Asymmetric exclusion model for mixed ionic condustors

TL;DR

This paper introduces a one-dimensional asymmetric diffusion model for mixed ionic conductors, capturing the deep conductivity minimum observed in experiments through exact and numerical analysis of particle interactions.

Contribution

It presents a novel asymmetric diffusion model with repulsive particles to explain ionic conductivity behavior in mixed alkali glasses.

Findings

Exact solutions for stationary current with perfect repulsion.

Numerical results showing a conductivity minimum due to particle correlations.

Model captures key experimental features of mixed ionic conductors.

Abstract

The ionic conductivity of mixed alkali glasses exhibits a deep minimum as a function of the relative concentrations of the two alkali ions. To study this behaviour we consider a simple one-dimensional model for asymmetric diffusion of two kinds of particles. Different particles are assumed to repulse each other. We consider two versions of the model: with or without overtaking of particles. For the case of perfect repulsion we find exact expressions for the stationary current. The model with weaker repulsion is studied by means of numerical simulations. The stationary current as a function of the ratio of particle concentrations is found to exhibit a minimum, related to correlations existing in this system.