Rotational motion of magnon and thermal Hall effect

Abstract

Due to the Berry curvature in momentum space, the magnon wavepacket undergoes two types of orbital motions in analogy with the electron system: the self-rotation motion and a motion along the boundary of the sample (edge current). The magnon edge current causes the thermal Hall effect, and these orbital motions give corrections to the thermal transport coefficients. We also apply our theory to the magnetostatic spin wave in a thin-film ferromagnet, and derive expression for the Berry curvature.