Valley and spin resonant tunneling current in ferromagnetic/nonmagnetic/ferromagnetic silicene junction

Abstract

We study the transport properties in a ferromagnetic/nonmagnetic/ferromagnetic (FNF) silicene junction in which an electrostatic gate potential, U, is attached to the nonmagnetic region. We show that the electrostatic gate potential U is a useful probe to control the band structure, quasi-bound states in the nonmagnetic barrier as well as the transport properties of the FNF silicene junction. In particular, by introducing the electrostatic gate potential, both the spin and valley conductances of the junction show an oscillatory behavior. The amplitude and frequency of such oscillations can be controlled by U. As an important result, we found that by increasing U, the second characteristic of the Klein tunneling is satisfied as a result of the quasiparticles chirality which can penetrate through a potential barrier. Moreover, it is found that for special values of U, the junction shows a gap in the spin and valley-resolve conductance and the amplitude of this gap is only controlled by the on-site potential difference, Δz. Our findings of high controllability of the spin and valley transport in such a FNF silicene junction may improve the performance of nano-electronics and spintronics devices.

Beyond Graphene: Chemistry of Group 14 Graphene Analogues: Silicene, Germanene, and Stanene

“…Recently, silicon, germanium, and tin 2D materials have been extensively studied due to their similarity to graphene. The graphene-like honeycomb structure of silicene (Si 6 ) n was theoretically investigated by Takeda, and in 2012, silicene was grown on silver(111) − and zirconium diboride substrates under UHV. In 2009, a germanium system analogous to graphene, germanene, was predicted by Cahangirov to be stable .…”

The perfect spin injection in silicene FS/NS junction

“…Silicene, monolayer of silicon with low-buckled structure, is one of the most fascinating Dirac materials following graphene [1][2][3]. Silicene possesses almost every remarkable properties with graphene, such as two inequivalent valleys (K, K ) at the corners of the first Brillioun zone, a linear band structure near the K (K ) points [4,5] as well as the Klein paradox [6]. In contrast to graphene, silicene has a large spin-orbit coupling (SOC) due to the low-buckled geometry which opens a gap between the conduction and valence bands, and the energy gap can be further tuned by an external electric field perpendicular to the silicene sheet [7,8].…”