Liao Liyang, Puebla Jorge, Yamamoto Kei, Kim Junyeon, Maekawa Sadamichi, Hwang Yunyoung, Ba You, Otani Yoshichika
Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan.
Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan.
Phys Rev Lett. 2023 Oct 27;131(17):176701. doi: 10.1103/PhysRevLett.131.176701.
Phonons and magnons are engineered by periodic potential landscapes in phononic and magnonic crystals, and their combined studies may enable valley phonon transport tunable by the magnetic field. Through nonreciprocal surface acoustic wave transmission, we demonstrate valley-selective phonon-magnon scattering in magnetoelastic superlattices. The lattice symmetry and the out-of-plane magnetization component control the sign of nonreciprocity. The phonons in the valleys play a crucial role in generating nonreciprocal transmission by inducing circularly polarized strains that couple with the magnons. The transmission spectra show a nonreciprocity peak near a transmission gap, matching the phononic band structure. Our results open the way for manipulating valley phonon transport through periodically varying magnon-phonon coupling.
声子和磁振子由声子晶体和磁子晶体中的周期性势场调控，对它们的联合研究可能实现可通过磁场调节的谷声子输运。通过非互易表面声波传输，我们在磁弹性超晶格中证明了谷选择性声子 - 磁振子散射。晶格对称性和面外磁化分量控制着非互易性的符号。谷中的声子通过诱导与磁振子耦合的圆偏振应变，在产生非互易传输中起关键作用。传输光谱在传输间隙附近显示出一个非互易峰，与声子能带结构相匹配。我们的结果为通过周期性变化的磁子 - 声子耦合来操控谷声子输运开辟了道路。
