Non-relativistic torque and Edelstein effect in noncollinear magnets

TL;DR

This paper demonstrates that non-collinear magnetic materials can exhibit a significant Edelstein effect and current-induced torque without relying on spin-orbit coupling, broadening the scope of electrically controllable magnetic systems.

Contribution

It reveals a new mechanism for current-induced torque in non-collinear magnets independent of spin-orbit coupling, supported by symmetry analysis, modeling, and simulations.

Findings

Large non-collinear magnets can generate Edelstein effect without spin-orbit coupling.

The induced torque magnitude is comparable to conventional spin-orbit torque.

Insulating non-collinear magnets can also exhibit this torque, enabling efficient control.

Abstract

The Edelstein effect is the origin of the spin-orbit torque: a current-induced torque that is used for the electrical control of ferromagnetic and antiferromagnetic materials. This effect originates from the relativistic spin-orbit coupling, which necessitates utilizing materials with heavy elements. Here we show that in magnetic materials with non-collinear magnetic order, the Edelstein effect and consequently also a current-induced torque can exist even in the absence of the spin-orbit coupling. Using group symmetry analysis, model calculations, and realistic simulations on selected compounds, we identify large classes of non-collinear magnet candidates and demonstrate that the current-driven torque is of similar magnitude as the celebrated spin-orbit torque in conventional transition metal structures. We also show that this torque can exist in an insulating material, which could allow for highly efficient electrical control of magnetic order.