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Hussain G, Cuono G, Dziawa P, Janaszko D, Sadowski J, Kret S, Kurowska B, Polaczyński J, Warda K, Sattar S, Canali CM, Lau A, Brzezicki W, Story T, Autieri C. Pentagonal nanowires from topological crystalline insulators: a platform for intrinsic core-shell nanowires and higher-order topology. NANOSCALE HORIZONS 2024; 9:1290-1300. [PMID: 38804204 DOI: 10.1039/d4nh00019f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
We report on the experimental realization of Pb1-xSnx Te pentagonal nanowires (NWs) with [110] orientation using molecular beam epitaxy techniques. Using first-principles calculations, we investigate the structural stability of NWs of SnTe and PbTe in three different structural phases: cubic, pentagonal with [001] orientation and pentagonal with [110] orientation. Within a semiclassical approach, we show that the interplay between ionic and covalent bonds favors the formation of pentagonal NWs. Additionally, we find that this pentagonal structure is more likely to occur in tellurides than in selenides. The disclination and twin boundary cause the electronic states originating from the NW core region to generate a conducting band connecting the valence and conduction bands, creating a symmetry-enforced metallic phase. The metallic core band has opposite slopes in the cases of Sn and Te twin boundaries, while the bands from the shell are insulating. We finally study the electronic and topological properties of pentagonal NWs unveiling their potential as a new platform for higher-order topology and fractional charge. These pentagonal NWs represent a unique case of intrinsic core-shell one-dimensional nanostructures with distinct structural, electronic and topological properties between the core and the shell region.
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Affiliation(s)
- Ghulam Hussain
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Giuseppe Cuono
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
- Consiglio Nazionale delle Ricerche (CNR-SPIN), Unitá di Ricerca presso Terzi c/o Universitá "G. DAnnunzio", 66100 Chieti, Italy
| | - Piotr Dziawa
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Dorota Janaszko
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Janusz Sadowski
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Slawomir Kret
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Bogusława Kurowska
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Jakub Polaczyński
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Kinga Warda
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
- Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Gdańsk 80-233, Poland
| | - Shahid Sattar
- Department of Physics and Electrical Engineering, Linnaeus University, 392 31 Kalmar, Sweden
| | - Carlo M Canali
- Department of Physics and Electrical Engineering, Linnaeus University, 392 31 Kalmar, Sweden
| | - Alexander Lau
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Wojciech Brzezicki
- Institute of Theoretical Physics, Jagiellonian University, ulica S. ojasiewicza 11, PL-30348 Kraków, Poland
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Tomasz Story
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Carmine Autieri
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland.
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Li S, Gong M, Li YH, Jiang H, Xie XC. High spin axion insulator. Nat Commun 2024; 15:4250. [PMID: 38762497 PMCID: PMC11102527 DOI: 10.1038/s41467-024-48542-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 05/03/2024] [Indexed: 05/20/2024] Open
Abstract
Axion insulators possess a quantized axion field θ = π protected by combined lattice and time-reversal symmetry, holding great potential for device applications in layertronics and quantum computing. Here, we propose a high-spin axion insulator (HSAI) defined in large spin-s representation, which maintains the same inherent symmetry but possesses a notable axion field θ = (s + 1/2)2π. Such distinct axion field is confirmed independently by the direct calculation of the axion term using hybrid Wannier functions, layer-resolved Chern numbers, as well as the topological magneto-electric effect. We show that the guaranteed gapless quasi-particle excitation is absent at the boundary of the HSAI despite its integer surface Chern number, hinting an unusual quantum anomaly violating the conventional bulk-boundary correspondence. Furthermore, we ascertain that the axion field θ can be precisely tuned through an external magnetic field, enabling the manipulation of bonded transport properties. The HSAI proposed here can be experimentally verified in ultra-cold atoms by the quantized non-reciprocal conductance or topological magnetoelectric response. Our work enriches the understanding of axion insulators in condensed matter physics, paving the way for future device applications.
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Affiliation(s)
- Shuai Li
- School of Physical Science and Technology, Soochow University, Suzhou, 215006, China
- Institute for Advanced Study, Soochow University, Suzhou, 215006, China
| | - Ming Gong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Yu-Hang Li
- School of Physics, Nankai University, Tianjin, 300071, China.
| | - Hua Jiang
- Institute for Advanced Study, Soochow University, Suzhou, 215006, China.
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China.
- Interdisciplinary Center for Theoretical Physics and Information Sciences (ICTPIS), Fudan University, Shanghai, 200433, China.
| | - X C Xie
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China
- Interdisciplinary Center for Theoretical Physics and Information Sciences (ICTPIS), Fudan University, Shanghai, 200433, China
- Hefei National Laboratory, Hefei, 230088, China
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Yang YB, Wang JH, Li K, Xu Y. Higher-order topological phases in crystalline and non-crystalline systems: a review. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:283002. [PMID: 38574683 DOI: 10.1088/1361-648x/ad3abd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 04/04/2024] [Indexed: 04/06/2024]
Abstract
In recent years, higher-order topological phases have attracted great interest in various fields of physics. These phases have protected boundary states at lower-dimensional boundaries than the conventional first-order topological phases due to the higher-order bulk-boundary correspondence. In this review, we summarize current research progress on higher-order topological phases in both crystalline and non-crystalline systems. We firstly introduce prototypical models of higher-order topological phases in crystals and their topological characterizations. We then discuss effects of quenched disorder on higher-order topology and demonstrate disorder-induced higher-order topological insulators. We also review the theoretical studies on higher-order topological insulators in amorphous systems without any crystalline symmetry and higher-order topological phases in non-periodic lattices including quasicrystals, hyperbolic lattices, and fractals, which have no crystalline counterparts. We conclude the review by a summary of experimental realizations of higher-order topological phases and discussions on potential directions for future study.
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Affiliation(s)
- Yan-Bin Yang
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region of China, People's Republic of China
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Jiong-Hao Wang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Kai Li
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yong Xu
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
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Hu LH, Zhang RX. Dislocation Majorana bound states in iron-based superconductors. Nat Commun 2024; 15:2337. [PMID: 38491015 PMCID: PMC10943028 DOI: 10.1038/s41467-024-46618-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 03/04/2024] [Indexed: 03/18/2024] Open
Abstract
We show that lattice dislocations of topological iron-based superconductors such as FeTe1-xSex will intrinsically trap non-Abelian Majorana quasiparticles, in the absence of any external magnetic field. Our theory is motivated by the recent experimental observations of normal-state weak topology and surface magnetism that coexist with superconductivity in FeTe1-xSex, the combination of which naturally achieves an emergent second-order topological superconductivity in a two-dimensional subsystem spanned by screw or edge dislocations. This exemplifies a new embedded higher-order topological phase in class D, where Majorana zero modes appear around the "corners" of a low-dimensional embedded subsystem, instead of those of the full crystal. A nested domain wall theory is developed to understand the origin of these defect Majorana zero modes. When the surface magnetism is absent, we further find that s± pairing symmetry itself is capable of inducing a different type of class-DIII embedded higher-order topology with defect-bound Majorana Kramers pairs. We also provide detailed discussions on the real-world material candidates for our proposals, including FeTe1-xSex, LiFeAs, β-PdBi2, and heterostructures of bismuth, etc. Our work establishes lattice defects as a new venue to achieve high-temperature topological quantum information processing.
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Affiliation(s)
- Lun-Hui Hu
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, USA
- Institute for Advanced Materials and Manufacturing, The University of Tennessee, Knoxville, TN, USA
- Center for Correlated Matter and School of Physics, Zhejiang University, Hangzhou, China
| | - Rui-Xing Zhang
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, USA.
- Institute for Advanced Materials and Manufacturing, The University of Tennessee, Knoxville, TN, USA.
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, USA.
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Vaidya S, Rechtsman MC, Benalcazar WA. Polarization and Weak Topology in Chern Insulators. PHYSICAL REVIEW LETTERS 2024; 132:116602. [PMID: 38563931 DOI: 10.1103/physrevlett.132.116602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 11/08/2023] [Accepted: 01/30/2024] [Indexed: 04/04/2024]
Abstract
Chern insulators, and more broadly, topological insulators, present an obstruction to the construction of exponentially localized electronic Wannier functions. This implies a fundamental difficulty in determining whether such insulators exhibit electric polarization. Here, we show that these insulators can indeed exhibit bound charges and adiabatic currents consistent with changes in bulk polarization over space and time, respectively. We also show that the change in polarization across crystalline domains within these strong topological insulators is quantized in the presence of crystalline symmetries.
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Affiliation(s)
- Sachin Vaidya
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Mikael C Rechtsman
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Lin KS, Palumbo G, Guo Z, Hwang Y, Blackburn J, Shoemaker DP, Mahmood F, Wang Z, Fiete GA, Wieder BJ, Bradlyn B. Spin-resolved topology and partial axion angles in three-dimensional insulators. Nat Commun 2024; 15:550. [PMID: 38228584 PMCID: PMC10791639 DOI: 10.1038/s41467-024-44762-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 01/04/2024] [Indexed: 01/18/2024] Open
Abstract
Symmetry-protected topological crystalline insulators (TCIs) have primarily been characterized by their gapless boundary states. However, in time-reversal- ([Formula: see text]-) invariant (helical) 3D TCIs-termed higher-order TCIs (HOTIs)-the boundary signatures can manifest as a sample-dependent network of 1D hinge states. We here introduce nested spin-resolved Wilson loops and layer constructions as tools to characterize the intrinsic bulk topological properties of spinful 3D insulators. We discover that helical HOTIs realize one of three spin-resolved phases with distinct responses that are quantitatively robust to large deformations of the bulk spin-orbital texture: 3D quantum spin Hall insulators (QSHIs), "spin-Weyl" semimetals, and [Formula: see text]-doubled axion insulator (T-DAXI) states with nontrivial partial axion angles indicative of a 3D spin-magnetoelectric bulk response and half-quantized 2D TI surface states originating from a partial parity anomaly. Using ab-initio calculations, we demonstrate that β-MoTe2 realizes a spin-Weyl state and that α-BiBr hosts both 3D QSHI and T-DAXI regimes.
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Affiliation(s)
- Kuan-Sen Lin
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA, 93106, USA.
| | - Giandomenico Palumbo
- School of Theoretical Physics, Dublin Institute for Advanced Studies, 10 Burlington Road, Dublin, 4, Ireland
| | - Zhaopeng Guo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yoonseok Hwang
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jeremy Blackburn
- Department of Computer Science, State University of New York at Binghamton, Binghamton, NY, 13902, USA
| | - Daniel P Shoemaker
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Fahad Mahmood
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Zhijun Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Gregory A Fiete
- Department of Physics, Northeastern University, Boston, MA, 02115, USA.
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Benjamin J Wieder
- Department of Physics, Northeastern University, Boston, MA, 02115, USA.
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Institut de Physique Théorique, Université Paris-Saclay, CEA, CNRS, F-91191, Gif-sur-Yvette, France.
| | - Barry Bradlyn
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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