Topological Phases in AB-Stacked MoTe2/WSe2: Z2 Topological Insulators, Chern Insulators, and Topological Charge Density Waves

We present a theory on the quantum phase diagram of AB-stacked MoTe2/WSe 2 using a self-consistent Hartree-Fock calculation performed in the plane-wave basis, motivated by the observation of topological states in this system. At filling factor v = 2 (two holes per moire unit cell), Coulomb interaction can stabilize a Z(2) topological insulator by opening a charge gap. At v = 1, the interaction induces three classes of competing states, spin density wave states, an in-plane ferromagnetic state, and a valley polarized state, which undergo first-order phase transitions tuned by an out-of-plane displacement field. The valley polarized state becomes a Chem insulator for certain displacement fields. Moreover, we predict a topological charge density wave forming a honeycomb lattice with ferromagnetism at v = 2/3. Future directions on this versatile system hosting a rich set of quantum phases are discussed.