Ding Guangqian, Sun Tingting, Wang Xiaotian
School of Science, Chongqing University of Posts and Telecommunications, Chongqing, 400065, China.
School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
Phys Chem Chem Phys. 2022 May 11;24(18):11175-11182. doi: 10.1039/d2cp00731b.
The topological interpretation of phonons provides a new platform for new concepts in phonon physics. While reports on topological electronic excitations are plenty, the number of reports on phonons is extremely limited. In this paper, we present some realistic materials as examples and demonstrate the appearance of ideal nodal-net, nodal-chain, and nodal-cage phonons in these materials based on first-principle calculations; 2 LiAlSe has a nodal-net phonon, which is composed of two nodal-chain phonons along the - and - directions; NaMgH has a nodal-chain phonon in the extended Brillouin zone (BZ), which comprises two Weyl nodal-ring phonons in the - and - planes. Moreover, 4/ AuBr has a nodal-cage phonon, which is composed of nodal-line phonons in the = 0, = π, = 0, and = 0 planes. Because the presented phonon bands and phonon surface states in these materials are quite clean, they can be easily detected in experiments. Our research results provide an ideal platform for realising complex geometric shapes (formed by nodal lines) in the momentum space of phonons.
声子的拓扑解释为声子物理学中的新概念提供了一个新平台。虽然关于拓扑电子激发的报道很多，但关于声子的报道数量极其有限。在本文中，我们给出一些实际材料作为示例，并基于第一性原理计算证明这些材料中理想的节面网、节链和节笼声子的出现；LiAlSe具有节面网声子，它由沿 和 方向的两个节链声子组成；NaMgH在扩展布里渊区（BZ）具有节链声子，它在 和 平面中由两个外尔节环声子组成。此外，AuBr具有节笼声子，它由 = 0、 = π、 = 0和 = 0平面中的节线声子组成。由于这些材料中呈现的声子能带和声子表面态相当纯净，它们在实验中很容易被检测到。我们的研究结果为在声子的动量空间中实现由节线形成的复杂几何形状提供了一个理想平台。
