%0 Journal Article
%T Thermophoresis of an Antiferromagnetic Soliton
%A Se Kwon Kim
%A Oleg Tchernyshyov
%A Yaroslav Tserkovnyak
%J Physics
%D 2015
%I arXiv
%R 10.1103/PhysRevB.92.020402
%X We study dynamics of an antiferromagnetic soliton under a temperature gradient. To this end, we start by phenomenologically constructing the stochastic Landau-Lifshitz-Gilbert equation for an antiferromagnet with the aid of the fluctuation-dissipation theorem. We then derive the Langevin equation for the soliton's center of mass by the collective coordinate approach. An antiferromagentic soliton behaves as a classical massive particle immersed in a viscous medium. By considering a thermodynamic ensemble of solitons, we obtain the Fokker-Planck equation, from which we extract the average drift velocity of a soliton. The diffusion coefficient is inversely proportional to a small damping constant $\alpha$, which can yield a drift velocity of tens of m/s under a temperature gradient of $1$ K/mm for a domain wall in an easy-axis antiferromagnetic wire with $\alpha \sim 10^{-4}$.
%U http://arxiv.org/abs/1503.07854v2