Spin-Transfer Torque in Altermagnets with Magnetic Textures

TL;DR

This paper predicts anisotropic spin-transfer torque effects in textured altermagnets, revealing unique domain wall and skyrmion dynamics that distinguish altermagnets from ordinary antiferromagnets.

Contribution

It generalizes the Zhang-Li torque to d-wave altermagnets and uncovers novel anisotropic effects on magnetic textures induced by spin-transfer torque.

Findings

Spin-splitter adiabatic torque can induce domain wall precession.

Domain wall response becomes anisotropic due to d-wave symmetry.

Skyrmion dynamics exhibit an anisotropic Hall effect.

Abstract

We predict the existence of anisotropic spin-transfer torque effect in textured altermagnets. To this end, we generalize the Zhang-Li torque to incorporate the symmetry associated with prototypical $d$-wave altermagnets and identify the spin-splitter adiabatic and nonadiabatic torques. Applying our results to domain wall dynamics induced by spin-transfer torque, we find that, in certain regimes, the spin-splitter adiabatic torque can induce domain wall precession, significantly slowing down domain wall motion. The response of the domain wall also becomes anisotropic, reflecting the $d$-wave symmetry of the altermagnet. Furthermore, we observe that the spin-splitter adiabatic torque modifies skyrmion dynamics, inducing anisotropic skyrmion Hall effect. The above phenomena can serve as a hallmark of altermagnetism in textured magnets, distinguishing it from the behavior of ordinary antiferromagnets.