Ab Initio Calculation of Structure and Thermodynamic Properties of Zintl Aluminide SrAl₂

Abstract

The structural and thermodynamic properties of the orthorhombic and cubic structure SrAl2 at pressure and temperature are investigated by using the ab initio plane-wave pseudopotential density functional theory methodwithin the generalised gradient approximation (GGA). The calculated lattice parameters are in agreement with the available experimental data and other theoretical results. The phase transition predicted takes place at 0.5 GPa from the orthorhombic to the cubic structure at zero temperature. The thermodynamic properties of the zinc-blende structure SrAl2 are calculated by the quasi-harmonic Debye model. The pressure–volume relationship and the variations inthe thermal expansion α are obtained systematically in the pressure and temperature ranges of 0–5 GPa and 0–500 K, respectively.