Unconventional phonon spectra and obstructed edge phonon modes  

作　　者：Ruihan Zhang Haohao Sheng Junze Deng Zhong Fang Zhilong Yang Zhijun Wang 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第4期114-118,共5页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.11974395,and 12188101);the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB33000000);the National Key R&D Program of Chain(Grant No.2022YFA1403800);the Center for Materials Genome。

摘　　要：Based on the elementary band representations(EBR),many topologically trivial materials are classified as unconventional ones(obstructed atomic limit),where the EBR decomposition for a set of electronic states is not consistent with atomic valenceelectron band representations.In the work,we identify that the unconventional nature can also exist in phonon spectra,where the EBR decomposition for a set of well-separated phonon modes is not consistent with atomic vibration band representations(ABR).The unconventionality has two types:typeⅠis on an empty site;and typeⅡis on an atom site with non-atomic vibration orbitals.The unconventionality is described by the nonzero real-space invariant at the site.Our detailed calculations show that the black phosphorus(BP)has the typeⅠunconventional phonon spectrum,while 1H-Mo Se_(2)has the typeⅡone,although their electronic structures are also unconventional.Accordingly,the obstructed phonon modes are obtained for two types of unconventional phonon spectra.

关 键 词：unconventional phonon spectra obstructed edge phonon mode typeⅠ&typeⅡunconventionality 

分 类 号：O469[理学—凝聚态物理]