Ab-initio study of structural, electronic, elastic, phonon properties, and phase transition path of sodium selenite

Abstract

The effects of pressure on structural, elastic, electronic, and vibrational properties of NaSe are studied using the SIESTA method. The dimensionless ratio, bulk modulus, elastic constants, Shear and Young modulus, and Poisson‘s ration are obtained for each phase. NaSe shows phase transitions from the P63/mmc phase (T = 0 K, P = 0) to the Cmcm phase at 10 GPa and from this phase to the Pmmm phase at 22 GPa. High pressure results in an improvement in resistance towards volume and shape change. Elastic constants evaluation indicates that the P63/mmc phase and the Cmcm phase of NaSe is mechanically stable. The B/G ratios of NaSe phases are also examined. It is found that NaSe has great ductility, however as pressure increases the ductility of NaSe decreases. Electronic and vibrational computation and analysis reveal that the P63/mmc phase and the Cmcm phase of NaSe demonstrate metallic character and both phases are dynamically stable. © 2020 Elsevier B.V.