Nb掺杂SrTiO₃的光学特性研究

The Study of Optical Properties of SrTiO₃ Doped Nb

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.