Spin field-effect transistor in a quantum spin-Hall device

TL;DR

This paper explores how Rashba spin-orbit coupling in a quantum spin-Hall insulator enables electrical control of spin-polarized currents through topologically protected edge states, with implications for spintronic devices.

Contribution

It demonstrates the modulation of ballistic conductance and spin polarization via all-electric tuning of Rashba interaction in a quantum spin-Hall device.

Findings

Conductance is modulated by Rashba strength.

Spin polarization can be electrically controlled.

Topologically protected edge states facilitate spin manipulation.

Abstract

We discuss the transport properties of a quantum spin-Hall insulator with sizable Rashba spin-orbit coupling in a disk geometry. The presence of topologically protected helical edge states allows for the control and manipulation of spin polarized currents: when ferromagnetic leads are coupled to the quantum spin-Hall device, the ballistic conductance is modulated by the Rashba strength. Therefore, by tuning the Rashba interaction via an all-electric gating, it is possible to control the spin polarization of injected electrons.