Transport through a Single Barrier on Monolayer MoS₂

We investigate theoretically quantum transport through a single barrier on monolayer MoS₂. It is found that the transmission properties of spin-up (down) electrons in the K valley are the same as spin-down (up) electrons in the K′ valley due to the time-reversal symmetry. Generally, the transmission probability for transport through an n–n–n (or p–p–p) junction is an oscillating function of incident angle, barrier height, as well as the incident energy of electrons. The present transmission shows a directional-dependent tunneling depending sensitively on the spin orientation for transport through a p–p–p junction. While for transport through an n–p–n junction, monolayers of MoS₂ become opaque for almost all angles of incident θ₀ except for θ₀ ∼ θ_0m (the resonant angles). The positions and numbers of resonant peaks in the transmission are determined by the distance between the two barriers and the spin orientation. The conductance in such systems can be tuned significantly by changing the height of the electric potential. (paper)