Nearly pure spin-valley sideband tunneling in silicene: effect of interplay of time periodic potential barrier and spin-valley-dependent Dirac mass

TL;DR

This paper investigates spin-valley filtering in silicene using a time-periodic potential, revealing nearly perfect selectivity through photon absorption and electric field manipulation, with potential applications in spin-valleytronics.

Contribution

It demonstrates nearly perfect spin-valley-sideband filtering in silicene via Floquet engineering and electric field control, a novel approach for spin-valleytronics.

Findings

Nearly perfect spin-valley filtering predicted

Electric field reversals control spin and valley selection

Photon absorption enables selective tunneling

Abstract

We study massive Dirac fermion tunneling through time periodic potential in a silicene-based N-TP-N junction, where Ns are normal silicene regions and TP is the time periodic potential barrier. The fermions would absorb or emit photons due to the presence of the Floquet sidebands created in the TP. The nearly perfect spin-valley-sideband filtering is predicted. Applying only the exchange field leads to just only the electron absorbing a single photon almost purely allowed to tunnel through the junction for the large electric field. Reversing direction of electric field can select spin of the allowed electron. In the case of applying only off-resonant circularly polarized light, just only the electron absorbing a single photon with spin up, is almost purely allowed to tunnel through the junction. The valley is also selected by reversing direction of the electric field. The controllable sideband channel may be applicable for sideband-based spin-valleytronics.