Elastic and thermodynamic properties of AuAl2 under pressures

First-principles calculation results of the structural, elastic and thermodynamic properties of AuAl2 in the cubic fluorite structure at high pressures have been carried out using the pseudopotentials plane wave method within the local density approximation (LDA). The obtained lattice constant and bulk modulus at ambient conditions are in excellent agreement with the previous experimental and theoretical results. The calculated value of three independent elastic constants C11, C12, and C44 for the cubic fluorite structure AuAl2 at ambient pressure is 159.53 GPa, 98.53 GPa, and 55.53 GPa, respectively. The elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's ratio and the Debye temperature under pressures are also extensively obtained. Additionally, the characters of the bonding of this alloy at high pressure have been analyzed and we find that the stronger metallic character of the bonds with increasing pressures. The dependence of heat capacity, thermal expansion coefficient, and Grüneisen parameter on pressure is also obtained in details.

► Elastic constants of AuAl2 at ambient pressure are obtained successfully. ► The elastic moduli under pressure shows it is more difficult to compress with pressure. ► Stronger metallic character with pressure is obtained by Blackman's diagram. ► Thermodynamic properties are investigated in details.