Title: First-principles study of the structural, phonon, elastic, and thermodynamic properties of Al₃Ta compound under high pressure
Author(s):

	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 C_ij, 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 C_p, 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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