Spin- and valley-dependent miniband structure and transport in silicene superlattices

Abstract

We investigate silicene superlattices in the presence of a tunable barrier potential $U$, an exchange field $M$, and a perpendicular electric field ${E}_{z}$. The resulting miniband structure depends on the spin and valley indices and on the fields $M$ and ${E}_{z}$. These fields determine the minigaps and also affect the additional Dirac points brought about by the periodic potential $U$. In addition, we consider diffusive transport and assess its dependence on the spin and valley indices as well as on temperature. The corresponding spin and valley polarizations strongly depend on the potential $U$ and can be made almost 100% at very low temperatures at particular values of the Fermi energy.