Xu Xifang, Zhang Wei, Wang Jiaojiao, Zhang Lifa
Department of Physics and Institute of Theoretical Physics, Nanjing Normal University, Nanjing 210023, People's Republic of China.
J Phys Condens Matter. 2018 Jun 6;30(22):225401. doi: 10.1088/1361-648X/aabf5e. Epub 2018 Apr 19.
Since chiral phonons were found in an asymmetric two-dimensional hexagonal lattice, there has been growing interest in the study of phonon chirality, which were experimentally verified very recently in monolayer tungsten diselenide (2018 Science 359 579). In this work, we find chiral phonons with nontrivial topology in center-stacked bilayer triangle lattices. At the Brillouin-zone corners, [Formula: see text]([Formula: see text]), circularly polarized phonons and nonzero phonon Berry curvature are observed. Moreover, we find that the phonon chirality remain robust with changing sublattice mass ratio and interlayer coupling. The chiral phonons at the valleys are demonstrated in doubler-layer sodium chloride along the [1 1 1] direction. We believe that the findings on topological chiral phonons in triangle lattices will give guidance in the study of chiral phonons in real materials and promote the phononic applications.
自从在不对称二维六角晶格中发现手性声子以来，对声子手性的研究兴趣日益浓厚，最近在单层二硒化钨中通过实验证实了这一点（《科学》2018年第359卷，第579页）。在这项工作中，我们在中心堆叠的双层三角形晶格中发现了具有非平凡拓扑结构的手性声子。在布里渊区角点，公式：见正文，观察到圆偏振声子和非零声子贝里曲率。此外，我们发现声子手性在改变子晶格质量比和层间耦合时保持稳健。沿[1 1 1]方向在双层氯化钠中展示了谷处的手性声子。我们相信，关于三角形晶格中拓扑手性声子的发现将为实际材料中手性声子的研究提供指导，并促进声子应用。
