Domain wall dynamics and magnetization switching in the presence of spin-orbit torques in low-symmetry materials

Conventional field-like and damping-like spin orbit torques (SOT) which appear at heavy-metal / ferromagnet interfaces are possible due to the breaking of inversion symmetry. Further symmetry breaking due to the structure of the materials allows for the possibility of additional types of SOT. In this work, we build a collective coordinate model to describe the motion of a ferromagnetic domain wall in response to low symmetry SOT. Our results show that these low symmetry SOT can be used to control the motion of domain walls in ways not possible using ordinary field-like or damping-like SOT. We then use ab initio methods to verify the presence of these torques in a CuPt/CoPt bilayer with threefold rotational symmetry, and apply this model to show how SOT compatible with this symmetry can allow the deterministic reversal of perpendicular magnetization, even in the absence of external magnetic fields, and compare our results to micromagnetic simulations.