  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.
