Intrinsic staggered spin-orbit torque for the electrical control of antiferromagnets: Application to CrI3

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 $\text{inversion}+\text{time-reversal}$ 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 two-dimensional van der Waals antiferromagnetic bilayer ${\mathrm{CrI}}_{3}$, 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.