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Related papers: Disordered Topological Insulators: A Non-Commutati…

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We prove a general theorem on the relation between the bulk topological quantum number and the edge states in two dimensional insulators. It is shown that whenever there is a topological order in bulk, characterized by a non-vanishing Chern…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Xiao-Liang Qi , Yong-Shi Wu , Shou-Cheng Zhang

We consider the two-dimensional topological Chern insulator in the presence of static disorder. Generic quantum states in this system are Anderson localized. However, topology requires the presence of a subset of critical states, with…

Mesoscale and Nanoscale Physics · Physics 2023-08-29 Mateo Moreno-Gonzalez , Johannes Dieplinger , Alexander Altland

Chern insulator or quantum anomalous Hall state is a topological state with integer Hall conductivity but in absence of Landau level. It had been well established on various two-dimensional lattices with periodic structure. Here, we report…

Mesoscale and Nanoscale Physics · Physics 2020-01-08 Ai-Lei He , Lu-Rong Ding , Yuan Zhou , Yi-Fei Wang , Chang-De Gong

We present an approach for the calculation of the $\mathbb{Z}_2$ topological invariant in non-crystalline two-dimensional quantum spin Hall insulators. While topological invariants were originally mathematically introduced for crystalline…

Mesoscale and Nanoscale Physics · Physics 2023-02-28 Roberta Favata , Antimo Marrazzo

Non-commutative analysis tools have successfully been applied to the integer quantum Hall effect, in particular for a proof of the stability of the Hall conductance in an Anderson localization regime and of the bulk-boundary correspondence.…

Mathematical Physics · Physics 2018-05-29 Giuseppe De Nittis , Hermann Schulz-Baldes

The quantum anomalous Hall (QAH) state is a two-dimensional topological insulating state that has quantized Hall resistance of h/Ce2 and vanishing longitudinal resistance under zero magnetic field, where C is called the Chern number. The…

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

Topologically protected surface modes of classical waves hold the promise to enable a variety of applications ranging from robust transport of energy to reliable information processing networks. The integer quantum Hall effect has delivered…

Mesoscale and Nanoscale Physics · Physics 2020-08-25 Weiyin Deng , Xueqin Huang , Jiuyang Lu , Valerio Peri , Feng Li , Sebastian D. Huber , Zhengyou Liu

This paper demonstrates the existence of topological models with gapped edge states but protected extended bulk states against disorder. Such systems will be labeled as trivial by the current classification of topological insulators. Our…

Disordered Systems and Neural Networks · Physics 2010-11-25 Hadassah Shulman , Emil Prodan

The aim of this series of two papers is to discuss topological invariants for interacting topological insulators (TIs). In the first paper (I), we provide a paradigm of efficient numerical evaluation scheme for topological invariants, in…

Strongly Correlated Electrons · Physics 2016-06-08 Yuan-Yao He , Han-Qing Wu , Zi Yang Meng , Zhong-Yi Lu

Strong directional disorder in local magnetic moments coupled to a Chern insulator gives rise to topological phases that cannot be continuously connected to the clean limit and are therefore genuinely disorder-driven. We demonstrate this in…

Mesoscale and Nanoscale Physics · Physics 2026-02-17 Devesh Vaish , Michael Potthoff

The Chern-Hopf insulator is an unconventional three-dimensional topological insulator with a bulk gap and gapless boundary states without protection from global discrete symmetries. This study investigates its fate in the presence of…

Disordered Systems and Neural Networks · Physics 2025-05-13 Soumya Bera , Ivan Dutta , Roderich Moessner , Kush Saha

Integer-valued topological indices, characterizing nonlocal properties of quantum states of matter, are known to directly predict robust physical properties of equilibrium systems. The Chern number, e.g., determines the quantized Hall…

The Spin-Chern ($C_s$) was originally introduced on finite samples by imposing spin boundary conditions at the edges. This definition lead to confusing and contradictory statements. On one hand the original paper by Sheng and collaborators…

Mesoscale and Nanoscale Physics · Physics 2009-09-24 Emil Prodan

Quantum Hall systems are characterized by the quantization of the Hall conductance -- a bulk property rooted in the topological structure of the underlying quantum states. In condensed matter devices, material imperfections hinder a direct…

Two-dimensional 2-bands insulators breaking time reversal symmetry can present topological phases indexed by a topological invariant called the Chern number. Here we first propose an efficient procedure to determine this topological index.…

Mesoscale and Nanoscale Physics · Physics 2012-05-28 Doru Sticlet , Frederic Piéchon , Jean-Noël Fuchs , Pavel Kalugin , Pascal Simon

Chern insulators exhibit fascinating properties which originate from the topologically nontrivial state characterized by the Chern number. How these properties change if the system is quenched between topologically distinct phases has…

Mesoscale and Nanoscale Physics · Physics 2017-10-25 Michael Schüler , Philipp Werner

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

We derive the expression for the local Hall conductivity for systems that lack translation symmetry and use it to study the local fluctuations of the Hall signal around disordered patches in magnetic insulators. We find that the regime in…

Mesoscale and Nanoscale Physics · Physics 2026-03-11 Zachariah Addison , Nandini Trivedi

Topological insulators present a bulk gap, but allow for dissipationless spin transport along the edges. These exotic states are characterized by the $Z_2$ topological invariant and are protected by time-reversal symmetry. The Kane-Mele…

Strongly Correlated Electrons · Physics 2013-12-10 Zi Yang Meng , Hsiang-Hsuan Hung , Thomas C. Lang