Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP

作     者：Bo Peng Shuichi Murakami Bartomeu Monserrat Tiantian Zhang 

作者机构：TCM GroupCavendish LaboratoryUniversity of CambridgeJ.J.Thomson AvenueCambridge CB30HEUnited Kingdom Department of PhysicsTokyo Institute of TechnologyOokayamaMeguro-kuTokyo 152-8551Japan Tokodai Institute for Element StrategyTokyo Institute of TechnologyNagatsutaMidori-kuYokohamaKanagawa 226-8503Japan Department of Materials Science and MetallurgyUniversity of Cambridge27 Charles Babbage RoadCambridge CB30FSUnited Kingdom 

出 版 物：《npj Computational Materials》 (计算材料学（英文）)

年 卷 期：2021年第7卷第1期

页      面：1792-1799页

核心收录：

学科分类：08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：B.P.and B.M.acknowledge support from the Winton Programme for the Physics of Sustainability,and B.M.also acknowledges support from the Gianna Angelopoulos Programme for Science,Technology,and Innovation.S.M.and T.Z.acknowledge the supports from JSPS KAKENHI Grants No.JP18H03678 and No.JP20H04633 Tokodai Institute for Element Strategy(TIES)funded by MEXT Elements Strategy Initiative to Form Core Research Center T.Z.also acknowledges the support by the Japan Society for the Promotion of Science(JSPS),KAKENHI Grant No.JP21K13865 The calculations are performed using resources provided by the Cambridge Tier-2 system operated by the University of Cambridge Research Computing Service(http://www.hpc.cam.ac.uk)and funded by EPSRC Tier-2 capital grant EP/P020259/1 also with computational support from the UK Materials and Molecular Modelling Hub,which is partially funded by EPSRC(EP/P020194),for which access is obtained via the UKCP consortium funded by EPSRC grant EP/P022561/1 

主　　题：topological symmetry quasi 

摘      要：Degenerate points/lines in the band structures of crystals have become a staple of the growing number of topological *** bulk-boundary correspondence provides a relation between bulk topology and surface *** line degeneracies of bulk excitations have been extensively characterised,line degeneracies of surface states are not well *** show that SnIP,a quasi-one-dimensional van der Waals material with a double helix crystal structure,exhibits topological nodal rings/lines in both the bulk phonon modes and their corresponding surface *** a combination of first-principles calculations,symmetrybased indicator theories and Zak phase analysis,we find that two neighbouring bulk nodal rings form doubly degenerate lines in their drumhead-like surface states,which are protected by the combination of time-reversal symmetry T and glide mirror symmetry *** results indicate that surface degeneracies can be generically protected by symmetries such as T My,and phonons provide an ideal platform to explore such degeneracies.