We report measurements demonstrating that when the Neel vector of the collinear antiferromagnet RuO2 is appropriately canted relative to the sample plane, the antiferromagnet generates a substantial out of plane damping-like torque. The measurements are in good accord with predictions that when an electric field, E is applied to the spin split band structure of RuO2 it can cause a strong transverse spin current even in the absence of spin-orbit coupling. This produces characteristic changes in all three components of the E induced torque vector as a function of the angle of E relative to the crystal axes, corresponding to a spin current with a well defined tilted spin orientation s approximately (but not exactly) parallel to the Neel vector, flowing perpendicular to both E and S. This angular dependence is the signature of an antiferromagnetic spin Hall effect with symmetries that are distinct from other mechanisms of spin-current generation reported in antiferromagnetic or ferromagnetic materials.
@article{arxiv.2108.09150,
title = {Tilted spin current generated by the collinear antiferromagnet RuO2},
author = {Arnab Bose and Nathaniel J. Schreiber and Rakshit Jain and Ding-Fu Shao and Hari P. Nair and Jiaxin Sun and Xiyue S. Zhang and David A. Muller and Evgeny Y. Tsymbal and Darrell G. Schlom and Daniel C. Ralph},
journal= {arXiv preprint arXiv:2108.09150},
year = {2023}
}