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

A series of recent experimental works on twisted MoTe₂ 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, and the fractional quantum anomalous Hall effect is observed at ν = -2/3 and ν = -3/5. In this work, we investigate the electronic properties of AA-stacked twisted bilayer MoTe₂ at ν = -2 by k-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 4^○. Our research proposes the potential of realizing a Chern insulator beyond ν = -1, and contributes fresh perspectives on the interplay between band topology and electron-electron correlations in moir'e superlattices.