p-d Hybridization and Superionicity in Silver Ternary Compounds

Abstract

The tight-binding electronic band calculations of β-Ag₃SX (X=I, Br) are carried out in order to clarify the high ionic conductivity of silver ions. The d bands of Ag ions are much more weakly coupled with the p bands of halogen ions, than with the p bands of S ions. The strength of p-d hybridization is discussed to connect with the activation energy for the ionic conduction. It is shown that the high ionic conductivity of β-Ag₃SX (X=I, Br) primarily stems from the weakness of the p-d hybridization.