Structural and dynamical features of multiple metastable glassy states in a colloidal system with competing interactions

TL;DR

This study explores how competing short-range attractions and long-range repulsions in colloidal systems lead to various metastable glassy states with distinct structural and dynamical properties, including gels and cluster glasses.

Contribution

It reveals the existence of multiple metastable glassy states in colloids with competing interactions and characterizes their transitions and underlying arrest mechanisms.

Findings

Identified gel, cluster glass, and Wigner glassy states with slow dynamics.

Discovered a continuous crossover between Wigner and cluster glasses.

Found a sharp transition between Wigner glass and gel driven by different arrest mechanisms.

Abstract

Systems in which a short-ranged attraction and long-ranged repulsion compete are intrinsically frustrated, leading their structure and dynamics to be dominated either by mesoscopic order or by metastable disorder. Here we report the latter case in a colloidal system with long-ranged electrostatic repulsions and short-ranged depletion attractions. We find a variety of states exhibiting slow non-diffusive dynamics: a gel, a glassy state of clusters, and a state reminiscent of a Wigner glass. Varying the interactions, we find a continuous crossover between the Wigner and cluster glassy states, and a sharp discontinuous transition between the Wigner glassy state and gel. This difference reflects the fact that dynamic arrest is driven by repulsion for the two glassy states and attraction in the case of the gel.