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We provide evidence that, alongside topologically protected edge states, two-dimensional Chern insulators also support localised bulk states deep in their valance and conduction bands. These states manifest when local potential gradients…

Mesoscale and Nanoscale Physics · Physics 2020-07-24 Chris N. Self , Alvaro Rubio-García , Juan Jose García-Ripoll , Jiannis K. Pachos

We investigate topological states of two-dimensional (2D) triangular lattices with multi-orbitals. Tight-binding model calculations of a 2D triangular lattice based on $\emph{p}_{x}$ and \emph{p}_{y} orbitals exhibit very interesting doubly…

Mesoscale and Nanoscale Physics · Physics 2018-03-29 Jiayong Zhang , Bao Zhao , Yang Xue , Tong Zhou , Zhongqin Yang

The study of topological property of band insulators is an interesting branch of condensed matter physics. Two types of topologically nontrivial insulators have been extensively studied. The first type is characterized by a nonzero TKNN…

Materials Science · Physics 2011-11-15 Yi-Dong Wu

Magic-angle twisted bilayer graphene is the best studied physical platform featuring moire potential induced narrow bands with non-trivial topology and strong electronic correlations. Despite their significance, the Chern insulating states…

Mesoscale and Nanoscale Physics · Physics 2024-06-11 Xiaoyu Wang , Oskar Vafek

In this paper, we derive a general formula for the quantized fractional corner charge in two-dimensional C_n-symmetric higher-order topological insulators. We assume that the electronic states can be described by the Wannier functions and…

Mesoscale and Nanoscale Physics · Physics 2021-05-19 Ryo Takahashi , Tiantian Zhang , Shuichi Murakami

Higher-order topological insulators have attracted significant interest in recent years. However, identifying a universal topological invariant capable of characterizing higher-order topology remains challenging. Here, we propose a…

Mesoscale and Nanoscale Physics · Physics 2025-12-12 Yu-Long Zhang , Cheng-Ming Miao , Qing-Feng Sun , Jian-Jun Liu , Ying-Tao Zhang

We study the edge states of twisted bilayer graphene and their topological origin. We show that the twisted bilayer graphene has special edge states associated with the moir\'{e} pattern, and the emergence of these moir\'{e} edge states is…

Mesoscale and Nanoscale Physics · Physics 2021-04-21 Manato Fujimoto , Mikito Koshino

A series of recent experimental works on twisted MoTe$_2$ homobilayers have unveiled an abundance of exotic states in this system. Valley-polarized quantum anomalous Hall states have been identified at hole doping of $\nu = -1$, and the…

Mesoscale and Nanoscale Physics · Physics 2024-04-16 Xiaoyu Liu , Chong Wang , Xiao-Wei Zhang , Ting Cao , Di Xiao

The topological insulator is an electronic phase stabilized by spin-orbit coupling that supports propagating edge states and is not adiabatically connected to the ordinary insulator. In several ways it is a spin-orbit-induced analogue in…

Mesoscale and Nanoscale Physics · Physics 2009-12-16 Andrew M. Essin , J. E. Moore

Manipulating the topological properties of insulators, encoded in invariants such as the Chern number and its generalizations, is now a major issue for realizing novel charge/spin responses in electron systems. We propose that a simple…

Materials Science · Physics 2010-06-30 Jun-ichi Inoue , Akihiro Tanaka

We propose a new type of instanton interference effect in two-dimensional higher-order topological insulators. The intercorner tunneling consists of the instanton and the anti-instanton pairs that travel through the boundary of the…

Mesoscale and Nanoscale Physics · Physics 2020-06-02 Moon Jip Park , Sunam Jeon , SungBin Lee , Hee Chul Park , Youngkuk Kim

The organization of the electrons in the ground state is classified by means of topological invariants, defined as global properties of the wavefunction. Here we address the Chern number of a two-dimensional insulator and we show that the…

Strongly Correlated Electrons · Physics 2012-01-23 Raffaello Bianco , Raffaele Resta

We prove that Chern insulators have topologically protected edge states which not only propagate unidirectionally along a straight line boundary, but also swerve around arbitrary-angled corners and geometric imperfections of the material…

Mathematical Physics · Physics 2020-06-30 Guo Chuan Thiang

We numerically and experimentally study corner states in a continuous elastic plate with em-bedded bolts in a hexagonal pattern. While preserving C6 crystalline symmetry, the system can transition from a topologically trivial to a…

Mesoscale and Nanoscale Physics · Physics 2020-09-09 Chun-Wei Chen , Rajesh Chaunsali , Johan Christensen , Georgios Theocharis , Jinkyu Yang

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

We analyse the topological transition and localization evolution of disordered two dimensional systems with non trivial topology based on bipartite lattices. Chern insulators with broken time reversal symmetry show non standard behavior for…

Mesoscale and Nanoscale Physics · Physics 2015-09-03 Eduardo V. Castro , M. Pilar López-Sancho , María A. H. Vozmediano

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

The recently discovered three dimensional or bulk topological insulators are expected to exhibit exotic quantum phenomena. It is believed that a trivial insulator can be twisted into a topological state by modulating the spin-orbit…

Mesoscale and Nanoscale Physics · Physics 2011-10-24 Su-Yang Xu , Y. Xia , L. A. Wray , D. Qian , Shuang Jia , J. H. Dil , F. Meier , J. Osterwalder , B. Slomski , H. Lin , R. J. Cava , M. Z. Hasan

Higher-order topological phases of matter have been extensively studied in various areas of physics. While the Aubry-Andr\'e-Harper model provides a paradigmatic example to study topological phases, it has not been explored whether a…

Mesoscale and Nanoscale Physics · Physics 2020-07-17 Qi-Bo Zeng , Yan-Bin Yang , Yong Xu

We consider a system consisting of two tunnel-coupled two-dimensional topological insulators proximitized by a top and bottom superconductor with a phase difference of $\pi$ between them. We show that this system exhibits a time-reversal…

Mesoscale and Nanoscale Physics · Physics 2020-11-13 Katharina Laubscher , Danial Chughtai , Daniel Loss , Jelena Klinovaja