First - Principles studies of CaX (X = In, Tl) intermetalic compounds

Abstract

Ab initio calculations based on the density functional theory within generalized-gradient (GGA) apraximation have been performed to carry out the structural, electronic, elastic, and thermodynamic properties of CaX (X=In, Tl), For the totalenergy calculations, we have used the projected augmented plane-wave (PAW) implemented in the Vienna Ab initio Simulation Package (VASP). We have investigated two different structures CsCl (B2) and NaTl (B32), and the present structural results are in excellent agreement with the available experimental works. The quasi-harmonic Debye model have been performed to evaluate the thermodynamics properties for CaX (X=In, Tl) compounds. We have, also, predicted the temperature and pressure variation of the volume, bulk modulus, thermal expansion coefficient, heat capacity and Debye temperature in a wide pressure (0-13 GPa) for CaIn and (0-11 GPa) for CaTl and temperature ranges (0-1800 K).