The primary goal of this study is to investigate the effect different exchange-correlation functionals on optoelectronic and elastic properties Ag2O chalcogenide compound. For electronic structures optical spectra, Tran-Blaha modified Becke-Johnson approach combined with GGA GGA+U (mBJ-GGA-PBEsol mBJ-GGA-PBEsol+U, respectively) was used. available theoretical experimental data for bandgap energ...

We have used density-functional theory generalized gradient approximation GGA to study lithium intercalation at low concentration into anatase TiO2. To describe the defect states produced by Li doping a Hubbard “+U” correction is applied to the Ti d states GGA+U . Uncorrected GGA calculations predict LixTiO2 to be metallic with the excess charge distributed over all Ti sites, whereas GGA+U pred...

The spinel cobalt oxide Co3O4 is a magnetic semiconductor containing cobalt ions in Co2+ and Co3+ oxidation states. We have studied the electronic, magnetic, and bonding properties of Co3O4 using density functional theory (DFT) at the Generalized Gradient Approximation (GGA), GGA+U, and PBE0 hybrid functional levels. The GGA correctly predicts Co3O4 to be a semiconductor but severely underestim...

The crystal structure, electronic and magnetic properties of LaMn(7)O(12) ((LaMn(3)(3+))(A)Mn(4)(3+)O(12)) are investigated by GGA (LSDA) and GGA + U (LSDA + U) (0.0 ≤ U ≤ 5.0 eV) methods. Based on two experimentally refined structures (distinguished by the distortion parameter Δ, namely S(I) (Δ = 8.5 × 10(-5)) and S(II) (Δ = 25.0 × 10(-4))), GGA and GGA + U with U < 3.0 eV calculations indicat...

Using first-principles density functional calculations, at both generalized gradient approximation GGA and GGA+U levels we have investigated the electronic structure and magnetic properties of Fe/Co codoped ZnO nanowire. Here we have addressed some of the key issues such as, the preferable sites that Fe/Co can occupy, the coupling mechanism, and role of defects in coupling. We found that the sp...

We examine the real space structure and the electronic structure (particularly Ce4f electron localization) of oxygen vacancies in CeO(2) (ceria) as a function of U in density functional theory studies with the rotationally invariant forms of the LDA+U and GGA+U functionals. The four nearest neighbor Ce ions always relax outwards, with those not carrying localized Ce4f charge moving furthest. Se...