Effect of strain engineering on magnetism-induced valley splitting in WSe2 based on the WSe2/CrSe2 heterojunction

Two-dimensional, honeycomb, and sandwich-structured transition metal dichalcogenides (TMDs) have two nonequivalent energy valleys at the six corners of the hexagonal first Brillouin zone, resulting in promising applications in valleytronics. Here, based on the WSe2/CrSe2 heterojunction, biaxial and uniaxial tensile strains with magnitudes of 0%-6% are demonstrated to have a similar effect on magnetism-induced valley splitting in the lowest conduction band of WSe2. However, at larger magnitudes of 6%-10%, uniaxial strain dramatically decreases the valley splitting. This decrease in valley splitting can be understood by the spin-orbit coupling induced different spin splitting between the two valleys. The findings provide valuable guidance for the valleytronic applications of TMDs.