Electron structure and density of states' calculations of Ag2S and Ag2Se crystals from first-principle

The results of calculations of the electron structure for Ag2S and Ag2Se crystals from first-principle in the framework of density functional theory (DFT) are presented in this work. The origin of the bands from s, p and d electron states of Ag, S and Se atoms are investigated. It was established that the orthorhombic Ag2Se crystal shows semiconductor properties in P222(1) and P2(1)2(1)2(1) space groups and semimetallic properties in Im-3m space groups with cubic crystal system. Monoclinic crystal type of Ag2S shows semiconductor properties in P2(1)/c space group. However, semimetallic properties manifested itself in monoclinic Ag2S in P2(1) and cubic Ag2S structure in Im-3m phases.