Medium range order in oxide and chalcogenide superionic glasses: A comparative study by using the average electronegativity

The material trends in oxide and chalcogenide ion-conducting glasses have been studied by focusing on the relationship between the first sharp diffraction peak (FSDP) and the average electronegativity. The average electronegativity has been defined in terms of the chemical composition of the compound and the electronegativity of the constituent elements. It is shown that in Li ion-conducting oxide glasses and Ag or Cu ion-conducting chalcogenide glasses, the FSDP wave number decreases with the increase of average electronegativity, whereas in Ag ion-conducting oxide glasses the FSDP wave number increases with the increase of average electronegativity. The found relationship is interpreted in terms of the tendency of network formation and dissociation, which is quantified by the average electronegativity.