Spin and valley transport in monolayers of MoS2

Abstract

We investigate theoretically quantum transport and Goos-Hänchen (GH) effect of electrons in a p-n-p junction on monolayers of MoS2. We find that the transmission properties of spin-up (spin-down) electrons in K valley are the same with spin-down (spin-up) electrons in K′ valley due to the time-reversal symmetry. The GH shifts for the transmitted K and K′ beams in the n-p interface are in the opposite direction, and GH shifts for the spin-up and spin-down electron beams at the same valley have different values in the same direction due to the different group velocities. Therefore, the spin-up and spin-down electrons can be separated after passing a sufficiently long channel created by a p-n-p junction. These features provide us a new way to generate a fully spin- and valley-polarized current in monolayers of MoS2.