Describing screening in dense ionic fluids with a charge-frustrated Ising model

TL;DR

This paper introduces a charge-frustrated Ising model that captures complex ionic correlations in dense ionic fluids, revealing non-monotonic screening length behavior and the influence of short-range interactions.

Contribution

It demonstrates that a Coulomb or charge-frustrated Ising model effectively describes ionic correlations and screening phenomena beyond classic theories.

Findings

Non-monotonic screening length dependence on temperature.

Short-range interactions significantly affect ionic correlations.

Model aligns with simulations and mean field predictions.

Abstract

Charge correlations in dense ionic fluids give rise to novel effects such as long-range screening and colloidal stabilization which are not predicted by the classic Debye-Huckel theory. We show that a Coulomb or charge-frustrated Ising model, which accounts for both long-range Coulomb and short-range molecular interactions, simply describes some of these ionic correlations. In particular, we obtain at mean field level and in simulations, a non-monotonic dependence of the screening length on the temperature. Using a combination of simulations and mean field theories, we study how the correlations in the various regimes are affected by the strength of the short ranged interactions.