DFT+ U Calculations of Electronic Structure and Optical Properties of Ag7GeS5I Compound

Abstract

This work investigates band structure, total and partial densities of states, and full complex of optical functions of Ag7GeS5I crystal belongs to the family of compounds with an argyrodite structure using the density functional theory (DFT) improved by an on-site Coulomb self-interaction potential $(\mathbf{DFT}+\boldsymbol{U})$. The lowest energy electronic transition occurs at the center of the Brillouin zone. The band gap energy is estimated in the DFT-LDA+U approximation, which is $E_{\mathbf{gd}}=1.68\mathbf{eV}$ ·