Multiply charged topological phonons in K2Pb2O3

作     者：Chenyang Wang Lei Jin Lu Tian Wei-Wang Yu Xiaoming Zhang Guodong Liu Ying Liu 

作者机构：State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin 300130 China and School of Materials Science and Engineering https://***/018hded08 Hebei University of Technology Tianjin 300130 China 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2024年第109卷第23期

页      面：235415-235415页

核心收录：

基　　金：Natural Science Foundation of Hebei Province, (A2023202009, A2023202032) Natural Science Foundation of Hebei Province CPSF, (GZC20230662, C20230320) 

主　　题：Charge Fermi surface Phonons Surface states Topological materials First-principles calculations 

摘      要：Topological phonons have attracted tremendous attention in recent years, particularly when topological phonons have nonzero topological numbers and exhibit many peculiar physical phenomena. However, studies on the coexistence of different phonons with nonzero topological charge are quite limited. Here, we reveal a realist material K2Pb2O3, which can realize the coexistence of three types of phonons, namely charge-1 Weyl point (WP), charge-2 triple point (TP), and charge-4 WP. We perform symmetry analysis for these points, presenting symmetry conditions to realize these topological phonons, and constructing an effective model to describe them. Meanwhile, we calculate the phonon spectrum, topological surface states, and the constant frequency slice for K2Pb2O3, and we perform the Wilson loop method to calculate the Chern number for WPs and TPs in the material. The results indicate that the material K2Pb2O3 has charge-1 WPs, charge-2 TPs, and charge-4 WPs at high-symmetry points in the range of 13–19 THz. In particular, the phonon spectrum within this range solely contains the bands responsible for forming these topological band-crossing points. The Fermi arcs emanating from the projections of a charge-1 WP, a charge-2 TP, and a charge-4 WP are connected with each other, forming a long Fermi arc extended in the whole Brillouin zone, which greatly facilitates observation in experiment by neutron scatterings or high-resolution electron energy loss spectroscopy. Our work provides a platform for studying charge-1 WP, charge-2 TP, and charge-4 WP in a phononic system.