Designing Topology and Fractionalization in Narrow Gap Semiconductor Films via Electrostatic Engineering.

We show that topological flat minibands can be engineered in a class of narrow gap semiconductor films using only an external electrostatic superlattice potential. We demonstrate that, for realistic material parameters, these bands are capable of hosting correlated topological phases such as integer and fractional quantum anomalous Hall states and composite Fermi liquid phases at zero magnetic field. Our results provide a path toward the realization of fractionalized topological states in a broad range of materials.