Colloidal crystal growth at externally imposed nucleation clusters

TL;DR

This study investigates how externally imposed clusters of colloidal particles can trigger crystal nucleation in a metastable colloidal fluid, using dynamical density functional theory and Brownian dynamics simulations in a 2D dipolar system.

Contribution

It introduces a detailed analysis of nucleation triggered by fixed colloidal clusters, combining theoretical and simulation approaches to understand the process.

Findings

Nucleation occurs after cluster relaxation to a stable crystal configuration.

Different cluster geometries influence nucleation pathways.

Theoretical predictions align with simulation results.

Abstract

We study the conditions under which and how an imposed cluster of fixed colloidal particles at prescribed positions triggers crystal nucleation from a metastable colloidal fluid. Dynamical density functional theory of freezing and Brownian dynamics simulations are applied to a two-dimensional colloidal system with dipolar interactions. The externally imposed nucleation clusters involve colloidal particles either on a rhombic lattice or along two linear arrays separated by a gap. Crystal growth occurs after the peaks of the nucleation cluster have first relaxed to a cutout of the stable bulk crystal.