Pressure effect on the structural, phonon, elastic and thermodynamic properties of L12 phase RH3TA: First-principles calculations

The phonon, elastic and thermodynamic properties of L1(2) phase Rh3Ta have been investigated by the density functional theory (DFT) approach combined with the quasiharmonic approximation model. The results of the phonon band structure show that L1(2) phase Rh3Ta possesses dynamical stability in the pressure range from 0-80 GPa due to the absence of imaginary frequencies. The pressure dependences with the elastic constants C-ij, shear modulus G, bulk modulus B, Young's modulus Y, Poisson's ratio and BIG ratio have been analyzed. The results of the elastic properties studies show that L1(2 )phase Rh3Ta compound is mechanically stable and possesses a higher hardness, improved ductility and plasticity under higher pressures. The pressure and temperature relationship of the thermodynamic properties, such as the Debye temperature Theta D, heat capacity C-p, thermal expansion coefficient alpha and the Gruneisen parameter gamma are predicted by the quasi-harmonic Debye model in a wide pressure (0-80 GPa) and temperature (0-750 K) ranges.