First principles calculations of structural, electronic and optical properties of AgAlTe2 compound

Abstract

We have conducted a first-principles study on the structural, electronic and optical properties of AgAlTe2 chalcopyrite compound using the full-potential linearized augmented plane wave (FP-LAPW) method based on the density functional theory. Generalized gradient approximation as proposed by  WuCohen (WC-GGA) was used for treatment of exchange-correlation effect in calculations. Additionally, the Tran-Blaha modified Becke–Johnson (mBJ) potential was also employed for electronic properties due to that it gives very accurate band gap of solids. The optimized equilibrium structural  parameters (a, c, and u) are in reasonable agreement with theoretical and experimental data. The calculated band structure reveals a direct band gap  (Γ-Γ) for the interested compound. Furthermore, optical properties such as complex dielectric function, refractive index and reflectivity spectra of the  titled compound were studied and analysed for incident electromagnetic waves in an energy range up to 15 eV. Several calculated results have been  compared with available experimental and other theoretical data.