摘要:
本文主要根据第一性原理的方法并应用Material Studio中的CASTEP模块分别对SrTiO3以及Nb掺杂SrTiO3两种材料的能带结构和态密度进行了仿真计算，然后对其进行相应的分析最后得出其光学特性。分析结果表明，未掺杂时SrTiO3的价带顶主要是由O原子的2p态组成，它的导带底则主要由Ti 3d态贡献；SrTiO3是间接跃迁能带结构，带隙宽度约为1.8 eV。掺杂后系统的带宽为2.02 eV，为直接跃迁能带结构，且与掺杂前相比系统的折射率与静介电常数都有不同程度的增大。
Abstract:
In this paper, based on first-principles method and application of the Material Studio CASTEP module, energy band structure and density of SrTiO3 and Nb-doped SrTiO3 materials were simulated, and we analyzed their energy bands structure and density of states and got the conclusion of optical properties. The analysis results show that the undoped SrTiO3 valence-band maximum is mainly composed by the 2p state of atom O, while the conduction band is mainly contributed by Ti 3d state; SrTiO3 is an indirect transition band structure, and the band width is about 1.8 eV. After doping, the SrTiO3 becomes a direct transition band structure with the band width of 2.02 eV, and the refractive index and static dielectric constant increase in different extent compared with before.