Quantum anomalous Hall effect in stanene on a nonmagnetic substrate

Abstract

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 $\mathrm{Pb}{\mathrm{I}}_{2}$ 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 $\mathrm{stanene}/\mathrm{Pb}{\mathrm{I}}_{2}$ heterostructure. Despite van der Waals interactions in the heterostructure, band inversions are found to be happening between Sn $(s$ and ${p}_{x,y}$ ) and $\mathrm{Pb}\phantom{\rule{0.16em}{0ex}}({p}_{x,y})$ 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 $\mathrm{Sn}/\mathrm{Pb}{\mathrm{I}}_{2}$ heterostructure. Our results demonstrate that QAH effects can be easily realized in the $\mathrm{Sn}/\mathrm{Pb}{\mathrm{I}}_{2}$ heterostructures in experiments.