Fei Xue, University of Alabama

"Novel spin-orbit torque in two-dimensional magnets without local inversion symmetry"

Abstract: In ferromagnetic systems lacking inversion symmetry, an applied electric field can control the ferromagnetic order parameters through spin-orbit torque. The prototypical example is a bilayer heterostructure composed of a ferromagnet and a heavy metal that acts as a spin current source. In addition to such ferromagnetic bilayers, spin-orbit coupling can mediate spin-orbit torques in ferromagnets that lack bulk inversion symmetry or antiferromagnets that lack local inversion symmetry. In this talk, I will present our recent first-principles calculations of novel spin-orbit torque in 2D noncentrosymmetric ferromagnets and 2D PT-symmetric antiferromagnets. In the first example [1], we show that monolayer Fe3GeTe2 supports new higher-order angular dependence of spin-orbit torque that gives rise to deterministic switching of perpendicular magnetization. In the second example [2], we show that bilayer CrI3 supports a new type of staggered dampinglike torque that can deterministically switch perpendicular Neel order and induce sub-THz magnetization oscillation.

[1] F. Xue, M. D. Stiles, P. M. Haney, “Angular dependence of spin-orbit torque in monolayer Fe3GeTe2”, Physical Review B 108, 144422 (2023).
[2] F. Xue, P. M. Haney, “Intrinsic staggered spin-orbit torque for the electrical control of antiferromagnets: Application to CrI3”, Physical Review B 104, 224414 (2021).