English

Gate-tunable antiferromagnetic Chern insulator in twisted bilayer transition metal dichalcogenides

Mesoscale and Nanoscale Physics 2024-04-16 v1

Abstract

A series of recent experimental works on twisted MoTe2_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 ν=1\nu = -1, and the fractional quantum anomalous Hall effect is observed at ν=2/3\nu = -2/3 and ν=3/5\nu = -3/5. In this work, we investigate the electronic properties of AA-stacked twisted bilayer MoTe2_2 at ν=2\nu=-2 by kk-space Hartree-Fock calculations. We find that the phase diagram is qualitatively similar to the phase diagram of a Kane-Mele-Hubbard with staggered onsite potential. A noteworthy phase within the diagram is the antiferromagnetic Chern insulator, stabilized by the external electric field. We attribute the existence of this Chern insulator to an antiferromagnetic instability at a topological phase transition between the quantum spin hall phase and a band insulator phase. We highlight that the antiferromagnetic Chern insulator phase is most evident at a twist angle of approximately 44^\circ. Our research proposes the potential of realizing a Chern insulator beyond ν=1\nu=-1, and contributes fresh perspectives on the interplay between band topology and electron-electron correlations in moir\'e superlattices.

Keywords

Cite

@article{arxiv.2308.07488,
  title  = {Gate-tunable antiferromagnetic Chern insulator in twisted bilayer transition metal dichalcogenides},
  author = {Xiaoyu Liu and Chong Wang and Xiao-Wei Zhang and Ting Cao and Di Xiao},
  journal= {arXiv preprint arXiv:2308.07488},
  year   = {2024}
}