Condensed Matter Physics, 2018, vol. 21, No. 1, 13601
DOI:10.5488/CMP.21.13601           arXiv:1803.11412

Title: First-principles study of the structural, phonon, elastic, and thermodynamic properties of Al3Ta compound under high pressure
  W. Leini (Anhui Sanlian University, Hefei 230601, P. R. China) ,
  T. Zhang (Chinese Academy of Sciences, Hefei 230031, P. R. China) ,
  Z. Wu (Anhui University, Hefei 230601, P. R. China) ,
  N. Wei (Anhui University, Hefei 230601, P. R. China)

We have investigated the phonon, elastic and thermodynamic properties of L12 phase Al3Ta by density functional theory approach combining with quasi-harmonic approximation model. The results of phonon band structure shows that L12 phase Al3Ta possesses dynamical stability in the pressure range from 0 to 80 GPa due to the absence of imaginary frequencies. The pressure dependences of the elastic constants Cij, bulk modulus B, shear modulus G, Young's modulus Y, B/G and Poisson's ratio ν have been analysed. The elastic constants are satisfied with mechanical stability criteria up to the external pressure of 80 GPa. The results of the elastic properties studies show that Al3Ta compound possesses a higher hardness, improved ductility and plasticity under higher pressures. Further, we systematically investigate the thermodynamic properties, such as the Debye temperature Θ, heat capacity Cp, and thermal expansion coefficient α, and provide the relationships between thermal parameters and pressure.

Key words: first-principles, phonon, elastic properties, thermodynamic properties
PACS: 61.82.Bg, 62.20.dc, 71.20.Be, 71.15.Mb

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