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Abstract: The all electrons full potential linearized augmented plane waves (FP-LAPW) method with GGA+U is used to study SrTbO3 perovskite in cubic and orthorhombic phases. The structural parameters and ground state magnetic properties are found consistent with the experimental results. The electronic band structures and density of states demonstrate that SrTbO3 is a wide band gap semiconductor in both phases. The magnetic studies of the material show that the nature of the compound is G-type anti-ferromagnetic. The calculated magnetic moment of Tb+4 is found consistent with the experiments. Furthermore, the optical properties demonstrate that the optical gap of the material is 1.8eV, which lies in the visible region of the electromagnetic spectrum and hence the compound can be used in optoelectronic devices. [Copyright &y& Elsevier]

Abstract: Structural and electronic properties of the cubic perovskite ZnTiO3 and spinel Zn2TiO4 are theoretically studied by the modified Becke–Johnson (mBJ) potential within the framework of density functional theory (DFT). The calculated lattice constants are found to be consistent with the experimental results. The electronic band structures of both the materials reveal that ZnTiO3 is an indirect band gap while Zn2TiO4 is a direct band gap semiconductor. The calculated fundamental band gaps of these compounds are 2.7eV and 3.18eV, which are consistent with the experimental band gaps of 2.9eV and 3.1eV, respectively. Zn2TiO4 is a wide and direct band gap compound and hence is an attractive material for optoelectronic applications, especially in near ultraviolet (UV) optoelectronics. Keeping in view the importance of Zn2TiO4 in low frequency UV devices its optical properties like dielectric functions, refractive index, reflectivity and energy loss function are also evaluated and discussed in detail. [Copyright &y& Elsevier]

Abstract: Spin polarization effects on electronic properties of pure LaCoO3 and doped compounds (La0.5Y0.5CoO3, LaCo0.5Mn0.5O3) in the rhombohedral phase have been studied. We have employed the full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA+U) under density functional theory (DFT). The calculated band structures along with total as well as partial densities of states reveal that Y and Mn impurities have a significant effect on the structural and electronic properties of LaCoO3. It is found that Mn alters insulating behavior of this compound to the half metallic for spin up state. Obtained results show that the magnetic moment for the Co-3d state is near 3.12μ B in LaCoO3 compound which increases and decreases with addition of Y and Mn dopants respectively. [Copyright &y& Elsevier]