Elastic and thermodynamic properties of the SiB2O4 (B=Mg, Zn and Cd) cubic spinels: An ab initio FP-LAPW study

The structural, elastic and thermodynamic properties of the SiB2O4 (B=Mg, Zn and Cd) cubic spinels have been investigated through ab initio full-potential linearized augmented plane wave calculations. The calculated structural parameters are in good agreement with the available experimental and theoretical data. The single crystal elastic constants are numerically estimated using total energy-strain approach with two different sets of distortions. The polycrystalline aggregate elastic parameters are calculated from the single crystal elastic constants via the Voigt–Reuss–Hill approximations. Mechanical stability, sound velocities, ductility/brittleness, elastic anisotropy, Debye temperature and pressure dependence of the elastic constants of the title compounds are also assessed. The temperature dependence of the lattice parameter, bulk modulus, volume thermal expansion coefficient, isochoric and isobaric heat capacity and Debye temperature in a wide temperature interval at some different fixed pressures is predicted through the quasi-harmonic Debye model.