Ground state of dipolar hard spheres confined in channels

TL;DR

This study explores the ground state configurations of dipolar hard spheres confined in channels, revealing phase transitions and complex structures as density varies, with implications for experimental colloidal systems.

Contribution

It provides a detailed analysis of the ground states and phase transitions of confined dipolar spheres, including complex buckling structures and dense packings.

Findings

First-order transition from vacuum to linear chains with increasing density

Emergence of undulated and buckled chain structures at higher densities

Densest packings exhibit complex magnetization patterns

Abstract

We investigate the ground state of a classical two-dimensional system of hard-sphere dipoles confined between two hard walls. Using lattice sum minimization techniques we reveal that at fixed wall separations, a first-order transition from a vacuum to a straight one-dimensional chain of dipoles occurs upon increasing the density. Further increase in the density yields the stability of an undulated chain as well as nontrivial buckling structures. We explore the close-packed configurations of dipoles in detail, and we find that, in general, the densest packings of dipoles possess complex magnetizations along the principal axis of the slit. Our predictions serve as a guideline for experiments with granular dipolar and magnetic colloidal suspensions confined in slit-like channel geometry.