Tunable valley splitting in two-dimensional CrBr3/VSe2 van der Waals heterostructure under strains and electric fields

Abstract

Valleytronics opens up fascinating opportunities for using the valley degree of freedom in information storage and quantum computation. Here, based on the first-principles calculations, we investigate the effects of biaxial strains and electric fields on the magnetic, electronic, and valleytronic properties of two-dimensional CrBr3/VSe2 van der Waals (vdW) heterostructure consisting of two ferromagnetic monolayers. An interlayer magnetic phase transition from parallel to antiparallel is found when a compressive strain exceeds or a tensile strain exceeds 4% is applied, while the interlayer magnetic configuration remains parallel under perpendicular electric fields. The valley splitting in the conduction bands is significantly enhanced by a compressive strain or an electric field pointing from the VSe2 to the CrBr3 layer. Specifically, a large valley splitting about 30.8 meV is obtained in the system with antiparallel interlayer magnetic configurations under a compressive strain of , which is more than three times that of pristine CrBr3/VSe2 heterostructure. Our findings provide new insights into the future valleytronic applications for two-dimensional magnetic vdW heterostructures.