Intrinsic staggered spin-orbit torque for the electrical control of antiferromagnets -- application to CrI$_3$

TL;DR

This paper demonstrates that staggered dampinglike spin-orbit torque can electrically control the Nél vector in antiferromagnets, exemplified by 2D CrI3, through first-principles calculations and spin dynamics analysis.

Contribution

It identifies the key role of staggered dampinglike spin-orbit torque in electrically switching the Nél vector in antiferromagnets, with a focus on CrI3.

Findings

Staggered dampinglike spin-orbit torque enables deterministic Nél vector switching.

First-principles calculations quantify the torque in doped CrI3.

Spin dynamics analysis confirms the control mechanism.

Abstract

Spin-orbit torque enables the electrical control of the orientation of ferromagnets' or antiferromagnets' order parameter. In this work we consider antiferromagnets in which the magnetic sublattices are connected by inversion+time reversal symmetry, and in which the exchange and anisotropy energies are similar in magnitude. We identify the staggered dampinglike spin-orbit torque as the key mechanism for electrical excitation of the N\'eel vector for this case. To illustrate this scenario, we examine the 2-d Van der Waals antiferromagnetic bilayer \ch{CrI3}, in the $n$-doped regime. Using a combination of first-principles calculations of the spin-orbit torque and an analysis of the ensuing spin dynamics, we show that the deterministic electrical switching of the N\'eel vector is the result of dampinglike spin-orbit torque which is staggered on the magnetic sublattices.