First-principles energy band calculation for undoped and S-doped TiO2 with anatase structure
First-principles energy band calculation for undoped and S-doped TiO2 with anatase structure
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DOI：
10.1016/j.jpcs.2006.10.011
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发表时间：
2007-02-01
影响因子：
4
通讯作者：
Kobayashi, Kenkichiro
中科院分区：
文献类型：
--
作者：
Matsushima, Shigenori;Takehara, Kenji;Kobayashi, Kenkichiro
在密度泛函理论（DFT）的框架下，计算了硫掺杂的TiO 2的电子结构，并优化了掺杂结构.为了计算，我们建立了四种超晶胞; A型和B型超晶胞由12和48个原子组成，中心Ti原子被S原子取代，而C型和D型超晶胞由12和48个原子组成，中心0原子被S原子取代。采用超电池（B型和D型）将TiO 2中的S-浓度调节到几个%的实验值。A型和B型超晶胞的晶格参数变化不明显。在C型和D型超晶胞中发生了从四方相到正交相的相变。在小超原胞（A型）中，S相关态位于-1.6到0 eV的范围内，并且S态是带状的。相比之下，在大的超晶胞（B型）中，S相关态出现在价带顶以上约0.9 eV处，并且S态是原子状的。在B型超原胞中，S相关态的局域化是显著的。在D型超晶胞中，S相关态与价带顶部合并，结果带隙能量变窄了0.7 eV。尽管在D型超晶胞中S浓度很低（3%），但S相关态有点带状。(c)2006爱思唯尔有限公司版权所有。
The electronic structure of S-doped TiO2 with an optimized anatase structure was calculated within the framework of the density functional theory (DFT). For the calculation we built four kinds of supercells; type-A and B supercells consist of 12 and 48 atoms and a centered Ti atom is substituted for an S atom, while type-C and D supercells consist of 12 and 48 atoms and a centered 0 atom is substituted for an S atom. The supercells (type-B and D) were employed to adjust the S-concentration in TiO2 to an experimental value of a few %. The changes of the lattice parameters are not significant in the type-A and B supercells. The phase transition from the tetragonal to the orthorhombic occurs in the type-C and D supercells. In the small supercell (type-A), S-related states are located in the range of -1.6 to 0 eV, and the S-states are band-like. In contrast, in the large supercell (type-B), S-related states appeared at about 0.9 eV above the top of the valence band, and the S-states are atomic-like. The localization of the S-related states is remarkable in the type-B supercell. In the type-D supercell, the S-related states were merged with the top of the valence band, and as a result the band-gap energy is narrowed by 0.7 eV. Despite a low S-concentration (3%) in the type-D supercell, the S-related states are somewhat band-like. (c) 2006 Elsevier Ltd. All rights reserved.