Partial clustering prevents global crystallization in a binary 2D colloidal glass former

TL;DR

This study demonstrates that partial clustering in a binary 2D colloidal system inhibits global crystallization, with clustering behavior influenced by particle concentration but not interaction strength, providing insights into glass transition mechanisms.

Contribution

It introduces a model system showing how partial clustering prevents crystallization in 2D colloids, using Minkowski functionals and structure factors for quantification.

Findings

Partial clustering depends on particle concentration.

Clustering is independent of interaction strength.

Partial clustering inhibits global crystallization.

Abstract

A mixture of two types of super-paramagnetic colloidal particles with long range dipolar interaction is confined by gravity to a flat interface of a hanging water droplet. The particles are observed by video microscopy and the dipolar interaction strength is controlled via an external magnetic field. The system is a model system to study the glass transition in 2D, and it exhibits partial clustering of the small particles. This clustering is strongly dependent on the relative concentration $\xi$ of big and small particles. However, changing the interaction strength $\Gamma$ reveals that the clustering does not depend on the interaction strength. The partial clustering scenario is quantified using Minkowski functionals and partial structure factors. Evidence that partial clustering prevents global crystallization is discussed.