Structural, electronic and thermo-elastic properties of Cu6Sn5 and Cu5Zn8 intermetallic compounds: First-principles investigation

The structural, elastic and thermodynamic properties of two important intermetallic compounds, Cu6Sn5 and Cu5Zn8, have been deeply investigated by performing the first-principles calculations based on density functional theory and using the quasi-harmonic approximation for the non-equilibrium Gibbs free energy. Key physical parameters, such as lattice constants, bulk modulus, heat capacity, Debye temperature and volume thermal expansion coefficients were calculated, and their dependences on temperature and pressure were also obtained. Our calculated results are in good agreement with the available experimental data. It is found that Cu6Sn5 is elastic anisotropy with relatively low bulk modulus, while Cu5Zn8 shows elastic isotropy with high bulk modulus. And the electronic origin of elastic properties was also analyzed in this paper.