Structural and dynamical heterogeneity in a glass forming liquid

TL;DR

This paper investigates the relationship between structural and dynamical heterogeneities in a glass-forming liquid using the isoconfigurational ensemble, revealing correlated clusters of low energy and mobility that emerge during structural relaxation.

Contribution

It demonstrates the existence of spatially correlated low-energy clusters and their correlation with dynamical heterogeneities in a glass-forming liquid.

Findings

Low potential energy clusters are observable during structural relaxation.

Structural heterogeneities correlate with dynamical heterogeneities.

Spatial correlations of potential energy are absent in instantaneous structure.

Abstract

We use the ``isoconfigurational ensemble'' [Phys. Rev. Lett. {\bf 93}, 135701 (2004)] to analyze both dynamical and structural properties in simulations of a glass forming molecular liquid. We show that spatially correlated clusters of low potential energy molecules are observable on the time scale of structural relaxation, despite the absence of spatial correlations of potential energy in the instantaneous structure of the system. We find that these structural heterogeneities correlate with dynamical heterogeneities in the form of clusters of low molecular mobility.