Stanene on a SiC(0001) surface: a candidate for realizing quantum anomalous Hall effect

Abstract

Stanene, a cousin of graphene, has p_z-orbital Dirac states, owing to its hexagonal symmetry. Nevertheless, stanene has to be obtained through growing on substrates with strong interfacial interactions, which generally damages their intrinsic π(p_z)-orbital Dirac states. Fortunately, we find that the quadratic topological states are derived from the p_x,y orbitals rather than p_z orbitals in stanene on 4H-SiC(0001), which survive even the strong interfacial interactions. We also find that the spin-orbital coupling simultaneously with the exchange field gives rise to an observable band gap of 22.97 meV. Berry curvature and edge state calculations further demonstrate the nontrivial topological phase of such quadratic topological states with a Chern number C = 2, showing its potential to realize quantum anomalous Hall effect at near room temperature. Finally, we construct a simple effective model to reveal the low-energy physics in this system. It is hoped this finding will be applicable to other two-dimensional materials, which should be useful for future investigations.