Structural disordering studies in Cu6+δPS5I single crystals

Temperature studies (77–325 K) of the optical Urbach absorption edge and isoabsorption studies of Cu6PS5I single crystals, synthesized at various technological procedures, are reported. The differences in technological conditions are shown to result in the changes of the Urbach optical absorption edge parameters, exciton–phonon interaction parameters and the characteristic temperatures of superionic and ferroelastic phase transitions. The observed changes of the Urbach edge parameters are related to the effect of statical structural disordering due to the deviation of copper content from stoichiometry.