Prediction of anomalous LA-TA splitting in electrides  

作　　者：Leilei Zhang Hua Y.Geng Q.Wu 

机构地区：[1]National Key Laboratory of Shock Wave and Detonation Physics,Institute of Fluid Physics,CAEP,P.O.Box 919-102,Mianyang,Sichuan 621900,People’s Republic of China

出　　处：《Matter and Radiation at Extremes》2021年第3期71-76,共6页极端条件下的物质与辐射（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant No.11672274);the National Natural Science Foundation of China and the China Academy of Engineering Physics(NSAF)(Grant No.U1730248);the Science Challenge Project(Grant No.TZ2016001);the China Academy of Engineering Physics Research Project No.CX2019002.

摘　　要：Electrides are an emerging class of materials with excess electrons localized in interstices and acting as anionic interstitial quasi-atoms(ISQs).The spatial ion–electron separation means that electrides can be treated physically as ionic crystals,and this unusual behavior leads to extraordinary physical and chemical phenomena.Here,a completely different effect in electrides is predicted.By recognizing the long-range Coulomb interactions between matrix atoms and ISQs that are unique in electrides,a nonanalytic correction to the forces exerted on the matrix atoms is proposed.This correction gives rise to a longitudinal acoustic-transverse acoustic splitting in the acoustic branch of lattice phonons near the zone center,similar to the well-known longitudinal optical–transverse optical splitting in the phonon spectra of ionic compounds.The factors that govern this splitting are investigated,with isotropic fcc-Li and anisotropic hP4-Na as the typical examples.It is found that not all electrides can induce a detectable splitting,and criteria are given for this type of splitting.The present prediction unveils the rich phenomena in electrides and could lead to unprecedented applications.

关 键 词：SPLITTING CORRECTION TRANSVERSE 

分 类 号：O57[理学—粒子物理与原子核物理]