Characterization of ferromagnetic semiconductors and valley polarization in janus VBXS₂(X = N, P) monolayers

Abstract The manipulation of the valley degree of freedom has attracted increasing attention in both fundamental scientific research and emerging applications. Here, we employ first-principles calculations to investigate the structural stability and electronic properties of Janus monolayers of VBXS 2 (X=N, P). These materials exhibit characteristics of ferromagnetic semiconductors, with their valence band maximum located at the K/K′ point. Due to the combined effects of inversion symmetry breaking and time reversal symmetry breaking, VBNS 2 and VBPS 2 exhibit exotic spontaneous valley polarization in their top valence bands, measured at magnitudes of 48.6 meV and 47.6 meV, respectively. Consequently, this phenomenon potentially enables the observation of the anomalous valley Hall effect (AVHE). The unique electronic and valleytronic properties exhibited by Janus VBXS 2 suggest a feasible experimental avenue for exploring ferrovalley (FV) and valley-related Hall effects within a two dimensional lattice.