Intrinsic spin Hall effect in silicene: transition from spin Hall to normal insulator

TL;DR

This paper theoretically investigates the intrinsic spin Hall effect in silicene, demonstrating a voltage-induced transition from a spin Hall insulator to a normal insulator, with potential for experimental observation due to strong spin-orbit coupling.

Contribution

It reveals a voltage-driven phase transition in silicene's spin Hall conductivity, expanding understanding of topological phases in two-dimensional materials.

Findings

Spin Hall conductivity transitions from spin Hall insulator to normal insulator with increasing voltage.

Transition resembles phase change observed in bilayer graphene.

Strong spin-orbit interaction in silicene makes the transition experimentally observable.

Abstract

Intrinsic contribution to the spin Hall effect in a two-dimensional silicene is considered theoretically within the linear response theory and Green function formalism. When an external voltage normal to the silicene plane is applied, the spin Hall conductivity is shown to reveal a transition from the spin Hall insulator phase at low voltages to the conventional insulator phase at higher voltages. This transition resembles recently reported phase transition in a bilayer graphene. The spin-orbit interaction responsible for this transition in silicene is much stronger than in graphene, which should make the transition observable experimentally.