Inverse-perovskite oxides with , Ge, Sn, Pb: Structural, elastic and thermal properties

First-principles pseudo-potential plane-wave calculations have been performed for the first time in order to investigate the systematic trends for structural, elastic and thermal properties of the ideal cubic inverse-perovskite oxides Ca3EO depending on the type of E atoms ( E = Si , Ge, Sn, Pb). The computed equilibrium lattice constants are in excellent agreement with the experimental findings. Pressure dependence up to 40 GPa of the single-crystals and polycrystalline elastic parameters, namely, C 11 , C 12 , C 44 , bulk modulus B , shear modulus G , Young’s modulus E , Poisson’s ratio σ , and Lamé’s constants λ and μ , have been investigated in detail. The analysis of the B / G ratios shows that all studied compounds can be classified as brittle materials. We have estimated the sound velocities in the principal directions: [100], [110] and [111]. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the temperature and pressure effects on the lattice constant, bulk modulus, heat capacity and Debye temperature are performed.