Transport properties of silicene-based ferromagnetic-insulator-superconductor junction

Abstract

We study the tunneling conductance of a silicene-based ferromagnet/insulator/superconductor (FIS) junction by the use of the spin-dependent Dirac-Bogoliubov de-Gennes equation. We demonstrate that the conductance spectra are strongly affected by exchange energy h, Fermi energy EF, and external perpendicular electric field Ez. In the thin barrier limit of insulator silicene IS, the zero-bias charge conductance of the FIS silicene junction oscillates as a function of barrier strength χG. It is shown that the period of oscillations changes from π/2 to π corresponding to undoped and doped silicene. Remarkably, in contrast to that of the graphene FIS junction where the conductance only vanishes at the exchange energy h=EF, here due to the buckled structure of silicene, there is a transport gap region for the range of h values and the magnitude of such a gap region can be controlled by Ez. Moreover, it is found that by appropriate choice of h and Ez, it is possible to achieve a fully spin and valley-polarized charge conductance through the FIS silicene junction. This property suggests experimentally measuring the Fermi energy of silicene.