Barrier to recombination of oppositely charged large polarons

TL;DR

This paper investigates how interference effects between oppositely charged large polarons in ionic materials can create a potential barrier, preventing their recombination despite Coulomb attraction, which impacts charge transport.

Contribution

It introduces the concept of a barrier caused by interference effects that can hinder polaron recombination in ionic materials.

Findings

Interference between ionic displacements can produce a repulsive interaction.

A potential barrier can form, impeding polaron recombination.

Repulsion can dominate over Coulomb attraction under certain conditions.

Abstract

Electronic charge carriers in ionic materials can self-trap to form large polarons. Interference between the ionic displacements associated with oppositely charged large polarons increases as they approach one another. Initially this interference produces an attractive potential that fosters their merger. However, for small enough separations this interference generates a repulsive interaction between oppositely charged large polarons. In suitable circumstances this repulsion can overwhelm their direct Coulomb attraction. Then the resulting net repulsion between oppositely charged large polarons constitutes a potential barrier which impedes their recombination.