A combined molecular dynamics simulation, experimental and coupling modelstudy of the ion dynamics in glassy ionic conductors

Abstract

Dielectric relaxation measurements of the ion dynamics in glassy, molten andcrystalline ionic conductors show general properties independent of chemicalcomposition and structure. These include the appearance of a near-constant lossat high frequencies/low temperatures and the transition to a many-particleion-hopping regime at lower frequencies. We use a combination of moleculardynamics simulation, experimental data analysis and the coupling model tocharacterize the ion dynamics in the near-constant-loss regime, the transitionzone, and the many-particle ion-hopping regime. An improved understanding isgained of the origin of the near-constant loss and the evolution of the iondynamics, from short times when the ions are caged, to long times when they areno longer caged but participate in the many-particle dynamics, giving risefinally to dc conductivity. Reasons are given to refute criticism of use ofthe electric modulus to represent and interpret experimental data.