FP-LAPW investigation of the structural, electronic and thermodynamic properties of Al3Ta compound

Abstract

The phase stability and electronic properties in Al 3 Ta compound are studied using the FP-LAPW method. In this approach, the generalized gradient approximation (GGA) is used for the exchange-correlation potential calculation. The total energy calculations show that the D 022 structure is more stable than that of D 023 and L1 2. The densities of states exhibit a pseudo gap near the Fermi level for all considered structures. By analyzing the electronic charge density we find a build-up of electrons in the interstitial region, and the bonds are directed from the Ta atoms to the Al atoms, which is the characteristic of covalent bonding. The temperature and pressure effects on the structural parameters, Debye temperature, Grüneisen parameter, heat capacities (Cv, Cp) and thermal expansion are predicted through the quasi-harmonic Debye model.