Orientational Order in Dense Colloidal Liquids and Glasses

We construct structural order parameters based on local angular and radial distribution functions in dense colloidal suspensions. All the order parameters show significant correlations to local dynamics in the supercooled and glass regime. In particular, the correlations between the orientational order and dynamical heterogeneity are consistently higher than those between the conventional two-body structural entropy and local dynamics. The structure-dynamics correlations can be explained by a excitation model with the energy barrier depending on local structural order. Our results suggest that in dense disordered packings, local orientational order is higher than translational order, and plays a more important role in determining the dynamics in glassy systems.

Automated summary

We constructed structural order parameters based on local angular and radial distribution functions in dense colloidal suspensions and found significant correlations between these parameters and local dynamics. In particular, the correlation between local orientational order and dynamical heterogeneity was consistently higher than the correlation between conventional two-body structural entropy and local dynamics. The structure-dynamics correlations can be explained by an excitation model where the energy barrier depends on local structural order. Our results suggest that in dense disordered packings, local orientational order is higher than translational order and plays a more important role in determining the dynamics in glassy systems.