Pub Date : 2024-11-07DOI: 10.1103/physrevb.110.184506
Ravi Kiran, Sudipta Biswas, Monodeep Chakraborty
This paper investigates the superconducting properties of a two-dimensional 𝑠-wave superconductor on a kagome lattice subjected to correlated disorder. Using the Bogoliubov–de Gennes theory, we analyze the impact of disorder correlations on superconducting behavior. Additionally, we derive the stiffness formula for the kagome lattice and calculate its superfluid stiffness. An intriguing finding of our paper is the bimodal characteristic in the probability distribution of the superconducting pairing amplitude at higher disorder correlation strengths for intermediate values of the disordered potential. Our results provide valuable insights into how disorder correlations influence superconductivity and underscore the role of lattice geometry in shaping superconducting properties.
{"title":"Effect of correlated disorder on superconductivity in a kagome lattice: A Bogoliubov–de Gennes analysis","authors":"Ravi Kiran, Sudipta Biswas, Monodeep Chakraborty","doi":"10.1103/physrevb.110.184506","DOIUrl":"https://doi.org/10.1103/physrevb.110.184506","url":null,"abstract":"This paper investigates the superconducting properties of a two-dimensional <mjx-container ctxtmenu_counter=\"78\" 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=\"latinletter\" data-semantic-speech=\"s\" data-semantic-type=\"identifier\"><mjx-c>𝑠</mjx-c></mjx-mi></mjx-math></mjx-container>-wave superconductor on a kagome lattice subjected to correlated disorder. Using the Bogoliubov–de Gennes theory, we analyze the impact of disorder correlations on superconducting behavior. Additionally, we derive the stiffness formula for the kagome lattice and calculate its superfluid stiffness. An intriguing finding of our paper is the bimodal characteristic in the probability distribution of the superconducting pairing amplitude at higher disorder correlation strengths for intermediate values of the disordered potential. Our results provide valuable insights into how disorder correlations influence superconductivity and underscore the role of lattice geometry in shaping superconducting properties.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"5 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597342","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 : 2024-11-07DOI: 10.1103/physrevb.110.195122
Mengfan Wang, Danqing Hu, Yi-feng Yang
Motivated by the recent proposal that the Monte Carlo sign problem might be used as an indicator of quantum phase transitions, we simulate the periodic Anderson model at half-filling with a staggered ionic potential using the determinant quantum Monte Carlo (DQMC) approach. We observe a phase transition from a band insulator to a Kondo insulator as the hybridization increases. At finite temperature, an intermediate metallic region emerges between two insulating phases, which is characterized by a pseudogap in the spectral functions near the boundary of the intermediate region and a quasiparticle peak in the middle. The latter coincides with a crossing point of the 𝑓-electron occupation on different sublattices as well as the maximum antiferromagnetic (AFM) correlations. The metallic region extrapolates to a single quantum critical point at zero temperature, which may result in exotic quasiparticle excitations associated with the emergent metallic state. The Monte Carlo sign problem is found to be most pronounced in the quantum critical region, implying a close connection between the two phenomena. Our results are qualitatively supported by the Hartree-Fock (HF) mean-field calculations. Our work reveals interesting physics in inhomogeneous Kondo lattice systems that may be worthwhile of more investigations in the future.
{"title":"Insulator-to-insulator transition and sign problem in the periodic Anderson model with a staggered potential","authors":"Mengfan Wang, Danqing Hu, Yi-feng Yang","doi":"10.1103/physrevb.110.195122","DOIUrl":"https://doi.org/10.1103/physrevb.110.195122","url":null,"abstract":"Motivated by the recent proposal that the Monte Carlo sign problem might be used as an indicator of quantum phase transitions, we simulate the periodic Anderson model at half-filling with a staggered ionic potential using the determinant quantum Monte Carlo (DQMC) approach. We observe a phase transition from a band insulator to a Kondo insulator as the hybridization increases. At finite temperature, an intermediate metallic region emerges between two insulating phases, which is characterized by a pseudogap in the spectral functions near the boundary of the intermediate region and a quasiparticle peak in the middle. The latter coincides with a crossing point of the <mjx-container ctxtmenu_counter=\"72\" 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=\"latinletter\" data-semantic-speech=\"f\" data-semantic-type=\"identifier\"><mjx-c>𝑓</mjx-c></mjx-mi></mjx-math></mjx-container>-electron occupation on different sublattices as well as the maximum antiferromagnetic (AFM) correlations. The metallic region extrapolates to a single quantum critical point at zero temperature, which may result in exotic quasiparticle excitations associated with the emergent metallic state. The Monte Carlo sign problem is found to be most pronounced in the quantum critical region, implying a close connection between the two phenomena. Our results are qualitatively supported by the Hartree-Fock (HF) mean-field calculations. Our work reveals interesting physics in inhomogeneous Kondo lattice systems that may be worthwhile of more investigations in the future.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"1 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597345","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 : 2024-11-07DOI: 10.1103/physrevb.110.l180402
C. W. J. Beenakker
It is known that the surface of a three-dimensional topological insulator (3D TI) supports a chiral Majorana edge mode at the interface between a superconductor and a magnetic insulator. The complexity of the materials combination is such that this state has not yet been observed. Here we show that a helical Majorana edge mode appears even in the absence of the magnetic insulator, if the Fermi level of the massless surface electrons is at the Dirac point. Specular Andreev reflection of Dirac fermions is at the origin of the effect. The simplified geometry may favor experimental observation of the helical Majorana mode, although it lacks the topological protection of its chiral counterpart.
{"title":"Poor man's Majorana edge mode enabled by specular Andreev reflection","authors":"C. W. J. Beenakker","doi":"10.1103/physrevb.110.l180402","DOIUrl":"https://doi.org/10.1103/physrevb.110.l180402","url":null,"abstract":"It is known that the surface of a three-dimensional topological insulator (3D TI) supports a chiral Majorana edge mode at the interface between a superconductor and a magnetic insulator. The complexity of the materials combination is such that this state has not yet been observed. Here we show that a helical Majorana edge mode appears even in the absence of the magnetic insulator, if the Fermi level of the massless surface electrons is at the Dirac point. Specular Andreev reflection of Dirac fermions is at the origin of the effect. The simplified geometry may favor experimental observation of the helical Majorana mode, although it lacks the topological protection of its chiral counterpart.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"18 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597403","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 : 2024-11-07DOI: 10.1103/physrevb.110.205117
Yin Shi, Long-Qing Chen
Perovskite rare-earth nickelates are a prototypical class of quantum materials that exhibit rich phase-transition physics with promising applications in neuromorphic computing. Although there is existing experimental evidence demonstrating that strain may strongly influence the phase transitions of nickelate thin films, it would be extremely challenging to experimentally construct temperature-strain phase diagrams for different film orientations to guide applications. Here, we use the Ginzburg-Landau theory to formulate the thermodynamics of strained nickelates and calculate temperature-strain phase diagrams of epitaxial <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="(2 0 1)"><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-owns="0 1" data-semantic-role="unknown" data-semantic-speech="upper S m upper N i upper O 3" data-semantic-type="subscript"><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="identifier"><mjx-c noic="true" style="padding-top: 0.673em;">S</mjx-c><mjx-c noic="true" style="padding-top: 0.673em;">m</mjx-c><mjx-c noic="true" style="padding-top: 0.673em;">N</mjx-c><mjx-c noic="true" style="padding-top: 0.673em;">i</mjx-c><mjx-c style="padding-top: 0.673em;">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="2" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-math></mjx-container> and <mjx-container ctxtmenu_counter="36" 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="unknown" data-semantic-speech="upper N d upper N i upper O 3" data-semantic-type="subscript"><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="identifier"><mjx-c noic="true" style="padding-top: 0.706em;">N</mjx-c><mjx-c noic="true" style="padding-top: 0.706em;">d</mjx-c><mjx-c noic="true" style="padding-top: 0.706em;">N</mjx-c><mjx-c noic="true" style="padding-top: 0.706em;">i</mjx-c><mjx-c style="padding-top: 0.706em;">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="2" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-math></mjx-container> thin films with various orientations, which are consistent with the limited existing experimental measureme
{"title":"Thermodynamics of strain engineering in𝑅NiO3(𝑅=Sm,Nd)","authors":"Yin Shi, Long-Qing Chen","doi":"10.1103/physrevb.110.205117","DOIUrl":"https://doi.org/10.1103/physrevb.110.205117","url":null,"abstract":"Perovskite rare-earth nickelates are a prototypical class of quantum materials that exhibit rich phase-transition physics with promising applications in neuromorphic computing. Although there is existing experimental evidence demonstrating that strain may strongly influence the phase transitions of nickelate thin films, it would be extremely challenging to experimentally construct temperature-strain phase diagrams for different film orientations to guide applications. Here, we use the Ginzburg-Landau theory to formulate the thermodynamics of strained nickelates and calculate temperature-strain phase diagrams of epitaxial <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=\"(2 0 1)\"><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-role=\"unknown\" data-semantic-speech=\"upper S m upper N i upper O 3\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.673em;\">S</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.673em;\">m</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.673em;\">N</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.673em;\">i</mjx-c><mjx-c style=\"padding-top: 0.673em;\">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=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-math></mjx-container> and <mjx-container ctxtmenu_counter=\"36\" 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=\"unknown\" data-semantic-speech=\"upper N d upper N i upper O 3\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.706em;\">N</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.706em;\">d</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.706em;\">N</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.706em;\">i</mjx-c><mjx-c style=\"padding-top: 0.706em;\">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=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-math></mjx-container> thin films with various orientations, which are consistent with the limited existing experimental measureme","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"9 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596929","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 : 2024-11-06DOI: 10.1103/physrevb.110.174410
Sike Zeng, Yu-Jun Zhao
In this paper, we propose a concept of bilayer stacking <mjx-container ctxtmenu_counter="32" 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="latinletter" data-semantic-speech="upper A" data-semantic-type="identifier"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnet (BSAA), in which two identical ferromagnetic monolayers are stacked with antiferromagnetic coupling to form a two-dimensional (2D) <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="latinletter" data-semantic-speech="upper A" data-semantic-type="identifier"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnet. By solving the stacking model, we derive all BSAAs for all layer groups and draw three key conclusions: (i) Only 17 layer groups can realize intrinsic <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="latinletter" data-semantic-speech="upper A" data-semantic-type="identifier"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnetism. All 2D <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="latinletter" data-semantic-speech="upper A" data-semantic-type="identifier"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnets must belong to these 17 layer groups, which will be helpful to search for 2D <mjx-container ctxtmenu_counter="36" 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="latinletter" data-semantic-speech="upper A" data-semantic-type="identifier"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnet. (ii) It is impossible to connect the two sublattices of BSAA using <mjx-container ctxtmenu_counter="37" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure
{"title":"Bilayer stacking𝐴-type altermagnet: A general approach to generating two-dimensional altermagnetism","authors":"Sike Zeng, Yu-Jun Zhao","doi":"10.1103/physrevb.110.174410","DOIUrl":"https://doi.org/10.1103/physrevb.110.174410","url":null,"abstract":"In this paper, we propose a concept of bilayer stacking <mjx-container ctxtmenu_counter=\"32\" 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=\"latinletter\" data-semantic-speech=\"upper A\" data-semantic-type=\"identifier\"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnet (BSAA), in which two identical ferromagnetic monolayers are stacked with antiferromagnetic coupling to form a two-dimensional (2D) <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=\"latinletter\" data-semantic-speech=\"upper A\" data-semantic-type=\"identifier\"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnet. By solving the stacking model, we derive all BSAAs for all layer groups and draw three key conclusions: (i) Only 17 layer groups can realize intrinsic <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=\"latinletter\" data-semantic-speech=\"upper A\" data-semantic-type=\"identifier\"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnetism. All 2D <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=\"latinletter\" data-semantic-speech=\"upper A\" data-semantic-type=\"identifier\"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnets must belong to these 17 layer groups, which will be helpful to search for 2D <mjx-container ctxtmenu_counter=\"36\" 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=\"latinletter\" data-semantic-speech=\"upper A\" data-semantic-type=\"identifier\"><mjx-c>𝐴</mjx-c></mjx-mi></mjx-math></mjx-container>-type altermagnet. (ii) It is impossible to connect the two sublattices of BSAA using <mjx-container ctxtmenu_counter=\"37\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"29 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588991","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 : 2024-11-06DOI: 10.1103/physrevb.110.205113
I. A. Shvets, E. V. Chulkov, S. V. Eremeev
Here we show that, in contrast to the observed surface states in well studied pnictogen chalcogenide van der Waals (vdW) topological insulators with quintuple layer (QL) or septuple layer (SL) structure, in superlattices, comprising the alternating QL and SL vdW blocks, the Dirac state becomes accompanied by emergent spin-polarized states of the Rashba type. This specific feature is caused by an inequivalence of the surface and subsurface structural blocks and an electrostatic potential bending near the surface. Within density functional theory and ab initio tight-binding calculations we analyze peculiarities of these states depending on the surface termination, structural parameters, and chemical composition. It is found that their possible hybridization with the Dirac state significantly affects its dispersion and spatial localization. We analyze the influence of intrinsic magnetism on behavior of the termination-dependent surface states for magnetic QL/SL superlattices. These findings provide a better understanding of the existing experimental observations of such QL/SL alternating superlattices.
在这里，我们展示了在具有五重层（QL）或七重层（SL）结构的对镱基氰基范德华（vdW）拓扑绝缘体中观察到的表面态，与之相反，在由交替的 QL 和 SL vdW 块组成的超晶格中，狄拉克态伴随着拉什巴类型的自旋极化态出现。这一特性是由表面和次表面结构块的不等价性以及表面附近的静电势弯曲造成的。在密度泛函理论和 ab initio 紧约束计算中，我们分析了这些态的特殊性取决于表面终端、结构参数和化学成分。研究发现，它们与狄拉克态的可能杂化会显著影响狄拉克态的色散和空间定位。我们分析了本征磁性对磁性 QL/SL 超晶格的终止相关表面态行为的影响。这些发现使我们能够更好地理解对这种 QL/SL 交替超晶格的现有实验观察结果。
{"title":"Interplay between Dirac and Rashba surface states specific for topologically nontrivial van der Waals superlattices","authors":"I. A. Shvets, E. V. Chulkov, S. V. Eremeev","doi":"10.1103/physrevb.110.205113","DOIUrl":"https://doi.org/10.1103/physrevb.110.205113","url":null,"abstract":"Here we show that, in contrast to the observed surface states in well studied pnictogen chalcogenide van der Waals (vdW) topological insulators with quintuple layer (QL) or septuple layer (SL) structure, in superlattices, comprising the alternating QL and SL vdW blocks, the Dirac state becomes accompanied by emergent spin-polarized states of the Rashba type. This specific feature is caused by an inequivalence of the surface and subsurface structural blocks and an electrostatic potential bending near the surface. Within density functional theory and <i>ab initio</i> tight-binding calculations we analyze peculiarities of these states depending on the surface termination, structural parameters, and chemical composition. It is found that their possible hybridization with the Dirac state significantly affects its dispersion and spatial localization. We analyze the influence of intrinsic magnetism on behavior of the termination-dependent surface states for magnetic QL/SL superlattices. These findings provide a better understanding of the existing experimental observations of such QL/SL alternating superlattices.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"18 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589003","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 : 2024-11-06DOI: 10.1103/physrevb.110.205115
Daniel Seleznev, Jennifer Cano, David Vanderbilt
It was recently argued that Bernal stacked bilayer graphene (BLG) exposed to a two-dimensional superlattice (SL) potential exhibits a variety of intriguing behaviors [Ghorashi et al., Phys. Rev. Lett.130, 196201 (2023)]. Chief among them is the appearance of flat Chern bands that are favorable to the appearance of fractional Chern insulator states. Here, we explore the application of spatially periodic out-of-plane orbital magnetic fields to the model of Ghorashi et al. to find additional means of inducing flat Chern bands. We focus on fields that vary on length scales much larger than the atomic spacing in BLG, generating what we refer to as magnetic SLs. The magnetic SLs we investigate either introduce no net magnetic flux to the SL unit cell or a single quantum of flux. We find that magnetic SLs acting on their own can induce topological flat bands, but richer behavior, such as the appearance of flat and generic bands with high Chern numbers, can be observed when the magnetic SLs act in conjunction with commensurate electric SLs. Finally, we propose a method of generating unit-flux-quantum magnetic SLs along with concomitant electric SLs. The magnetic SL is generated by periodic arrays of flux vortices originating from type II superconductors, while the electric SL arises due to a magnetic SL-induced charge density on the surface of a magnetoelectric material. Tuning the vortex lattice and the magnetoelectric coupling permits control of both SLs, and we study their effects on the band structure of BLG.
{"title":"Inducing topological flat bands in bilayer graphene with electric and magnetic superlattices","authors":"Daniel Seleznev, Jennifer Cano, David Vanderbilt","doi":"10.1103/physrevb.110.205115","DOIUrl":"https://doi.org/10.1103/physrevb.110.205115","url":null,"abstract":"It was recently argued that Bernal stacked bilayer graphene (BLG) exposed to a two-dimensional superlattice (SL) potential exhibits a variety of intriguing behaviors [Ghorashi <i>et al.</i>, <span>Phys. Rev. Lett.</span> <b>130</b>, 196201 (2023)]. Chief among them is the appearance of flat Chern bands that are favorable to the appearance of fractional Chern insulator states. Here, we explore the application of spatially periodic out-of-plane orbital magnetic fields to the model of Ghorashi <i>et al.</i> to find additional means of inducing flat Chern bands. We focus on fields that vary on length scales much larger than the atomic spacing in BLG, generating what we refer to as magnetic SLs. The magnetic SLs we investigate either introduce no net magnetic flux to the SL unit cell or a single quantum of flux. We find that magnetic SLs acting on their own can induce topological flat bands, but richer behavior, such as the appearance of flat and generic bands with high Chern numbers, can be observed when the magnetic SLs act in conjunction with commensurate electric SLs. Finally, we propose a method of generating unit-flux-quantum magnetic SLs along with concomitant electric SLs. The magnetic SL is generated by periodic arrays of flux vortices originating from type II superconductors, while the electric SL arises due to a magnetic SL-induced charge density on the surface of a magnetoelectric material. Tuning the vortex lattice and the magnetoelectric coupling permits control of both SLs, and we study their effects on the band structure of BLG.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"90 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589005","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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