Quantum anomalous Hall effect in a nonmagnetic bismuth monolayer with a high Chern number.

Abstract

The quantum anomalous Hall effect (QAHE) with a high Chern number hosts multiple dissipationless chiral edge channels, which is of fundamental interest and promising for applications in spintronics. However, QAHE is currently limited in two-dimensional (2D) ferromagnets with Chern number . Using a tight-binding model, we put forward that Floquet engineering offers a strategy to achieve QAHE in 2D nonmagnets, and, in contrast to generally reported QAHE in 2D ferromagnets, a high-Chern-number is obtained accompanied by the emergence of two chiral edge states. Moreover, based on the first-principles calculations, we identify tetragonal bismuth as an experimentally feasible candidate of the proposed light-induced QAHE, where remarkably a topological phase transition from the 2D ₂ topological insulator to QAHE occurs. Our results open new opportunities to realize exotic QAH physics that increases the feasibility of experimental realization and applications in spintronics devices.