Spin Current Induced by Phonon Waves in an Insulating Ferromagnet

We investigate theoretically the DC spin current induced by phonon waves in a coupled spin–lattice system. Via the Holstein–Primakoff transformation, the system is mapped to a coupled magnon–phonon one. By using both the dynamic method and perturbation theory, we demonstrate that a DC spin current can be generated by a lattice wave. The spin current density is found to be on the order of [Formula: see text] [Formula: see text] (in electric units). Several influencing factors for the spin current have also been addressed briefly, including spin anisotropy, temperature and properties of the phonon waves. These factors may be used to optimize the spin current further. Our results thus suggest efficient generation of spin currents by phonon waves and could be useful for future spintronics.