Pub Date : 2024-11-05DOI: 10.1103/physrevb.110.195113
Ai-Lei He, Lu Qi, Yongjun Liu, Yi-Fei Wang
Fractional Chern insulators (FCIs) have attracted intensive attention for the realization of fractional quantum Hall states in the absence of an external magnetic field. Most FCIs have been proposed on two-dimensional (2D) Euclidean lattice models with various boundary conditions. In this work, we investigate hyperbolic FCIs which are constructed in hyperbolic geometry with constant negative curvature. Through the studies on hyperbolic analogs of kagome lattices with hard-core bosons loaded into topological flat bands, we find convincing numerical evidences of two types of <mjx-container ctxtmenu_counter="70" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(6 0 1 (5 2 3 4))"><mjx-mrow data-semantic-children="0,5" data-semantic-content="1" data-semantic- data-semantic-owns="0 1 5" data-semantic-role="equality" data-semantic-speech="nu equals 1 divided by 2" data-semantic-type="relseq"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="6" data-semantic-role="greekletter" data-semantic-type="identifier"><mjx-c>𝜈</mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator="relseq,=" data-semantic-parent="6" data-semantic-role="equality" data-semantic-type="relation" space="4"><mjx-c>=</mjx-c></mjx-mo><mjx-mrow data-semantic-added="true" data-semantic-children="2,4" data-semantic-content="3" data-semantic- data-semantic-owns="2 3 4" data-semantic-parent="6" data-semantic-role="division" data-semantic-type="infixop" space="4"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="5" data-semantic-role="integer" data-semantic-type="number"><mjx-c>1</mjx-c></mjx-mn><mjx-mo data-semantic- data-semantic-operator="infixop,/" data-semantic-parent="5" data-semantic-role="division" data-semantic-type="operator"><mjx-c>/</mjx-c></mjx-mo><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="5" data-semantic-role="integer" data-semantic-type="number"><mjx-c>2</mjx-c></mjx-mn></mjx-mrow></mjx-mrow></mjx-math></mjx-container> FCI states, i.e., conventional and unconventional FCIs. Multiple branches of edge excitations and geometry-dependent wave functions for both conventional and unconventional <mjx-container ctxtmenu_counter="71" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(6 0 1 (5 2 3 4))"><mjx-mrow data-semantic-children="0,5" data-semantic-content="1" data-semantic- data-semantic-owns="0 1 5" data-semantic-role="equality" data-semantic-speech="nu equals 1 divided by 2" data-semantic-type="relseq"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="6" data-semantic-role="greeklett
Pub Date : 2024-11-05DOI: 10.1103/physrevb.110.195114
Mykhailo V. Rakov, Luca Tagliacozzo, Maciej Lewenstein, Jakub Zakrzewski, Titas Chanda
We investigate a quasi-two-dimensional system consisting of two species of alkali atoms confined in a specific optical lattice potential [<span>Phys. Rev. A</span> <b>95</b>, 053608 (2017)]. In the low-energy regime, this system is governed by a unique <mjx-container ctxtmenu_counter="70" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(2 0 1)"><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-owns="0 1" data-semantic-role="numbersetletter" data-semantic-speech="double struck upper Z Subscript upper N" data-semantic-type="subscript"><mjx-mi data-semantic-font="double-struck" data-semantic- data-semantic-parent="2" data-semantic-role="numbersetletter" data-semantic-type="identifier"><mjx-c>ℤ</mjx-c></mjx-mi><mjx-script style="vertical-align: -0.15em;"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="2" data-semantic-role="latinletter" data-semantic-type="identifier" size="s"><mjx-c>𝑁</mjx-c></mjx-mi></mjx-script></mjx-msub></mjx-math></mjx-container> gauge theory, where field theory arguments have suggested that it may exhibit two exotic gapless deconfined phases, namely a dipolar liquid phase and a Bose liquid phase, along with two gapped (confined and deconfined) phases. We address these predictions numerically by using large-scale density matrix renormalization group simulations. Our findings provide conclusive evidence for the existence of a gapless Bose liquid phase for <mjx-container ctxtmenu_counter="71" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(3 0 1 2)"><mjx-mrow data-semantic-children="0,2" data-semantic-content="1" data-semantic- data-semantic-owns="0 1 2" data-semantic-role="inequality" data-semantic-speech="upper N greater than or equals 7" data-semantic-type="relseq"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="3" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c>𝑁</mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator="relseq,≥" data-semantic-parent="3" data-semantic-role="inequality" data-semantic-type="relation" space="4"><mjx-c>≥</mjx-c></mjx-mo><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="3" data-semantic-role="integer" data-semantic-type="number" space="4"><mjx-c>7</mjx-c></mjx-mn></mjx-mrow></mjx-math></mjx-container>. We demonstrate that this gapless phase shares the same critical properties as one-dimensional critical phases, resembling weakly coupled chains of Luttinger liquids. In the range of ladder and cylinder geometries and <mjx-container ctxtmenu_counter="72" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-ex
我们研究了一个由两种碱原子组成的准二维系统，它被限制在一个特定的光学晶格势中[Phys. Rev. A 95, 053608 (2017)]。在低能体系中，该体系受一个独特的ℤ𝑁规理论支配，场论论证表明它可能表现出两个奇异的无间隙去致密相，即双极液相和玻色液相，以及两个间隙（致密和去致密）相。我们利用大尺度密度矩阵重正化群模拟对这些预测进行了数值处理。我们的发现为𝑁≥7 存在无间隙玻色液相提供了确凿的证据。我们证明了这种无间隙相具有与一维临界相相同的临界性质，类似于弱耦合的鲁丁格液体链。在所考虑的梯形和圆柱体几何形状及𝑁 的范围内，理论上预测的无间隙偶极相仍然难以捉摸，其特征可能需要全面的二维处理。
{"title":"Gapless deconfined phase in aℤ𝑁-symmetric Hamiltonian created in a cold-atom setup","authors":"Mykhailo V. Rakov, Luca Tagliacozzo, Maciej Lewenstein, Jakub Zakrzewski, Titas Chanda","doi":"10.1103/physrevb.110.195114","DOIUrl":"https://doi.org/10.1103/physrevb.110.195114","url":null,"abstract":"We investigate a quasi-two-dimensional system consisting of two species of alkali atoms confined in a specific optical lattice potential [<span>Phys. Rev. A</span> <b>95</b>, 053608 (2017)]. In the low-energy regime, this system is governed by a unique <mjx-container ctxtmenu_counter=\"70\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(2 0 1)\"><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-role=\"numbersetletter\" data-semantic-speech=\"double struck upper Z Subscript upper N\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-font=\"double-struck\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"numbersetletter\" data-semantic-type=\"identifier\"><mjx-c>ℤ</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\" size=\"s\"><mjx-c>𝑁</mjx-c></mjx-mi></mjx-script></mjx-msub></mjx-math></mjx-container> gauge theory, where field theory arguments have suggested that it may exhibit two exotic gapless deconfined phases, namely a dipolar liquid phase and a Bose liquid phase, along with two gapped (confined and deconfined) phases. We address these predictions numerically by using large-scale density matrix renormalization group simulations. Our findings provide conclusive evidence for the existence of a gapless Bose liquid phase for <mjx-container ctxtmenu_counter=\"71\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(3 0 1 2)\"><mjx-mrow data-semantic-children=\"0,2\" data-semantic-content=\"1\" data-semantic- data-semantic-owns=\"0 1 2\" data-semantic-role=\"inequality\" data-semantic-speech=\"upper N greater than or equals 7\" data-semantic-type=\"relseq\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c>𝑁</mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator=\"relseq,≥\" data-semantic-parent=\"3\" data-semantic-role=\"inequality\" data-semantic-type=\"relation\" space=\"4\"><mjx-c>≥</mjx-c></mjx-mo><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"integer\" data-semantic-type=\"number\" space=\"4\"><mjx-c>7</mjx-c></mjx-mn></mjx-mrow></mjx-math></mjx-container>. We demonstrate that this gapless phase shares the same critical properties as one-dimensional critical phases, resembling weakly coupled chains of Luttinger liquids. In the range of ladder and cylinder geometries and <mjx-container ctxtmenu_counter=\"72\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-ex","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"87 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-05DOI: 10.1103/physrevb.110.174502
Haoyang Liu, Ashwani Kumar, Liuqi Yu, Richard P. Barber, Jr., Peng Xiong
Superconductivity in two dimensions has attracted renewed interest in the context of two-dimensional (2D) van der Waals materials. Key questions remain regarding the nature and manifestations of the superconductivity in these materials. One open question is whether superconducting fluctuations in such 2D systems can be described by the classic Aslamazov-Larkin (A-L) equation. While the A-L model has long been found to accurately describe the paraconductivity of some conventional 2D superconductors, its applicability in ultrathin limit near the superconductor-insulator transition (SIT) has not been established. Here, we report a systematic study of superconducting fluctuation and paraconductivity in ultrathin 2D amorphous Pb films near the SIT. Pb films were incrementally deposited, and the electrical measurements were performed <i>in situ</i> at each thickness in a dilution refrigerator, resulting in a series of sheet resistance curves <mjx-container ctxtmenu_counter="57" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(11 0 (10 (3 1 2) 9 (7 4 5 6)) 8)"><mjx-mrow data-semantic-children="10" data-semantic-content="0,8" data-semantic- data-semantic-owns="0 10 8" data-semantic-role="leftright" data-semantic-speech="left bracket upper R Subscript white square Baseline left parenthesis upper T right parenthesis right bracket" data-semantic-type="fenced"><mjx-mo data-semantic- data-semantic-operator="fenced" data-semantic-parent="11" data-semantic-role="open" data-semantic-type="fence" style="vertical-align: -0.02em;"><mjx-c>[</mjx-c></mjx-mo><mjx-mrow data-semantic-added="true" data-semantic-annotation="clearspeak:simple" data-semantic-children="3,7" data-semantic-content="9,1" data-semantic- data-semantic-owns="3 9 7" data-semantic-parent="11" data-semantic-role="simple function" data-semantic-type="appl"><mjx-msub data-semantic-children="1,2" data-semantic- data-semantic-owns="1 2" data-semantic-parent="10" data-semantic-role="simple function" data-semantic-type="subscript"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-operator="appl" data-semantic-parent="3" data-semantic-role="simple function" data-semantic-type="identifier"><mjx-c>𝑅</mjx-c></mjx-mi><mjx-script style="vertical-align: -0.15em;"><mjx-mo data-semantic- data-semantic-parent="3" data-semantic-role="geometry" data-semantic-type="relation" size="s"><mjx-c>□</mjx-c></mjx-mo></mjx-script></mjx-msub><mjx-mo data-semantic-added="true" data-semantic- data-semantic-operator="appl" data-semantic-parent="10" data-semantic-role="application" data-semantic-type="punctuation"><mjx-c></mjx-c></mjx-mo><mjx-mrow data-semantic-children="5" data-semantic-content="4,6" data-semantic- data-semantic-owns="4 5 6" data-semantic-parent="10" data-semantic-role="leftright" data-semantic-type="fenced" space="2"><mjx-mo data-semantic- data
二维范德华材料的超导性再次引起了人们的兴趣。有关这些材料中超导性的性质和表现形式的关键问题依然存在。一个悬而未决的问题是，这种二维系统中的超导波动是否可以用经典的阿斯拉马佐夫-拉金（A-L）方程来描述。虽然人们早已发现 A-L 模型能准确描述一些传统二维超导体的副导性，但它在超导体-绝缘体转变（SIT）附近的超薄极限中的适用性尚未确定。在此，我们报告了对 SIT 附近超薄二维非晶铅薄膜中超导波动和副导性的系统研究。铅薄膜以递增的方式沉积，在稀释冰箱中对每个厚度进行原位电学测量，从而得到一系列横跨 SIT 的片电阻曲线[𝑅□(𝑇)]。然后，顺磁杂质（Cr）被沉积在同一超导薄膜上，使其回到绝缘状态，并产生了另一组𝑅□(𝑇)。这两种类型的𝑅□(𝑇) 曲线都用 A-L 方程进行了分析。在所有薄膜厚度（和 𝑇𝐶's）下，我们都观察到本底副电导率明显大于 A-L 值。随着薄膜厚度的减小和 SIT 的接近，副电导率急剧上升，在 SIT 附近比 A-L 值高出一个数量级以上。伴随着过剩副电导率的存在及其随厚度减小而增加，副电导率随𝑇高于𝑇𝐶呈指数缩放，其温度范围和斜率随薄膜厚度减小而相应变化。与此相反，磁性杂质对𝑇𝐶的抑制导致过剩副电导率的增加要弱得多，而指数𝑇缩放的温度范围和斜率变化不大。这些观察结果与强烈无序、形态上名义上均匀的非晶态薄膜中出现的高于𝑇𝐶的局部超导配对相一致。空间局域化超导可能会导致超出 A-L 理论的超导和渗流超导跃迁。这种电子不均匀性会随着薄膜厚度的减小而增大，尤其是在 SIT 附近。
{"title":"Superconducting fluctuations and paraconductivity in ultrathin amorphous Pb films near superconductor-insulator transitions","authors":"Haoyang Liu, Ashwani Kumar, Liuqi Yu, Richard P. Barber, Jr., Peng Xiong","doi":"10.1103/physrevb.110.174502","DOIUrl":"https://doi.org/10.1103/physrevb.110.174502","url":null,"abstract":"Superconductivity in two dimensions has attracted renewed interest in the context of two-dimensional (2D) van der Waals materials. Key questions remain regarding the nature and manifestations of the superconductivity in these materials. One open question is whether superconducting fluctuations in such 2D systems can be described by the classic Aslamazov-Larkin (A-L) equation. While the A-L model has long been found to accurately describe the paraconductivity of some conventional 2D superconductors, its applicability in ultrathin limit near the superconductor-insulator transition (SIT) has not been established. Here, we report a systematic study of superconducting fluctuation and paraconductivity in ultrathin 2D amorphous Pb films near the SIT. Pb films were incrementally deposited, and the electrical measurements were performed <i>in situ</i> at each thickness in a dilution refrigerator, resulting in a series of sheet resistance curves <mjx-container ctxtmenu_counter=\"57\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(11 0 (10 (3 1 2) 9 (7 4 5 6)) 8)\"><mjx-mrow data-semantic-children=\"10\" data-semantic-content=\"0,8\" data-semantic- data-semantic-owns=\"0 10 8\" data-semantic-role=\"leftright\" data-semantic-speech=\"left bracket upper R Subscript white square Baseline left parenthesis upper T right parenthesis right bracket\" data-semantic-type=\"fenced\"><mjx-mo data-semantic- data-semantic-operator=\"fenced\" data-semantic-parent=\"11\" data-semantic-role=\"open\" data-semantic-type=\"fence\" style=\"vertical-align: -0.02em;\"><mjx-c>[</mjx-c></mjx-mo><mjx-mrow data-semantic-added=\"true\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-children=\"3,7\" data-semantic-content=\"9,1\" data-semantic- data-semantic-owns=\"3 9 7\" data-semantic-parent=\"11\" data-semantic-role=\"simple function\" data-semantic-type=\"appl\"><mjx-msub data-semantic-children=\"1,2\" data-semantic- data-semantic-owns=\"1 2\" data-semantic-parent=\"10\" data-semantic-role=\"simple function\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-operator=\"appl\" data-semantic-parent=\"3\" data-semantic-role=\"simple function\" data-semantic-type=\"identifier\"><mjx-c>𝑅</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mo data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"geometry\" data-semantic-type=\"relation\" size=\"s\"><mjx-c>□</mjx-c></mjx-mo></mjx-script></mjx-msub><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"appl\" data-semantic-parent=\"10\" data-semantic-role=\"application\" data-semantic-type=\"punctuation\"><mjx-c></mjx-c></mjx-mo><mjx-mrow data-semantic-children=\"5\" data-semantic-content=\"4,6\" data-semantic- data-semantic-owns=\"4 5 6\" data-semantic-parent=\"10\" data-semantic-role=\"leftright\" data-semantic-type=\"fenced\" space=\"2\"><mjx-mo data-semantic- data","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"18 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-05DOI: 10.1103/physrevb.110.195406
Misa Nozaki, Peter Krüger
A versatile method for angle-resolved photoemission spectra (ARPES) calculations is reported within the one-step model of photoemission. The initial states are obtained from a repeated-slab calculation using the projector-augmented wave (PAW) method. ARPES final states are constructed by matching the repeated-slab eigenstates of positive energy with free electron states that satisfy the time-reversed low-energy electron diffraction boundary conditions. Nonphysical solutions of the matching equations, which do not respect the flux conservation, are discarded. The method is applied to surface-normal photoemission from graphene as a function of photon energy from threshold up to 100 eV. The results are compared with independently performed multiple scattering calculations and very good agreement is obtained, provided that the photoemission matrix elements are computed with all-electron waves reconstructed from the PAW pseudowaves. However, if the pseudowaves are used directly, the relative intensity between 𝜎- and 𝜋-band emission is wrong by an order of magnitude. The graphene ARPES intensity has a strong photon energy dependence including resonances. The normal emission spectrum from the 𝜋 band shows a hitherto unreported sharp resonance at a photon energy of 31 eV. The resonance is due to a two-dimensional interband transition and highlights the importance of matrix element effects beyond the final-state plane-wave approximation.
在一步光发射模型中，报告了一种用于角度分辨光发射光谱（ARPES）计算的多功能方法。初始态是利用投影增强波（PAW）方法通过重复板计算获得的。ARPES 最终状态是通过将正能量的重复板特征状态与满足时间逆转低能量电子衍射边界条件的自由电子状态相匹配而构建的。匹配方程中不遵守通量守恒的非物理解将被舍弃。该方法被应用于石墨烯的表面正常光发射，作为从阈值到 100 eV 的光子能量的函数。将计算结果与独立进行的多重散射计算结果进行了比较，如果光发射矩阵元素是用从 PAW 伪波重建的全电子波计算的，则结果非常吻合。但是，如果直接使用伪波，𝜎 波段和𝜋 波段发射的相对强度就会出现数量级的误差。石墨烯 ARPES 强度与包括共振在内的光子能量有很大关系。𝜋波段的正常发射光谱在 31 eV 的光子能量处显示出迄今未报道的尖锐共振。该共振是由二维带间转变引起的，突出了矩阵元素效应在终态平面波近似之外的重要性。
{"title":"Computational method for angle-resolved photoemission spectra from repeated-slab band structure calculations","authors":"Misa Nozaki, Peter Krüger","doi":"10.1103/physrevb.110.195406","DOIUrl":"https://doi.org/10.1103/physrevb.110.195406","url":null,"abstract":"A versatile method for angle-resolved photoemission spectra (ARPES) calculations is reported within the one-step model of photoemission. The initial states are obtained from a repeated-slab calculation using the projector-augmented wave (PAW) method. ARPES final states are constructed by matching the repeated-slab eigenstates of positive energy with free electron states that satisfy the time-reversed low-energy electron diffraction boundary conditions. Nonphysical solutions of the matching equations, which do not respect the flux conservation, are discarded. The method is applied to surface-normal photoemission from graphene as a function of photon energy from threshold up to 100 eV. The results are compared with independently performed multiple scattering calculations and very good agreement is obtained, provided that the photoemission matrix elements are computed with all-electron waves reconstructed from the PAW pseudowaves. However, if the pseudowaves are used directly, the relative intensity between <mjx-container ctxtmenu_counter=\"33\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"greekletter\" data-semantic-speech=\"sigma\" data-semantic-type=\"identifier\"><mjx-c>𝜎</mjx-c></mjx-mi></mjx-math></mjx-container>- and <mjx-container ctxtmenu_counter=\"34\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"greekletter\" data-semantic-speech=\"pi\" data-semantic-type=\"identifier\"><mjx-c>𝜋</mjx-c></mjx-mi></mjx-math></mjx-container>-band emission is wrong by an order of magnitude. The graphene ARPES intensity has a strong photon energy dependence including resonances. The normal emission spectrum from the <mjx-container ctxtmenu_counter=\"35\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"greekletter\" data-semantic-speech=\"pi\" data-semantic-type=\"identifier\"><mjx-c>𝜋</mjx-c></mjx-mi></mjx-math></mjx-container> band shows a hitherto unreported sharp resonance at a photon energy of 31 eV. The resonance is due to a two-dimensional interband transition and highlights the importance of matrix element effects beyond the final-state plane-wave approximation.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"68 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-05DOI: 10.1103/physrevb.110.174102
Qiu Feng, Zhengwei Xiong, Zhangyang Zhou, Jun Yang, Gang Yao, Sen Chen, Zeming Tang, Zhipeng Gao
The phase transitions of ferroelectric ceramics under dynamic compressions are of importance for materials and applications design. However, there are very few effective methods for describing the shock-induced phase transition process in ferroelectric ceramics, due to the tiny structural volume change during compression. Here the phase transition behaviors of KNbO3 ceramics under compression are studied by measuring electrical responses. A model describing the phase variation in ferroelectric ceramics under uniaxial compressions with respect to pressures has been established, which may provide a reference for studying dynamic phase transitions in ferroelectrics under shock waves. Unlike hydrostatic high-pressure processes, the shock-induced phase transition initiates at relatively low pressures and increases progressively as the pressure rises. Random orientations of the grains in ceramics lead to different pressure conditions of each grain, which is responsible for the gradual phase transition processes. The proportion of phase transitions in three-dimensional space can be visualized using ab initio density functional theory. These findings have significant implications for material design and optimization.
{"title":"Dynamic phase transition modeling of potassium niobate under shock compression","authors":"Qiu Feng, Zhengwei Xiong, Zhangyang Zhou, Jun Yang, Gang Yao, Sen Chen, Zeming Tang, Zhipeng Gao","doi":"10.1103/physrevb.110.174102","DOIUrl":"https://doi.org/10.1103/physrevb.110.174102","url":null,"abstract":"The phase transitions of ferroelectric ceramics under dynamic compressions are of importance for materials and applications design. However, there are very few effective methods for describing the shock-induced phase transition process in ferroelectric ceramics, due to the tiny structural volume change during compression. Here the phase transition behaviors of <mjx-container ctxtmenu_counter=\"10\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(5 0 4 (3 1 2))\"><mjx-mrow data-semantic-annotation=\"clearspeak:unit\" data-semantic-children=\"0,3\" data-semantic-content=\"4\" data-semantic- data-semantic-owns=\"0 4 3\" data-semantic-role=\"implicit\" data-semantic-speech=\"upper K upper N b normal upper O 3\" data-semantic-type=\"infixop\"><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.706em;\">K</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.706em;\">N</mjx-c><mjx-c style=\"padding-top: 0.706em;\">b</mjx-c></mjx-mi><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"infixop,\" data-semantic-parent=\"5\" data-semantic-role=\"multiplication\" data-semantic-type=\"operator\"><mjx-c></mjx-c></mjx-mo><mjx-msub data-semantic-children=\"1,2\" data-semantic- data-semantic-owns=\"1 2\" data-semantic-parent=\"5\" data-semantic-role=\"latinletter\" data-semantic-type=\"subscript\" space=\"2\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c>O</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-mrow></mjx-math></mjx-container> ceramics under compression are studied by measuring electrical responses. A model describing the phase variation in ferroelectric ceramics under uniaxial compressions with respect to pressures has been established, which may provide a reference for studying dynamic phase transitions in ferroelectrics under shock waves. Unlike hydrostatic high-pressure processes, the shock-induced phase transition initiates at relatively low pressures and increases progressively as the pressure rises. Random orientations of the grains in ceramics lead to different pressure conditions of each grain, which is responsible for the gradual phase transition processes. The proportion of phase transitions in three-dimensional space can be visualized using <i>ab initio</i> density functional theory. These findings have significant implications for material design and optimization.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"7 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Understanding solid nitrogen through molecular dynamics simulations with a machine-learning potential","authors":"Marcin Kirsz, Ciprian G. Pruteanu, Peter I. C. Cooke, Graeme J. Ackland","doi":"10.1103/physrevb.110.184107","DOIUrl":"https://doi.org/10.1103/physrevb.110.184107","url":null,"abstract":"We construct a fast, transferable, general purpose, machine-learning interatomic potential suitable for large-scale simulations of <mjx-container ctxtmenu_counter=\"60\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(2 0 1)\"><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-role=\"latinletter\" data-semantic-speech=\"normal upper N 2\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c>N</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>2</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-math></mjx-container>. The potential is trained only on high quality quantum chemical molecule-molecule interactions; no condensed phase information is used. Although there are no explicit or implicit many-molecule interaction terms, the potential reproduces the experimental phase diagram including the melt curve and the molecular solid phases of nitrogen up to <mjx-container ctxtmenu_counter=\"61\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(4 0 3 2)\"><mjx-mrow data-semantic-annotation=\"clearspeak:unit\" data-semantic-children=\"0,2\" data-semantic-content=\"3\" data-semantic- data-semantic-owns=\"0 3 2\" data-semantic-role=\"implicit\" data-semantic-speech=\"10 upper G upper P a\" data-semantic-type=\"infixop\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"4\" data-semantic-role=\"integer\" data-semantic-type=\"number\"><mjx-c noic=\"true\" style=\"padding-top: 0.642em;\">1</mjx-c><mjx-c style=\"padding-top: 0.642em;\">0</mjx-c></mjx-mn><mjx-mspace data-semantic- data-semantic-operator=\"infixop,\" data-semantic-parent=\"4\" data-semantic-role=\"space\" data-semantic-type=\"operator\" style=\"width: 0.4em;\"></mjx-mspace><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"4\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\" space=\"2\"><mjx-c noic=\"true\" style=\"padding-top: 0.669em;\">G</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.669em;\">P</mjx-c><mjx-c style=\"padding-top: 0.669em;\">a</mjx-c></mjx-mi></mjx-mrow></mjx-math></mjx-container>. This demonstrates that many-molecule interactions are unnecessary to explain the condensed phases of <mjx-container ctxtmenu_counter=\"62\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(2 0 1)\"><mjx-msub data-semantic-c","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"44 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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