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class="help"><a href="https://info.arxiv.org/help">Help</a> | <a href="https://arxiv.org/search/advanced">Advanced Search</a></p> </div> <div class="control"> <div class="select is-small"> <select name="searchtype" aria-label="Field to search"> <option value="all" selected="selected">All fields</option> <option value="title">Title</option> <option value="author">Author</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="author_id">arXiv author ID</option> <option value="help">Help pages</option> <option value="full_text">Full text</option> </select> </div> </div> <input type="hidden" name="source" 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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="Yue, S"> <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/2408.14306">arXiv:2408.14306</a> <span> [<a href="https://arxiv.org/pdf/2408.14306">pdf</a>, <a href="https://arxiv.org/format/2408.14306">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> </div> </div> <p class="title is-5 mathjax"> Delta-Learning approach combined with the cluster Gutzwiller approximation for strongly correlated bosonic systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lin%2C+Z">Zhi Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+T">Tong Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng Yue</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.14306v1-abstract-short" style="display: inline;"> The cluster Gutzwiller method is widely used to study the strongly correlated bosonic systems, owing to its ability to provide a more precise description of quantum fluctuations. However, its utility is limited by the exponential increase in computational complexity as the cluster size grows. To overcome this limitation, we propose an artificial intelligence-based method known as $螖$-Learning. Thi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14306v1-abstract-full').style.display = 'inline'; document.getElementById('2408.14306v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.14306v1-abstract-full" style="display: none;"> The cluster Gutzwiller method is widely used to study the strongly correlated bosonic systems, owing to its ability to provide a more precise description of quantum fluctuations. However, its utility is limited by the exponential increase in computational complexity as the cluster size grows. To overcome this limitation, we propose an artificial intelligence-based method known as $螖$-Learning. This approach constructs a predictive model by learning the discrepancies between lower-precision (small cluster sizes) and high-precision (large cluster sizes) implementations of the cluster Gutzwiller method, requiring only a small number of training samples. Using this predictive model, we can effectively forecast the outcomes of high-precision methods with high accuracy. Applied to various Bose-Hubbard models, the $螖$-Learning method effectively predicts phase diagrams while significantly reducing the computational resources and time. Furthermore, we have compared the predictive accuracy of $螖$-Learning with other direct learning methods and found that $螖$-Learning exhibits superior performance in scenarios with limited training data. Therefore, when combined with the cluster Gutzwiller approximation, the $螖$-Learning approach offers a computationally efficient and accurate method for studying phase transitions in large, complex bosonic systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14306v1-abstract-full').style.display = 'none'; document.getElementById('2408.14306v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.08215">arXiv:2404.08215</a> <span> [<a href="https://arxiv.org/pdf/2404.08215">pdf</a>, <a href="https://arxiv.org/format/2404.08215">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Stability and noncentered PT symmetry of real topological phases </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S+J">S. J. Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Q">Qing Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+S+A">Shengyuan A. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+Y+X">Y. X. Zhao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2404.08215v2-abstract-short" style="display: inline;"> Real topological phases protected by the spacetime inversion (P T) symmetry are a current research focus. The basis is that the P T symmetry endows a real structure in momentum space, which leads to Z2 topological classifications in 1D and 2D. Here, we provide solutions to two outstanding problems in the diagnosis of real topology. First, based on the stable equivalence in K-theory, we clarify tha… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.08215v2-abstract-full').style.display = 'inline'; document.getElementById('2404.08215v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.08215v2-abstract-full" style="display: none;"> Real topological phases protected by the spacetime inversion (P T) symmetry are a current research focus. The basis is that the P T symmetry endows a real structure in momentum space, which leads to Z2 topological classifications in 1D and 2D. Here, we provide solutions to two outstanding problems in the diagnosis of real topology. First, based on the stable equivalence in K-theory, we clarify that the 2D topological invariant remains well defined in the presence of nontrivial 1D invariant, and we develop a general numerical approach for its evaluation, which was hitherto unavailable. Second, under the unit-cell convention, noncentered P T symmetries assume momentum dependence, which violates the presumption in previous methods for computing the topological invariants. We clarify the classifications for this case and formulate the invariants by introducing a twisted Wilson-loop operator for both 1D and 2D. A simple model on a rectangular lattice is constructed to demonstrate our theory, which can be readily realized using artificial crystals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.08215v2-abstract-full').style.display = 'none'; document.getElementById('2404.08215v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.00564">arXiv:2404.00564</a> <span> [<a href="https://arxiv.org/pdf/2404.00564">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"> First Principles Studies of Stacking Fault Energies in Ternary Magnesium Alloys </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Qiu%2C+Q">Qiwen Qiu</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Stephen Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+J">Jun Song</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2404.00564v1-abstract-short" style="display: inline;"> Magnesium (Mg) alloys have emerged as promising materials due to their low density and high strength-to-weight ratio, offering a wide range of applications across multiple industries. Nevertheless, the inherent brittleness of Mg alloys poses a significant hurdle, necessitating innovative approaches to enhance their mechanical performance. Among the various strategies, manipulating stacking fault e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.00564v1-abstract-full').style.display = 'inline'; document.getElementById('2404.00564v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.00564v1-abstract-full" style="display: none;"> Magnesium (Mg) alloys have emerged as promising materials due to their low density and high strength-to-weight ratio, offering a wide range of applications across multiple industries. Nevertheless, the inherent brittleness of Mg alloys poses a significant hurdle, necessitating innovative approaches to enhance their mechanical performance. Among the various strategies, manipulating stacking fault energy (SFE) has been a key focus, although primarily within the realm of binary alloys. This study investigates SFE in Mg alloys, focusing on ternary compositions. Utilizing first-principles DFT calculations, we analyze solute interactions and their influence on SFE, particularly in Mg-Al-X and Mg-Zn-X configurations. Predictive models are developed for estimating SFE effects, revealing solute pairs that mimic rare earth elements and show potential for improved ductility. The findings contribute to fundamental insights into Mg alloy behavior, offering practical directions for designing advanced materials with superior mechanical properties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.00564v1-abstract-full').style.display = 'none'; document.getElementById('2404.00564v1-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> 31 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">29 pages, 15 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/2403.10848">arXiv:2403.10848</a> <span> [<a href="https://arxiv.org/pdf/2403.10848">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Ultrafast carriers' separation imaging in WS2-WSe2 in plane heterojunction by transient reflectivity microscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhong%2C+Y">Yangguang Zhong</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shuai Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+H">Huawei Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Xia%2C+Y">Yuexing Xia</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+A">Anlian Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+S">Shula Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+X">Xinfeng Liu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.10848v1-abstract-short" style="display: inline;"> Carrier transport in nanodevices plays a crucial role in determining their functionality. In the post-Moore era, the behavior of carriers near surface or interface domains the function of the whole devices. However, the femtosecond dynamics and nanometer-scale movement of carriers pose challenges for imaging their behavior. Techniques with high spatial-temporal resolution become imperative for tra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.10848v1-abstract-full').style.display = 'inline'; document.getElementById('2403.10848v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.10848v1-abstract-full" style="display: none;"> Carrier transport in nanodevices plays a crucial role in determining their functionality. In the post-Moore era, the behavior of carriers near surface or interface domains the function of the whole devices. However, the femtosecond dynamics and nanometer-scale movement of carriers pose challenges for imaging their behavior. Techniques with high spatial-temporal resolution become imperative for tracking their intricate dynamics. In this study, we employed transient reflectivity microscopy to directly visualize the charge separation in the atomic interface of WS2-WSe2 in-plane heterojunctions. The carriers' drifting behavior was carefully tracked, enabling the extraction of drift velocities of 30 nm/ps and 10.6 nm/ps for electrons and holes. Additionally, the width of the depletion layer was determined to be 300 nm based on the carriers' moving trajectory. This work provides essential parameters for the potential effective utilization of these covalent in-plane heterojunctions,and demonstrates the success of transient optical imaging in unraveling the electrical behavior of nano devices, paving the way for a new avenue of electro-optical analysis. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.10848v1-abstract-full').style.display = 'none'; document.getElementById('2403.10848v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.17251">arXiv:2312.17251</a> <span> [<a href="https://arxiv.org/pdf/2312.17251">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Computer Vision and Pattern Recognition">cs.CV</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="Machine Learning">cs.LG</span> </div> </div> <p class="title is-5 mathjax"> Semantic segmentation of SEM images of lower bainitic and tempered martensitic steels </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bie%2C+X">Xiaohan Bie</a>, <a href="/search/cond-mat?searchtype=author&query=Arthanari%2C+M">Manoj Arthanari</a>, <a href="/search/cond-mat?searchtype=author&query=de+Melo%2C+E+B">Evelin Barbosa de Melo</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+J">Juancheng Li</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Stephen Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Brahimi%2C+S">Salim Brahimi</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+J">Jun Song</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.17251v1-abstract-short" style="display: inline;"> This study employs deep learning techniques to segment scanning electron microscope images, enabling a quantitative analysis of carbide precipitates in lower bainite and tempered martensite steels with comparable strength. Following segmentation, carbides are investigated, and their volume percentage, size distribution, and orientations are probed within the image dataset. Our findings reveal that… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.17251v1-abstract-full').style.display = 'inline'; document.getElementById('2312.17251v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.17251v1-abstract-full" style="display: none;"> This study employs deep learning techniques to segment scanning electron microscope images, enabling a quantitative analysis of carbide precipitates in lower bainite and tempered martensite steels with comparable strength. Following segmentation, carbides are investigated, and their volume percentage, size distribution, and orientations are probed within the image dataset. Our findings reveal that lower bainite and tempered martensite exhibit comparable volume percentages of carbides, albeit with a more uniform distribution of carbides in tempered martensite. Carbides in lower bainite demonstrate a tendency for better alignment than those in tempered martensite, aligning with the observations of other researchers. However, both microstructures display a scattered carbide orientation, devoid of any discernible pattern. Comparative analysis of aspect ratios and sizes of carbides in lower bainite and tempered martensite unveils striking similarities. The deep learning model achieves an impressive pixelwise accuracy of 98.0% in classifying carbide/iron matrix at the individual pixel level. The semantic segmentation derived from deep learning extends its applicability to the analysis of secondary phases in various materials, offering a time-efficient, versatile AI-powered workflow for quantitative microstructure analysis. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.17251v1-abstract-full').style.display = 'none'; document.getElementById('2312.17251v1-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.04516">arXiv:2311.04516</a> <span> [<a href="https://arxiv.org/pdf/2311.04516">pdf</a>, <a href="https://arxiv.org/format/2311.04516">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.109.115155">10.1103/PhysRevB.109.115155 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Projective symmetry determined topology in flux Su-Schrieffer-Heeger model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+G">Gang Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Z+Y">Z. Y. Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S+J">S. J. Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Rui%2C+W+B">W. B. Rui</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+X">Xiao-Ming Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+S+A">Shengyuan A. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+Y+X">Y. X. Zhao</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="2311.04516v1-abstract-short" style="display: inline;"> In the field of symmetry-protected topological phases, a common wisdom is that the symmetries fix the topological classifications, but they alone cannot determine whether a system is topologically trivial or not. Here, we show that this is no longer true in cases where symmetries are projectively represented. Particularly, the Zak phase, a topological invariant of a one-dimensional system, can be… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04516v1-abstract-full').style.display = 'inline'; document.getElementById('2311.04516v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.04516v1-abstract-full" style="display: none;"> In the field of symmetry-protected topological phases, a common wisdom is that the symmetries fix the topological classifications, but they alone cannot determine whether a system is topologically trivial or not. Here, we show that this is no longer true in cases where symmetries are projectively represented. Particularly, the Zak phase, a topological invariant of a one-dimensional system, can be entirely determined by the projective symmetry algebra (PSA). To demonstrate this remarkable effect, we propose a minimal model, termed as flux Su-Schrieffer-Heeger (SSH) model, where the bond dimerization in the original SSH model is replaced by a flux dimerization. We present experimental realization of our flux SSH model in an electric-circuit array, and our predictions are directly confirmed by experimental measurement. Our work refreshes the understanding of the relation between symmetry and topology, opens up new avenues for exploring PSA determined topological phases, and suggests flux dimerization as a novel approach for designing topological crystals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04516v1-abstract-full').style.display = 'none'; document.getElementById('2311.04516v1-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 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">6 pages, 3 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 109, 115155 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.05371">arXiv:2307.05371</a> <span> [<a href="https://arxiv.org/pdf/2307.05371">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="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.jpclett.3c01416">10.1021/acs.jpclett.3c01416 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Idealizing Tauc Plot for Accurate Bandgap Determination of Semiconductor with UV-Vis: A Case Study for Cubic Boron Arsenide </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhong%2C+H">Hong Zhong</a>, <a href="/search/cond-mat?searchtype=author&query=Pan%2C+F">Fengjiao Pan</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shuai Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Qin%2C+C">Chengzhen Qin</a>, <a href="/search/cond-mat?searchtype=author&query=Hadjiev%2C+V">Viktor Hadjiev</a>, <a href="/search/cond-mat?searchtype=author&query=Tian%2C+F">Fei Tian</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+X">Xinfeng Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+F">Feng Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhiming Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Ren%2C+Z">Zhifeng Ren</a>, <a href="/search/cond-mat?searchtype=author&query=Bao%2C+J">Jiming Bao</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="2307.05371v1-abstract-short" style="display: inline;"> The Tauc plot method is widely used to determine the bandgap of semiconductors via UV-visible optical spectroscopy due to its simplicity and perceived accuracy. However, the actual Tauc plot often exhibits significant baseline absorption below the expected bandgap, leading to discrepancies in the calculated bandgap depending on whether the linear fit is extrapolated to zero or non-zero baseline. I… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.05371v1-abstract-full').style.display = 'inline'; document.getElementById('2307.05371v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.05371v1-abstract-full" style="display: none;"> The Tauc plot method is widely used to determine the bandgap of semiconductors via UV-visible optical spectroscopy due to its simplicity and perceived accuracy. However, the actual Tauc plot often exhibits significant baseline absorption below the expected bandgap, leading to discrepancies in the calculated bandgap depending on whether the linear fit is extrapolated to zero or non-zero baseline. In this study, we show that both extrapolation methods can produce significant errors by simulating Tauc plots with varying levels of baseline absorption. To address this issue, we propose a new method that involves idealizing the absorption spectrum by removing its baseline before constructing the Tauc plot. Experimental verification of this method using a gallium phosphide (GaP) wafer with intentionally introduced baseline absorptions shows promising results. Furthermore, we apply this new method to cubic boron arsenide (c-BAs) and resolve discrepancies in c-BAs bandgap values reported by different groups, obtaining a converging bandgap of 1.835 eV based on both previous and new transmission spectra. The method is applicable to both indirect and direct bandgap semiconductors, regardless of whether the absorption spectrum is measured via transmission or diffuse reflectance, will become essential to obtain accurate values of their bandgaps. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.05371v1-abstract-full').style.display = 'none'; document.getElementById('2307.05371v1-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.03873">arXiv:2307.03873</a> <span> [<a href="https://arxiv.org/pdf/2307.03873">pdf</a>, <a href="https://arxiv.org/ps/2307.03873">ps</a>, <a href="https://arxiv.org/format/2307.03873">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="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> </div> <p class="title is-5 mathjax"> Why does dissolving salt in water decrease its dielectric permittivity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+C">Chunyi Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shuwen Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Panagiotopoulos%2C+A+Z">Athanassios Z. Panagiotopoulos</a>, <a href="/search/cond-mat?searchtype=author&query=Klein%2C+M+L">Michael L. Klein</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+X">Xifan Wu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2307.03873v1-abstract-short" style="display: inline;"> The dielectric permittivity of salt water decreases on dissolving more salt. For nearly a century, this phenomenon has been explained by invoking saturation in the dielectric response of the solvent water molecules. Herein, we employ an advanced deep neural network (DNN), built using data from density functional theory, to study the dielectric permittivity of sodium chloride solutions. Notably, th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.03873v1-abstract-full').style.display = 'inline'; document.getElementById('2307.03873v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.03873v1-abstract-full" style="display: none;"> The dielectric permittivity of salt water decreases on dissolving more salt. For nearly a century, this phenomenon has been explained by invoking saturation in the dielectric response of the solvent water molecules. Herein, we employ an advanced deep neural network (DNN), built using data from density functional theory, to study the dielectric permittivity of sodium chloride solutions. Notably, the decrease in the dielectric permittivity as a function of concentration, computed using the DNN approach, agrees well with experiments. Detailed analysis of the computations reveals that the dominant effect, caused by the intrusion of ionic hydration shells into the solvent hydrogen-bond network, is the disruption of dipolar correlations among water molecules. Accordingly, the observed decrease in the dielectric permittivity is mostly due to increasing suppression of the collective response of solvent waters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.03873v1-abstract-full').style.display = 'none'; document.getElementById('2307.03873v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">has accepted by Physical Review Letters</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.14191">arXiv:2210.14191</a> <span> [<a href="https://arxiv.org/pdf/2210.14191">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="Machine Learning">cs.LG</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> </div> <p class="title is-5 mathjax"> A Database of Ultrastable MOFs Reassembled from Stable Fragments with Machine Learning Models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Nandy%2C+A">Aditya Nandy</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shuwen Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Oh%2C+C">Changhwan Oh</a>, <a href="/search/cond-mat?searchtype=author&query=Duan%2C+C">Chenru Duan</a>, <a href="/search/cond-mat?searchtype=author&query=Terrones%2C+G+G">Gianmarco G. Terrones</a>, <a href="/search/cond-mat?searchtype=author&query=Chung%2C+Y+G">Yongchul G. Chung</a>, <a href="/search/cond-mat?searchtype=author&query=Kulik%2C+H+J">Heather J. Kulik</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="2210.14191v1-abstract-short" style="display: inline;"> High-throughput screening of large hypothetical databases of metal-organic frameworks (MOFs) can uncover new materials, but their stability in real-world applications is often unknown. We leverage community knowledge and machine learning (ML) models to identify MOFs that are thermally stable and stable upon activation. We separate these MOFs into their building blocks and recombine them to make a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.14191v1-abstract-full').style.display = 'inline'; document.getElementById('2210.14191v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.14191v1-abstract-full" style="display: none;"> High-throughput screening of large hypothetical databases of metal-organic frameworks (MOFs) can uncover new materials, but their stability in real-world applications is often unknown. We leverage community knowledge and machine learning (ML) models to identify MOFs that are thermally stable and stable upon activation. We separate these MOFs into their building blocks and recombine them to make a new hypothetical MOF database of over 50,000 structures that samples orders of magnitude more connectivity nets and inorganic building blocks than prior databases. This database shows an order of magnitude enrichment of ultrastable MOF structures that are stable upon activation and more than one standard deviation more thermally stable than the average experimentally characterized MOF. For the nearly 10,000 ultrastable MOFs, we compute bulk elastic moduli to confirm these materials have good mechanical stability, and we report methane deliverable capacities. Our work identifies privileged metal nodes in ultrastable MOFs that optimize gas storage and mechanical stability simultaneously. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.14191v1-abstract-full').style.display = 'none'; document.getElementById('2210.14191v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 October, 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/2210.06129">arXiv:2210.06129</a> <span> [<a href="https://arxiv.org/pdf/2210.06129">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-022-34043-9">10.1038/s41467-022-34043-9 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of Gapped Dirac Cones in a Two-Dimensional Su-Schrieffer-Heeger Lattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Geng%2C+D">Daiyu Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+H">Hui Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shaosheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhenyu Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+P">Peng Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+S">Sheng Meng</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+K">Kehui Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+B">Baojie Feng</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="2210.06129v1-abstract-short" style="display: inline;"> The Su-Schrieffer-Heeger (SSH) model in a two-dimensional rectangular lattice features gapless or gapped Dirac cones with topological edge states along specific peripheries. While such a simple model has been recently realized in photonic/acoustic lattices and electric circuits, its material realization in condensed matter systems is still lacking. Here, we study the atomic and electronic structur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.06129v1-abstract-full').style.display = 'inline'; document.getElementById('2210.06129v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.06129v1-abstract-full" style="display: none;"> The Su-Schrieffer-Heeger (SSH) model in a two-dimensional rectangular lattice features gapless or gapped Dirac cones with topological edge states along specific peripheries. While such a simple model has been recently realized in photonic/acoustic lattices and electric circuits, its material realization in condensed matter systems is still lacking. Here, we study the atomic and electronic structure of a rectangular Si lattice on Ag(001) by angle-resolved photoemission spectroscopy and theoretical calculations. We demonstrate that the Si lattice hosts gapped Dirac cones at the Brillouin zone corners. Our tight-binding analysis reveals that the Dirac bands can be described by a 2D SSH model with anisotropic polarizations. The gap of the Dirac cone is driven by alternative hopping amplitudes in one direction and staggered potential energies in the other one and hosts topological edge states. Our results establish an ideal platform to explore the rich physical properties of the 2D SSH model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.06129v1-abstract-full').style.display = 'none'; document.getElementById('2210.06129v1-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 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">Accepted for publication in Nature Communications</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat. Commun. 13, 7000 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.00946">arXiv:2207.00946</a> <span> [<a href="https://arxiv.org/pdf/2207.00946">pdf</a>, <a href="https://arxiv.org/format/2207.00946">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> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.physleta.2022.128577">10.1016/j.physleta.2022.128577 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Generalized effective-potential Landau theory for a tunable state-dependent hexagonal optical lattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+D">Dan-Yang Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+C">Chenrong Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+M">Ming Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+Z">Zhi Lin</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="2207.00946v1-abstract-short" style="display: inline;"> We analytically study the ground-state phase diagrams of ultracold bosons with various values of the effective magnetic quantum number $m$ in a state-dependent hexagonal optical lattice by using the generalized effective-potential Landau theory, where the site-offset energy between the two triangular sublattice A and B is tunable. Our analytical calculations of third-order corrections are in reaso… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.00946v1-abstract-full').style.display = 'inline'; document.getElementById('2207.00946v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.00946v1-abstract-full" style="display: none;"> We analytically study the ground-state phase diagrams of ultracold bosons with various values of the effective magnetic quantum number $m$ in a state-dependent hexagonal optical lattice by using the generalized effective-potential Landau theory, where the site-offset energy between the two triangular sublattice A and B is tunable. Our analytical calculations of third-order corrections are in reasonably good agreement with the previous cluster Gutzwiller calculations. Furthermore, we reveal the reason why the regions of the Mott lobes $(n,n)$ in phase diagrams for $m=0.02$ are unexpectedly expanded with increasing $J/U$ in deep lattice. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.00946v1-abstract-full').style.display = 'none'; document.getElementById('2207.00946v1-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 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.07549">arXiv:2206.07549</a> <span> [<a href="https://arxiv.org/pdf/2206.07549">pdf</a>, <a href="https://arxiv.org/ps/2206.07549">ps</a>, <a href="https://arxiv.org/format/2206.07549">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.scib.2022.05.017">10.1016/j.scib.2022.05.017 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exfoliation of 2D van der Waals crystals in ultrahigh vacuum for interface engineering </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhenyu Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+X">Xu Han</a>, <a href="/search/cond-mat?searchtype=author&query=Cai%2C+Z">Zhihao Cai</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shaosheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Geng%2C+D">Daiyu Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Rong%2C+D">Dongke Rong</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+L">Lin Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Y">Yi-Qi Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+P">Peng Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+X">Xingjiang Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+Y">Yuan Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+K">Kehui Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+B">Baojie Feng</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="2206.07549v1-abstract-short" style="display: inline;"> Two-dimensional (2D) materials and their heterostructures have been intensively studied in recent years due to their potential applications in electronic, optoelectronic, and spintronic devices. Nonetheless, the realization of 2D heterostructures with atomically flat and clean interfaces remains challenging, especially for air-sensitive materials, which hinders the in-depth investigation of interf… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.07549v1-abstract-full').style.display = 'inline'; document.getElementById('2206.07549v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.07549v1-abstract-full" style="display: none;"> Two-dimensional (2D) materials and their heterostructures have been intensively studied in recent years due to their potential applications in electronic, optoelectronic, and spintronic devices. Nonetheless, the realization of 2D heterostructures with atomically flat and clean interfaces remains challenging, especially for air-sensitive materials, which hinders the in-depth investigation of interface-induced phenomena and the fabrication of high-quality devices. Here, we circumvented this challenge by exfoliating 2D materials in an ultrahigh vacuum. Remarkably, ultraflat and clean substrate surfaces can assist the exfoliation of 2D materials, regardless of the substrate and 2D material, thus providing a universal method for the preparation of heterostructures with ideal interfaces. In addition, we studied the properties of two prototypical systems that cannot be achieved previously, including the electronic structure of monolayer phospherene and optical responses of transition metal dichalcogenides on different metal substrates. Our work paves the way to engineer rich interface-induced phenomena, such as proximity effects and moir茅 superlattices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.07549v1-abstract-full').style.display = 'none'; document.getElementById('2206.07549v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">17 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Sci. Bull. 2022 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.01583">arXiv:2111.01583</a> <span> [<a href="https://arxiv.org/pdf/2111.01583">pdf</a>, <a href="https://arxiv.org/ps/2111.01583">ps</a>, <a href="https://arxiv.org/format/2111.01583">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="Computational Physics">physics.comp-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.nanolett.2c00778">10.1021/acs.nanolett.2c00778 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of topological flat bands in the kagome semiconductor Nb$_3$Cl$_8$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhenyu Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+H">Hui Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+C">Cuixiang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Kumar%2C+S">Shiv Kumar</a>, <a href="/search/cond-mat?searchtype=author&query=Geng%2C+D">Daiyu Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shaosheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Han%2C+X">Xin Han</a>, <a href="/search/cond-mat?searchtype=author&query=Haraguchi%2C+Y">Yuya Haraguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Shimada%2C+K">Kenya Shimada</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+P">Peng Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Shi%2C+Y">Youguo Shi</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+K">Kehui Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+S">Sheng Meng</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+B">Baojie Feng</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="2111.01583v2-abstract-short" style="display: inline;"> The destructive interference of wavefunctions in a kagome lattice can give rise to topological flat bands (TFBs) with a highly degenerate state of electrons. Recently, TFBs have been observed in several kagome metals, including Fe$_3$Sn$_2$, FeSn, CoSn, and YMn$_6$Sn$_6$. Nonetheless, kagome materials that are both exfoliable and semiconducting are lacking, which seriously hinders their device app… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.01583v2-abstract-full').style.display = 'inline'; document.getElementById('2111.01583v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.01583v2-abstract-full" style="display: none;"> The destructive interference of wavefunctions in a kagome lattice can give rise to topological flat bands (TFBs) with a highly degenerate state of electrons. Recently, TFBs have been observed in several kagome metals, including Fe$_3$Sn$_2$, FeSn, CoSn, and YMn$_6$Sn$_6$. Nonetheless, kagome materials that are both exfoliable and semiconducting are lacking, which seriously hinders their device applications. Herein, we show that Nb$_3$Cl$_8$, which hosts a breathing kagome lattice, is gapped out because of the absence of inversion symmetry, while the TFBs survive because of the protection of the mirror reflection symmetry. By angle-resolved photoemission spectroscopy measurements and first-principles calculations, we directly observe the TFB and a moderate band gap in Nb$_3$Cl$_8$. By mechanical exfoliation, we successfully obtain monolayers of Nb$_3$Cl$_8$ and confirm that they are stable under ambient conditions. In addition, our calculations show that monolayers of Nb$_3$Cl$_8$ have a magnetic ground state, thus providing opportunities to study the interplay between geometry, topology, and magnetism. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.01583v2-abstract-full').style.display = 'none'; document.getElementById('2111.01583v2-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 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">6 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nano Lett. 22, 4596 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.03133">arXiv:2110.03133</a> <span> [<a href="https://arxiv.org/pdf/2110.03133">pdf</a>, <a href="https://arxiv.org/ps/2110.03133">ps</a>, <a href="https://arxiv.org/format/2110.03133">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="Computational Physics">physics.comp-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.nanolett.1c03862">10.1021/acs.nanolett.1c03862 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of one-dimensional Dirac fermions in silicon nanoribbons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shaosheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+H">Hui Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+Y">Ya Feng</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y">Yue Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhenyu Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Geng%2C+D">Daiyu Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Arita%2C+M">Masashi Arita</a>, <a href="/search/cond-mat?searchtype=author&query=Kumar%2C+S">Shiv Kumar</a>, <a href="/search/cond-mat?searchtype=author&query=Shimada%2C+K">Kenya Shimada</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+P">Peng Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Yao%2C+Y">Yugui Yao</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+S">Sheng Meng</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+K">Kehui Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+B">Baojie Feng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2110.03133v2-abstract-short" style="display: inline;"> Dirac materials, which feature Dirac cones in the reciprocal space, have been one of the hottest topics in condensed matter physics in the past decade. To date, 2D and 3D Dirac Fermions have been extensively studied, while their 1D counterparts are rare. Recently, Si nanoribbons (SiNRs), which are composed of alternating pentagonal Si rings, have attracted intensive attention. However, the electro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.03133v2-abstract-full').style.display = 'inline'; document.getElementById('2110.03133v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.03133v2-abstract-full" style="display: none;"> Dirac materials, which feature Dirac cones in the reciprocal space, have been one of the hottest topics in condensed matter physics in the past decade. To date, 2D and 3D Dirac Fermions have been extensively studied, while their 1D counterparts are rare. Recently, Si nanoribbons (SiNRs), which are composed of alternating pentagonal Si rings, have attracted intensive attention. However, the electronic structure and topological properties of SiNRs are still elusive. Here, by angle-resolved photoemission spectroscopy, scanning tunneling microscopy/spectroscopy measurements, first-principles calculations, and tight-binding model analysis, we demonstrate the existence of 1D Dirac Fermions in SiNRs. Our theoretical analysis shows that the Dirac cones derive from the armchairlike Si chain in the center of the nanoribbon and can be described by the Su-Schrieffer-Heeger model. These results establish SiNRs as a platform for studying the novel physical properties in 1D Dirac materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.03133v2-abstract-full').style.display = 'none'; document.getElementById('2110.03133v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nano Lett. 22, 695-701 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.06978">arXiv:2103.06978</a> <span> [<a href="https://arxiv.org/pdf/2103.06978">pdf</a>, <a href="https://arxiv.org/ps/2103.06978">ps</a>, <a href="https://arxiv.org/format/2103.06978">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="Chemical Physics">physics.chem-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/5.0050068">10.1063/5.0050068 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Vapor-liquid equilibrium of water with the MB-pol many-body potential </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Muniz%2C+M+C">Maria Carolina Muniz</a>, <a href="/search/cond-mat?searchtype=author&query=Gartner%2C+T+E">Thomas E. Gartner III</a>, <a href="/search/cond-mat?searchtype=author&query=Riera%2C+M">Marc Riera</a>, <a href="/search/cond-mat?searchtype=author&query=Knight%2C+C">Christopher Knight</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shuwen Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Paesani%2C+F">Francesco Paesani</a>, <a href="/search/cond-mat?searchtype=author&query=Panagiotopoulos%2C+A+Z">Athanassios Z. Panagiotopoulos</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="2103.06978v2-abstract-short" style="display: inline;"> Among the many existing molecular models of water, the MB-pol many-body potential has emerged as a remarkably accurate model, capable of reproducing thermodynamic, structural, and dynamic properties across water's solid, liquid, and vapor phases. In this work, we assessed the performance of MB-pol with respect to an important set of properties related to vapor-liquid coexistence and interfacial be… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.06978v2-abstract-full').style.display = 'inline'; document.getElementById('2103.06978v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.06978v2-abstract-full" style="display: none;"> Among the many existing molecular models of water, the MB-pol many-body potential has emerged as a remarkably accurate model, capable of reproducing thermodynamic, structural, and dynamic properties across water's solid, liquid, and vapor phases. In this work, we assessed the performance of MB-pol with respect to an important set of properties related to vapor-liquid coexistence and interfacial behavior. Through direct coexistence classical molecular dynamics simulations at temperatures 400 K < T < 600 K, we calculated properties such as equilibrium coexistence densities, vapor-liquid interfacial tension, vapor pressure, and enthalpy of vaporization, and compared the MB-pol results to experimental data. We also compared rigid vs. fully flexible variants of the MB-pol model and evaluated system size effects for the properties studied. We found that the MB-pol model predictions are in good agreement with experimental data, even for temperatures approaching the vapor-liquid critical point; this agreement was largely insensitive to system size or the rigid vs. flexible treatment of the intramolecular degrees of freedom. These results attest to the chemical accuracy of MB-pol and its high degree of transferability, thus enabling MB-pol's application across a large swath of water's phase diagram. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.06978v2-abstract-full').style.display = 'none'; document.getElementById('2103.06978v2-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 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.02769">arXiv:2103.02769</a> <span> [<a href="https://arxiv.org/pdf/2103.02769">pdf</a>, <a href="https://arxiv.org/format/2103.02769">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.103.184302">10.1103/PhysRevB.103.184302 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Crystal-symmetry-based selection rules for anharmonic phonon-phonon scattering from a group theory formalism </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yang%2C+R">Runqing Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shengying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Quan%2C+Y">Yujie Quan</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</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="2103.02769v1-abstract-short" style="display: inline;"> Anharmonic phonon-phonon scattering serves a critical role in heat conduction in solids. Previous studies have identified many selection rules for possible phonon-phonon scattering channels imposed by phonon energy and momentum conservation conditions and crystal symmetry. However, the crystal-symmetry-based selection rules have mostly been \textit{ad hoc} so far in selected materials, and a gener… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.02769v1-abstract-full').style.display = 'inline'; document.getElementById('2103.02769v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.02769v1-abstract-full" style="display: none;"> Anharmonic phonon-phonon scattering serves a critical role in heat conduction in solids. Previous studies have identified many selection rules for possible phonon-phonon scattering channels imposed by phonon energy and momentum conservation conditions and crystal symmetry. However, the crystal-symmetry-based selection rules have mostly been \textit{ad hoc} so far in selected materials, and a general formalism that can summarize known selection rules and lead to new ones in any given crystal is still lacking. In this work, we apply a general formalism for symmetry-based scattering selection rules based on the group theory to anharmonic phonon-phonon scatterings, which can reproduce known selection rules and guide the discovery of new selection rules between phonon branches imposed by the crystal symmetry. We apply this formalism to analyze the phonon-phonon scattering selection rules imposed by the in-plane symmetry of graphene, and demonstrate the significant impact of symmetry-breaking strain on the lattice thermal conductivity. Our work quantifies the critical influence of the crystal symmetry on the lattice thermal conductivity in solids and suggests routes to engineer heat conduction by tuning the crystal symmetry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.02769v1-abstract-full').style.display = 'none'; document.getElementById('2103.02769v1-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 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">26 pages, 9 figures. Comments are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 103, 184302 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.06766">arXiv:2102.06766</a> <span> [<a href="https://arxiv.org/pdf/2102.06766">pdf</a>, <a href="https://arxiv.org/format/2102.06766">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/5.0047372">10.1063/5.0047372 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electric field effect on the thermal conductivity of wurtzite GaN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Quan%2C+Y">Yujie Quan</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</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="2102.06766v1-abstract-short" style="display: inline;"> Gallium nitride (GaN), a wide band-gap semiconductor, has been broadly used in power electronic devices due to its high electron mobility and high breakdown voltage. Its relatively high thermal conductivity makes GaN a favorable material for such applications, where heat dissipation is a major concern for device efficiency and long-term stability. However, in GaN-based transistors, where the activ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.06766v1-abstract-full').style.display = 'inline'; document.getElementById('2102.06766v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.06766v1-abstract-full" style="display: none;"> Gallium nitride (GaN), a wide band-gap semiconductor, has been broadly used in power electronic devices due to its high electron mobility and high breakdown voltage. Its relatively high thermal conductivity makes GaN a favorable material for such applications, where heat dissipation is a major concern for device efficiency and long-term stability. However, in GaN-based transistors, where the active region can withstand extremely strong electric fields, the field effect on the thermal transport properties has drawn little attention so far. In this work, we apply first-principles methods to investigate phonon properties of wurtzite GaN in the presence of a near-breakdown electric field applied along different crystallographic directions. We find that the electric field changes thermal conductivity considerably via impacting the bond stiffness and ionicity as well as the crystal symmetry, although it has little effect on phonon dispersions. The presence of an out-of-plane electric field increases (decreases) the thermal conductivity parallel (perpendicular) to the electric field, which is attributed to different changes of the Ga-N bond stiffness and ionicity. When an in-plane electric field is applied, the sizable decrease of thermal conductivities along all directions is attributed to the crystal symmetry breaking that enhances the phonon-phonon scattering. Our study provides insights into the effect of extreme external electric fields on phonon transport properties in wide-gap semiconductors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.06766v1-abstract-full').style.display = 'none'; document.getElementById('2102.06766v1-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, 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, 7 figures. Comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.01827">arXiv:2102.01827</a> <span> [<a href="https://arxiv.org/pdf/2102.01827">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"> Impact of Electron-Phonon Interaction on Thermal Transport: A Review </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Quan%2C+Y">Yujie Quan</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shengying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</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="2102.01827v1-abstract-short" style="display: inline;"> A thorough understanding of the microscopic picture of heat conduction in solids is critical to a broad range of applications, from thermal management of microelectronics to more efficient thermoelectric materials. The transport properties of phonons, the major microscopic heat carriers in semiconductors and insulators, particularly their scattering mechanisms, have been a central theme in microsc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.01827v1-abstract-full').style.display = 'inline'; document.getElementById('2102.01827v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.01827v1-abstract-full" style="display: none;"> A thorough understanding of the microscopic picture of heat conduction in solids is critical to a broad range of applications, from thermal management of microelectronics to more efficient thermoelectric materials. The transport properties of phonons, the major microscopic heat carriers in semiconductors and insulators, particularly their scattering mechanisms, have been a central theme in microscale heat conduction research. In the past two decades, significant advancements have been made in computational and experimental efforts to probe phonon-phonon, phonon-impurity, and phonon-boundary scattering channels in detail. In contrast, electron-phonon scatterings were long thought to have negligible effects on thermal transport in most materials under ambient conditions. This article reviews the recent progress in first-principles computations and experimental methods that show clear evidence for a strong impact of electron-phonon interaction on phonon transport in a wide variety of technologically relevant solid-state materials. Under thermal equilibrium conditions, electron-phonon interactions can modify the total phonon scattering rates and renormalize the phonon frequency, as determined by the imaginary part and the real part of the phonon self-energy, respectively. Under nonequilibrium transport conditions, electron-phonon interactions can affect the coupled transport of electrons and phonons in the bulk through the "phonon or electron drag" mechanism as well as the interfacial thermal transport. Based on these recent results, we evaluate the potential use of electron-phonon interactions to control thermal transport in solids. We also provide an outlook on future directions of computational and experimental developments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.01827v1-abstract-full').style.display = 'none'; document.getElementById('2102.01827v1-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 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">23 pages, 5 figures. Comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.10112">arXiv:2012.10112</a> <span> [<a href="https://arxiv.org/pdf/2012.10112">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/10.1016/j.corsci.2021.109701">10.1016/j.corsci.2021.109701 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A novel approach to assess hydrogen embrittlement (HE) susceptibility and mechanisms in high strength martensitic steels </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Das%2C+T">Tuhin Das</a>, <a href="/search/cond-mat?searchtype=author&query=Brahimi%2C+S+V">Salim V. Brahimi</a>, <a href="/search/cond-mat?searchtype=author&query=Song%2C+J">Jun Song</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Stephen Yue</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2012.10112v1-abstract-short" style="display: inline;"> A rapid fracture test in four-point bending is proposed to assess hydrogen embrittlement (HE) susceptibility of high strength martensitic steels. The novelty of this technique is the rapid rate of loading, whereas conventional approaches require prolonged slow strain rate testing. The essential fractographic features required to identify the mechanisms of HE failure remain evident, despite the fas… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.10112v1-abstract-full').style.display = 'inline'; document.getElementById('2012.10112v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.10112v1-abstract-full" style="display: none;"> A rapid fracture test in four-point bending is proposed to assess hydrogen embrittlement (HE) susceptibility of high strength martensitic steels. The novelty of this technique is the rapid rate of loading, whereas conventional approaches require prolonged slow strain rate testing. The essential fractographic features required to identify the mechanisms of HE failure remain evident, despite the fast loading conditions. To demonstrate these attributes, two quenched and tempered steels at two different strength levels were tested, with and without pre-charging of hydrogen. Stress coupled hydrogen diffusion finite element analysis (FEA) was performed to calculate both stress and hydrogen concentration distributions. In addition to fractographic analysis, a mechanistic description rooted in hydrogen enhanced decohesion (HEDE) mechanism was used to corroborate the mechanical test data. The study shows that the approach is capable of quantifying HE susceptibility by being responsive to key factors affecting hydrogen induced fracture, thus developing further understanding on the HE of martensitic steels. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.10112v1-abstract-full').style.display = 'none'; document.getElementById('2012.10112v1-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 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">62 pages, 26 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Corrosion Science. 2021: 109701 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.07293">arXiv:2012.07293</a> <span> [<a href="https://arxiv.org/pdf/2012.07293">pdf</a>, <a href="https://arxiv.org/ps/2012.07293">ps</a>, <a href="https://arxiv.org/format/2012.07293">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.104.L241408">10.1103/PhysRevB.104.L241408 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of quantum spin Hall states in Ta$_2$Pd$_3$Te$_5$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wang%2C+X">Xuguang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Geng%2C+D">Daiyu Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+D">Dayu Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+W">Wenqi Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+H">Hexu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shaosheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhenyu Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Kumar%2C+S">Shiv Kumar</a>, <a href="/search/cond-mat?searchtype=author&query=Shimada%2C+K">Kenya Shimada</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+P">Peng Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Nie%2C+S">Simin Nie</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhijun Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Shi%2C+Y">Youguo Shi</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Y">Yi-Qi Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+K">Kehui Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+B">Baojie Feng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2012.07293v1-abstract-short" style="display: inline;"> Two-dimensional topological insulators (2DTIs), which host the quantum spin Hall (QSH) effect, are one of the key materials in next-generation spintronic devices. To date, experimental evidence of the QSH effect has only been observed in a few materials, and thus, the search for new 2DTIs is at the forefront of physical and materials science. Here, we report experimental evidence of a 2DTI in the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.07293v1-abstract-full').style.display = 'inline'; document.getElementById('2012.07293v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.07293v1-abstract-full" style="display: none;"> Two-dimensional topological insulators (2DTIs), which host the quantum spin Hall (QSH) effect, are one of the key materials in next-generation spintronic devices. To date, experimental evidence of the QSH effect has only been observed in a few materials, and thus, the search for new 2DTIs is at the forefront of physical and materials science. Here, we report experimental evidence of a 2DTI in the van der Waals material Ta$_2$Pd$_3$Te$_5$. First-principles calculations show that each monolayer of Ta$_2$Pd$_3$Te$_5$ is a 2DTI with weak interlayer interactions. Combined transport, angle-resolved photoemission spectroscopy, and scanning tunneling microscopy measurements confirm the existence of a band gap at the Fermi level and topological edge states inside the gap. These results demonstrate that Ta$_2$Pd$_3$Te$_5$ is a promising material for fabricating spintronic devices based on the QSH effect. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.07293v1-abstract-full').style.display = 'none'; document.getElementById('2012.07293v1-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 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 3 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 104, L241408 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.16152">arXiv:2010.16152</a> <span> [<a href="https://arxiv.org/pdf/2010.16152">pdf</a>, <a href="https://arxiv.org/ps/2010.16152">ps</a>, <a href="https://arxiv.org/format/2010.16152">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.102.201401">10.1103/PhysRevB.102.201401 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental observation of Dirac cones in artificial graphene lattices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shaosheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+H">Hui Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Geng%2C+D">Daiyu Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhenyu Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Arita%2C+M">Masashi Arita</a>, <a href="/search/cond-mat?searchtype=author&query=Shimada%2C+K">Kenya Shimada</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+P">Peng Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Meng%2C+S">Sheng Meng</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+K">Kehui Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+B">Baojie Feng</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="2010.16152v1-abstract-short" style="display: inline;"> Artificial lattices provide a tunable platform to realize exotic quantum devices. A well-known example is artificial graphene (AG), in which electrons are confined in honeycomb lattices and behave as massless Dirac fermions. Recently, AG systems have been constructed by manipulating molecules using scanning tunnelling microscope tips, but the nanoscale size typical for these constructed systems ar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.16152v1-abstract-full').style.display = 'inline'; document.getElementById('2010.16152v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.16152v1-abstract-full" style="display: none;"> Artificial lattices provide a tunable platform to realize exotic quantum devices. A well-known example is artificial graphene (AG), in which electrons are confined in honeycomb lattices and behave as massless Dirac fermions. Recently, AG systems have been constructed by manipulating molecules using scanning tunnelling microscope tips, but the nanoscale size typical for these constructed systems are impossible for practical device applications and insufficient for direct investigation of the electronic structures using angle-resolved photoemission spectroscopy (ARPES). Here, we demonstrate the synthesis of macroscopic AG by self-assembly of C$_{60}$ molecules on metal surfaces. Our theoretical calculations and ARPES measurements directly confirm the existence of Dirac cones at the $K$ ($K^\prime$) points of the Brillouin zone (BZ), in analogy to natural graphene. These results will stimulate ongoing efforts to explore the exotic properties in artificial lattices and provide an important step forward in the realization of novel molecular quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.16152v1-abstract-full').style.display = 'none'; document.getElementById('2010.16152v1-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, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">to appear in Physical Review 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 102, 201401(R) (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.03528">arXiv:2010.03528</a> <span> [<a href="https://arxiv.org/pdf/2010.03528">pdf</a>, <a href="https://arxiv.org/ps/2010.03528">ps</a>, <a href="https://arxiv.org/format/2010.03528">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="Computational Physics">physics.comp-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.102.155109">10.1103/PhysRevB.102.155109 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Topological electronic structure in the antiferromagnet HoSbTe </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shaosheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Qian%2C+Y">Yuting Qian</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+M">Meng Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Geng%2C+D">Daiyu Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Yi%2C+C">Changjiang Yi</a>, <a href="/search/cond-mat?searchtype=author&query=Kumar%2C+S">Shiv Kumar</a>, <a href="/search/cond-mat?searchtype=author&query=Shimada%2C+K">Kenya Shimada</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+P">Peng Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhijun Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Weng%2C+H">Hongming Weng</a>, <a href="/search/cond-mat?searchtype=author&query=Shi%2C+Y">Youguo Shi</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+K">Kehui Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+B">Baojie Feng</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="2010.03528v1-abstract-short" style="display: inline;"> Magnetic topological materials, in which the time-reversal symmetry is broken, host various exotic quantum phenomena, including the quantum anomalous Hall effect, axion insulator states, and Majorana fermions. The study of magnetic topological materials is at the forefront of condensed matter physics. Recently, a variety of magnetic topological materials have been reported, such as Mn$_3$Sn, Co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.03528v1-abstract-full').style.display = 'inline'; document.getElementById('2010.03528v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.03528v1-abstract-full" style="display: none;"> Magnetic topological materials, in which the time-reversal symmetry is broken, host various exotic quantum phenomena, including the quantum anomalous Hall effect, axion insulator states, and Majorana fermions. The study of magnetic topological materials is at the forefront of condensed matter physics. Recently, a variety of magnetic topological materials have been reported, such as Mn$_3$Sn, Co$_3$Sn$_2$S$_2$, Fe$_3$Sn$_2$, and MnBi$_2$Te$_4$. Here, we report the observation of a topological electronic structure in an antiferromagnet, HoSbTe, a member of the ZrSiS family of materials, by angle-resolved photoemission spectroscopy measurements and first-principles calculations. We demonstrate that HoSbTe is a Dirac nodal line semimetal when spin-orbit coupling (SOC) is neglected. However, our theoretical calculations show that the strong SOC in HoSbTe fully gaps out the nodal lines and drives the system to a weak topological insulator state, with each layer being a two-dimensional topological insulator. Because of the strong SOC in HoSbTe, the gap is as large as hundreds of meV along specific directions, which is directly observed by our ARPES measurements. The existence of magnetic order and topological properties in HoSbTe makes it a promising material for realization of exotic quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.03528v1-abstract-full').style.display = 'none'; document.getElementById('2010.03528v1-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 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">5 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 102, 155109 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.10916">arXiv:2004.10916</a> <span> [<a href="https://arxiv.org/pdf/2004.10916">pdf</a>, <a href="https://arxiv.org/ps/2004.10916">ps</a>, <a href="https://arxiv.org/format/2004.10916">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.101.161407">10.1103/PhysRevB.101.161407 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental evidence of monolayer AlB$_2$ with symmetry-protected Dirac cones </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Geng%2C+D">Daiyu Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Yu%2C+K">Kejun Yu</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shaosheng Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Cao%2C+J">Jin Cao</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+W">Wenbin Li</a>, <a href="/search/cond-mat?searchtype=author&query=Ma%2C+D">Dashuai Ma</a>, <a href="/search/cond-mat?searchtype=author&query=Cui%2C+C">Chaoxi Cui</a>, <a href="/search/cond-mat?searchtype=author&query=Arita%2C+M">Masashi Arita</a>, <a href="/search/cond-mat?searchtype=author&query=Kumar%2C+S">Shiv Kumar</a>, <a href="/search/cond-mat?searchtype=author&query=Schwier%2C+E+F">Eike F. Schwier</a>, <a href="/search/cond-mat?searchtype=author&query=Shimada%2C+K">Kenya Shimada</a>, <a href="/search/cond-mat?searchtype=author&query=Cheng%2C+P">Peng Cheng</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+L">Lan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+K">Kehui Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Yao%2C+Y">Yugui Yao</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+B">Baojie Feng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2004.10916v1-abstract-short" style="display: inline;"> Monolayer AlB$_2$ is composed of two atomic layers: honeycomb borophene and triangular aluminum. In contrast with the bulk phase, monolayer AlB$_2$ is predicted to be a superconductor with a high critical temperature. Here, we demonstrate that monolayer AlB$_2$ can be synthesized on Al(111) via molecular beam epitaxy. Our theoretical calculations revealed that the monolayer AlB$_2$ hosts several D… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.10916v1-abstract-full').style.display = 'inline'; document.getElementById('2004.10916v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.10916v1-abstract-full" style="display: none;"> Monolayer AlB$_2$ is composed of two atomic layers: honeycomb borophene and triangular aluminum. In contrast with the bulk phase, monolayer AlB$_2$ is predicted to be a superconductor with a high critical temperature. Here, we demonstrate that monolayer AlB$_2$ can be synthesized on Al(111) via molecular beam epitaxy. Our theoretical calculations revealed that the monolayer AlB$_2$ hosts several Dirac cones along the $螕$--M and $螕$--K directions; these Dirac cones are protected by crystal symmetries and are thus resistant to external perturbations. The extraordinary electronic structure of the monolayer AlB$_2$ was confirmed via angle-resolved photoemission spectroscopy measurements. These results are likely to stimulate further research interest to explore the exotic properties arising from the interplay of Dirac fermions and superconductivity in two-dimensional materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.10916v1-abstract-full').style.display = 'none'; document.getElementById('2004.10916v1-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 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 101, 161407(R) (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.10124">arXiv:2001.10124</a> <span> [<a href="https://arxiv.org/pdf/2001.10124">pdf</a>, <a href="https://arxiv.org/format/2001.10124">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.102.235428">10.1103/PhysRevB.102.235428 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phonon softening near topological phase transitions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shengying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Deng%2C+B">Bowen Deng</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Y">Yanming Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Quan%2C+Y">Yujie Quan</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+R">Runqing Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</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="2001.10124v2-abstract-short" style="display: inline;"> Topological phase transitions occur when the electronic bands change their topological properties, typically featuring the closing of the bandgap. While the influence of topological phase transitions on electronic and optical properties has been extensively studied, its implication on phononic properties and thermal transport remains unexplored. In this work, we use first-principles simulations to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.10124v2-abstract-full').style.display = 'inline'; document.getElementById('2001.10124v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.10124v2-abstract-full" style="display: none;"> Topological phase transitions occur when the electronic bands change their topological properties, typically featuring the closing of the bandgap. While the influence of topological phase transitions on electronic and optical properties has been extensively studied, its implication on phononic properties and thermal transport remains unexplored. In this work, we use first-principles simulations to show that certain phonon modes are significantly softened near topological phase transitions, leading to increased phonon-phonon scattering and reduced lattice thermal conductivity. We demonstrate this effect using two model systems: pressure-induced topological phase transition in $\rm ZrTe_5$ and chemical composition induced topological phase transition in $\rm{Hg_{1-x}Cd_{x}Te}$. We attribute the phonon softening to emergent Kohn anomalies associated with the closing of the bandgap. Our study reveals the strong connection between electronic band structures and lattice instabilities and opens up a potential direction towards controlling heat conduction in solids. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.10124v2-abstract-full').style.display = 'none'; document.getElementById('2001.10124v2-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 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 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">8 pages, 5 figures. Comments are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 102, 235428 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.07149">arXiv:1910.07149</a> <span> [<a href="https://arxiv.org/pdf/1910.07149">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/10.1016/j.mtphys.2020.100194">10.1016/j.mtphys.2020.100194 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photoluminescence mapping and time-domain thermo-photoluminescence for rapid imaging and measurement of thermal conductivity of boron arsenide </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shuai Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Gamage%2C+G+A">Geethal Amila Gamage</a>, <a href="/search/cond-mat?searchtype=author&query=Mohebinia%2C+M">Mohammadjavad Mohebinia</a>, <a href="/search/cond-mat?searchtype=author&query=Mayerich%2C+D">David Mayerich</a>, <a href="/search/cond-mat?searchtype=author&query=Talari%2C+V">Vishal Talari</a>, <a href="/search/cond-mat?searchtype=author&query=Deng%2C+Y">Yu Deng</a>, <a href="/search/cond-mat?searchtype=author&query=Tian%2C+F">Fei Tian</a>, <a href="/search/cond-mat?searchtype=author&query=Dai%2C+S">Shenyu Dai</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+H">Haoran Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Hadjiev%2C+V+G">Viktor G. Hadjiev</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+W">Wei Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+G">Guoying Feng</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+J">Jonathan Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+D">Dong Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhiming Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Ren%2C+Z">Zhifeng Ren</a>, <a href="/search/cond-mat?searchtype=author&query=Bao%2C+J">Jiming Bao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1910.07149v1-abstract-short" style="display: inline;"> Cubic boron arsenide (BAs) is attracting greater attention due to the recent experimental demonstration of ultrahigh thermal conductivity \k{appa} above 1000 W/mK. However, its bandgap has not been settled and a simple yet effective method to probe its crystal quality is missing. Furthermore, traditional \k{appa} measurement methods are destructive and time consuming, thus they cannot meet the urg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.07149v1-abstract-full').style.display = 'inline'; document.getElementById('1910.07149v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.07149v1-abstract-full" style="display: none;"> Cubic boron arsenide (BAs) is attracting greater attention due to the recent experimental demonstration of ultrahigh thermal conductivity \k{appa} above 1000 W/mK. However, its bandgap has not been settled and a simple yet effective method to probe its crystal quality is missing. Furthermore, traditional \k{appa} measurement methods are destructive and time consuming, thus they cannot meet the urgent demand for fast screening of high \k{appa} materials. After we experimentally established 1.82 eV as the indirect bandgap of BAs and observed room-temperature band-edge photoluminescence, we developed two new optical techniques that can provide rapid and non-destructive characterization of \k{appa} with little sample preparation: photoluminescence mapping (PL-mapping) and time-domain thermo-photoluminescence (TDTP). PL-mapping provides nearly real-time image of crystal quality and \k{appa} over mm-sized crystal surfaces; while TDTP allows us to pick up any spot on the sample surface and measure its \k{appa} using nanosecond laser pulses. These new techniques reveal that the apparent single crystals are not only non-uniform in \k{appa}, but also are made of domains of very distinct \k{appa}. Because PL-mapping and TDTP are based on the band-edge PL and its dependence on temperature, they can be applied to other semiconductors, thus paving the way for rapid identification and development of high-\k{appa} semiconducting materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.07149v1-abstract-full').style.display = 'none'; document.getElementById('1910.07149v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1909.11692">arXiv:1909.11692</a> <span> [<a href="https://arxiv.org/pdf/1909.11692">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Production of ultra-low radioactivity NaI(Tl) crystals for Dark Matter detectors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+Y">Y. Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S+H">S. H. Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Ge%2C+Z+W">Z. W. Ge</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+Y+W">Y. W. Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Yin%2C+X+J">X. J. Yin</a>, <a href="/search/cond-mat?searchtype=author&query=Dafinei%2C+I">I. Dafinei</a>, <a href="/search/cond-mat?searchtype=author&query=DImperio%2C+G">G. DImperio</a>, <a href="/search/cond-mat?searchtype=author&query=Diemoz%2C+M">M. Diemoz</a>, <a href="/search/cond-mat?searchtype=author&query=Pettinacci%2C+V">V. Pettinacci</a>, <a href="/search/cond-mat?searchtype=author&query=Nisi%2C+S">S. Nisi</a>, <a href="/search/cond-mat?searchtype=author&query=Tomei%2C+C">C. Tomei</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+H+B">H. B. Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+B">B. Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Fang%2C+J">J. Fang</a>, <a href="/search/cond-mat?searchtype=author&query=Q"> Q</a>, <a href="/search/cond-mat?searchtype=author&query=Tu%2C+.+W">. W. Tu</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="1909.11692v1-abstract-short" style="display: inline;"> Scintillating NaI(Tl) crystals are widely used in a large variety of experimental applications. However, for the use as Dark Matter (DM) detectors, such crystals demand a high level of radio-purity, not achievable by means of standard industrial techniques. One of the main difficulties comes from the presence of potassium that always accompanies sodium in alkali halides. On the other hand, the arg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.11692v1-abstract-full').style.display = 'inline'; document.getElementById('1909.11692v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.11692v1-abstract-full" style="display: none;"> Scintillating NaI(Tl) crystals are widely used in a large variety of experimental applications. However, for the use as Dark Matter (DM) detectors, such crystals demand a high level of radio-purity, not achievable by means of standard industrial techniques. One of the main difficulties comes from the presence of potassium that always accompanies sodium in alkali halides. On the other hand, the arguable DM detection by DAMA experiment using NaI(Tl) scintillating crystals requires a reliable verification able to either confirm the existence of DM or rule out the DAMA claim. Ultra-low radioactivity NaI(Tl) crystals, particularly with very low potassium content, are therefore indispensable to overcome the current stalemate in Dark Matter searches. Nonetheless, apart from DAMA-LIBRA experiments, to date, no other experiment has succeeded in building a detector from NaI(Tl) crystals with potassium content of ppb level. This work describes recent results in the preparation of ultra-radio-pure NaI(Tl) crystals using a modified Bridgman method. A double-walled platinum crucible technique has been designed and reliability tests show that 5 ppb of potassium in the NaI(Tl) crystals of 2 and 3 inches in diameter can be achieved starting from NaI powder with potassium content of the order of 10 ppb. The potassium excess is segregated in the tail-side of the as grown ingot where measured potassium concentration is above 20 ppb. The purifying effect of Bridgman growth for larger NaI(Tl) crystals is currently being tested. The work also reports on scintillation parameters of our NaI(Tl) crystals measured in a dedicated setup conceived for naked, hygroscopic crystals. The reproducible and reliable production of ultra-low radioactivity NaI(Tl) crystals reported in this work will hopefully spur the construction of new DM search experiments and, anyway, clarify the controversial DAMA-LIBRA results. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.11692v1-abstract-full').style.display = 'none'; document.getElementById('1909.11692v1-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 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">5 pages, 5 figures; work presented as poster at the conference: 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 10-17 November 2018, International Convention Centre Sydney, Australia</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.03810">arXiv:1908.03810</a> <span> [<a href="https://arxiv.org/pdf/1908.03810">pdf</a>, <a href="https://arxiv.org/format/1908.03810">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevResearch.1.033101">10.1103/PhysRevResearch.1.033101 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Soft phonons and ultralow lattice thermal conductivity in the Dirac semimetal Cd3As2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shengying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Chorsi%2C+H+T">Hamid T. Chorsi</a>, <a href="/search/cond-mat?searchtype=author&query=Goyal%2C+M">Manik Goyal</a>, <a href="/search/cond-mat?searchtype=author&query=Schumann%2C+T">Timo Schumann</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+R">Runqing Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+T">Tashi Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Deng%2C+B">Bowen Deng</a>, <a href="/search/cond-mat?searchtype=author&query=Stemmer%2C+S">Susanne Stemmer</a>, <a href="/search/cond-mat?searchtype=author&query=Schuller%2C+J+A">Jon A. Schuller</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1908.03810v1-abstract-short" style="display: inline;"> Recently, Cd3As2 has attracted intensive research interest as an archetypical Dirac semimetal, hosting three-dimensional linear-dispersive electronic bands near the Fermi level. Previous studies have shown that single-crystalline Cd3As2 has an anomalously low lattice thermal conductivity, ranging from 0.3 W/mK to 0.7 W/mK at 300 K, which has been attributed to point defects. In this work, we combi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.03810v1-abstract-full').style.display = 'inline'; document.getElementById('1908.03810v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.03810v1-abstract-full" style="display: none;"> Recently, Cd3As2 has attracted intensive research interest as an archetypical Dirac semimetal, hosting three-dimensional linear-dispersive electronic bands near the Fermi level. Previous studies have shown that single-crystalline Cd3As2 has an anomalously low lattice thermal conductivity, ranging from 0.3 W/mK to 0.7 W/mK at 300 K, which has been attributed to point defects. In this work, we combine first-principles lattice dynamics calculations and temperature-dependent high-resolution Raman spectroscopy of high-quality single-crystal thin films grown by molecular beam epitaxy to reveal the existence of a group of soft optical phonon modes at the Brillouin zone center of Cd3As2. These soft phonon modes significantly increase the scattering phase space of heat-carrying acoustic phonons and are the origin of the low lattice thermal conductivity of Cd3As2. Furthermore, we show that the interplay between the phonon-phonon Umklapp scattering rates and the soft optical phonon frequency explains the unusual non-monotonic temperature dependence of the lattice thermal conductivity of Cd3As2. Our results further suggest that the soft phonon modes are potentially induced by a Kohn anomaly associated with the Dirac nodes, in analogy to similar, nonetheless weaker, effects in graphene and Weyl semimetals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.03810v1-abstract-full').style.display = 'none'; document.getElementById('1908.03810v1-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 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 4 figure. Comments are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 1, 033101 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.12105">arXiv:1907.12105</a> <span> [<a href="https://arxiv.org/pdf/1907.12105">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1002/adom.201901192">10.1002/adom.201901192 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Widely Tunable Optical and Thermal Properties of Dirac Semimetal Cd$_3$As$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chorsi%2C+H+T">Hamid T. Chorsi</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shengying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Iyer%2C+P+P">Prasad P. Iyer</a>, <a href="/search/cond-mat?searchtype=author&query=Goyal%2C+M">Manik Goyal</a>, <a href="/search/cond-mat?searchtype=author&query=Schumann%2C+T">Timo Schumann</a>, <a href="/search/cond-mat?searchtype=author&query=Stemmer%2C+S">Susanne Stemmer</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</a>, <a href="/search/cond-mat?searchtype=author&query=Schuller%2C+J+A">Jon A. Schuller</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1907.12105v1-abstract-short" style="display: inline;"> In this paper we report a detailed analysis of the temperature-dependent optical properties of epitaxially grown cadmium arsenide (Cd$_3$As$_2$), a newly discovered three-dimensional Dirac semimetal. Dynamic Fermi level tuning -- instigated from Pauli-blocking in the linear Dirac cone -- and varying Drude response, generate large variations in the mid and far-infrared optical properties. We demons… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.12105v1-abstract-full').style.display = 'inline'; document.getElementById('1907.12105v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.12105v1-abstract-full" style="display: none;"> In this paper we report a detailed analysis of the temperature-dependent optical properties of epitaxially grown cadmium arsenide (Cd$_3$As$_2$), a newly discovered three-dimensional Dirac semimetal. Dynamic Fermi level tuning -- instigated from Pauli-blocking in the linear Dirac cone -- and varying Drude response, generate large variations in the mid and far-infrared optical properties. We demonstrate thermo-optic shifts larger than those of traditional III-V semiconductors, which we attribute to the obtained large thermal expansion coefficient as revealed by first-principles calculations. Electron scattering rate, plasma frequency edge, Fermi level shift, optical conductivity, and electron effective mass analysis of Cd$_3$As$_2$ thin-films are quantified and discussed in detail. Our ab initio density functional study and experimental analysis of epitaxially grown Cd$_3$As$_2$ promise applications for nanophotonic and nanoelectronic devices, such as reconfigurable metamaterials and metasurfaces, nanoscale thermal emitters, and on-chip directional antennas. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.12105v1-abstract-full').style.display = 'none'; document.getElementById('1907.12105v1-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 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Advanced Optical Materials, 2020 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1904.11011">arXiv:1904.11011</a> <span> [<a href="https://arxiv.org/pdf/1904.11011">pdf</a>, <a href="https://arxiv.org/format/1904.11011">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.100.115408">10.1103/PhysRevB.100.115408 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Controlling Thermal Conductivity of Two-dimensional Materials via Externally Induced Phonon-Electron Interaction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+R">Runqing Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</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="1904.11011v1-abstract-short" style="display: inline;"> Phonon scattering by electrons, or "phonon-electron scattering", has been recognized as a significant scattering channel for phonons in materials with high electron concentration, such as thermoelectrics and nanoelectronics, even at room temperature. Despite the abundant previous studies of phonon-electron scattering in different types of three-dimensional (3D) bulk materials, its impact on the ph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.11011v1-abstract-full').style.display = 'inline'; document.getElementById('1904.11011v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1904.11011v1-abstract-full" style="display: none;"> Phonon scattering by electrons, or "phonon-electron scattering", has been recognized as a significant scattering channel for phonons in materials with high electron concentration, such as thermoelectrics and nanoelectronics, even at room temperature. Despite the abundant previous studies of phonon-electron scattering in different types of three-dimensional (3D) bulk materials, its impact on the phonon transport, and thus the heat transfer properties, of two-dimensional (2D) materials has not been understood. In this work, we apply ab initio methods to calculate the phonon-electron scattering rates in two representative 2D materials, silicene and phosphorene, and examine the potential of controlling the thermal conductivity of these materials via externally induced phonon-electron scattering by electrostatic gating. We also develop an analytical model to explain the impact of reduced dimensionality and distinct electron and phonon dispersions in 2D on phonon-electron scattering processes. We find that over 40\% reduction of the lattice thermal conductivity can be achieved in silicene with an induced charge carrier concentration in the range of $10^{13}~cm^{-2}$, which is experimentally achievable. Our study not only generates new fundamental insights into phonon transport in 2D materials but also provides practical guidelines to search for 2D materials with strong phonon-electron scattering for potential thermal switching applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.11011v1-abstract-full').style.display = 'none'; document.getElementById('1904.11011v1-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 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">21 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 100, 115408 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1904.03316">arXiv:1904.03316</a> <span> [<a href="https://arxiv.org/pdf/1904.03316">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.100.165401">10.1103/PhysRevB.100.165401 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coherent Phonon Transport in Two-dimensional Graphene Superstructures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Choudhry%2C+U">Usama Choudhry</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shengying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</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="1904.03316v1-abstract-short" style="display: inline;"> Coherent wave effects of thermal phonons hold promise of transformative opportunities in thermal transport control but remain largely unexplored due to the small wavelength of thermal phonons, typically below a few nanometers. This small length scale indicates that, instead of artificial phononic crystals, a more promising direction is to examine the coherent phonon effects in natural materials wi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.03316v1-abstract-full').style.display = 'inline'; document.getElementById('1904.03316v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1904.03316v1-abstract-full" style="display: none;"> Coherent wave effects of thermal phonons hold promise of transformative opportunities in thermal transport control but remain largely unexplored due to the small wavelength of thermal phonons, typically below a few nanometers. This small length scale indicates that, instead of artificial phononic crystals, a more promising direction is to examine the coherent phonon effects in natural materials with hierarchical superstructures matching the thermal phonon wavelength. In this work, we use first-principles simulations to characterize the previously unstudied thermal properties of D-graphene and T-graphene, two-dimensional carbon allotropes based upon the traditional graphene structure but containing a secondary, in-plane periodicity. We find that despite very similar atomic structure and bonding strength, D-graphene and T-graphene possess significantly different thermal properties than that of pristine graphene. At room temperature, the calculated thermal conductivity of D-graphene and T-graphene is 600 Wm-1K-1 and 800 Wm-1K-1 compared to over 3000 Wm-1K-1 for graphene. We attribute these distinct properties to the presence of naturally occurring, low frequency optical phonon modes that display characteristics of phonon coherence and arise from a folding of the acoustic modes and the associated frequency gap opening, a phenomenon also found in superlattices where an out of plane periodicity is introduced. Furthermore, we observe significantly enhanced Umklapp scatterings in D- and T-graphene that largely suppress the hydrodynamic phonon transport in pristine graphene. Our study presents D-graphene and T-graphene as ideal model systems to explore the coherent phonon effects in 2D and demonstrates the potential of using coherent phonon effects to significantly modify thermal transport of 2D materials without making drastic changes to their fundamental compositions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.03316v1-abstract-full').style.display = 'none'; document.getElementById('1904.03316v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 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">19 pages, 4 figures, 1 table</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 100, 165401 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1901.03455">arXiv:1901.03455</a> <span> [<a href="https://arxiv.org/pdf/1901.03455">pdf</a>, <a href="https://arxiv.org/format/1901.03455">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevMaterials.3.034603">10.1103/PhysRevMaterials.3.034603 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Reduced thermal conductivity of epitaxial GaAs on Si due to symmetry-breaking biaxial strain </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Vega-Flick%2C+A">Alejandro Vega-Flick</a>, <a href="/search/cond-mat?searchtype=author&query=Jung%2C+D">Daehwan Jung</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shengying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Bowers%2C+J+E">John E. Bowers</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</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="1901.03455v1-abstract-short" style="display: inline;"> Epitaxial growth of III-V semiconductors on Si is a promising route for silicon photonics. Threading dislocations and the residual thermal stress generated during growth are expected to affect the thermal conductivity of the III-V semiconductors, which is crucial for efficient heat dissipation from photonic devices built on this platform. In this work, we combine a non-contact laser-induced transi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1901.03455v1-abstract-full').style.display = 'inline'; document.getElementById('1901.03455v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1901.03455v1-abstract-full" style="display: none;"> Epitaxial growth of III-V semiconductors on Si is a promising route for silicon photonics. Threading dislocations and the residual thermal stress generated during growth are expected to affect the thermal conductivity of the III-V semiconductors, which is crucial for efficient heat dissipation from photonic devices built on this platform. In this work, we combine a non-contact laser-induced transient thermal grating technique with ab initio phonon simulations to investigate the in-plane thermal transport of epitaxial GaAs-based buffer layers on Si, employed in the fabrication of III-V quantum dot lasers. Surprisingly, we find a significant reduction of the in-plane thermal conductivity of GaAs, up to 19%, as a result of a small in-plane biaxial stress of 250 MPa. Using ab initio phonon calculations, we attribute this effect to the enhancement of phonon-phonon scattering caused by the in-plane biaxial stress, which breaks the cubic crystal symmetry of GaAs. Our results indicate the importance of eliminating the residual thermal stress in the epitaxial III-V layers on Si to avoid the reduction of thermal conductivity and facilitate heat dissipation. Additionally, our results showcase potential means of effectively controlling thermal conductivity of solids with external strain/stress. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1901.03455v1-abstract-full').style.display = 'none'; document.getElementById('1901.03455v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 January, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">8 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. Materials 3, 034603 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1809.07872">arXiv:1809.07872</a> <span> [<a href="https://arxiv.org/pdf/1809.07872">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"> Ultralow Thermal Conductivity in a Two-Dimensional Material due to Surface Enhanced Resonant Bonding </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Xu%2C+T">Tashi Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1809.07872v1-abstract-short" style="display: inline;"> Crystalline materials with ultralow thermal conductivity are highly desirable for thermoelectric applications. Many known crystalline materials with low thermal conductivity, including PbTe and Bi2Te3, possess a special kind of chemical bond called "resonant bond". Resonant bonds consist of superposition of degenerate bonding configurations that leads to structural instability, anomalous long-rang… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.07872v1-abstract-full').style.display = 'inline'; document.getElementById('1809.07872v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1809.07872v1-abstract-full" style="display: none;"> Crystalline materials with ultralow thermal conductivity are highly desirable for thermoelectric applications. Many known crystalline materials with low thermal conductivity, including PbTe and Bi2Te3, possess a special kind of chemical bond called "resonant bond". Resonant bonds consist of superposition of degenerate bonding configurations that leads to structural instability, anomalous long-range interatomic interaction and soft optical phonons. These factors contribute to large lattice anharmonicity and strong phonon-phonon scattering, which result in low thermal conductivity. In this work, we use first-principles simulation to investigate the effect of resonant bonding in two dimensions (2D), where resonant bonds are in proximity to the surface. We find that the long-range interatomic interaction due to resonant bonding becomes more prominent in 2D due to reduced screening of the atomic-displacement-induced charge density distortion. To demonstrate this effect, we analyze the phonon properties of quasi-2D Bi2PbTe4 with an ultralow thermal conductivity of 0.74 W/mK at 300K. By comparing the interatomic force constants of quasi-2D Bi2PbTe4 and its bulk counterpart, and the properties of resonant bonds near the surface and in the bulk, we conclude that resonant bonds are significantly enhanced in reduced dimensions and are more effective in reducing the lattice thermal conductivity. Our results will provide new clues to searching for thermal insulators in low-dimensional materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.07872v1-abstract-full').style.display = 'none'; document.getElementById('1809.07872v1-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, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 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/1808.10860">arXiv:1808.10860</a> <span> [<a href="https://arxiv.org/pdf/1808.10860">pdf</a>, <a href="https://arxiv.org/format/1808.10860">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.5055389">10.1063/1.5055389 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Insight of the thermal conductivity of $蔚-$iron at Earth's core conditions from the newly developed direct $ab~initio$ methodology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+M">Ming Hu</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="1808.10860v1-abstract-short" style="display: inline;"> The electronic thermal conductivity of iron at Earth's core conditions is an extremely important physical property in geophysics field. However, the exact value of electronic thermal conductivity of iron under extreme pressure and temperature still remains poorly known both experimentally and theoretically. A few recent experimental studies measured the value of the electronic thermal conductivity… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.10860v1-abstract-full').style.display = 'inline'; document.getElementById('1808.10860v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.10860v1-abstract-full" style="display: none;"> The electronic thermal conductivity of iron at Earth's core conditions is an extremely important physical property in geophysics field. However, the exact value of electronic thermal conductivity of iron under extreme pressure and temperature still remains poorly known both experimentally and theoretically. A few recent experimental studies measured the value of the electronic thermal conductivity directly and some theoretical works have predicted the electronic thermal conductivity of iron at Earth's core conditions based on the Kubo-Greenwood method. However, these results differ largely from each other. A very recent research has confirmed that for iron at Earth's core conditions the strength of electron-electron scattering could be comparable to that for electron-phonon scattering, meaning that the electron-electron scattering should also be considered when evaluating the electronic thermal conductivity in the Earth's core situations. Here, by utilizing a newly developed methodology based on direct non-equilibrium $ab~initio$ molecular dynamics simulation coupled with the concept of electrostatic potential oscillation, we predict the electronic thermal conductivity of iron in h.c.p phase. Our methodology inherently includes the electron-phonon and electron-electron interactions under extreme conditions. Our results are comparable to the previous theoretical and experimental studies. More importantly, our methodology provides a new physical picture to describe the heat transfer process in $蔚-$iron at Earth's core conditions from the electrostatic potential oscillation point of view and offers a new approach to study thermal transport property of pure metals in planet's cores with different temperature and pressures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.10860v1-abstract-full').style.display = 'none'; document.getElementById('1808.10860v1-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> 31 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">7 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/1806.07345">arXiv:1806.07345</a> <span> [<a href="https://arxiv.org/pdf/1806.07345">pdf</a>, <a href="https://arxiv.org/format/1806.07345">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Hydrodynamic Phonon Transport Perpendicular to Diffuse-Gray Boundaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yang%2C+R">Runqing Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shengying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Liao%2C+B">Bolin Liao</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="1806.07345v3-abstract-short" style="display: inline;"> In this paper, we examine the application of an ideal phonon-hydrodynamic material as the heat transfer medium between two non-hydrodynamic contacts with a finite temperature difference. We use the integral-equation approach to solve a modified phonon Boltzmann transport equation with the displaced Bose-Einstein distribution as the equilibrium distribution between two boundaries perpendicular to t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.07345v3-abstract-full').style.display = 'inline'; document.getElementById('1806.07345v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1806.07345v3-abstract-full" style="display: none;"> In this paper, we examine the application of an ideal phonon-hydrodynamic material as the heat transfer medium between two non-hydrodynamic contacts with a finite temperature difference. We use the integral-equation approach to solve a modified phonon Boltzmann transport equation with the displaced Bose-Einstein distribution as the equilibrium distribution between two boundaries perpendicular to the heat transfer direction. When the distance between the boundaries is smaller than the phonon normal scattering mean free path, our solution converges to the ballistic limit as expected. In the other limit, we find that, although the local thermal conductivity in the bulk of the hydrodynamic material approaches infinity, the thermal boundary resistance at the hydrodynamic/non-hydrodynamic interfaces becomes dominant. Our study provides insights to both the steady-state thermal characterization of phonon-hydrodynamic materials and the practical application of phonon-hydrodynamic materials for thermal management. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.07345v3-abstract-full').style.display = 'none'; document.getElementById('1806.07345v3-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 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">7 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/1707.03978">arXiv:1707.03978</a> <span> [<a href="https://arxiv.org/pdf/1707.03978">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="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Observation of unusual optical band structure of CH3NH3PbI3 perovskite single crystal </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">Wei Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Shizhong Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Y">Yu Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+L">Laipan Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Jin%2C+P">Peng Jin</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+Q">Qing Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Y">Yang Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Y">Yanan Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+K">Kong Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Liang%2C+P">Ping Liang</a>, <a href="/search/cond-mat?searchtype=author&query=Qu%2C+S">Shengchun Qu</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Z">Zhijie Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Y">Yonghai Chen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1707.03978v3-abstract-short" style="display: inline;"> Extensive efforts have been undertaken on the photoelectric physics of hybrid organolead halide perovskites to unveil the reason for the attractive photovoltaic performance. Yet, the resulting evidences are far from being fully conclusive. Herein, we provide another direct support for this issue. In addition to the observation on the conventional band edge at 1.58 eV that presents a blueshift towa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.03978v3-abstract-full').style.display = 'inline'; document.getElementById('1707.03978v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.03978v3-abstract-full" style="display: none;"> Extensive efforts have been undertaken on the photoelectric physics of hybrid organolead halide perovskites to unveil the reason for the attractive photovoltaic performance. Yet, the resulting evidences are far from being fully conclusive. Herein, we provide another direct support for this issue. In addition to the observation on the conventional band edge at 1.58 eV that presents a blueshift toward temperature increase, interestingly, we also observe an unusual optical band edge at 1.48 eV in CH3NH3PbI3 perovskite single crystals. Contrary to the conventional band edge, this one shows an obvious redshift toward the enhancement in temperature, in agreement with the Varshni relation. More interestingly, the unusual band edge exhibits a series of obvious absorption and photocurrent signals, but the according photoluminescence signals are not observable. This indicates that this band edge is particularly beneficial for the photovoltaic effect due to the inhibited radiative recombination. The kinetics on photo-involved charge transition and transfer are investigated using the pump-probe photoconductivity technique, and a changeable band structure model was proposed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.03978v3-abstract-full').style.display = 'none'; document.getElementById('1707.03978v3-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, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">32 pages, 16 figures, and 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1603.07755">arXiv:1603.07755</a> <span> [<a href="https://arxiv.org/pdf/1603.07755">pdf</a>, <a href="https://arxiv.org/format/1603.07755">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="Computational Physics">physics.comp-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.94.075149">10.1103/PhysRevB.94.075149 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Methodology for determining the electronic thermal conductivity of metals via direct non-equilibrium ab initio molecular dynamics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+X">Xiaoliang Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Stackhouse%2C+S">Stephen Stackhouse</a>, <a href="/search/cond-mat?searchtype=author&query=Qin%2C+G">Guangzhao Qin</a>, <a href="/search/cond-mat?searchtype=author&query=Di+Napoli%2C+E">Edoardo Di Napoli</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+M">Ming Hu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1603.07755v2-abstract-short" style="display: inline;"> Many physical properties of metals can be understood in terms of the free electron model, as proven by the Wiedemann-Franz law. According to this model, electronic thermal conductivity ($魏_{el}$) can be inferred from the Boltzmann transport equation (BTE). However, the BTE does not perform well for some complex metals, such as Cu. Moreover, the BTE cannot clearly describe the origin of the thermal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.07755v2-abstract-full').style.display = 'inline'; document.getElementById('1603.07755v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1603.07755v2-abstract-full" style="display: none;"> Many physical properties of metals can be understood in terms of the free electron model, as proven by the Wiedemann-Franz law. According to this model, electronic thermal conductivity ($魏_{el}$) can be inferred from the Boltzmann transport equation (BTE). However, the BTE does not perform well for some complex metals, such as Cu. Moreover, the BTE cannot clearly describe the origin of the thermal energy carried by electrons or how this energy is transported in metals. The charge distribution of conduction electrons in metals is known to reflect the electrostatic potential (EP) of the ion cores. Based on this premise, we develop a new methodology for evaluating $魏_{el}$ by combining the free electron model and non-equilibrium ab initio molecular dynamics (NEAIMD) simulations. We demonstrate that the kinetic energy of thermally excited electrons originates from the energy of the spatial electrostatic potential oscillation (EPO), which is induced by the thermal motion of ion cores. This method directly predicts the $魏_{el}$ of pure metals with a high degree of accuracy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.07755v2-abstract-full').style.display = 'none'; document.getElementById('1603.07755v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 March, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 3 figures, with Supplementary Information of 19 pages, 7 figures and 7 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 94, 075149 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.01766">arXiv:1602.01766</a> <span> [<a href="https://arxiv.org/pdf/1602.01766">pdf</a>, <a href="https://arxiv.org/ps/1602.01766">ps</a>, <a href="https://arxiv.org/format/1602.01766">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1039/c6nr01349j">10.1039/c6nr01349j <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Diverse anisotropy of phonon transport in two-dimensional IV-VI compounds: A comparative study </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Qin%2C+G">Guangzhao Qin</a>, <a href="/search/cond-mat?searchtype=author&query=Qin%2C+Z">Zhenzhen Qin</a>, <a href="/search/cond-mat?searchtype=author&query=Fang%2C+W">Wu-Zhang Fang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+L">Li-Chuan Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+Q">Qing-Bo Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+M">Ming Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Su%2C+G">Gang Su</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="1602.01766v2-abstract-short" style="display: inline;"> New classes two-dimensional (2D) materials beyond graphene, including layered and non-layered, and their heterostructures, are currently attracting increasing interest due to their promising applications in nanoelectronics, optoelectronics and clean energy, where thermal transport property is one of the fundamental physical parameters. In this paper, we systematically investigated the phonon trans… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.01766v2-abstract-full').style.display = 'inline'; document.getElementById('1602.01766v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.01766v2-abstract-full" style="display: none;"> New classes two-dimensional (2D) materials beyond graphene, including layered and non-layered, and their heterostructures, are currently attracting increasing interest due to their promising applications in nanoelectronics, optoelectronics and clean energy, where thermal transport property is one of the fundamental physical parameters. In this paper, we systematically investigated the phonon transport properties of 2D orthorhombic group IV-VI compounds of $GeS$, $GeSe$, $SnS$ and $SnSe$ by solving the Boltzmann transport equation (BTE) based on first-principles calculations. Despite the similar puckered (hinge-like) structure along the armchair direction as phosphorene, the four monolayer compounds possess diverse anisotropic properties in many aspects, such as phonon group velocity, Young's modulus and lattice thermal conductivity ($魏$), etc. Especially, the $魏$ along the zigzag and armchair directions of monolayer $GeS$ shows the strongest anisotropy while monolayer $SnS$ and $SnSe$ shows an almost isotropy in phonon transport. The origin of the diverse anisotropy is fully studied and the underlying mechanism is discussed in detail. With limited size, the $魏$ could be effectively lowered, and the anisotropy could be effectively modulated by nanostructuring, which would extend the applications in nanoscale thermoelectrics and thermal management. Our study offers fundamental understanding of the anisotropic phonon transport properties of 2D materials, and would be of significance for further study, modulation and aplications in emerging technologies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.01766v2-abstract-full').style.display = 'none'; document.getElementById('1602.01766v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">14 pages, 8 figures, 2 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nanoscale, 2016, 8, 11306-11319 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1409.0279">arXiv:1409.0279</a> <span> [<a href="https://arxiv.org/pdf/1409.0279">pdf</a>, <a href="https://arxiv.org/ps/1409.0279">ps</a>, <a href="https://arxiv.org/format/1409.0279">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="Computational Physics">physics.comp-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1039/c4cp04858j">10.1039/c4cp04858j <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Anisotropic intrinsic lattice thermal conductivity of phosphorene from first principles </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Qin%2C+G">Guangzhao Qin</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+Q">Qing-Bo Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Qin%2C+Z">Zhenzhen Qin</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Hu%2C+M">Ming Hu</a>, <a href="/search/cond-mat?searchtype=author&query=Su%2C+G">Gang Su</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="1409.0279v2-abstract-short" style="display: inline;"> Phosphorene, the single layer counterpart of black phosphorus, is a novel two-dimensional semiconductor with high carrier mobility and a large fundamental direct band gap, which has attracted tremendous interest recently. Its potential applications in nano-electronics and thermoelectrics call for a fundamental study of the phonon transport. Here, we calculate the intrinsic lattice thermal conducti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.0279v2-abstract-full').style.display = 'inline'; document.getElementById('1409.0279v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1409.0279v2-abstract-full" style="display: none;"> Phosphorene, the single layer counterpart of black phosphorus, is a novel two-dimensional semiconductor with high carrier mobility and a large fundamental direct band gap, which has attracted tremendous interest recently. Its potential applications in nano-electronics and thermoelectrics call for a fundamental study of the phonon transport. Here, we calculate the intrinsic lattice thermal conductivity of phosphorene by solving the phonon Boltzmann transport equation (BTE) based on first-principles calculations. The thermal conductivity of phosphorene at $300\,\mathrm{K}$ is $30.15\,\mathrm{Wm^{-1}K^{-1}}$ (zigzag) and $13.65\,\mathrm{Wm^{-1}K^{-1}}$ (armchair), showing an obvious anisotropy along different directions. The calculated thermal conductivity fits perfectly to the inverse relation with temperature when the temperature is higher than Debye temperature ($螛_D = 278.66\,\mathrm{K}$). In comparison to graphene, the minor contribution around $5\%$ of the ZA mode is responsible for the low thermal conductivity of phosphorene. In addition, the representative mean free path (MFP), a critical size for phonon transport, is also obtained. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.0279v2-abstract-full').style.display = 'none'; document.getElementById('1409.0279v2-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 February, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 August, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2014. </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 and 6 figures, Supplemental Material available as http://www.rsc.org/suppdata/cp/c4/c4cp04858j/c4cp04858j1.pdf</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Chem. Chem. Phys., (2015), 17, 4854 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1406.0261">arXiv:1406.0261</a> <span> [<a href="https://arxiv.org/pdf/1406.0261">pdf</a>, <a href="https://arxiv.org/ps/1406.0261">ps</a>, <a href="https://arxiv.org/format/1406.0261">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="Computational Physics">physics.comp-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/srep06946">10.1038/srep06946 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Hinge-like structure induced unusual properties of black phosphorus and new strategies to improve the thermoelectric performance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Qin%2C+G">Guangzhao Qin</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+Q">Qing-Bo Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Qin%2C+Z">Zhenzhen Qin</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Cui%2C+H">Hui-Juan Cui</a>, <a href="/search/cond-mat?searchtype=author&query=Zheng%2C+Q">Qing-Rong Zheng</a>, <a href="/search/cond-mat?searchtype=author&query=Su%2C+G">Gang Su</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="1406.0261v4-abstract-short" style="display: inline;"> We systematically investigated the geometric, electronic and thermoelectric (TE) properties of bulk black phosphorus (BP) under strain. The hinge-like structure of BP brings unusual mechanical responses such as anisotropic Young's modulus and negative Poisson's ratio. A sensitive electronic structure of BP makes it transform among metal, direct and indirect semiconductors under strain. The maximal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.0261v4-abstract-full').style.display = 'inline'; document.getElementById('1406.0261v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1406.0261v4-abstract-full" style="display: none;"> We systematically investigated the geometric, electronic and thermoelectric (TE) properties of bulk black phosphorus (BP) under strain. The hinge-like structure of BP brings unusual mechanical responses such as anisotropic Young's modulus and negative Poisson's ratio. A sensitive electronic structure of BP makes it transform among metal, direct and indirect semiconductors under strain. The maximal figure of merit $ZT$ of BP is found to be 0.72 at $800\,\mathrm{K}$ that could be enhanced to 0.87 by exerting an appropriate strain, revealing BP could be a potential medium-high temperature TE material. Such strain-induced enhancements of TE performance are often observed to occur at the boundary of the direct-indirect band gap transition, which can be attributed to the increase of degeneracy of energy valleys at the transition point. By comparing the structure of BP with SnSe, a family of potential TE materials with hinge-like structure are suggested. This study not only exposes various novel properties of BP under strain, but also proposes effective strategies to seek for better TE materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.0261v4-abstract-full').style.display = 'none'; document.getElementById('1406.0261v4-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 October, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 June, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2014. </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 figures. Supplemental Information is available in Scientific Reports and also involved in this source package</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Scientific Reports 4, 6946 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1308.5024">arXiv:1308.5024</a> <span> [<a href="https://arxiv.org/pdf/1308.5024">pdf</a>, <a href="https://arxiv.org/ps/1308.5024">ps</a>, <a href="https://arxiv.org/format/1308.5024">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.carbon.2014.01.023">10.1016/j.carbon.2014.01.023 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electronic and magnetic properties of twisted graphene nanoribbon and M枚bius strips: first-principles calculations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Sheng-Ying Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+Q">Qing-Bo Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+Z">Zhen-Gang Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Cui%2C+H">Hui-Juan Cui</a>, <a href="/search/cond-mat?searchtype=author&query=Zheng%2C+Q">Qing-Rong Zheng</a>, <a href="/search/cond-mat?searchtype=author&query=Su%2C+G">Gang Su</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="1308.5024v1-abstract-short" style="display: inline;"> The geometrical, electronic, and magnetic properties of twisted zigzag-edged graphene nanoribbons (ZGNRs) and novel graphene M枚bius strips (GMS) are systematically investigated using first-principles density functional calculations. The structures of ZGNRs and GMS are optimized, and their stabilities are examined. The molecular energy levels and the spin polarized density of states are calculated.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1308.5024v1-abstract-full').style.display = 'inline'; document.getElementById('1308.5024v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1308.5024v1-abstract-full" style="display: none;"> The geometrical, electronic, and magnetic properties of twisted zigzag-edged graphene nanoribbons (ZGNRs) and novel graphene M枚bius strips (GMS) are systematically investigated using first-principles density functional calculations. The structures of ZGNRs and GMS are optimized, and their stabilities are examined. The molecular energy levels and the spin polarized density of states are calculated. It is found that for twisted ZGNRs, the atomic bonding energy decreases quadratically with the increase of the twisted angle, and the HOMO-LUMO gap are varying in a sine-like behavior with the twisted angle. The calculated spin densities reveal that the ZGNRs and GMS have antiferromagnetic ground states, which persist during the twisting. The spin flips on the zigzag edges of GMS are observed at some positions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1308.5024v1-abstract-full').style.display = 'none'; document.getElementById('1308.5024v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 August, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">22 pages,6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Carbon, 71, 150-158 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1204.4270">arXiv:1204.4270</a> <span> [<a href="https://arxiv.org/pdf/1204.4270">pdf</a>, <a href="https://arxiv.org/ps/1204.4270">ps</a>, <a href="https://arxiv.org/format/1204.4270">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.85.195101">10.1103/PhysRevB.85.195101 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the transport and thermodynamic properties of quasi-two-dimensional purple bronzes A$_{0.9}$Mo$_6$O$_{17}$ (A=Na, K) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Xu%2C+X">Xiaofeng Xu</a>, <a href="/search/cond-mat?searchtype=author&query=Bangura%2C+A+F">A. F. Bangura</a>, <a href="/search/cond-mat?searchtype=author&query=Niu%2C+C+Q">C. Q. Niu</a>, <a href="/search/cond-mat?searchtype=author&query=Greenblatt%2C+M">M. Greenblatt</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Song Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Panagopoulos%2C+C">C. Panagopoulos</a>, <a href="/search/cond-mat?searchtype=author&query=Hussey%2C+N+E">N. E. Hussey</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="1204.4270v1-abstract-short" style="display: inline;"> We report a comparative study of the specific heat, electrical resistivity and thermal conductivity of the quasi-two-dimensional purple bronzes Na$_{0.9}$Mo$_6$O$_{17}$ and K$_{0.9}$Mo$_6$O$_{17}$, with special emphasis on the behavior near their respective charge-density-wave transition temperatures $T_P$. The contrasting behavior of both the transport and the thermodynamic properties near $T_P$… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1204.4270v1-abstract-full').style.display = 'inline'; document.getElementById('1204.4270v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1204.4270v1-abstract-full" style="display: none;"> We report a comparative study of the specific heat, electrical resistivity and thermal conductivity of the quasi-two-dimensional purple bronzes Na$_{0.9}$Mo$_6$O$_{17}$ and K$_{0.9}$Mo$_6$O$_{17}$, with special emphasis on the behavior near their respective charge-density-wave transition temperatures $T_P$. The contrasting behavior of both the transport and the thermodynamic properties near $T_P$ is argued to arise predominantly from the different levels of intrinsic disorder in the two systems. A significant proportion of the enhancement of the thermal conductivity above $T_P$ in Na$_{0.9}$Mo$_6$O$_{17}$, and to a lesser extent in K$_{0.9}$Mo$_6$O$_{17}$, is attributed to the emergence of phason excitations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1204.4270v1-abstract-full').style.display = 'none'; document.getElementById('1204.4270v1-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 April, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">8 pages, 6 figures, To appear in Physical Review B</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PRB 85, 195101 (2012) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0712.3880">arXiv:0712.3880</a> <span> [<a href="https://arxiv.org/pdf/0712.3880">pdf</a>, <a href="https://arxiv.org/ps/0712.3880">ps</a>, <a href="https://arxiv.org/format/0712.3880">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/10.1088/1367-2630/10/2/023043">10.1088/1367-2630/10/2/023043 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Raman study of the Charge-Density-Wave State in A$_{0.3}$MoO$_3$ (A = K,Rb) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sagar%2C+D+M">D. M. Sagar</a>, <a href="/search/cond-mat?searchtype=author&query=Fausti%2C+D">D. Fausti</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">S. Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Kuntscher%2C+C+A">C. A. Kuntscher</a>, <a href="/search/cond-mat?searchtype=author&query=van+Smaalen%2C+S">S. van Smaalen</a>, <a href="/search/cond-mat?searchtype=author&query=van+Loosdrecht%2C+P+H+M">P. H. M. van Loosdrecht</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="0712.3880v1-abstract-short" style="display: inline;"> We report a comparative Raman spectroscopic study of the quasi-one-dimensional charge-density-wave systems \ab (A = K, Rb). The temperature and polarization dependent experiments reveal charge-coupled vibrational Raman features. The strongly temperature-dependent collective amplitudon mode in both materials differ by about 3 cm, thus revealing the role of alkali atom. We discus the observed vibr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0712.3880v1-abstract-full').style.display = 'inline'; document.getElementById('0712.3880v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0712.3880v1-abstract-full" style="display: none;"> We report a comparative Raman spectroscopic study of the quasi-one-dimensional charge-density-wave systems \ab (A = K, Rb). The temperature and polarization dependent experiments reveal charge-coupled vibrational Raman features. The strongly temperature-dependent collective amplitudon mode in both materials differ by about 3 cm, thus revealing the role of alkali atom. We discus the observed vibrational features in terms of charge-density-wave ground state accompanied by change in the crystal symmetry. A frequency-kink in some modes seen in \bb between T = 80 K and 100 K supports the first-order lock-in transition, unlike \rb. The unusually sharp Raman lines(limited by the instrumental response) at very low temperatures and their temperature evolution suggests that the decay of the low energy phonons is strongly influenced by the presence of the temperature dependent charge density wave gap. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0712.3880v1-abstract-full').style.display = 'none'; document.getElementById('0712.3880v1-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 December, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">13 pages, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/cond-mat/0501332">arXiv:cond-mat/0501332</a> <span> [<a href="https://arxiv.org/pdf/cond-mat/0501332">pdf</a>, <a href="https://arxiv.org/ps/cond-mat/0501332">ps</a>, <a href="https://arxiv.org/format/cond-mat/0501332">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Doping Effects on the Charge-Density-Wave Dynamics in Blue Bronze </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">S. Yue</a>, <a href="/search/cond-mat?searchtype=author&query=Kuntscher%2C+C+A">C. A. Kuntscher</a>, <a href="/search/cond-mat?searchtype=author&query=Dressel%2C+M">M. Dressel</a>, <a href="/search/cond-mat?searchtype=author&query=van+Smaalen%2C+S">S. van Smaalen</a>, <a href="/search/cond-mat?searchtype=author&query=Ritter%2C+F">F. Ritter</a>, <a href="/search/cond-mat?searchtype=author&query=Assmus%2C+W">W. Assmus</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/0501332v1-abstract-short" style="display: inline;"> The temperature dependences of the dc resistivity and the nonlinear transport properties in pure, Rb-doped, and W-doped blue bronze K$_{0.3}$MoO$_{3}$ single crystals are presented. In comparison with the Rb doping, the W doping has larger effects on the electrical transport properties and the Peierls transition. In particular, the maximum in the temperature dependence of the threshold field for… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('cond-mat/0501332v1-abstract-full').style.display = 'inline'; document.getElementById('cond-mat/0501332v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="cond-mat/0501332v1-abstract-full" style="display: none;"> The temperature dependences of the dc resistivity and the nonlinear transport properties in pure, Rb-doped, and W-doped blue bronze K$_{0.3}$MoO$_{3}$ single crystals are presented. In comparison with the Rb doping, the W doping has larger effects on the electrical transport properties and the Peierls transition. In particular, the maximum in the temperature dependence of the threshold field for nonlinear transport, observed in pure and Rb-doped samples around 100 K, is absent in W-doped K$_{0.3}$MoO$_{3}$. These results are discussed with respect to the proposed incommensurate-commensurate transition of the charge-density-wave and its interaction with impurities and normal carriers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('cond-mat/0501332v1-abstract-full').style.display = 'none'; document.getElementById('cond-mat/0501332v1-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 January, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2005. </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, 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/cond-mat/9803251">arXiv:cond-mat/9803251</a> <span> [<a href="https://arxiv.org/pdf/cond-mat/9803251">pdf</a>, <a href="https://arxiv.org/ps/cond-mat/9803251">ps</a>, <a href="https://arxiv.org/format/cond-mat/9803251">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="Pattern Formation and Solitons">nlin.PS</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevE.58.4763">10.1103/PhysRevE.58.4763 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Traffic Equations and Granular Convection </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hong%2C+D+C">Daniel C. Hong</a>, <a href="/search/cond-mat?searchtype=author&query=Yue%2C+S">Su Yue</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/9803251v1-abstract-short" style="display: inline;"> We investigate both numerically and analytically the convective instability of granular materials by two dimensional traffic equations. In the absence of vibrations the traffic equations assume two distinctive classes of fixed bed solutions with either a spatially uniform or nonuniform density profile. The former one exists only when the function V(蟻) that monitors the relaxation of grains assum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('cond-mat/9803251v1-abstract-full').style.display = 'inline'; document.getElementById('cond-mat/9803251v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="cond-mat/9803251v1-abstract-full" style="display: none;"> We investigate both numerically and analytically the convective instability of granular materials by two dimensional traffic equations. In the absence of vibrations the traffic equations assume two distinctive classes of fixed bed solutions with either a spatially uniform or nonuniform density profile. The former one exists only when the function V(蟻) that monitors the relaxation of grains assumes a cut off at the closed packed density, 蟻_c, with V(蟻_c)=0, while the latter one exists for any form of V. Since there is little difference between the uniform and nonuniform solution deep inside the bed, the convective instability of the bulk may be studied by focusing on the stability of the uniform solution. In the presence of vibrations, we find that the uniform solution bifurcates into a bouncing solution, which then undergoes a supercritical bifurcation to the convective instability. We determine the onset of convection as a function of control parameters and confirm this picture by solving the traffic equations numerically, which reveals bouncing solutions, two convective rolls, and four convective rolls. Further, convective patterns change as the aspect ratio changes: in a vertically long container, the rolls move toward the surface, and in a horizontally long container, the rolls move toward the walls. We compare these results with those reported previously with a different continuum model by Hayakawa, Yue and Hong[Phys. Rev. Lett. 75,2328, 1995]. Finally, we also present a derivation of the traffic equations from Enskoq equation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('cond-mat/9803251v1-abstract-full').style.display = 'none'; document.getElementById('cond-mat/9803251v1-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 March, 1998; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 1998. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">34 pages, 10 figures</span> </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" 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