First principle calculation electronic structure and optical of orthorhombic Al-dope Ca2Si

Abstract:

The band structure，density of states and optical properties of Ca2Siand Al-dope Ca2Si were calculated by the first-principles method. Optimized results Showed that local lattice distorted , volume was increased after induced Al. The Fermi energy moved into valence band. Al-doped Ca2Si of is a P-type semiconductor and the band gap decreased from 0.26eV to 0.144eV.The valance bands of orthorhombic Al-dope Ca2Si are mainly composed of 3P of Si，3P off Al，4s of Ca and 3d，3P of Si. The calculation of Optical properties indicated that after induced Al the static dielectric constant ε1 (0) enlarged，ε2 (ω) moved to a low-energy region, absorption and refractive index increased and reflectivity decreased.