Conductance modulation and spin/valley polarized transmission in silicene coupled with ferroelectric layer

Abstract

We investigate the interplay of the Rashba spin orbit coupling (SOC) and the Klein tunneling effect on the valley and spin polarized transport in a heterostructure consisting of silicene coupled with a ferroelectric layer in a n-p-n configuration. We found that the combination of SOC and electric field, which opens up an energy gap, can significantly modulate the carrier transmission properties in ferroelectrically coupled silicene, in marked contrast with those of gapless two-dimensional (2D) systems. The combined effects of the SOC, electric field, and the coupling to the ferroelectric layer suppress the transmission probability at normal incidence compared to the conventional Klein effect. We also show that when the electric field, Fermi energy and barrier height are appropriately tuned, the transmitted current is composed of primarily one spin (valley) contribution for a fixed valley (spin) selection, resulting in almost pure spin/ valley polarized current. Our results have ramifications for prospective device applications of silicene heterostructures and next-generation spintronics and valleytronics.