Defect-Induced Surface Sublattice Melting of Ionic Conductor Thin Film –Parallel Ionic Conductivity–

Theoretical study on the ion-hopping conduction of an ionic conductor thin film sandwiched with insulators is carried out in terms of the interacting lattice gas model. The defect-induced phase transition is promoted due to plenty of defects existing in the interface region, giving rise to the maximum ionic conductivity near there, where it is the front of the order-disorder phase transition. This phase transition suggests that a sandwiched superionic conductor thin film can be realized at temperature far below the bulk superionic transition temperature.