Optical properties of ZnSe using linear response theory

The electronic structure and optical response of ZnSe are studied in this work. The studies are carried out using first-principles full-potential linearized augmented plane wave method. After settling the crystal structure, the electronic band structure of the ground state of ZnSe is calculated. Linear response theory is applied to study optical response considering bootstrap (BS) and the long range contribution (LRC) kernels for the first time. We also use the random phase and adiabatic local density approximations for comparison. A procedure based on empirical pseudopotential method is developed to find material dependent parameter alpha required in the LRC kernel. The results are assessed by calculating the real and imaginary parts of linear dielectric function, refractive index, reflectivity, and the absorption coefficient. Results are compared with other calculations and available experimental data. The results of LRC kernel finding alpha from the proposed scheme are encouraging and at par with the BS kernel.