Current induced magnetization reversal on the surface of a topological insulator

TL;DR

This paper investigates how electric currents can induce magnetization reversal on the surface of a topological insulator, revealing a novel mechanism driven by the inverse spin-galvanic effect without needing an additional ferromagnet.

Contribution

It demonstrates current-induced magnetization dynamics on topological insulator surfaces and highlights a new reversal mechanism relying on the inverse spin-galvanic effect.

Findings

Current injection causes magnetization dynamics on the surface.

The torque depends on transmission probability and exchange coupling.

Magnetization reversal can occur without an extra ferromagnet.

Abstract

We study dynamics of the magnetization coupled to the surface Dirac fermions of a three di- mensional topological insulator. By solving the Landau-Lifshitz-Gilbert equation in the presence of charge current, we find current induced magnetization dynamics and discuss the possibility of mag- netization reversal. The torque from the current injection depends on the transmission probability through the ferromagnet and shows nontrivial dependence on the exchange coupling. The mag- netization dynamics is a direct manifestation of the inverse spin-galvanic effect and hence another ferromagnet is unnecessary to induce spin transfer torque in contrast to the conventional setup.