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[en] Magnetic, electronic and structural properties of titanium dioxide material with different structural defects are studied using the first-principles ab-initio calculations and the Korringa–Kohn–Rostoker method (KKR) combined with the coherent potential approximation (CPA) method in connection with the local density approximation (LDA). We investigated all structural defects in rutile TiO_2 such as Titanium interstitial (Ti_i), Titanium anti-sites (Ti_o), Titanium vacancies (V_T_i), Oxygen interstitial (O_i), Oxygen anti-sites (O_T_i) and oxygen vacancies (V_o). Mechanisms of hybridization and interaction between magnetic atoms are investigated. The transition temperature is computed using the Mean Field Approximation (MFA).Magnetic stability energy of ferromagnetic and disordered local moment states is calculated to determine the most stable state. Titanium anti-sites have a half-metallic aspect. We also studied the change type caused by structural defects in this material. - Highlights: • Green function technique is used to study disordered systems. • We used DFT to study electronic structure of TiO_2 perturbed by defects. • TiO_2 with titanium antisite defect posesses a magnetic behavior. • The transition temperature is computed using the Mean Field Approximation.
[en] First-principles density functional theory calculations were carried out to study the structural, electronic, optical and electrical properties of fluorine-doped zinc oxide in detail. Fluorine substitutions of the oxygen sites create shallow donors derived mainly from the orbital 2p of fluorine. Additionally, the calculated optical properties reveal that the energy band gap gradually expands when increasing the fluorine doping level, which leads to a blue-shift in the optical transparency. More interestingly, the electrical conductivity is significantly enhanced after fluorine doping. (paper)
[en] We discuss the fundamental transparent conducting properties of halogens doped SnO2 rutile systems include the structural, electronic structure, optical and electrical properties. Within this study, we employ the first-principles calculation of the full potential linearized augmented plane wave (FP-LAPW) method based on the density function theory and semiclassical Boltzmann equations. It is found that the halogens substitutional doping cause an expansion of SnO2 lattice constants and low thermodynamic perturbation. The dopants act as shallow donors by creating impurity states at the bottom of the conduction band that lead to blue-shift in the optical transparency. Moreover, the electrical conductivity of SnO2 Rutile is significantly improving by halogens doping. In fact, these results could stimulate the future experimental works for elaborating new generations of the transparent conducting oxides in an optimal way.