Crystallization Mechanism of Hard Sphere Glasses

TL;DR

This study uses computer simulations to reveal how hard-sphere glasses can crystallize through stochastic micro-nucleation events driven by dynamic heterogeneity, despite suppressed diffusion.

Contribution

It uncovers the microscopic mechanism of crystallization in hard-sphere glasses, highlighting the role of dynamic heterogeneity and stochastic nucleation without significant particle diffusion.

Findings

Crystalline patches form without large particle diffusion.

Dynamic heterogeneity enhances neighboring mobility during crystallization.

Crystallization proceeds via stochastic micro-nucleation events.

Abstract

In supercooled liquids, vitrification generally suppresses crystallization. Yet some glasses can still crystallize despite the arrest of diffusive motion. This ill-understood process may limit the stability of glasses, but its microscopic mechanism is not yet known. Here we present extensive computer simulations addressing the crystallization of monodisperse hard-sphere glasses at constant volume (as in a colloid experiment). Multiple crystalline patches appear without particles having to diffuse more than one diameter. As these patches grow, the mobility in neighbouring areas is enhanced, creating dynamic heterogeneity with positive feedback. The future crystallization pattern cannot be predicted from the coordinates alone: crystallization proceeds by a sequence of stochastic micro-nucleation events, correlated in space by emergent dynamic heterogeneity.