Interplay between topology and correlations in the second moiré band of twisted bilayer MoTe2

The interplay between topology and correlations gives rise to intriguing quantum states of matter. Two-dimensional semiconducting transition metal dichalcogenide have emerged as highly tunable platform for investigating correlated and topological quantum phases. Recently, fractional quantum anomalous Hall effects were experimentally realized in twisted bilayer MoTe2. Here we present the electrical transport study on approximately 3-degree twisted bilayer MoTe2, especially for the second moiré band. We observed ferromagnetism in the second moiré band, and a Chern insulator state driven by out-of-plane magnetic field at ν=-3. In addition, at ν=-2 and -4, we found evidences of time-reversal-symmetric single and double quantum spin Hall states. Our results establish the topological nature of the second moiré band in approximately 3-degree tMoTe2, demonstrating a series of correlated and topological phases formed in this band. This opens the door to further explore more exotic quantum states, such as the non-Abelian FQAH state, in the second moiré flat band.