Abstract
The structural, elastic, electronic, optical and thermodynamic properties of the cubic perovskite-type hydride KMgH3 have been investigated using pseudo-potential plane-wave method based on the density functional theory. Computed equilibrium lattice constant agrees well with the available experimental and theoretical data. The elastic constants and their pressure dependence are predicted using the static finite strain technique. A linear pressure dependence of the elastic stiffnesses is found. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young's modulus, Poisson's ratio, average sound velocity and Debye temperature are numerically estimated in the frame work of the Voigt-Reuss-Hill approximation for KMgH3 polycrystalline aggregate. The analysis of the site-projected l-decomposed density of states and charge density shows that the bonding is predominantly of ionic nature. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the temperature effect on the lattice constant, bulk modulus, heat capacity and Debye temperature is calculated. (C) 2010 Elsevier Masson SAS. All rights reserved.