关键词: Ca2Ge;电子结构;介电函数;极化;第一性原理

Abstract: The electronic structure, dielectric function and dielectric polarization characteristics of Ca 2 Ge were studied by the first-principles pseudo-potential method.The results show that Ca 2 Ge is a direct band gap semiconductor with the band gap of 0.483 eV.The valence bands are mainly composed of Ca 3d and Ge 4p, existed in s-p-d orbital hybridization and p-d orbital hybridization.The conduction bands are mainly composed of Ca 3d, non-existed in orbital hybridization.The dielectric function of orthorhombic Ca2 Ge existes in aeolotropism.In the direction of (100) and (001) the dielectric function are decreased and the electron transition are increased by polarized .In the direction of (010) the dielectric function is increased by polarized.The results show that polarization is promoted the electron transition , is an effective means for regulating the electron transition , is provided a theoretical reference to the study of Ca2 Ge.

Key words: Ca2 Ge;electronic structure;dielectric function;polarized;first principles