Microscopic mechanism of fractional Chern-insulator and fractional quantum anomalous Hall states

Determine the microscopic mechanism underlying fractional Chern-insulator and fractional quantum anomalous Hall states in rhombohedral graphene/hBN moiré superlattices.

Background

The paper reports fractional Chern-insulator states, fractional quantum anomalous Hall states, and displacement-field-driven transitions among these and other correlated phases in rhombohedral graphene/hBN moiré superlattices. Although the transport measurements reveal semicircle relations and support a spatially separated two-phase interpretation, the authors state that the underlying microscopic mechanism remains theoretically unresolved. Establishing this mechanism would clarify the origin of the observed fractional phases and their relationship to the underlying flat Chern band.