光学学报, 2011, 31 (6): 0616003, 网络出版: 2020-06-18
Co掺杂β-FeSi2电子结构及光学性质的第一性原理研究 下载: 561次
First Principles Study of Electronic Structure and Optical Properties for Co-doped β-FeSi2
材料 电子结构 光学性质 掺杂 第一性原理 materials β-FeSi β-FeSi2 electronic structure optical properties doping first principle
摘要
采用基于密度泛函理论的第一性原理赝势平面波方法,对不同Co含量的β-FeSi2的能带结构,态密度、分态密度和光学性质进行了计算和比较。几何结构和电子结构的计算结果表明,Co掺杂使得β-FeSi2的晶格常数a增大,b和c变化不大,晶格体积增大。Fe1-xCoxSi2的能带结构变为直接带隙,禁带宽度从0.74 eV减小到0.07 eV,Co的掺入削弱了Fe的3d态电子,但费米能级附近的电子态密度仍主要由Fe的3d态电子贡献。此外,Co掺杂导致β-FeSi2的晶格体积增大,这对掺杂后β-FeSi2的带隙变窄起到一定的调制作用。光学性质的计算表明,Co掺入后介电函数虚部ε2(ω)向低能方向偏移,且光学跃迁强度明显减弱,吸收边发生了红移,光学带隙随Co含量增加而减小。计算结果为β-FeSi2光电材料的设计和应用提供了理论依据。
Abstract
By using the first principle pseudo-potential plane-wave method based on the density function theory, geometrical structure, electronic structure and optical properties of Co-doped β-FeSi2 are calculated and analyzed. The calculated results of the geometrical structure and electronic structure show that the lattice constant a increases while b and c have little change, the volume of lattice expands, the band structure changes from indirect to direct and the band gap reduces from 0.74 eV to 0.07 eV with increasing of Co from 0 to 0.25. Moreover, it was found that Co-doping can increase the volume of β-FeSi2, which also reduces the band gap. Optical properties calculation indicates that after doping Co, the imaginary part of the dielectric function ε2(ω) moves to a lower energy, the intensity in optical transition decreases, the optical absorption edge generates a red shift, and the optical band gap decreases with increasing concentrations of Co. These results offer theoretical data for design and application of optoelectronic material of β-FeSi2.
闫万珺, 周士芸, 谢泉, 桂放, 张春红, 郭笑天. Co掺杂β-FeSi2电子结构及光学性质的第一性原理研究[J]. 光学学报, 2011, 31(6): 0616003. Yan Wanjun, Zhou Shiyun, Xie Quan, Gui Fang, Zhang Chunhong, Guo Xiaotian. First Principles Study of Electronic Structure and Optical Properties for Co-doped β-FeSi2[J]. Acta Optica Sinica, 2011, 31(6): 0616003.