RESUMO
CONTEXT: The present study reports the properties of pressure-induced phase transition, electronic and optical of phosphides XSiP2 under pressure in chalcopyrite, sodium chloride (rock salt), and Wurtzite phases. The study shows the chalcopyrite phase as the most stable phase among the other studied phases. The obtained structural parameters in the chalcopyrite and rock-salt phases reasonably agree with the literature. The computed band structures revealed a semiconductor behavior in chalcopyrite structure and metallic behavior for rock- salt and wurtzite structures. In the energy range of 0 to 30 eV, optical parameters such as the real and imaginary parts of the dielectric constant, refractive index, and reflectivity are calculated and compared with existing data. Our optical properties findings are predictive for the rock-salt and wurtzite phases. Since no results are available in the literature, these results may serve as references for other theoretical and experimental studies. METHOD: The calculations are performed by employing the "full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT)."