中文摘要：

采用基于第一性原理的赝势平面波方法系统地计算了β-FeSi2基态的几何结构、能带结构和光学性质.能带结构计算表明β-FeSi2属于一种准直接带隙半导体,禁带宽度为0.74eV;其能态密度主要由Fe的3d层电子和Si的3p层电子的能态密度决定;利用计算的能带结构和态密度分析了带间跃迁占主导地位的β-FeSi2材料的介电函数、反射谱、折射率以及消光系数等光学性质计算结果,复介电函数的计算结果表明β-FeSi2具有各向异性的性质;吸收系数最大峰值为2.67×10^5cm^-1.

英文摘要：

The geometric parameters and the electric and optical properties of β-FeSi2 are calculated using first principle methods based on plane-wave pseudo-potential theory in detail. The results indicate that： （1） β-FeSi2 is a quasi-direct semiconductor and the band gap is 0.74eV. The density of states is mainly composed of Fe 3d and Si 3p. （2） The valences electronic state of β-FeSi2 is asymmetric and has a strong local area characteristic. These have an important influence on the electronic structure and the bonding characteristics of β-FeSi2. （3） The calculation of the dielectric function reveals that β-FeSi2 is anisotropic,the biggest peak of absorption is 2.67 × 10^5 cm^-1, the extinction coefficient shows strong absorption characteristic near the band edge,and the mechanism of the electric and optical properties of β-FeSi2 dominated by electron inter-band transitions are analyzed in terms of calculated band structure and density of states.