Electric-field control of spin-orbit torque in a magnetically doped topological insulator

TL;DR

This paper demonstrates that electric fields can effectively control spin-orbit torque in a Cr-doped topological insulator, enabling significant modulation of SOT strength and magnetization switching, advancing spintronic device technology.

Contribution

It presents the first demonstration of electric-field control of giant spin-orbit torque in a topological insulator, with potential for energy-efficient spintronic devices.

Findings

SOT strength modulated by a factor of 4 with gate voltage

Strong correlation between SOT and spin-polarized surface current

Magnetization switching achieved via gate voltage scanning

Abstract

Electric-field manipulation of magnetic order has proved of both fundamental and technological importance in spintronic devices. So far, electric-field control of ferromagnetism, magnetization and magnetic anisotropy has been explored in various magnetic materials, but the efficient electric-field control of spin-orbit torque (SOT) still remains elusive. Here, we report the effective electric-field control of a giant SOT in a Cr-doped topological insulator (TI) thin film using a top-gate FET structure. The SOT strength can be modulated by a factor of 4 within the accessible gate voltage range, and it shows strong correlation with the spin-polarized surface current in the film. Furthermore, we demonstrate the magnetization switching by scanning gate voltage with constant current and in-plane magnetic field applied in the film. The effective electric-field control of SOT and the giant spin-torque efficiency in Cr-doped TI may lead to the development of energy-efficient gate-controlled spin-torque devices compatible with modern field-effect semiconductor technologies.