Enhanced valley polarization at valence/conduction band in transition- metal-doped WTe_2 under strain force

摘要

Valleytronics has gained significantly numerous research interests, relative to consideration of the valley index in particular materials. The effects of the strain force on the valley polarization properties in transition metal doped WTe2 are thoroughly investigated in this paper through first principles calculations. The results demonstrate that significant valley polarization can be exclusively observed in Co-doped WTe2 via consideration of the spin-orbit coupling. Additionally, the valley polarization can be enhanced by the strain force. Moreover, a giant valley polarization can be observed both in the valence band and the conduction band in the Co-doped WTe2 under appropriate tension strain. Electrons and holes with opposite spins would occupy these valley-polarized energy levels, thus, a novel spin valley Hall device with high efficiency and low energy consumption can be designed based on these special valley polarization properties. In general, this work would open up a new insight into the detection and application of valleytronics.