First-Principles Prediction of High-Pressure Phase of CaC6  

作　　者：李岩 张立军 崔田 刘艳辉 马琰铭 邹广田 

机构地区：[1]National Lab of Superhard Materials, Jilin University, Changchun 130012

出　　处：《Chinese Physics Letters》2007年第6期1668-1670,共3页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under No 10676011, the National Key Basic Research Programme of China under Nos 2005CB724400 and 2001CB711201, the Specialized Research Fund for the Doctoral Programme of Higher Education of China under Grant No 20050183062, the SRF for R0CS of SEM, the Programme for 2005 New Century Excellent Talents in University, and the2006 Project for Scientific and Technical Development of Jilin Province.

摘　　要：The lattice dynamics of rhombohedral GaG6 is studied as a function orpressure to probe Its high pressure phase with low superconducting transition temperature using the density functional liner-response theory. The pressureinduced phase transition in CaC6 is attributable to the softening transverse acoustic （TA） phonon mode at the zone boundary X （0.5, 0.0, 0.5） point. The high pressure phase is then explored by performing fully structural optimization in the supercell which accommodates the atomic displacements corresponding to the eigenvectors of the unstable mode of TA（X）. The high-pressure phase is predicted to be a monoclinic unit cell with space group P21/m.The lattice dynamics of rhombohedral GaG6 is studied as a function orpressure to probe Its high pressure phase with low superconducting transition temperature using the density functional liner-response theory. The pressureinduced phase transition in CaC6 is attributable to the softening transverse acoustic （TA） phonon mode at the zone boundary X （0.5, 0.0, 0.5） point. The high pressure phase is then explored by performing fully structural optimization in the supercell which accommodates the atomic displacements corresponding to the eigenvectors of the unstable mode of TA（X）. The high-pressure phase is predicted to be a monoclinic unit cell with space group P21/m.

关 键 词：SUPERCONDUCTIVITY PSEUDOPOTENTIALS 

分 类 号：O52[理学—高压高温物理]