Quantum anomalous Hall effect in stanene on a nonmagnetic substrate

Since the quantum anomalous Hall (QAH) effect was realized in magnetic topological insulators, research on the effect has become a hot topic. The very harsh realizing requirements of the effect in experiments, however, hinder its practical applications. Based on ab initio methods, we find that nonmagnetic PbI2 films are ideal substrates for the two-dimensional honeycomb stanene. The QAH effect with a pretty large band gap (up to 90 meV) can be achieved in the functionalized stanene/PbI2 heterostructure. Despite van der Waals interactions in the heterostructure, band inversions are found to be happening between Sn (s and p(x, y)) and Pb(p(x, y)) orbitals, playing a key role in determining the nontrivial topology and the large band gap of the system. Having no magnetic atoms is imperative to triggering the QAH effect. A very stable rudimentary device having QAH effects is proposed based on the Sn/PbI2 heterostructure. Our results demonstrate that QAH effects can be easily realized in the Sn/PbI2 heterostructures in experiments.