Valley polarization in monolayer CrX2 (X = S, Se) with magnetically doping and proximity coupling

Abstract

Manipulating the valley degree of freedom as an information carrier has been a focused topic for both fundamental and applied research. Here, using first-principles calculations, we report the identification of monolayer CrX2 (X = S, Se) as a novel two-dimensional valleytronic crystal. It shows large valley spin splitting in the valence band, attractive for the integration of valleytronics and spintronics. More importantly, through proximity coupling with monolayer CrCl3, the valley polarization in monolayer CrX2 is achieved, which can be further engineered by stacking patterns. Also, the valley polarization in monolayer CrX2 can be obtained via magnetically doping V and Mn. Specially for V-doped monolayer CrSe2, there are no impurity states in the band gap, beneficial for its practical applications. Our works thus provide not only exceptional two-dimensional valleytronic crystals but also promising ways for realizing valley polarizations in them.