First-principles investigation on vibrational, anisotropic elastic and thermodynamic properties for L1₂ structure of Al₃Er and Al₃Yb under high pressure

Abstract

To better clarify the physical properties for Al₃RE precipitates, first-principles calculations are performed to investigate the vibrational, anisotropic elastic and thermodynamic properties of Al₃Er and Al₃Yb. The calculated results agree well with available experimental and theoretical ones. The vibrational properties indicate that Al₃Er and Al₃Yb will keep their dynamical stabilities with L1₂ structure up to 100 GPa. The elastic constants are satisfied with mechanical stability criteria up to the external pressure of 100 GPa. The mechanical anisotropy is predicted by anisotropic constants A ^G , A ^U , A ^Z and 3D curved surface of Young’s modulus. The calculated results show that both Al₃Er and Al₃Yb are isotropic at zero pressure and obviously anisotropic under high pressure. Further, we systematically investigate the thermodynamic properties and provide the relationships between thermal parameters and pressure. Finally, the pressure-dependent behaviours of density of states, Mulliken charge and bond length are discussed.

Keywords:

• First-principles calculation
• Al₃Er and Al₃Yb
• vibrational properties
• elastic properties
• thermodynamic properties

Additional information

Funding

This project was supported by the Program for Scientific Technology Plan of the Educational Department of Liaoning Province of China [grant number L2014051]; the Program for Liaoning Innovative Research Team in University [grant number LT2014004]; the Program for the Young Teacher Cultivation Fund of Shenyang University of Technology [grant number 005612].