In-plane magnetization-induced quantum anomalous Hall effect in atomic crystals of group-V elements

We theoretically demonstrate that the in-plane magnetization-induced quantum anomalous Hall effect (QAHE) can be realized in the atomic crystal layers of group-V elements with a buckled honeycomb lattice. Based on sp(3) tight-binding models with parameters being extracted from first-principles results, we show that for weak and strong spin-orbit couplings, the systems harbor QAHEs with Chern numbers of C = +/- 1 and +/- 2, respectively. For C = +/- 1 phases, we find the critical magnetization to realize QAHE can be extremely small by tuning the spin-orbit coupling strength. For C = +/- 2 phases, we find that although the critical magnetization is larger, it can be decreased effectively by strain. Moreover, the band gap is large enough for a room-temperature observation. These features suggest that it is experimentally feasible to realize high-temperature QAHEs from in-plane magnetization in the atomic crystal layers of group-V elements.