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

We investigate silicene superlattices in the presence of a tunable barrier potential U, an exchange field M, and a perpendicular electric field Ez. The resulting miniband structure depends on the spin and valley indices and on the fields M and Ez. 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.