Special Seminar: "Hofstadter states and re-entrant charge order in a semiconductor moiré lattice"

Jan 3, 2023, 11:00 am12:00 pm
Faculty, Postdocs, graduate students



Event Description

Abstract: In this talk, I will present local electronic compressibility measurements on a twisted transition metal dichalcogenide heterobilayer, which reveal a rich phase diagram of Hofstadter states and novel electron crystalline orders. We show that this reflects the coexistence of both flat and dispersive moiré bands whose relative energies, and therefore occupations, are tuned by density and magnetic field. At high densities, Hofstadter states are generally favored as dispersive bands are populated, but are suppressed by a surprising intervening region of reentrant charge-ordered states in which holes originating from multiple bands cooperatively crystallize. Generalized Wigner crystals involving doubly occupied moiré sites and tunable singlet-triplet spin transitions are instead favored at low densities. These results together clarify essential microscopic ingredients that favor distinct correlated ground states in semiconductor moiré systems, and they demonstrate an emergent lattice model system in which correlated electronic phases can be precisely controlled.


Reference: https://arxiv.org/abs/2212.05068

Department of Physics (Host: Ali Yazdani)