Floquet Quantum Anomalous Hall Effect with Tunable and High Chern Numbers in Two-Dimensional Antiferromagnet KMnBi.

Abstract

The quantum anomalous Hall effect (QAHE) holds significant fundamental and technological importance in low-dissipation spintronics. We employ a tight-binding model and first-principles calculations to illustrate that Floquet engineering offers a fertile playground to realize high-Chern-number QAHE in two-dimensional (2D) antiferromagnets. Via tuning of light frequency, we put forward an abundant topological phase map, i.e., topological phase transitions from trivial phase to QAHE, and that between QAHE with tunable high Chern numbers of <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>C</mi></math> = ±3 and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>C</mi></math> = ±4. Analysis of edge states further confirms the topologically nontrivial natures, where three or four chiral edge states are clearly visible within the global band gaps. Moreover, we identify intrinsic KMnBi quintuple layers as the experimentally feasible example of the proposed mechanism of Floquet-engineered QAHE with high and tunable Chern numbers, bridging the QAHE, Floquet engineering, and 2D antiferromagnets with a strong likelihood of inventive applications in low-dissipation antiferromagnetic spintronics.