Structural origin of dynamic heterogeneity in three-dimensional colloidal glass formers andits link to crystal nucleation

Abstract

The physical understanding of glass transition remains a major challenge of physics andmaterials science. Among various glass-forming liquids, a colloidal liquid interacting withhard-core repulsion is now regarded as one of the most ideal model systems. Here we studythe structure and dynamics of three-dimensional polydisperse colloidal liquids byBrownian dynamics simulations. We reveal that medium-range crystalline bondorientational order of the hexagonal close packed structure grows in size and lifetimewith increasing packing fraction. We show that dynamic heterogeneity may be adirect consequence of this transient structural ordering, which suggests its origin isthermodynamic rather than kinetic. We also reveal that nucleation of crystalspreferentially occurs in regions of high medium-range order, reflecting the lowcrystal–liquid interfacial energy there. These findings may shed new light not only on thefundamental nature of the glass transition, but also the mechanism of crystal nucleation.