Simple Lattice-Models of Ion Conduction: Counter Ion Model vs. Random Energy Model

TL;DR

This study uses Monte Carlo simulations of two lattice models to investigate how Coulomb interactions influence ion conduction, revealing that static disorder type critically affects whether these interactions hinder or promote ion mobility.

Contribution

It compares two simple lattice models to clarify the impact of Coulomb interactions on ion dynamics, highlighting the role of static disorder.

Findings

Coulomb interactions impede dynamics in the Random Energy Model.

Coulomb interactions enhance dynamics in the Counter Ion Model.

Static disorder type determines the effect of Coulomb interactions.

Abstract

The role of Coulomb interaction between the mobile particles in ionic conductors is still under debate. To clarify this aspect we perform Monte Carlo simulations on two simple lattice models (Counter Ion Model and Random Energy Model) which contain Coulomb interaction between the positively charged mobile particles, moving on a static disordered energy landscape. We find that the nature of static disorder plays an important role if one wishes to explore the impact of Coulomb interaction on the microscopic dynamics. This Coulomb type interaction impedes the dynamics in the Random Energy Model, but enhances dynamics in the Counter Ion Model in the relevant parameter range.