2020/08/31 by Haining Pan, Fengcheng Wu, Sankar Das Sarma · 2 citations
Physics and Astronomy · #cond-mat.str-el #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.102.201104
published as Phys. Rev. B 102, 201104 (2020) · 5 + 7 pages, 6 + 12 figures
arxiv created 2020/11/06 · arxiv updated 2020/11/11
We theoretically study a generalized Hubbard model on moiré superlattices of twisted bilayers, and find very rich filling-factor-dependent quantum phase diagrams tuned by interaction strength and twist angle. Strong long-range Coulomb interaction in the moiré-Hubbard model induces Wigner crystals at a series of fractional filling factors. The effective lattice of the Wigner crystal is controlled by the filling factor, and can be triangle, rectangle, honeycomb, kagome, etc, providing a single platform to realize many different spin models on various lattices by simply tuning carrier density. In addition to Wigner crystals that are topologically trivial, interaction-induced Chern insulators emerge in the phase diagram. This finding paves a way for engineering interaction-induced quantum anomalous Hall effect in moiré-Hubbard systems where the corresponding single-particle moiré band is topologically trivial.