Crystal nuclei and structural correlations in two-dimensional colloidal mixtures: experiment versus simulation

TL;DR

This study compares experimental and simulation data on two-dimensional binary colloidal mixtures, revealing detailed structural correlations, crystal nucleation, and the effects of varying interaction strength.

Contribution

It provides a comprehensive comparison between experiments and Monte Carlo simulations for 2D colloidal mixtures, highlighting structural details and nucleation processes.

Findings

Excellent agreement between experiment and simulation for pair distribution functions

Identification of local crystal nuclei using bond-orientational order parameters

Analysis of the influence of interaction strength and composition on structure

Abstract

We examine binary mixtures of superparamagnetic colloidal particles confined to a two-dimensional water-air interface both by real-space experiments and Monte-Carlo computer simulations at high coupling strength. In the simulations, the interaction is modelled as a pairwise dipole-dipole repulsion. While the ratio of magnetic dipole moments is fixed, the interaction strength governed by the external magnetic field and the relative composition is varied. Excellent agreement between simulation and experiment is found for the partial pair distribution functions including the fine structure of the neighbour shells at high coupling. Furthermore local crystal nuclei in the melt are identified by bond-orientational order parameters and their contribution to the pair structure is discussed.