Overscreening and Underscreening in Solid-Electrolyte Grain Boundary Space-Charge Layers

Autor: Dean, Jacob M., Coles, Samuel W., Saunders, William R., McCluskey, Andrew R., Wolf, Matthew J., Walker, Alison B., Morgan, Benjamin J.
Rok vydání: 2021
Předmět:
Zdroj: Phys. Rev. Lett. 127, 135502 (2021)
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevLett.127.135502
Popis: Polycrystalline solids can exhibit material properties that differ significantly from those of equivalent single-crystal samples, in part, because of a spontaneous redistribution of mobile point defects into so-called space-charge regions adjacent to grain boundaries. The general analytical form of these space-charge regions is known only in the dilute limit, where defect-defect correlations can be neglected. Using kinetic Monte Carlo simulations of a three-dimensional Coulomb lattice gas, we show that grain-boundary space-charge regions in non-dilute solid electrolytes exhibit overscreening -- damped oscillatory space-charge profiles -- and underscreening -- decay lengths that are longer than the corresponding Debye length and that increase with increasing defect-defect interaction strength. Overscreening and underscreening are known phenomena in concentrated liquid electrolytes, and the observation of functionally analogous behaviour in solid electrolyte space-charge regions suggests that the same underlying physics drives behaviour in both classes of systems. We therefore expect theoretical approaches developed to study non-dilute liquid electrolytes to be equally applicable to future studies of solid electrolytes.
Databáze: arXiv