Theoretical simulations of the structural stabilities, elastic, thermodynamic and electronic properties of Pt3Sc and Pt3Y compounds

Ab-initio calculations based on density functional theory have been performed to study the structural, electronic, thermodynamic and mechanical properties of intermetallic compounds Pt3Sc and Pt3Y using the full-potential linearized augmented plane wave(FP-LAPW) method. The total energy calculations performed for L1(2), D0(22) and D0(24) structures confirm the experimental phase stability. Using the generalized gradient approximation (GGA), the values of enthalpies formation are -1.23 eV/atom and -1.18 eV/atom for Pt3Sc and Pt3Y, respectively. The densities of states (DOS) spectra show the existence of a pseudo-gap at the Fermi level for both compounds which indicate the strong spd hybridization and directing covalent bonding. Furthermore, the density of states at the Fermi level N(E-F), the electronic specific heat coefficient (gamma(ele)) and the number of bonding electrons per atom are predicted in addition to the elastic constants (C-11, C-12 and C-44). The shear modulus (G(H)), Young's modulus (E), Poisson's ratio (upsilon), anisotropy factor (A), ratio of B/G(H) and Cauchy pressure (C-12-C-44) are also estimated. These parameters show that the Pt3Sc and Pt3Y are ductile compounds. The thermodynamic properties were calculated using the quasi-harmonic Debye model to account for their lattice vibrations. In addition, the influence of the temperature and pressure was analyzed on the heat capacities (C-p and C-v), thermal expansion coefficient (alpha), Debye temperature (theta(eta)) and Gruneisen parameter (gamma).