Thermal Hall effect from Magnon-Phonon Couplings*

In this letter, we propose a new mechanism to realize the thermal Hall effect from magnon-phonon couplings in exchange spin wave systems. We study a collinear ferromagnetic system on the 2D square lattice with an in-plane Dzyaloshinskii-Moriya interaction, where neither the magnon system nor the phonon system alone shows the thermal Hall effect. However, the magnon-phonon interaction can lead to a thermal Hall effect of a hybrid magnon-phonon system. Such an interaction can be directly tuned by an out-plane gate voltage.