“Interaction-induced topological crystals: theory and phenomenology”
Recent predictions and possible discoveries of extended quantum anomalous Hall regions in moiré materials have revived interest in topological crystals, phases of matter where crystalline order coexists with, or indeed gives rise to, a quantized topological response. However, analytically tractable theories of topological crystals are largely lacking. In this talk, we introduce a simple, realistic and controlled setup for interaction-driven Hall crystals, a type of topological crystal, with diverse Chern numbers. Our setup involves a two-dimensional semiconductor or graphene subject to a magnetic field and a one-dimensional periodic potential, mimicking aspects of moiré physics. We present a beyond-mean-field analysis of these interaction-stabilized Hall crystals, provide a simple picture of the global phase diagram, and combine it with an interpretation as a “spontaneous” Hofstadter effect. Finally, we discuss potential experimental realizations as well as other novel aspects of topological crystals in 2d systems.
Host: Meng Cheng