First-principles density function calculations of physical properties of triclinic Cu7In3

First principles density functional theory calculations within the generalized gradient approximation are performed to comprehensively study the structural, elastic, electronic and thermodynamic properties of triclinic single and polycrystalline Cu₇In₃. The polycrystalline elastic properties are predicted using the Voigt-Reuss-Hill approximation and the thermodynamic properties are evaluated based on the quasi-harmonic Debye model. Their temperature, hydrostatic pressure or crystal orientation dependences are also addressed, and the predicted physical properties are compared with the literature experimental and theoretical data and also with those of three other Cu-In compounds, i.e., CuIn, Cu₂In and Cu₁₁In₉. The present calculations show that in addition to being a much better conductor compared to Cu₂In and Cu₁₁In₉, Cu₇In₃ crystal reveals weak elastic anisotropy, high ductility and low stiffness, and tends to become more elastically isotropic at very high hydrostatic pressure. Moreover, the Cu₇In₃ holds the largest high-temperature heat capacity among the four Cu-In compounds.