Electronic correlation-driven quantum anomalous valley Hall effect in intrinsic ferrovalley FeClBr

Abstract

Both ferrovalley and quantum anomalous valley Hall effect (QAVHE) are practically desirable and inherently fascinating for new-style device applications. However, works realizing the intrinsic ferrovalley and QAVHE in a single ferromagnetic system with a high Curie temperature are still lacking. We predict that monolayer FeClBr exhibits the ferrovalley phase with a substantial valley polarization of 116 meV and high Curie temperature of approximately 565 K. When considering electronic correlation effects, within the range of Ueff = 0.87 eV and Ueff = 1.13 eV, the QAVHE of nontrivial topology is present. A Chern number of C = −1 is confirmed by chiral edge states and an anomalous Hall conductivity. Intriguingly, the emergence of out-of-plane easy magnetization when Ueff < 1.13 eV is conducive to realizing the intrinsic ferrovalley and QAVHE. The QAVHE is also present in monolayers of FeClI and FeBrI. Our study offers potential candidate materials for the advancement of multifunctional quantum devices in topology and valleytronics.