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Narrow band electron systems are particularly likely to exhibit correlated many-body phases driven by interaction effects. Examples include magnetic materials, heavy fermion systems, and topological phases such as fractional quantum Hall…

Strongly Correlated Electrons · Physics 2016-07-19 Ching Hua Lee , Daniel P. Arovas , Ronny Thomale

We point out the possibility of nearly flat band with Chern number C=2 on the dice lattice in a simple nearest-neighbor tightbinding model. This lattice can be naturally formed by three adjacent $(111)$ layers of cubic lattice, which may be…

Strongly Correlated Electrons · Physics 2012-03-21 Fa Wang , Ying Ran

As lattice analogs of fractional quantum Hall systems, fractional Chern insulators (FCIs) exhibit enigmatic physical properties resulting from the intricate interplay between single-body and many-body physics. In particular, the design of…

Strongly Correlated Electrons · Physics 2017-10-31 Ching Hua Lee , Martin Claassen , Ronny Thomale

We construct a continuum model for the Moir\'e superlattice of twisted bilayer MnBi$_2$Te$_4$, and study the band structure of the bilayer in both ferromagnetic (FM) and antiferromagnetic (AFM) phases. We find the system exhibits highly…

Mesoscale and Nanoscale Physics · Physics 2023-02-17 Biao Lian , Zhaochen Liu , Yuanbo Zhang , Jing Wang

The realization of fractional Chern insulators opens up the possibility of exploring fractionally charged excitations and anyonic statistics in the absence of a magnetic field. One of the central questions is whether lattice-based systems…

Mesoscale and Nanoscale Physics · Physics 2025-12-29 Zexu Li , Wenxuan Wang , Fajie Wang , Zaizhe Zhang , Qiu Yang , Kenji Watanabe , Takashi Taniguchi , X. C. Xie , Jie Wang , Kaihui Liu , Zhida Song , Xiaobo Lu

A simple, general rule for generating a three-band model with arbitrary Chern numbers is given. The rule is based on the idea of monopole charge-changing unitary operations and can be realized by two types of simple unitary operations on…

Strongly Correlated Electrons · Physics 2014-11-11 Soo-Yong Lee , Jin-Hong Park , Gyungchoon Go , Jung Hoon Han

We present a pedagogical review of the physics of fractional Chern insulators with a particular focus on the connection to the fractional quantum Hall effect. While the latter conventionally arises in semiconductor heterostructures at low…

Strongly Correlated Electrons · Physics 2015-10-05 S. A. Parameswaran , R. Roy , S. L. Sondhi

The Hofstadter model is a popular choice for theorists investigating the fractional quantum Hall effect on lattices, due to its simplicity, infinite selection of topological flat bands, and increasing applicability to real materials. In…

Strongly Correlated Electrons · Physics 2021-09-09 Bartholomew Andrews , Titus Neupert , Gunnar Möller

We discuss a number of illuminating results for tight binding models supporting a band with variable Chern number, and illustrate them explicitly for a simple class of two-banded models. First, for models with a fixed number of bands, we…

Strongly Correlated Electrons · Physics 2014-10-21 Masafumi Udagawa , Emil J. Bergholtz

The integer quantum Hall state occurs when the Landau levels are fully occupied by the fermions, while the fractional quantum Hall state usually emerges when the Landau level is partially filled by the strongly correlated fermions or…

Strongly Correlated Electrons · Physics 2021-09-22 Wei-Wei Luo , Ai-Lei He , Yi-Fei Wang , Yuan Zhou , Chang-De Gong

We describe a systematic method to construct models of Chern insulators whose Berry curvature and the quantum volume form coincide and are flat over the Brillouin zone; such models are known to be suitable for hosting fractional Chern…

Mesoscale and Nanoscale Physics · Physics 2021-09-28 Bruno Mera , Tomoki Ozawa

We report the presence of exactly and nearly flat bands with non-trivial topology in three-dimensional (3D) lattice models. We first show that an exactly flat band can be realized in a 3D lattice model characterized by a 3D topological…

Mesoscale and Nanoscale Physics · Physics 2024-08-07 Ivan Dutta , Kush Saha

We construct generalized Hofstadter models that possess "color-entangled" flat bands and study interacting many-body states in such bands. For a system with periodic boundary conditions and appropriate interactions, there exist gapped…

Strongly Correlated Electrons · Physics 2015-01-29 Ying-Hai Wu , J. K. Jain , Kai Sun

The Harper-Hofstadter model provides a fractal spectrum containing topological bands of any integer Chern number, $C$. We study the many-body physics that is realized by interacting particles occupying Harper-Hofstadter bands with $|C|>1$.…

Strongly Correlated Electrons · Physics 2015-09-28 Gunnar Möller , Nigel R. Cooper

Topological flat bands play an essential role in inducing exotic interacting physics, ranging from fractional Chern insulators to superconductivity, in moir\'e materials. In this work, we propose a design principle for realizing topological…

Mesoscale and Nanoscale Physics · Physics 2026-02-03 Yunzhe Liu , Anoj Aryal , Kaijie Yang , Dumitru Calugaru , Zhenyao Fang , Haoyu Hu , Qimin Yan , B. Andrei Bernevig , Chao-xing Liu

We devise local lattice models whose ground states are model fractional Chern insulators---Abelian and non-Abelian topologically ordered states characterized by exact ground state degeneracies at any finite size and infinite entanglement…

Strongly Correlated Electrons · Physics 2016-05-31 Jörg Behrmann , Zhao Liu , Emil J. Bergholtz

An interesting route to the realization of topological Chern bands in ultracold atomic gases is through the use of optical flux lattices. These models differ from the tight-binding real-space lattice models of Chern insulators that are…

Quantum Gases · Physics 2015-04-24 A. Sterdyniak , B. Andrei Bernevig , Nigel R. Cooper , N. Regnault

We show that bilayer graphene in the presence of a 2D superlattice potential provides a highly tunable setup that can realize a variety of flat band phenomena. We focus on two regimes: (i) topological flat bands with non-zero Chern numbers,…

Mesoscale and Nanoscale Physics · Physics 2023-06-16 Sayed Ali Akbar Ghorashi , Aaron Dunbrack , Ahmed Abouelkomsan , Jiacheng Sun , Xu Du , Jennifer Cano

We investigate the possibility of exactly flat non-trivial Chern bands in tight binding models with local (strictly short-ranged) hopping parameters. We demonstrate that while any two of three criteria can be simultaneously realized…

Strongly Correlated Electrons · Physics 2014-04-14 Li Chen , Tahereh Mazaheri , Alexander Seidel , Xiang Tang

When one of the graphene layers of Magic Angle Twisted Bilayer Graphene is nearly aligned with its hexagonal boron nitride substrate (a configuration dubbed TBG/hBN), the active electronic bands are nearly flat, and have a Chern number…

Strongly Correlated Electrons · Physics 2019-12-25 Cécile Repellin , T. Senthil