Strain-Tailored Valley Polarization and Magnetic Anisotropy in Two-Dimensional 2H-VS2/Cr2C Heterostructures

摘要

Valleytronics is proposed as a novel approach to information storage by utilizing the valley degree of freedom where the valley polarization in monolayer transition metal dichalcogenides (TMDs) can be tailored by magnetic proximity effects (MPE), etc. The 2H-VS2 monolayer on valleytronics is limited due to the valence band maximum (VBM) located at Gamma. The MPE of the two-dimensional (2D) ferromagnetic monolayer on spontaneously valley-polarized TMDs is rarely reported. Here, the electronic structure and magnetic properties of 2D 2H-VS2/Cr2C heterostructures with different stacking patterns have been investigated systematically. When V atoms locate right above Cr atoms, the heterostructure shows semiconducting characteristics where the VBM of 2H-VS2 turns from Gamma to K'. The valley polarization of VS2 is preserved in all heterostructures with spin-orbital coupling, which can be modulated by the magnetization direction, biaxial strain, and interfacial distance. Tensile strain increases valley polarization. Different stacking patterns affect the magnetic anisotropy energy of monolayer VS2. As V (5) atoms locate right above Cr (C) atoms, 2H-VS2 in the heterostructure has a smaller in-plane magnetic anisotropy (IMA) than that of pristine monolayer 2H-VS2. Tensile strain increases IMA, which is still smaller than that of pristine monolayer 2H-VS2. These results suggest that 2H-VS2/Cr2C heterostructures are the potential candidates in valleytronics.