Interfaces in driven Ising models: shear enhances confinement

TL;DR

This study investigates how shear flow affects fluid interfaces in a driven two-dimensional Ising model, revealing that shear reduces interfacial width and alters correlation decay, with implications for understanding driven phase-separated systems.

Contribution

The paper demonstrates that shear flow stabilizes interfaces in a driven Ising model, reducing interfacial width and modifying correlation functions, a novel insight into driven interfacial phenomena.

Findings

Shear flow reduces interfacial width in the driven Ising model.

Correlation functions decay faster under shear, similar to colloidal dispersions.

Steady state profiles resemble equilibrium profiles with rescaled length.

Abstract

We use a phase-separated driven two-dimensional Ising lattice gas to study fluid interfaces exposed to shear flow parallel to the interface. The interface is stabilized by two parallel walls with opposing surface fields and a driving field parallel to the walls is applied which (i) either acts locally at the walls or (ii) varies linearly with distance across the strip. Using computer simulations with Kawasaki dynamics, we find that the system reaches a steady state in which the magnetisation profile is the same as that in equilibrium, but with a rescaled length implying a reduction of the interfacial width. An analogous effect was recently observed in sheared phase-separated colloidal dispersions. Pair correlation functions along the interface decay more rapidly with distance under drive than in equilibrium and for cases of weak drive can be rescaled to the equilibrium result.