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Topological phases and topological phase transitions (TPT) are among the most fantastic phenomena in Nature. Here we show that injecting a current may lead to new topological phases, especially new gapless topological metallic phases with…

Mesoscale and Nanoscale Physics · Physics 2023-03-14 Fadi Sun , Jinwu Ye

We consider a time reversal symmetry (TRS) broken Kane-Mele model superimposed with Haldane model and chart out the phase diagram using spin Chern number to investigate the fate of quantum anomalous Hall insulator (QAHI) and quantum spin…

Mesoscale and Nanoscale Physics · Physics 2021-06-29 Sudarshan Saha , Tanay Nag , Saptarshi Mandal

Quantum phase transitions are intriguing and fundamental cooperative phenomena in physics. Analyzing a superconducting nanowire with spin-dependent non-Hermitian hopping, we discover a topological quantum phase transition driven by…

Mesoscale and Nanoscale Physics · Physics 2019-09-02 Nobuyuki Okuma , Masatoshi Sato

Non-Hermitian physics has added new ingredients to topological physics, leading to the rising frontier of non-Hermitian topological phases. In this study, we investigate Chern insulator phases emerging from non-Hermitian kagome models with…

Materials Science · Physics 2024-05-13 Li-Wei Wang , Zhi-Kang Lin , Jian-Hua Jiang

Topological insulators (TIs) are promising for achieving dissipationless transport devices due to the robust gapless states inside the insulating bulk gap. However, currently realized 2D TIs, quantum spin Hall (QSH) insulators, suffer from…

This article studies a non-Hermitian Su-Schrieffer-Heeger (SSH) model which has periodically staggered Hermitian and non-Hermitian dimers. The changes in topological phases of the considered chiral symmetric model with respect to the…

Quantum Physics · Physics 2024-12-30 A Niveth , S Karthiga , M Senthilvelan

Conventional wisdom holds that, in the simplest time-reversal-symmetric setting, strongly coupling two QSH layers yields a trivial $\mathbb Z_2$ phase and no protected topological edge states. We demonstrate that, in a regime with…

Mesoscale and Nanoscale Physics · Physics 2025-12-17 Mengjie Yang , Ching Hua Lee

Higher-order topological phases are characterized by protected states localized at the corners or hinges of the system. By applying time-periodic quenches to a two-dimensional lattice with balanced gain and loss, we obtain a rich variety of…

Mesoscale and Nanoscale Physics · Physics 2020-09-23 Jiaxin Pan , Longwen Zhou

Topological insulators are a broad class of unconventional materials that are insulating in the interior but conduct along the edges. This edge transport is topologically protected and dissipationless. Until recently, all existing…

Topological phases in quantum and classical systems have been of significant recent interest due to their fascinating physical properties. While a range of different mechanisms to induce topological order have been introduced, a quest for…

Materials Science · Physics 2019-08-07 Mengyao Li , Xiang Ni , Matthew Weiner , Andrea Alù , Alexander B. Khanikaev

Non-Hermiticity alters topology with the presence of non-Hermitian factors in topological systems. Most existing non-Hermitian topological systems derive their topological phases from Hermitian components, that is, the gain and loss of the…

The discovery of topological phases in non-Hermitian open classical and quantum systems challenges our current understanding of topological order. Non-Hermitian systems exhibit unique features with no counterparts in topological Hermitian…

Mesoscale and Nanoscale Physics · Physics 2019-06-26 Stefano Longhi

We consider two-dimensional Chern insulators and time-reversal invariant topological insulators and discuss the effect of perturbations breaking either particle-number conservation or time-reversal symmetry. The appearance of trivial mass…

Strongly Correlated Electrons · Physics 2016-08-18 Stephan Rachel

Focusing on the recently-discovered candidate topological insulator $\alpha$-(BEDT-TSeF)$_2$I$_3$ -- having two-dimensional charge-neutral Dirac cones in a low symmetry lattice -- we combine ab-initio and extended-Hubbard model calculations…

Mesoscale and Nanoscale Physics · Physics 2022-05-24 Daigo Ohki , Kazuyoshi Yoshimi , Akito Kobayashi

We focus on a scenario of non-Hermitian bulk--boundary correspondence that uses a topological invariant defined in a bulk geometry under a modified periodic boundary condition. Although this has succeeded in describing the topological…

Mesoscale and Nanoscale Physics · Physics 2023-11-23 Chihiro Ishii , Yositake Takane

Non-Hermiticity gives rise to distinctive topological phenomena absent in Hermitian systems. However, connection between such intrinsic non-Hermitian topology and Hermitian topology has remained largely elusive. Here, considering the bulk…

Mesoscale and Nanoscale Physics · Physics 2025-01-07 Shu Hamanaka , Tsuneya Yoshida , Kohei Kawabata

We propose a two-dimensional non-Hermitian Chern insulator with inversion symmetry, which is anisotropic and has staggered gain and loss in both x and y directions. In this system, conventional bulk-boundary correspondence holds. The Chern…

Mesoscale and Nanoscale Physics · Physics 2019-10-11 H. C. Wu , L. Jin , Z. Song

In light of recent progress in the study of amorphous topological phases, we investigate the effects of structural disorder on the topological properties of a two-dimensional quantum spin Hall insulator modeled by the Bernevig-Hughes-Zhang…

Disordered Systems and Neural Networks · Physics 2025-10-28 Ranadeep Roy , Yuan-Ming Lu

Non-Hermitian systems can host topological states with novel topological invariants and bulk-edge correspondences that are distinct from conventional Hermitian systems. Here we show that two unique classes of non-Hermitian 2D topological…

Mesoscale and Nanoscale Physics · Physics 2021-03-10 Junpeng Hou , Ya-Jie Wu , Chuanwei Zhang

We present models of topological insulating Hamiltonians exhibiting intrinsic altermagnetic features, protected by combined three-fold or four-fold rotational symmetries with time-reversal. We demonstrate that the spin Chern number serves…

Mesoscale and Nanoscale Physics · Physics 2026-02-19 Rafael Gonzalez-Hernandez , Bernardo Uribe