Phonon-Assisted Ion Hopping in Superionic Conductors Based on the Lattice Gas Model

Abstract

The jump diffusion of interacting mobile ions in superionic conductors (SIC) is studied by the phonon-assisted hopping theory. The interacting mobile ions are described by the lattice gas model. In order to study the correlated hopping of mobile ions, we calculate the average jump rate taking account of the average distribution of mobile ions at the nearest neighboring sites around the hopping ion after and before the hopping. We find that the average jump rate is thermally activated and that its activation energy is low at high concentration of mobile ions. This suggests that a low activation energy of SIC is due to the mutual interaction of mobile ions.