Structural Signature of Slow and Heterogeneous Dynamics in Glass-Forming Liquids

TL;DR

This paper introduces a new structural characterization method based on local density correlations that links dense-packed environments to slow dynamics and heterogeneity in glass-forming liquids, revealing a structural origin of these phenomena.

Contribution

It proposes a novel structural signature based on local density correlations that correlates with slow dynamics and heterogeneity in glass-formers, advancing understanding of the glass transition.

Findings

Locally dense-packed regions correlate with slow particle relaxation.

Cluster size of dense-packed particles increases as temperature decreases.

Static length scale correlates with relaxation time across supercooling levels.

Abstract

One of the central problems of the liquid-glass transition is whether there is a structural signature that can qualitatively distinguish different dynamic behaviors at different degrees of supercooling. Here, we propose a novel structural characterization based on the spatial correlation of local density and we show the locally dense-packed structural environment has a direct link with the slow dynamics as well as dynamic heterogeneity in glass-formers. We find that particles with large local density relax slowly and the size of cluster formed by the dense-packed particles increases with decreasing the temperature. Moreover, the extracted static length scale shows clear correlation with the relaxation time at different degrees of supercooling. This suggests that the temporarily but continuously formed locally dense-packed structural environment may be the structural origin of slow dynamics and dynamic heterogeneity of the glass-forming liquids.