Structural, electronic and optical properties of copper, silver and gold sulfide: a DFT study

Structural, electronic and optical properties of copper, silver and gold sulfides have been analyzed using density functional theory (DFT). A systematic study of all these properties using different functionals has been carried out and compared to the performance of more expensive hybrids functionals (HSE06). On-site Coulomb repulsion terms (DFT + U) and the inclusion of London dispersion forces (B86b-vdW) seem to be crucial for the good description of these solids, even improving the predictions of hybrids functionals in some cases. This article describes how the inclusion of some corrections in GGA functional makes possible a balanced description of the properties of this group of complex materials and makes affordable the future investigation of more complex systems that contain these solids within a reasonable computational cost.