BAND STRUCTURE AND BINDING ENERGY IN Cu2X AND AgCuX (X = S, Se, Te) COMPOUNDS

10.25712/ASTU.1811-1416.2026.01.004

Abstract

This paper presents the results of calculating the band structure, density of states, and energy of binary chalcogenides Cu₂X and ternary copper and silver chalcogenides AgCuX (X = S, Se, Te) in the high-temperature cubic phase using BIOVIA Materials Studio DMol³. The electron density distribution was calculated using the Quantum Espresso software, which are based on the theory of electronic density functional. It is established that the band structure is characterized by p-d and s-p hybridization of the energy levels of the metals and chalcogen. Binary copper chalcogenides Cu₂X and ternary copper and silver chalcogenides AgCuX (X = S, Se, Te) in the high-temperature cubic phase are narrow-bandgap semiconductors. Ternary compounds have a larger band gap than binary compounds.  

It is known that one of the factors influencing the value of ionic conductivity is the binding energy. It has been shown that the anionic substitution of Te-Se-S in Cu₂X and AgCuX compounds results in a decrease in the binding energy per pair of ions, which promotes the transition of cations to a mobile state and, accordingly, leads to an increase in ionic conductivity.