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This paper demonstrates numerically and experimentally that it is possible to tailor flexural band gaps in the low-frequency regime by appropriate choice of cutout characteristics. The finite element method is used to obtain the numerical…

We consider the stability of fragile topological bands protected by space-time inversion symmetry in the presence of strong electron-electron interactions. At the single-particle level, the topological nature of the bands prevents the…

Strongly Correlated Electrons · Physics 2022-02-21 Ari M. Turner , Erez Berg , Ady Stern

Fractionalization in ideal Chern bands and non-Hermitian topological physics are two active but so far separate research directions. Merging these, we generalize the notion of ideal Chern bands to the non-Hermitian realm and uncover several…

Mesoscale and Nanoscale Physics · Physics 2026-05-26 Jiong-Hao Wang , Christopher Ekman , Raul Perea-Causin , Hui Liu , Emil J. Bergholtz

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

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

We investigate topological phase transitions in Chern insulators within three-band models, focusing on the empty band and lowest band populated by spinless fermions. We consider Lieb and kagome lattices and notice phase transitions driven…

Strongly Correlated Electrons · Physics 2017-10-19 P. Potasz , B. Jaworowski , M. Kupczyński , M. Brzezińska , P. Kaczmarkiewicz , A. Wójs

Some materials can have the dispersionless parts in their electronic spectra. These parts are usually called flat bands and generate the corps of unusual physical properties of such materials. These flat bands are induced by the…

Strongly Correlated Electrons · Physics 2019-05-22 V. R. Shaginyan , A. Z. Msezane , V. A. Stephanovich , G. S. Japaridze , E. V. Kirichenko

Recent experiments on bilayer graphene twisted near the magic angle have observed spontaneous integer quantum Hall states in the presence of an aligned hexagonal boron nitride (hBN) substrate. These states arise from valley ferromagnetism,…

Strongly Correlated Electrons · Physics 2020-06-18 Patrick J. Ledwith , Grigory Tarnopolsky , Eslam Khalaf , Ashvin Vishwanath

Moir\'e flatbands with high Chern numbers (C>1) offer opportunities to study the fractional quantum anomalous Hall effects that go beyond the Landau level paradigm with C=1, which remain unexplored yet. Here, we target the novel topological…

Bernal-stacked bilayer graphene modulated by a superlattice potential is a highly tunable system predicted to realize isolated topological flat bands. In this work we calculate the band structure and quantum geometry of bilayer graphene…

Mesoscale and Nanoscale Physics · Physics 2025-05-12 Dathan Ault-McCoy , M. Nabil Y. Lhachemi , Aaron Dunbrack , Sayed Ali Akbar Ghorashi , Jennifer Cano

Fractional Chern insulators realize the remarkable physics of the fractional quantum Hall effect (FQHE) in crystalline systems with Chern bands. The lowest Landau level (LLL) is known to host the FQHE, but not all Chern bands are suitable…

Strongly Correlated Electrons · Physics 2024-04-22 Patrick J. Ledwith , Ashvin Vishwanath , Daniel E. Parker

Dispersionless bands, such as Landau levels, serve as a good starting point for obtaining interesting correlated states when interactions are added. With this motivation in mind, we study a variety of dispersionless ("flat") band structures…

Strongly Correlated Electrons · Physics 2013-05-29 Dmitry Green , Luiz Santos , Claudio Chamon

In the presence of strong electronic interactions, a partially filled Chern band may stabilize a fractional Chern insulator (FCI) state, the zero-field analog of the fractional quantum Hall phase. While FCIs have long been hypothesized,…

Strongly Correlated Electrons · Physics 2024-10-15 Gal Shavit , Yuval Oreg

We treat elementary excitations, the spin-liquid state, and the anomalous Hall effect (including the quantum one in purely 2D situation) in layered highly correlated systems. The mechanisms of the formation of a topological state associated…

Strongly Correlated Electrons · Physics 2022-03-02 V. Yu. Irkhin , Yu. N. Skryabin

Topological flat bands (TFBs) provide a promising platform to investigate intriguing fractionalization phenomena, such as the fractional Chern insulators (FCIs). Most of TFB models are established in two-dimensional Euclidean lattices with…

Strongly Correlated Electrons · Physics 2024-08-30 Dong-Hao Guan , Lu Qi , Yuan Zhou , Ai-Lei He , Yi-Fei Wang

We propose a general principle for the low-energy theory of narrow bands with concentrated Berry curvature and Fubini-Study metric in the form of a map to Anderson-"+" models composed of heavy fermions hybridizing and interacting with…

The emergence of topologically non-trivial flat bands in moir\'e materials provides an opportunity to explore the interplay between topological physics and correlation effects, leading to the recent experimental realization of interacting…

Mesoscale and Nanoscale Physics · Physics 2024-05-24 Kaijie Yang , Yunzhe Liu , Frank Schindler , Chao-Xing Liu

Motivated by the abundance of symmetry breaking states in magic-angle twisted bilayer graphene and other two-dimensional materials, we study superconducting (SC) and charge orders in two-dimensional topological flat bands in the strong…

Strongly Correlated Electrons · Physics 2024-09-16 Penghao Zhu , Shi Feng , Yuan-Ming Lu

We consider twisted bilayer graphene on a transition metal dichalcogenide substrate, where proximity-induced spin-orbit coupling significantly alters the eight flat bands which occur near the magic angle. The resulting band structure…

Strongly Correlated Electrons · Physics 2020-12-24 Tianle Wang , Nick Bultinck , Michael P. Zaletel

We present a simple prescription to flatten isolated Bloch bands with non-zero Chern number. We first show that approximate flattening of bands with non-zero Chern number is possible by tuning ratios of nearest-neighbor and next-nearest…

Strongly Correlated Electrons · Physics 2011-06-10 Titus Neupert , Luiz Santos , Claudio Chamon , Christopher Mudry