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Related papers: Imaging orbital ferromagnetism in a moir\'e Chern …

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We study an unique form of metallic ferromagnetism in which orbital moments surpasses the role of spin moments in shaping the overall magnetization. This system emerges naturally upon doping a topologically non-trivial Chern band in the…

Mesoscale and Nanoscale Physics · Physics 2024-02-27 Mainak Das , Chunli Huang

We establish that the interplay of itinerant fermions with localized magnetic moments on a checkerboard lattice leads to magnetic flux-phases. For weak itineracy the flux-phase is coplanar and the electronic dispersion takes the shape of…

Strongly Correlated Electrons · Physics 2015-06-04 Jörn W. F. Venderbos , Maria Daghofer , Jeroen van den Brink , Sanjeev Kumar

We consider fractional quantum Hall states in systems where two flat Chern number $C=\pm 1$ bands are labeled by an approximately conserved 'valley' index and interchanged by time reversal symmetry. At filling factor $\nu=1$ this setting…

Strongly Correlated Electrons · Physics 2023-05-02 Yves H. Kwan , Yichen Hu , Steven H. Simon , S. A. Parameswaran

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

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

Motivated by the fact that many bilayer quantum magnets occur in nature, we generalize the study of thermal Hall transports of spin excitations to bilayer magnetic systems. It is shown that bilayer magnetic systems can be coupled either…

Strongly Correlated Electrons · Physics 2016-09-07 S. A. Owerre

We study the quantum anomalous Hall states in the $p$-orbital bands of the honeycomb optical lattices loaded with the single component fermions. Such an effect has not been realized in both condensed matter and cold atom systems yet. By…

Quantum Gases · Physics 2011-03-02 Machi Zhang , Hsiang-hsuan Hung , Chuanwei Zhang , Congjun Wu

The modern theory of orbital magnetization (OM) was developed by using Wannier function method, which has a formalism similar with the Berry phase. In this manuscript, we perform a numerical study on the fate of the OM under disorder, by…

Mesoscale and Nanoscale Physics · Physics 2020-07-22 Si-Si Wang , Yan-Yang Zhang , Ji-Huan Guan , Yan Yu , Yang Xia , Shu-Shen Li

Rhombohedral-stacked multilayer graphene aligned with hexagonal boron nitride has emerged as an excellent platform for investigating exotic quantum phenomena arising from the interplay between electron correlations and nontrivial topology.…

We consider magic-angle twisted bilayer graphene (TBG) at filling $\nu=+3$, where experiments have observed a robust quantized anomalous Hall effect. This has been attributed to the formation of a valley- and spin-polarized Chern insulating…

Strongly Correlated Electrons · Physics 2021-09-27 Yves H. Kwan , Glenn Wagner , Nilotpal Chakraborty , Steven H. Simon , S. A. Parameswaran

A new type of anomalous Hall effect is shown to arise from the interaction of conduction electrons with dipolar spin waves in ferromagnets. This effect exists even in homogeneous ferromagnets without relativistic spin-orbit coupling. The…

Materials Science · Physics 2015-10-14 Kei Yamamoto , Koji Sato , Eiji Saitoh , Hiroshi Kohno

In a heterostructure of graphene and the ferromagnetic insulator EuO, the Eu atoms induce proximity exchange and inter-valley interactions in the graphene layer. Constrained by the lattice symmetries, and guided by ab initio calculations, a…

Materials Science · Physics 2017-04-11 Shanshan Su , Yafis Barlas , Roger K. Lake

In the real space formalism of orbital magnetization (OM) for a Chern insulator without an external electric field, it is correct to average the local OM either over the bulk region or over the whole sample. However for a layered Chern…

Mesoscale and Nanoscale Physics · Physics 2023-04-17 Si-Si Wang , Yi-Ming Dai , Hui-Hui Wang , Hao-Can Chen , Biao Zhang , Yan-Yang Zhang

Spin-orbit coupling introduces chirality into electronic structure. This can have profound effects on the magnetization induced by orbital motion of electrons. Here we derive a formula for the orbital magnetization of interacting electrons…

Strongly Correlated Electrons · Physics 2014-09-23 R. Nourafkan , G. Kotliar , A. -M. S. Tremblay

We demonstrate that spin-orbit coupled electrons in a magnetically doped system exert a spin torque on the local magnetization, without a flowing current, when the chemical potential is modulated in a magnetic field. The spin torque is…

Mesoscale and Nanoscale Physics · Physics 2015-09-17 Kentaro Nomura , Daichi Kurebayashi

We present the current-induced switching of the internal magnetization direction in a magnetic topological insulator/topological insulator heterostructure in the quantum anomalous Hall regime. The switching process is based on the bias…

Unlike an earlier theory, by avoiding both the electromagnetic gauge field shift and the assumption of the zero average of electromagnetic field fluctuation the fermion Chern-Simons gauge theory is reformulated to obtain mean field…

Condensed Matter · Physics 2007-05-23 Tae-Hyoung Gimm , Sung-Ho Suck Salk

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

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

Quantum spin Hall (QSH) insulators are two-dimensional electronic materials that have a bulk band gap like an ordinary insulator but have topologically protected pairs of edge modes of opposite chiralities. To date, experimental studies…

Mesoscale and Nanoscale Physics · Physics 2024-02-13 Kaifei Kang , Bowen Shen , Yichen Qiu , Kenji Watanabe , Takashi Taniguchi , Jie Shan , Kin Fai Mak