Cluster multipole dynamics in noncollinear antiferromagnets

In this paper, the authors study spin dynamics in the noncollinear antiferromagnet Mn3Sn. They derive an effective low-energy model based on the cluster multipole expansion of the magnetic structure and show that the cluster multipole degrees of freedom dominate its low-energy dynamics. They also show that Mn3Sn has a high domain wall velocity without a Walker breakdown and a stable uniform precession mode with a tunable frequency.