金属掺杂锐钛矿相TiO2的第一性原理计算

摘要

采用基于密度泛函理论的从头算平面波超软赝势方法,计算了纯锐钛矿相TiO2及5种不同金属掺杂TiO2的晶格常数、能带结构、态密度与光吸收系数.结果表明,掺杂后能级的变化主要是过渡金属Co3d、Fe3d、Zr4d、Zr4p、V3p、V3d、W5d及W5p轨道的贡献.随着Co、Fe、V掺杂浓度的增加,禁带宽度呈减小趋势；Zr掺杂对能带结构几乎不产生影响；W掺杂能级远离禁带,只对价带构成产生了影响.金属掺杂使禁带宽度变化或出现新杂质能级,导致了TiO2吸收边沿红移或在可见光区域出现新的吸收峰;其中Co、Fe掺杂的吸收边沿明显红移,而W掺杂时在可见光区域出现较强的吸收峰.%The lattice constant, band structure, density of states and optical properties of pure and Co,Fe,Zr, V,W doping TiO2 were calculated using the first-principle plane-wave ultrasoft pseudopotential methods based on the density functional theory. The results indicate that the formation of impurity level is mainly contributed by mixing with Co3d, Fe3d, Zr4p, Zr4d, V3p. V3d, W5p, W5d orbital of the transition metal. The band gap decreases with increasing Co, Fe, V concentration. There is no impurity level present in the band structure of Zr doping TiO2. Impurity level of W doping TiO2 leaves away from the band gap, only causes the constitution of valence band. The doping with metallic icons is responsible for the changes of band gap or new appearance of impurity level, which brings the red shift of TiQ2 absorption wavelength or the appearance of new absorption peak in the visible light region. The doping of Co, Fe brings the red shift of TiQ2 absorption wavelength obviously and W-doping causes a strong absorption peak in the visible light region.