Massive Dirac fermions in moiré superlattices: a route toward correlated Chern insulators

Strong electronic correlation in flat minibands renders moiré superlattices fascinating for accessing novel quantum states.  Recently, the Mott insulator and correlated Chern insulator have been reported to coexist in a heterobilayer of transition metal dichalcogenides (TMD) [1] that provides an ideal platform to investigate the interplay between strong correlation and  topology. In this work, we demonstrate a generic mechanism to realize topological moiré minibands by considering a massive Dirac fermion moving in a moiré potential, which can be achieved in the TMD heterobilayer. We take the MoTe2/WSe2 heterobilayer as an example and show that the topological phase can be driven by a vertical electric field due to the lattice corrugation. Thus a correlated Chern insulator can be stabilized by the Coulomb interaction that breaks the time-reversal symmetry spontaneously. Our work explains the recent experiment on the observation of Chern insulating state in the AB-stacked MoTe2/WSe2 and unveils a general strategy to design topological moiré materials.

1. T. Li, S. Jiang, B. Shen, Y. Zhang, L. Li, T. Devakul, K. Watanabe, T.Taniguchi, L. Fu, J. Shan, and K. F. Mak, Quantum anomalous hall effect from intertwined moiré bands, arXiv:2107.01796 (2021).