The first principle study of electronic and optical properties in rhombohedral BiAlO3

We studied the crystal structure of perovskite BiAlO3 using ab initio density functional theory (DFT) calculations. Using the atomic positions given by the previous literature, we were able to create a lattice structure using visualization software Material Studio. Such sophisticated structure is found in rhombohedral perovskite system with space group with R3c (#161) and lattice parameter of [Formula: see text], bond angle of [Formula: see text], while treating the exchange–correlation potential with the local density approximations (LDA) method. The calculations were performed to investigate the electronic, optical, elastic and phonon properties.

Elastic properties and electronic structure of the Ni3Sb (cF16) intermetallic

ABSTRACTThe possibilities of Ni as contact material in electronic applications has motivated the interest on the intermetallic phases of the Ni-Sb system, in relation to their use in lead free micro-soldering processes. In this work, a detailed theoretical study of the cohesive and thermodynamic properties of the compound Ni3Sb in the (cF16) Fm-3m structure is reported. To this aim, the Full Potential Linearized Augmented Plane Waves method, within the framework of the Density Functional Theory and both Generalized Gradient and Local Density approximations, has been applied. The structural parameters, cohesive and elastic properties of this compound and its constituent elements have been determined. In particular, the equilibrium structural properties are determined through the minimization of the energy, including the full relaxation of the internal degrees of freedom of the cell. It is shown that the calculated properties agree well with the available experimental data. Moreover, various contributions to the electronic density of sates are studied. On this basis, a discussion is presented of the bonding characteristics of this compound, in the framework of the current ideas about cohesion in p-d bonded intermetallics.

Local Density Approximations for the Energy of a Periodic Coulomb Model

We deal with local density approximations for the kinetic and exchange energy term, ℰ kin (ρ) and ℰ ex (ρ), of a periodic Coulomb model. We study asymptotic approximations of the energy when the number of particles goes to infinity and for densities close to the constant averaged density. For the kinetic energy, we recover the usual combination of the von-Weizsäcker term and the Thomas–Fermi term. Furthermore, we justify the inclusion of the Dirac term for the exchange energy and the Slater term for the local exchange potential.