2013/08/31 by Lifa Zhang, Qian Niu · 3 citations
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.mtrl-sci #cond-mat.stat-mech #quant-ph
paper · pdf · doi:10.1103/physrevlett.112.085503
published as PRL 112, 085503 (2014) · Accepted by Phys. Rev. Lett. Detailed supplementary file is included
arxiv created 2014/01/29 · arxiv updated 2014/03/03
We study angular momentum of phonons in a magnetic crystal. In the presence of a spin-phonon interaction, we obtain a nonzero angular momentum of phonons, which is an odd function of magnetization. At zero temperature, phonon has a zero-point angular momentum besides a zero-point energy. With increasing temperature, the total phonon angular momentum diminishes and approaches to zero in the classical limit. The nonzero phonon angular momentum can have a significant impact on the Einstein-de Haas effect. To obtain the change of angular momentum of electrons, the change of phonon angular momentum needs to be subtracted from the opposite change of lattice angular momentum. Furthermore, the finding of phonon angular momentum gives a potential method to study the spin-phonon interaction. Possible experiments on phonon angular momentum are also discussed.