The isovalent alloying assisted anomalous valley Hall effect in a hexagonal antiferromagnetic monolayer

Abstract

Exploring the combination of antiferromagnetic (AFM) spintronics and the anomalous valley Hall effect (AVHE) is one of the most important aspects for developing valleytronic applications. The key to address this issue is to achieve spin splitting around the valleys in AFM systems. Here, we propose a possible way for achieving the AVHE in a hexagonal AFM monolayer, which involves the isovalent alloying. This can break the combined symmetry (PT symmetry) of spatial inversion (P) and time reversal (T), giving rise to spin splitting. More specifically, the large spin splitting around the Fermi energy level is attributed to d orbital mismatch among the different transition metal ions. Based on first-principles calculations, the proposed way can be verified in an out-of-plane AFM CrMoC₂S₆ monolayer, which possesses spontaneous valley polarization and spitting, providing possibility to realize the AVHE. It is also proved that tensile strain can strengthen the valley splitting and maintain the out-of-plane AFM ordering. Our work provides an experimentally feasible way for developing AFM valleytronic devices.