Normal electric field enhanced light-induced polarizations in silicene

TL;DR

This paper investigates how an external electric field enhances light-induced spin and pseudo-spin polarizations in silicene, revealing potential for valleytronic applications and protection of spin states.

Contribution

It demonstrates the role of staggered potential and electric fields in enhancing and protecting spin and pseudo-spin polarizations in silicene under circularly polarized light.

Findings

Electric field induces pseudo-spin resolved states near Dirac points.

Spin-valley locking enhances polarization and protects against relaxation.

Pseudo-spin current can be generated by circularly polarized light.

Abstract

The role of staggered potential on light-induced spin and pseudo-spin polarization has been investigated in silicene. It has been shown that non-equilibrium spin and pseudo-spin polarizations are emerged in silicene sheet by applying an external perpendicular electric field in the presence of circularly polarized light emission. This electric field results in pseudo-spin resolved states very close to the Dirac points therefore could be considered as a pseudomagnetic field. It has been shown that staggered potential induced spin-valley locking and pseudo-spin resolved bands are responsible for enhancement of the spin and pseudo-spin polarizations. Meanwhile, spin-valley locking suggests a coexistence of both spin and valley polarizations with nearly identical population imbalance at low Fermi energies which could be employed for magnetic detection of the valley polarization. It has been shown that spin-valley locking results in protection of the spin polarizations against the relaxations in elastic scattering regime. In addition results indicate that the pseudo-spin current can be generated by the circularly polarized light which could be explained by asymmetric light absorption of the states in k-space.