First-principles study of structural, elastic, electronic and optical properties of perovskites hydrides XLiH₃ (X = Ba and Sr) under pressure

¹ Département de Physique, Faculté des Sciences, Université de Sétif, Sétif, 19000, Algeria
² Département de Physique, Centre Universitaire, Bordj Bou-Arréridj, 34000, Algeria
³ Laboratoire de Physique et Mécanique des Matériaux Métalliques (LP3M), Université de Sétif, Sétif, 19000, Algeria

Corresponding author: ^* bghebouli@yahoo.fr

Received: 16 December 2009
Revised: 3 June 2010
Accepted: 7 June 2010
Published online: 22 July 2010

Abstract

The stability, structural, elastic, electronic and optical properties of perovskite hydrides BaLiH₃ and SrLiH₃ were investigated by the density functional theory. The calculated lattice parameters are in well agreement with previous calculation and experimental data. The energy band structure, density of states, born effective charge and Mulliken charge population were obtained. BaLiH₃ and SrLiH₃ present an indirect band gap of 2.23 eV and 1.86 eV at equilibrium. The top of the valence band reflects the s electronic character for both structures. Furthermore, the absorption spectrum, refractive index, extinction coefficient, reflectivity, energy-loss spectrum and dielectric function were calculated. The origin of the spectral peaks was interpreted based on the electronic structure. The static dielectric constant and static refractive index are proportional to the fundamental indirect band gap.