All-electric spin transistor based on a side-gate-modulated two-dimensional topological insulator

TL;DR

This paper proposes an all-electric spin transistor utilizing a two-dimensional topological insulator with side-gate modulation, enabling control of spin transport via interference effects in topological edge states.

Contribution

It introduces a novel spin transistor design based on topological insulators that allows simple electric control of spin polarization through a side-gate voltage.

Findings

Conductance can be controlled by side-gate voltage.

Device acts as a spin-polarization rotator.

Linear relationship between gate voltage and rotation angle.

Abstract

We propose and investigate a spin transistor device consisting of two ferromagnetic leads connected by a two-dimensional topological insulator as the channel material. It exploits the unique features of the topological spin-helical edge states, such that the injected carriers with a non-collinear spin-direction would travel through both edges and show interference effect. The conductance of the device can be controlled in a simple and allelectric manner by a side-gate voltage, which effectively rotates the spin-polarization of the carrier. At low voltages, the rotation angle is linear in the gate voltage, and the device can function as a good spin-polarization rotator by replacing the drain electrode with a paramagnetic material.