Correlation between crystalline order and vitrification in colloidal monolayers.
We investigate experimentally the relationship between local structure and dynamical arrest in a quasi-2d colloidal model system which approximates hard discs. We introduce polydispersity to the system to suppress crystallisation. Upon compression, the increase in structural relaxation time is accompanied by the emergence of local hexagonal symmetry. Examining the dynamical heterogeneity of the system, we identify three types of motion: 'zero-dimensional' corresponding to β-relaxation, 'one-dimensional' or stringlike motion and '2D' motion. The dynamic heterogeneity is correlated with the local order, that is to say locally hexagonal regions are more likely to be dynamically slow. However, we find that lengthscales corresponding to dynamic heterogeneity and local structure do not appear to scale together approaching the glass transition.
Institut Lumière Matière, Université Lyon 1, 69100 Villeurbanne, France. Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
Elisa
E
Tamborini
C Patrick
CP
Royall
Pietro
P
Cicuta