Quantum spin Hall effect induced by electric field in silicene

TL;DR

This paper demonstrates that an external electric field can induce the quantum spin Hall effect in silicene by creating spin-filtered edge states, highlighting potential applications in spintronics.

Contribution

It reveals how electric fields induce the quantum spin Hall effect in silicene through control of Rashba spin-orbit couplings and sublattice potential.

Findings

Electric field opens a bulk gap in silicene nanoribbons.

Gapless, spin-filtered edge states appear under certain conditions.

Edge states are robust against non-magnetic disorder.

Abstract

We investigate the transport properties in a zigzag silicene nanoribbon in the presence of an external electric field. The staggered sublattice potential and two kinds of Rashba spin-orbit couplings can be induced by the external electric field due to the buckled structure of the silicene. A bulk gap is opened by the staggered potential and gapless edge states appear in the gap by tuning the two kinds of Rashba spin-orbit couplings properly. Furthermore, the gapless edge states are spin-filtered and are insensitive to the non-magnetic disorder. These results prove that the quantum spin Hall effect can be induced by an external electric field in silicene, which may have certain practical significance in applications for future spintronics device.