Spin Orbit Torque in two dimensional Antiferromagnetic Topological Insulators

TL;DR

This paper explores spin transport and torque in two-dimensional antiferromagnetic topological insulators, revealing disorder-induced antidamping torque that could enable control of antiferromagnetic states.

Contribution

It demonstrates the emergence of an antidamping spin torque in disordered 2D AFTI, a novel effect with potential for manipulating antiferromagnetic order.

Findings

Disorder induces an antidamping spin torque along the edges.

Antidamping torque diminishes with increasing system size.

Transition to trivial insulator reduces the antidamping effect.

Abstract

We investigate spin transport in two dimensional ferromagnetic (FTI) and antiferromagnetic (AFTI) topological insulators. In presence of an in plane magnetization AFTI supports zero energy modes, which enables topologically protected edge conduction at low energy. We address the nature of current-driven spin torque in these structures and study the impact of spin-independent disorder. Interestingly, upon strong disorder the spin torque develops an antidamping component (i.e. {\em even} upon magnetization reversal) along the edges, which could enable current-driven manipulation of the antiferromagnetic order parameter. This antidamping torque decreases when increasing the system size and when the system enters the trivial insulator regime.