Novel spin-orbit torque in collinear antiferromagnetic RuO2

Ruthenium oxide (RuO2) has several intriguing properties such as electrically-conduction like metal, topological electronic band structure called Dirac nodal line, and room temperature collinear antiferromagnet (AFM) [T. Berlijn et al, Phys. Rev. Lett. 118, 077201 (2017)]. We have discovered a novel spin-orbit torque (SOT) generation in epitaxially grown RuO2 thin films originated from recently predicted magnetic spin Hall effect (MSHE) [R. Gonzalez-Hernandez et al, arXiv:2002.07073(2020)]. The detected both damping-like and field-like torques clearly follow the Neel vector directions against the applied current directions in the epitaxial RuO2(101) and RuO2(100) films which have different Neel vectors on the substrate plane. We further discuss the mechanism of the SOT and the related phenomena in the AFM RuO2 films on this conference.