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Abstract: We have performed accurate ab initio total energy calculations using the full-potential linear augmented plane wave plus local orbitals method with the local density approximation for the exchange–correlation potential to investigate the systematic trends for structural and elastic properties of the cubic LaFe4A12 skutterudites’ family depending on the type of A pnicogen atom (A stands for P, As and Sb). The calculated equilibrium lattice constants and internal free parameters are in good agreement with the experimental results. For the first time, the numerical estimates of the independent elastic constants and their pressure dependence are performed using the total energy variation as function of strain technique. Isotropic elastic parameters and related properties, namely bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, Lamé’s coefficients, average sound velocity and Debye temperature, are estimated in the framework of the Voigt–Reuss–Hill approximation for ideal polycrystalline LaFe4A12 aggregates. [Copyright &y& Elsevier]

Abstract: We have performed first principles full-potential augmented plane wave plus local orbitals (FP-APW+lo) calculations within the local density approximation (LDA) and the generalized gradient approximation (GGA), with the aim to determine and predict the elastic constants and their pressure dependence for the alkali-metal sulfides Li2S, Na2S, K2S and Rb2S. The ground state properties are found to agree with the experimental and other theoretical results. The calculated elastic constants at zero pressure for Li2S and Na2S are compared with the available experimental data and other theoretical results. With regard to K2S and Rb2S, we are not aware of any experimental or theoretical data for the elastic constants and their pressure dependence, so that the data here represent the first determination of these quantities. The shear modulus, Young’s modulus and the Poisson’s ratio for these compounds are derived. The Debye temperature is also estimated from the average sound velocity. [Copyright &y& Elsevier]

Abstract: Using first-principles calculations, the structural and elastic properties of Sc2AC, with A=Al, Ga, In and Tl, were studied by means of the pseudo-potential plane-waves method. Calculations were performed within the local density approximation to the exchange-correlation approximation energy. The effect of high pressures, up to 20 GPa, on the lattice constants and the internal parameters is calculated. The elastic constants are calculated using the static finite strain technique. We derived the bulk and shear moduli, Young’s moduli and Poisson’s ratio for ideal polycrystalline Sc2AC aggregates. We estimated the Debye temperature of Sc2AC from the average sound velocity. This is the first quantitative theoretical prediction of the elastic properties of Sc2AlC, Sc2GaC, Sc2InC and Sc2TlC compounds, and it still awaits the experimental confirmation. [Copyright &y& Elsevier]

Abstract: A theoretical study of structural, electronic and optical properties of cubic BaTiO3 and BaZrO3 perovskites is presented, using the full-potential linear augmented plane wave (FP-LAPW) method as implemented in the WIEN2K code. In this approach the local density approximation (LDA) is used for the exchange–correlation (XC) potential. Results are given for lattice constant, bulk modulus, its pressure derivative, band structure, density of states, pressure coefficients of energy gaps and refractive indices. The results are compared with previous calculations and experimental data. [Copyright &y& Elsevier]