TiO_2材料(100)典型晶面的形成与电子结构的研究

Study on Formation and Electronic Structure of (100) Characteristic Plane of TiO_2 Material

在超软赝势密度泛函理论基础上计算分析了TiO_2基(100)晶面低维材料的形成、电子结构和光学性质。结果表明,TiO_2基(100)晶面低维材料的形成焓大于TiO_2块体材料的形成焓,其稳定性比TiO_2块体材料低。TiO_2基(100)晶面低维材料带隙为2. 760 eV,高于其体材料,其带隙为间接型。其价带顶和导带底主要分别由O p电子和Ti d电子形成,并且Ti的d电子和O的p电子在-2. 5 eV处有局域作用。TiO_2基(100)晶面低维材料电子局域化程度增大,Ti和O之间的离子性结合程度增强。TiO_2基(100)晶面低维材料在140. 8 nm处有最强的反射峰,其反射系数达23. 9%,其在34. 5 nm处有强的选择性吸收,并且在33. 3 nm和138. 9 nm处有最强的能量损失。

The formation, electronic structure as well as optical properties of the (100) plane low dimensional TiO 2 based material was researched by ultra-soft pseudo-potential density functional theory method. The results show that the formation enthalpy of (100) plane low dimensional TiO 2 based material is larger than that of the bulk material, its stability is relatively lower. The band gap of (100) plane low dimensional TiO 2 based material is 2.760 eV, which is larger than that of the bulk material. The band gap is indirect. The top valance band and the bottom conduction band is composed by O p and Ti d electrons, the O p and Ti d electrons have strong localized interaction at -2.5 eV. The electron localization trend is strengthened for the (100) plane low dimensional TiO 2 based material, the ionic bonds between Ti and O are enhanced. There is strong reflectivity at 140.8 nm for the (100) plane low dimensional TiO 2 based material, the reflectivity is 23.9%. It has strong absorption at 34.5 nm and it has strong loss function both at 33.3 nm and 138.9 nm.