Study on the Electronic Structure and Optical Properties of Stressed BaSi2

Abstract

A theoretical study of electronic structure and optical properties of BaSi2 under isotropic lattice deformation was performed by first-principles pseudopotential method based on the density function theory (DFT). The energy gap irregularly varies from 93% lattice to 107% lattice. When the crystal lattice is 93% compressed, the indirect band gap is 0.8286 eV; 107% stretched, the indirect band gap is 0.8961eV. As the lattice constants decrease from 107 ô€€€ to 93 ô€€€, curves of dielectric function and refractive index drift toward the high energy region.The static dielectric function increases along with the decrease of the lattice constants. When compressed, the absorption coefficient enhances, and then improves the photoelectric conversion efficiency.