Reconstructed Chern insulator in moderately correlated twisted bilayer MoTe2

Abstract

Twisted bilayer MoTe2 (tMoTe2) is a prototypical moiré material in which long-wavelength superlattices amplify electron correlations, enabling a wealth of emergent quantum phases. To date, experimental efforts have focused primarily on small twist angles (typically < 4°), whereas the larger-angle regime—where moiré bands become more dispersive and correlations are reduced—has remained largely unexplored. Here we chart the topological phase space of tMoTe2 at a relatively large twist angle of approximately 4.54°, accessing a moderately correlated regime with enhanced bandwidth. In contrast to small-angle devices that predominantly host fractional quantum anomalous Hall or spin Hall responses, we uncover multiple Chern-insulating states with |C| = 1 at moiré fillings ν = −1, −0.53 and −1/2. Strikingly, at ν = −2/3 a magnetic field induces a fractional Chern insulator accompanied by an insulator–metal transition. Our results broaden the topological phase diagram of tMoTe2 and establish large-angle moiré superlattices as a versatile platform for engineering robust topological states beyond the strong-correlation limit.