应力下OsSi_2电子结构和光学特性研究

The study on the electronic structure and optical properties of stressed OsSi_2

采用基于第一性原理的密度泛函理论(Density Functional Theory)赝势法,对各向同性形变下OsSi2的电子结构、态密度和光学性质进行了理论计算.计算结果表明,当晶格常数从96%,100%,104%依次进行各向同性形变时,OsSi2的带隙逐渐减小.当晶格参数被压缩到原来的96%时,OsSi2的间接带隙值Eg=0.928eV,当晶格参数被拉伸到原来的104%时,OsSi2的间接带隙值Eg=0.068eV.其光学特性曲线向低能方向漂移,晶格拉伸使得OsSi2的静态介电函数增大而压缩使其减小;晶格压缩可以使其吸收响应增强,进而提高光电转换效率.

A detailed theoretical study of electronic structure, density of states and optical properties of OsSi2 under isotropic lattice deformation was performed by means of first-principles pseudopotential method. It was found that the isotropic lattice deformation results in the decrease in the energy gap from 96% lattice to 104% lattice. When the crystal lattice is 96% compressed, the indirect band gap is 0.928 eV; 104% stretched, the indirect band gap is 0.068 eV. Furthermore, the curve of optical properties tend to low-energy direction, When the crystal lattice is stretched, the static dielectric function increases; when compressed, the absorption enhances, and then improves the photoelectric conversion efficiency.