First principles study on electronic structure and optical properties of novel Na-hP4 high pressure phase

The electronic structure and optical properties of novel Na-hP4 high pressure phase at different pressures (260, 320, 400 and 600 GPa) were investigated by the density functional theory (DFT) with the generalized gradient approximation (GGA) for the exchange and correlation energy. The band structure along the higher symmetry axes in the Brillouin zone, the density of states (DOS) and the partial density of states (PDOS) were presented. The band gap increases and the energy band expands to some extent with the pressure increasing. The dielectric function, reflectivity, energy-loss function, optical absorption coefficient, optical conductivity, refractive index and extinction coefficient were calculated for discussing the optical properties of Na-hP4 high pressure phase at different pressures.