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Moir\'e superlattices based on rhombohedral multilayer graphene have emerged as a highly tunable platform for engineering correlated topological phases. Here, we systematically investigate the transport properties of the hole-doped side in…

We show that the valley Chern number of the low energy band in twisted double bilayer graphene can be tuned through two successive topological transitions, where the direct bandgap closes, by changing the electric field perpendicular to the…

Mesoscale and Nanoscale Physics · Physics 2021-05-05 Priyanka Mohan , Unmesh Ghorai , Rajdeep Sensarma

For generic time-reversal invariant systems with spin-orbit couplings, we clarify a close relationship between the Z$_2$ topological order and the spin Chern number proposed by Kane and Mele and by Sheng {\it et al.}, respectively, in the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 T. Fukui , Y. Hatsugai

In this study, we examine the introduction of the Haldane model into the dice lattice by altering the flow between the next-nearest-neighbour sites. This breaks the lattice's inversion and time-reversal symmetries. We demonstrate the…

Other Condensed Matter · Physics 2026-04-27 Othmane Benhaida , Lalla Btissam Drissi , El Hassan Saidi

We propose models of twisted multilayer graphene that exhibit exactly flat Bloch bands with arbitrary Chern numbers and ideal band geometries. The models are constructed by twisting two sheets of Bernal-stacked multiple graphene layers with…

Mesoscale and Nanoscale Physics · Physics 2023-12-19 Jie Wang , Zhao Liu

Band geometry plays a substantial role in topological lattice models. The Berry curvature, which resembles the effect of magnetic field in reciprocal space, usually fluctuates throughout the Brillouin zone. Motivated by the analogy with…

Strongly Correlated Electrons · Physics 2022-04-11 Daniel Varjas , Ahmed Abouelkomsan , Kang Yang , Emil J. Bergholtz

We study the emergence of electronic edge states in superconducting (SC) monolayer, bilayer, and trilayer graphene for both spin-singlet and spin-triplet SC order parameters. We focus mostly on the gapped chiral $p+ip'$- and $d+id'$-wave SC…

Ideal $C=1$ Chern bands exhibit a Landau level correspondence: they factorize as a lowest Landau levels and a spinor wavefunction that spans the layer index. We demonstrate that, in single Dirac moir\'e models, the spinor develops generally…

Mesoscale and Nanoscale Physics · Physics 2024-08-26 Daniele Guerci , Jie Wang , Christophe Mora

Perfectly flat bands with nontrivial quantum geometry have emerged as a frontier for exotic topological phenomena and superconductors. Here, we unveil a universal family of quantized Berry-dipole flat bands in chiral-symmetric (2n+1)-band…

Mesoscale and Nanoscale Physics · Physics 2026-02-05 Qingyang Mo , Shuang Zhang

Rhombohedral multilayer graphene (RMG) proximity-coupled to a Haldane substrate provides a platform to investigate the interplay between band topology, layer number, and electric-field control of orbital magnetism. Using a tight-binding…

Mesoscale and Nanoscale Physics · Physics 2026-03-10 Sovan Ghosh , Bheema Lingam Chittari

The isospin flavors in condensed matters can be continuously broken, forming various symmetry-broken quantum states. In moir\'e crystals, the competition between different isospin configurations can be effectively tuned by the twist angles…

Mesoscale and Nanoscale Physics · Physics 2026-01-08 Wenxuan Wang , Yijie Wang , Zaizhe Zhang , Zihao Huo , Gengdong Zhou , Kenji Watanabe , Takashi Taniguchi , X. C. Xie , Kaihui Liu , Zhida Song , Xiaobo Lu

Twisted bilayer graphene (TBG) near the magic twist angle of $\sim1.1^{o}$ exhibits a rich phase diagram. However, the interplay between different phases and their dependence on twist angle is still elusive. Here, we explore the stability…

The realization of fractional Chern insulators in moir\'e materials has sparked the search for further novel phases of matter in this platform. In particular, recent works have demonstrated the possibility of realizing quantum anomalous…

Mesoscale and Nanoscale Physics · Physics 2025-07-29 Raul Perea-Causin , Hui Liu , Emil J. Bergholtz

The physics of massless relativistic quantum particles has recently arisen in the electronic properties of solids following the discovery of graphene. Around the accidental crossing of two energy bands, the electronic excitations are…

Mesoscale and Nanoscale Physics · Physics 2015-10-21 Thibaud Louvet , Pierre Delplace , Andrei A. Fedorenko , David Carpentier

The recent observation of the fractional quantum anomalous Hall effect in moir\'e fractional Chern insulators provides an opportunity to investigate zero magnetic field anyons. To potentially realize non-Abelian anyons, one approach is to…

We introduce a second-quantized field theory for Chern insulators in which the Hamiltonian features a static vector potential that has the periodicity of the crystal's lattice and spontaneously breaks time-reversal symmetry in the system's…

Mesoscale and Nanoscale Physics · Physics 2026-01-30 Jason G. Kattan , J. E. Sipe

We study the electronic band structure and the topological property of the twisted double bilayer graphene, or a pair of AB-stacked bilayer graphenes rotationally stacked on top of each other. We consider two different arrangements, AB-AB…

Mesoscale and Nanoscale Physics · Physics 2019-06-10 Mikito Koshino

Magnetic transition metal chalcogenides form an emerging platform for exploring spin-orbit driven Berry phase phenomena owing to the nontrivial interplay between topology and magnetism. Here we show that the anomalous Hall effect in…

Magic-angle helical trilayer graphene relaxes into commensurate moir\'e domains, whose topological and well-isolated set of narrow bands possess ideal characteristics for realizing robust correlated topological phases, compared with other…

Strongly Correlated Electrons · Physics 2023-08-21 Yves H. Kwan , Patrick J. Ledwith , Chiu Fan Bowen Lo , Trithep Devakul

We investigate an effective model of proximity modified graphene (or symmetrylike materials) with broken time-reversal symmetry. We predict the appearance of quantum anomalous Hall phases by computing bulk band gap and Chern numbers for…

Mesoscale and Nanoscale Physics · Physics 2020-04-07 Petra Högl , Tobias Frank , Klaus Zollner , Denis Kochan , Martin Gmitra , Jaroslav Fabian