Superionic Conductors: Theory of the Phase Transition to the Cation Disordered State

Abstract

We suggest that it is the interaction of interstitial cation defects with the strain field they induce which is primarily responsible for the phase transition to the cation disordered state of the superionic conductor. This idea is developed in terms of a simple model that yields an analytic solution for the phase transition and relates the necessary strength of the interaction to anomalously large free volumes of cation interstitial formation.