Renormalization group study of interaction-driven quantum anomalous Hall and quantum spin Hall phases in quadratic band crossing systems

摘要

It is shown that topological insulating phases driven by interactions can berealized without the need for spin-orbit coupling or large intersiteinteraction in a two-dimensional system of spin-1/2 fermions with a single pairof parabolically touching bands. Using a weak-coupling, Wilsonianrenormalization group procedure, we show that a quantum anomalous Hall phase isrealized for Hubbard interaction, while a quantum spin Hall phase is favoredfor longer-ranged interactions.