-abstract-short" style="display: inline;"> We systematically test the performance of several Monte Carlo update schemes for the $(2+1)$d XY phase transition of quantum rotor model. By comparing the local Metropolis (LM), LM plus over-relaxation (OR), Wolff-cluster (WC), hybrid Monte Carlo (HM), hybrid Monte Carlo with Fourier acceleration (FA) scheme, it is clear that among the five different update schemes, at the quantum critical point,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.08229v4-abstract-full').style.display = 'inline'; document.getElementById('1912.08229v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.08229v4-abstract-full" style="display: none;"> We systematically test the performance of several Monte Carlo update schemes for the $(2+1)$d XY phase transition of quantum rotor model. By comparing the local Metropolis (LM), LM plus over-relaxation (OR), Wolff-cluster (WC), hybrid Monte Carlo (HM), hybrid Monte Carlo with Fourier acceleration (FA) scheme, it is clear that among the five different update schemes, at the quantum critical point, the WC and FA schemes acquire the smallest autocorrelation time and cost the least amount of CPU hours in achieving the same level of relative error, and FA enjoys a further advantage of easily implementable for more complicated interactions such as the long-range ones. These results bestow one with the necessary knowledge of extending the quantum rotor model, which plays the role of ferromagnetic/antiferromagnetic critical bosons or Z$_2$ topological order, to more realistic and yet challenging models such as Fermi surface Yukawa-coupled to quantum rotor models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.08229v4-abstract-full').style.display = 'none'; document.getElementById('1912.08229v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. B 31, 040504 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.01814">arXiv:1912.01814</a> <span> [<a href="https://arxiv.org/pdf/1912.01814">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="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Graphene-assisted preparation of large-scale single crystal Ag(111) nanoparticle arrays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Dong%2C+Y">Yibo Dong</a>, <a href="/search/cond-mat?searchtype=author&query=Xie%2C+Y">Yiyang Xie</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+L">Liangchen Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+C">Chen Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Guo%2C+W">Weiling Guo</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Guanzhong Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Q">Qiuhua Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Qian%2C+F">Fengsong Qian</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+J">Jie Sun</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1912.01814v1-abstract-short" style="display: inline;"> Surface plasmon resonance of metal nanostructures has broad application prospects in the fields of photocatalysis, optical sensing, biomarkers and surface-enhanced Raman scattering. This paper reports a graphene-assisted method for preparing large-scale single crystal Ag(111) nanoparticle arrays based on ion implantation technique. By surface periodic treatment and annealing of the implanted sampl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.01814v1-abstract-full').style.display = 'inline'; document.getElementById('1912.01814v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.01814v1-abstract-full" style="display: none;"> Surface plasmon resonance of metal nanostructures has broad application prospects in the fields of photocatalysis, optical sensing, biomarkers and surface-enhanced Raman scattering. This paper reports a graphene-assisted method for preparing large-scale single crystal Ag(111) nanoparticle arrays based on ion implantation technique. By surface periodic treatment and annealing of the implanted sample, regularly arranged Ag nanoparticles can be prepared on the sample surface. A new application for graphene is proposed, that is, as a perfect barrier layer to prevent metal atoms from evaporating or diffusing. All the Ag NPs show (111) crystal orientation. Besides, the Ag atoms are covered by graphene immediately when they precipitate from the substrate, which can prevent them from being oxidized. On the basis of this structure, as one of the applications of metal SPR, we measured the Raman enhancement effect, and found that the G peak of the Raman spectrum of graphene achieved about 20 times enhancement. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.01814v1-abstract-full').style.display = 'none'; document.getElementById('1912.01814v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1904.07355">arXiv:1904.07355</a> <span> [<a href="https://arxiv.org/pdf/1904.07355">pdf</a>, <a href="https://arxiv.org/format/1904.07355">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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/10.1088/1361-648X/ab3295">10.1088/1361-648X/ab3295 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Revealing Fermionic Quantum Criticality from New Monte Carlo Techniques </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Xu%2C+X+Y">Xiao Yan Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Z+H">Zi Hong Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Qi%2C+Y">Yang Qi</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="1904.07355v2-abstract-short" style="display: inline;"> This review summarizes recent developments in the study of fermionic quantum criticality, focusing on new progress in numerical methodologies, especially quantum Monte Carlo methods, and insights that emerged from recently large-scale numerical simulations. Quantum critical phenomena in fermionic systems have attracted decades of extensive research efforts, partially lured by their exotic properti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.07355v2-abstract-full').style.display = 'inline'; document.getElementById('1904.07355v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1904.07355v2-abstract-full" style="display: none;"> This review summarizes recent developments in the study of fermionic quantum criticality, focusing on new progress in numerical methodologies, especially quantum Monte Carlo methods, and insights that emerged from recently large-scale numerical simulations. Quantum critical phenomena in fermionic systems have attracted decades of extensive research efforts, partially lured by their exotic properties and potential technology applications and partially awaked by the profound and universal fundamental principles that govern these quantum critical systems. Due to the complex and non-perturbative nature, these systems belong to the most difficult and challenging problems in the study of modern condensed matter physics, and many important fundamental problems remain open. Recently, new developments in model design and algorithm improvements enabled unbiased large-scale numerical solutions to be achieved in the close vicinity of these quantum critical points, which paves a new pathway towards achieving controlled conclusions through combined efforts of theoretical and numerical studies, as well as possible theoretical guidance for experiments in heavy-fermion compounds, Cu-based and Fe-based superconductors, ultra-cold fermionic atomic gas, twisted graphene layers, etc., where signatures of fermionic quantum criticality exist. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.07355v2-abstract-full').style.display = 'none'; document.getElementById('1904.07355v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 April, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 13 figures, invited Topical Review article, comments on content and references are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J. Phys.: Condens. Matter 31 463001 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.08878">arXiv:1808.08878</a> <span> [<a href="https://arxiv.org/pdf/1808.08878">pdf</a>, <a href="https://arxiv.org/format/1808.08878">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1073/pnas.1901751116">10.1073/pnas.1901751116 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Itinerant Quantum Critical Point with Fermion Pockets and Hot Spots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Z+H">Zi Hong Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Gaopei Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+X+Y">Xiao Yan Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+Z+Y">Zi Yang Meng</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="1808.08878v3-abstract-short" style="display: inline;"> Metallic quantum criticality is among the central theme in the understanding of correlated electronic systems, and converging results between analytical and numerical approaches are still under calling. In this work, we develop state-of-art large scale quantum Monte Carlo simulation technique and systematically investigate the itinerant quantum critical point on a 2D square lattice with antiferrom… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.08878v3-abstract-full').style.display = 'inline'; document.getElementById('1808.08878v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.08878v3-abstract-full" style="display: none;"> Metallic quantum criticality is among the central theme in the understanding of correlated electronic systems, and converging results between analytical and numerical approaches are still under calling. In this work, we develop state-of-art large scale quantum Monte Carlo simulation technique and systematically investigate the itinerant quantum critical point on a 2D square lattice with antiferromagnetic spin fluctuations at wavevector $\mathbf{Q}=(蟺,蟺)$ -- a problem that resembles the Fermi surface setup and low-energy antiferromagnetic fluctuations in high-Tc cuprates and other critical metals, which might be relevant to their non-Fermi-liquid behaviors. System sizes of $60\times 60 \times 320$ ($L \times L \times L_蟿$) are comfortably accessed, and the quantum critical scaling behaviors are revealed with unprecedingly high precision. We found that the antiferromagnetic spin fluctuations introduce effective interactions among fermions and the fermions in return render the bare bosonic critical point into a new universality, different from both the bare Ising universality class and the Hertz-Mills-Moriya RPA prediction. At the quantum critical point, a finite anomalous dimension $畏\sim 0.125$ is observed in the bosonic propagator, and fermions at hot spots evolve into a non-Fermi-liquid. In the antiferromagnetically ordered metallic phase, fermion pockets are observed as energy gap opens up at the hot spots. These results bridge the recent theoretical and numerical developments in metallic quantum criticality and can be served as the stepping stone towards final understanding of the 2D correlated fermions interacting with gapless critical excitations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.08878v3-abstract-full').style.display = 'none'; document.getElementById('1808.08878v3-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, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 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">11 pages, 10 figures, revised version with more discussion and updated references</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PNAS first published August 1, 2019 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1606.05756">arXiv:1606.05756</a> <span> [<a href="https://arxiv.org/pdf/1606.05756">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"> Suppression of magnetoresistance in thin $WTe_2$ flakes by surface oxidation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Woods%2C+J+M">J. M. Woods</a>, <a href="/search/cond-mat?searchtype=author&query=Shen%2C+J">J. Shen</a>, <a href="/search/cond-mat?searchtype=author&query=Kumaravadivel%2C+P">P. Kumaravadivel</a>, <a href="/search/cond-mat?searchtype=author&query=Pang%2C+Y">Y. Pang</a>, <a href="/search/cond-mat?searchtype=author&query=Xie%2C+Y">Y. Xie</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G+A">G. A. Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+M">M. Li</a>, <a href="/search/cond-mat?searchtype=author&query=Altman%2C+E+I">E. I. Altman</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+L">L. Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Cha%2C+J+J">J. J. Cha</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="1606.05756v1-abstract-short" style="display: inline;"> Recent renewed interest in layered transition metal dichalcogenides stems from the exotic electronic phases predicted and observed in the single- and few-layer limit. Realizing these electronic phases requires preserving the desired transport properties down to a monolayer, which is challenging. Here, using semimetallic $WTe_2$ that exhibits large magnetoresistance, we show that surface oxidation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.05756v1-abstract-full').style.display = 'inline'; document.getElementById('1606.05756v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1606.05756v1-abstract-full" style="display: none;"> Recent renewed interest in layered transition metal dichalcogenides stems from the exotic electronic phases predicted and observed in the single- and few-layer limit. Realizing these electronic phases requires preserving the desired transport properties down to a monolayer, which is challenging. Here, using semimetallic $WTe_2$ that exhibits large magnetoresistance, we show that surface oxidation and Fermi level pinning degrade the transport properties of thin $WTe_2$ flakes significantly. With decreasing $WTe_2$ flake thickness, we observe a dramatic suppression of the large magnetoresistance. This is explained by fitting a two-band model to the transport data, which shows that mobility of the electron and hole carriers decreases significantly for thin flakes. The microscopic origin of this mobility decrease is attributed to a ~ 2 nm-thick amorphous surface oxide layer that introduces disorder. The oxide layer also shifts the Fermi level by ~ 300 meV at the $WTe_2$ surface. However, band bending due to this Fermi level shift is not the dominant cause for the suppression of magnetoresistance as the electron and hole carrier densities are balanced down to ~ 13 nm based on the two-band model. Our study highlights the critical need to investigate often unanticipated and sometimes unavoidable extrinsic surface effects on the transport properties of layered dichalcogenides and other 2D materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.05756v1-abstract-full').style.display = 'none'; document.getElementById('1606.05756v1-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, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">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/1508.05171">arXiv:1508.05171</a> <span> [<a href="https://arxiv.org/pdf/1508.05171">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/10.1088/2053-1583/2/3/031002">10.1088/2053-1583/2/3/031002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Synthesis of thin-film black phosphorus on a flexible substrate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Li%2C+X">Xuesong Li</a>, <a href="/search/cond-mat?searchtype=author&query=Deng%2C+B">Bingchen Deng</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+X">Xiaomu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+S">Sizhe Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Vaisman%2C+M">Michelle Vaisman</a>, <a href="/search/cond-mat?searchtype=author&query=Karato%2C+S">Shun-ichiro Karato</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Grace Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+M+L">Minjoo Larry Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Cha%2C+J">Judy Cha</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+H">Han Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Xia%2C+F">Fengnian Xia</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="1508.05171v1-abstract-short" style="display: inline;"> We report a scalable approach to synthesize a large-area (up to 4 mm) thin black phosphorus (BP) film on a flexible substrate. We first deposited a red phosphorus (RP) thin-film on a flexible polyester substrate, followed by its conversion to BP in a high-pressure multi-anvil cell at room temperature. Raman spectroscopy and transmission electron microscopy measurements confirmed the formation of a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1508.05171v1-abstract-full').style.display = 'inline'; document.getElementById('1508.05171v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1508.05171v1-abstract-full" style="display: none;"> We report a scalable approach to synthesize a large-area (up to 4 mm) thin black phosphorus (BP) film on a flexible substrate. We first deposited a red phosphorus (RP) thin-film on a flexible polyester substrate, followed by its conversion to BP in a high-pressure multi-anvil cell at room temperature. Raman spectroscopy and transmission electron microscopy measurements confirmed the formation of a nano-crystalline BP thin-film with a thickness of around 40 nm. Optical characterization indicates a bandgap of around 0.28 eV in the converted BP, similar to the bandgap measured in exfoliated thin-films. Thin-film BP transistors exhibit a field-effect mobility of around 0.5 cm2/Vs, which can probably be further enhanced by the optimization of the conversion process at elevated temperatures. Our work opens the avenue for the future demonstration of large-scale, high quality thin-film black phosphorus. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1508.05171v1-abstract-full').style.display = 'none'; document.getElementById('1508.05171v1-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, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2D Materials 2, 031002 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1502.03835">arXiv:1502.03835</a> <span> [<a href="https://arxiv.org/pdf/1502.03835">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1049/iet-cds.2014.0204">10.1049/iet-cds.2014.0204 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> RF Transport Electromagnetic Properties of CVD Graphene from DC to 110 MHz </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Awan%2C+S+A">Shakil Ahmed Awan</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Genhua Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Taan%2C+L+M+A">Laith M. Al Taan</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+B">Bing Li</a>, <a href="/search/cond-mat?searchtype=author&query=Jamil%2C+N">Nawfal Jamil</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1502.03835v1-abstract-short" style="display: inline;"> We report measurement of the radio-frequency (RF) transport electromagnetic properties of chemical vapour deposition (CVD) graphene over the DC to 110 MHz frequency range at room temperature. Graphene on Si/SiO2 substrate was mounted in a shielded four terminal-pair (4TP) adaptor which enabled direct connection to a calibrated precision impedance analyser for measurements. Good agreement is observ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.03835v1-abstract-full').style.display = 'inline'; document.getElementById('1502.03835v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1502.03835v1-abstract-full" style="display: none;"> We report measurement of the radio-frequency (RF) transport electromagnetic properties of chemical vapour deposition (CVD) graphene over the DC to 110 MHz frequency range at room temperature. Graphene on Si/SiO2 substrate was mounted in a shielded four terminal-pair (4TP) adaptor which enabled direct connection to a calibrated precision impedance analyser for measurements. Good agreement is observed for the DC four-probe resistance and the 4TP resistance at 40 Hz, both yielding R ~ 104 惟. In general the apparent graphene channel electromagnetic properties are found to be strongly influenced by the substrate parasitic capacitance and resistance, particularly for high-frequencies f > 1 MHz. A phenomenological lumped-parameter equivalent circuit model is presented which matches the frequency response of the graphene 4TP impedance device over approximately seven decades of the frequency range of the applied transport alternating current. Based on this model, it is shown for the first time, that the intrinsic graphene channel resistance of the 4TP device is frequency-independent (i.e. dissipationless) with RG ~ 105 惟 or sheet resistance of approximately 182 惟 / sq. The parasitic substrate impedance of the device is found shunt RG with RP ~ 2.2 惟 in series with CP ~ 600 pF. These results suggest that our new RF 4TP method is in good agreement with the conventional DC four-probe method for measuring the intrinsic sheet resistance of single-atom thick materials and could potentially open up new applications in RF electronics, AC quantum Hall effect metrology and sensors based on graphene 4TP devices operating over broad range of frequencies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.03835v1-abstract-full').style.display = 'none'; document.getElementById('1502.03835v1-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, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">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> IET Circuits Devices Syst., vol 9 (1), pp 46-51, 2015 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1306.4906">arXiv:1306.4906</a> <span> [<a href="https://arxiv.org/pdf/1306.4906">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.88.064103">10.1103/PhysRevB.88.064103 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Periodic elastic nanodomains in ultrathin tetrogonal-like BiFeO3 films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Luo%2C+Z">Zhenlin Luo</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Z">Zuhuang Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+Y">Yuanjun Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+H">Heng-Jui Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+C">Chuanwei Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+H">Haoliang Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+H">Haibo Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+M">Meng-Meng Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+C">Chuansheng Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Guoqiang Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Wen%2C+W">Wen Wen</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+X">Xiaolong Li</a>, <a href="/search/cond-mat?searchtype=author&query=He%2C+Q">Qing He</a>, <a href="/search/cond-mat?searchtype=author&query=Sritharan%2C+T">Thirumany Sritharan</a>, <a href="/search/cond-mat?searchtype=author&query=Chu%2C+Y">Ying-Hao Chu</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lang Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Gao%2C+C">Chen Gao</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="1306.4906v2-abstract-short" style="display: inline;"> We present a synchrotron grazing incidence x-ray diffraction analysis of the domain structure and polar symmetry of highly strained BiFeO3 thin films grown on LaAlO3 substrate. We revealed the existence of periodic elastic nanodomains in the pure tetragonal-like BFO ultrathin films down to a thickness of 6 nm. A unique shear strain accommodation mechanism is disclosed. We further demonstrated that… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.4906v2-abstract-full').style.display = 'inline'; document.getElementById('1306.4906v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1306.4906v2-abstract-full" style="display: none;"> We present a synchrotron grazing incidence x-ray diffraction analysis of the domain structure and polar symmetry of highly strained BiFeO3 thin films grown on LaAlO3 substrate. We revealed the existence of periodic elastic nanodomains in the pure tetragonal-like BFO ultrathin films down to a thickness of 6 nm. A unique shear strain accommodation mechanism is disclosed. We further demonstrated that the periodicity of the nanodomains increases with film thickness but deviates from the classical Kittel's square root law in ultrathin thickness regime (6 - 30 nm). Temperature-dependent experiments also reveal the disappearance of periodic modulation above 90C due to a MC-MA structural phase transition. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.4906v2-abstract-full').style.display = 'none'; document.getElementById('1306.4906v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 August, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 June, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted in Phys. Rev. B</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 88, 064103 (2013) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1209.0489">arXiv:1209.0489</a> <span> [<a href="https://arxiv.org/pdf/1209.0489">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"> Growth of large area graphene from sputtered films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Genhua Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Heath%2C+M">Mark Heath</a>, <a href="/search/cond-mat?searchtype=author&query=Horsell%2C+D">David Horsell</a>, <a href="/search/cond-mat?searchtype=author&query=Wears%2C+M+L">M. Lesley Wears</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="1209.0489v4-abstract-short" style="display: inline;"> Techniques for mass-production of large area graphene using an industrial scale thin film deposition tool could be the key to the practical realization of a wide range of technological applications of this material. Here, we demonstrate the growth of large area polycrystalline graphene from sputtered films (a carbon-containing layer and a metallic layer) using in-situ or ex-situ rapid thermal proc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1209.0489v4-abstract-full').style.display = 'inline'; document.getElementById('1209.0489v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1209.0489v4-abstract-full" style="display: none;"> Techniques for mass-production of large area graphene using an industrial scale thin film deposition tool could be the key to the practical realization of a wide range of technological applications of this material. Here, we demonstrate the growth of large area polycrystalline graphene from sputtered films (a carbon-containing layer and a metallic layer) using in-situ or ex-situ rapid thermal processing in the temperature range from 650 to 1000 oC. It was found that graphene always grows on the top surface of the stack, in close contact with the Ni or Ni-silicide. Raman spectra typical of high quality exfoliated monolayer graphene were obtained for samples under optimised conditions. A fast cooling rate was found to be essential to the formation of monolayer graphene. Samples with Ni atop SiC produced the best monolayer graphene spectra with ~40% surface area coverage, whereas samples with Ni below SiC produced poorer quality graphene but 99% coverage. The flexibility of the sputtering process allows further optimization of the growth, with possibility of transferring the graphene to any insulator substrate in vacuum. We present a potential route for the production of graphene-on-insulator wafers, which would facilitate easy integration of graphene into modern semiconductor device process flows. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1209.0489v4-abstract-full').style.display = 'none'; document.getElementById('1209.0489v4-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 February, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 September, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2012. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1201.6018">arXiv:1201.6018</a> <span> [<a href="https://arxiv.org/pdf/1201.6018">pdf</a>, <a href="https://arxiv.org/ps/1201.6018">ps</a>, <a href="https://arxiv.org/format/1201.6018">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="Quantum Physics">quant-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/PhysRevLett.109.115301">10.1103/PhysRevLett.109.115301 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Collective Dipole Oscillation of a Spin-Orbit Coupled Bose-Einstein Condensate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+J">Jin-Yi Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Ji%2C+S">Si-Cong Ji</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Z">Zhu Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+L">Long Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Du%2C+Z">Zhi-Dong Du</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+B">Bo Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Ge-Sheng Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+B">Bo Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Deng%2C+Y">Youjin Deng</a>, <a href="/search/cond-mat?searchtype=author&query=Zhai%2C+H">Hui Zhai</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+S">Shuai Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</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="1201.6018v2-abstract-short" style="display: inline;"> We present an experimental study of the collective dipole oscillation of a spin-orbit coupled Bose-Einstein condensate in a harmonic trap. Dynamics of the center-of-mass dipole oscillation is studied in a broad parameter region, as a function of spin-orbit coupling parameters as well as oscillation amplitude. Anharmonic properties beyond effective-mass approximation are revealed, such as amplitude… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1201.6018v2-abstract-full').style.display = 'inline'; document.getElementById('1201.6018v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1201.6018v2-abstract-full" style="display: none;"> We present an experimental study of the collective dipole oscillation of a spin-orbit coupled Bose-Einstein condensate in a harmonic trap. Dynamics of the center-of-mass dipole oscillation is studied in a broad parameter region, as a function of spin-orbit coupling parameters as well as oscillation amplitude. Anharmonic properties beyond effective-mass approximation are revealed, such as amplitude-dependent frequency and finite oscillation frequency at place with divergent effective mass. These anharmonic behaviors agree quantitatively with variational wave-function calculations. Moreover, we experimentally demonstrate a unique feature of spin-orbit coupled system predicted by a sum-rule approach, stating that spin polarization susceptibility--a static physical quantity--can be measured via dynamics of dipole oscillation. The divergence of polarization susceptibility is observed at the quantum phase transition that separates magnetic nonzero-momentum condensate from nonmagnetic zero-momentum phase. The good agreement between the experimental and theoretical results provides a bench mark for recently developed theoretical approaches. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1201.6018v2-abstract-full').style.display = 'none'; document.getElementById('1201.6018v2-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 July, 2012; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 January, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures, 0 table</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 109, 115301 (2012) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0802.1458">arXiv:0802.1458</a> <span> [<a href="https://arxiv.org/pdf/0802.1458">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div 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/e2007-00335-8">10.1140/epjb/e2007-00335-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mean-free path effects in magnetoresistance of ferromagnetic nanocontacts </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Useinov%2C+A+N">A. N. Useinov</a>, <a href="/search/cond-mat?searchtype=author&query=Tagirov%2C+L+R">L. R. Tagirov</a>, <a href="/search/cond-mat?searchtype=author&query=Deminov%2C+R+G">R. G. Deminov</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+Y">Y. Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">G. Pan</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="0802.1458v1-abstract-short" style="display: inline;"> We investigated the mean-free path effects on the magnetoresistance of ferromagnetic nanocontacts. For most combinations of parameters the magnetoresistance monotonously decreases with increasing the contact cross-section. However, for a certain choice of parameters the calculations show non-monotonous behavior of the magnetoresistance in the region in which the diameter of the contact becomes c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0802.1458v1-abstract-full').style.display = 'inline'; document.getElementById('0802.1458v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0802.1458v1-abstract-full" style="display: none;"> We investigated the mean-free path effects on the magnetoresistance of ferromagnetic nanocontacts. For most combinations of parameters the magnetoresistance monotonously decreases with increasing the contact cross-section. However, for a certain choice of parameters the calculations show non-monotonous behavior of the magnetoresistance in the region in which the diameter of the contact becomes comparable with the mean-free path of electrons. We attribute this effect to different conduction regimes in the vicinity of the nanocontact: ballistic for electrons of one spin projection, and simultaneously diffusive for the other. Furthermore, at certain combinations of spin asymmetries of the bulk mean-free paths in a heterocontact, the magnetoresistance can be almost constant, or may even grow as the contact diameter increases. Thus, our calculations suggest a way to search for combinations of material parameters, for which high magnetoresistances can be achieved not only at the nanometric size of the contact, but also at much larger cross-sections of nanocontacts which can be easier for fabrication with current technologies. The trial calculations of the magnetoresistance with material parameters close to those for the Mumetal-Ni heterocontacts agree satisfactorily with the available experimental data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0802.1458v1-abstract-full').style.display = 'none'; document.getElementById('0802.1458v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 February, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 7 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 60, 187-192 (2007) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0707.2774">arXiv:0707.2774</a> <span> [<a href="https://arxiv.org/pdf/0707.2774">pdf</a>, <a href="https://arxiv.org/ps/0707.2774">ps</a>, <a href="https://arxiv.org/format/0707.2774">other</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> <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/10.1209/0295-5075/80/40010">10.1209/0295-5075/80/40010 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mesoscopic model for the fluctuating hydrodynamics of binary and ternary mixtures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tuzel%2C+E">Erkan Tuzel</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Guoai Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Ihle%2C+T">Thomas Ihle</a>, <a href="/search/cond-mat?searchtype=author&query=Kroll%2C+D+M">Daniel M. Kroll</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="0707.2774v1-abstract-short" style="display: inline;"> A recently introduced particle-based model for fluid dynamics with continuous velocities is generalized to model immiscible binary mixtures. Excluded volume interactions between the two components are modeled by stochastic multiparticle collisions which depend on the local velocities and densities. Momentum and energy are conserved locally, and entropically driven phase separation occurs for hig… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0707.2774v1-abstract-full').style.display = 'inline'; document.getElementById('0707.2774v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0707.2774v1-abstract-full" style="display: none;"> A recently introduced particle-based model for fluid dynamics with continuous velocities is generalized to model immiscible binary mixtures. Excluded volume interactions between the two components are modeled by stochastic multiparticle collisions which depend on the local velocities and densities. Momentum and energy are conserved locally, and entropically driven phase separation occurs for high collision rates. An explicit expression for the equation of state is derived, and the concentration dependence of the bulk free energy is shown to be the same as that of the Widom-Rowlinson model. Analytic results for the phase diagram are in excellent agreement with simulation data. Results for the line tension obtained from the analysis of the capillary wave spectrum of a droplet agree with measurements based on the Laplace's equation. The introduction of "amphiphilic" dimers makes it possible to model the phase behavior and dynamics of ternary surfactant mixtures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0707.2774v1-abstract-full').style.display = 'none'; document.getElementById('0707.2774v1-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 July, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2007. </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 including 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/0706.0266">arXiv:0706.0266</a> <span> [<a href="https://arxiv.org/pdf/0706.0266">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div 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/10.1088/0953-8984/19/19/196215">10.1088/0953-8984/19/19/196215 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Giant magnetoresistance in nanoscale ferromagnetic heterocontacts </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Useinov%2C+A+N">A. N. Useinov</a>, <a href="/search/cond-mat?searchtype=author&query=Deminov%2C+R+G">R. G. Deminov</a>, <a href="/search/cond-mat?searchtype=author&query=Tagirov%2C+L+R">L. R. Tagirov</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">G. Pan</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="0706.0266v1-abstract-short" style="display: inline;"> A quasiclassical theory of giant magnetoresistance in nanoscale point contacts between different ferromagnetic metals is developed. The contacts were sorted by three types of mutual positions of the conduction spin-subband bottoms which are shifted one against another by the exchange interaction. A model of linear domain wall has been used to account for the finite contact length. The magnetores… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0706.0266v1-abstract-full').style.display = 'inline'; document.getElementById('0706.0266v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0706.0266v1-abstract-full" style="display: none;"> A quasiclassical theory of giant magnetoresistance in nanoscale point contacts between different ferromagnetic metals is developed. The contacts were sorted by three types of mutual positions of the conduction spin-subband bottoms which are shifted one against another by the exchange interaction. A model of linear domain wall has been used to account for the finite contact length. The magnetoresistance is plotted against the size of the nanocontact. In heterocontacts the magnetoresistance effect turned out to be not only negative, as usual, but can be positive as well. Relevance of the results to existing experiments on GMR in point heterocontacts is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0706.0266v1-abstract-full').style.display = 'none'; document.getElementById('0706.0266v1-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 June, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2007. </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> J. Phys.: Condens. Matter 19 (2007) 196215 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/cond-mat/0607608">arXiv:cond-mat/0607608</a> <span> [<a href="https://arxiv.org/pdf/cond-mat/0607608">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.2337538">10.1063/1.2337538 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetoresistance in Thin Permalloy Film (10nm-thick and 30-200nm-wide) Nanocontacts Fabricated by e-Beam Lithography </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Garcia%2C+N">Nicolas Garcia</a>, <a href="/search/cond-mat?searchtype=author&query=Hao%2C+C">Cheng Hao</a>, <a href="/search/cond-mat?searchtype=author&query=Yonghua%2C+L">Lu Yonghua</a>, <a href="/search/cond-mat?searchtype=author&query=Munoz%2C+M">Manuel. Munoz</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Y">Yifang Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+Z">Zhengqi Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+Y">Yun Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+G">Genhua Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Cui%2C+Z">Zheng Cui</a>, <a href="/search/cond-mat?searchtype=author&query=Pasa%2C+A+A">A. A. Pasa</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="cond-mat/0607608v1-abstract-short" style="display: inline;"> In this paper we show spin dependent transport experiments in nanoconstrictions ranging from 30 to 200nm. These nanoconstrictions were fabricated combining electron beam lithography and thin film deposition techniques. Two types of geometries have been fabricated and investigated. We compare the experimental results with the theoretical estimation of the electrical resistance. Finally we show th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('cond-mat/0607608v1-abstract-full').style.display = 'inline'; document.getElementById('cond-mat/0607608v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="cond-mat/0607608v1-abstract-full" style="display: none;"> In this paper we show spin dependent transport experiments in nanoconstrictions ranging from 30 to 200nm. These nanoconstrictions were fabricated combining electron beam lithography and thin film deposition techniques. Two types of geometries have been fabricated and investigated. We compare the experimental results with the theoretical estimation of the electrical resistance. Finally we show that the magnetoresistance for the different geometries does not scale with the resistance of the structure and obtain drops in voltage of 20mV at 20Oe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('cond-mat/0607608v1-abstract-full').style.display = 'none'; document.getElementById('cond-mat/0607608v1-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, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2006. </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. 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