(α,β,γ)-Nb_5Si_3电子结构和光学性质研究

Electronic structure and optical properties of(α,β,γ)-Nb_5Si_3

基于第一性原理的密度泛函理论赝势平面波方法,采用局域密度近似,计算了不同结构的α-Nb_5Si_3,β-Nb_5Si_3和γ-Nb_5Si_3的电子结构、态密度以及光学性质.计算结果表明,Nb_5Si_3费米能级附近价带主要是由Nb的4d轨道及Si的3s和3p轨道贡献,导带主要由Nb的4d轨道贡献;Nb_5Si_3的光学性质具有各向异性的特征,其零频介电常数ε_1(0)=207,折射率n_0=13;在15 eV以上的高能区表现为无色透明.

Based on the first-principles density functional theory, the electronic structures, densities of states and optical properties of the structures α-Nb5Si3, β-Nb5Si33 and γ-Nb5Si are calculated by using the local density approximation and plane wave pseudopotential method. The calculation results show that the valence band of Nb5Si3 near the Fermi energy is composed of Nb 4d, Si 3s, 3p orbits and the conduction band is comprised mainly of Nb 4d orbit; the optical properties of Nb5Si3 possess anisotropic characteristics, the static dielectric function ε1（0） of Nb5Si3 is about 207, and the refractive index n0 is 13. Their absorptions in a range above 15 eV approach to zero, showing the optical transparent behaviors.