Dynamical heterogeneity and jamming in glass-forming liquids

TL;DR

This study investigates the connection between spatially heterogeneous dynamics and jamming in glass-forming liquids, finding no peak in force distribution at the glass transition and linking force experiences to particle mobility.

Contribution

It provides new insights into the relationship between interparticle forces, dynamical heterogeneity, and jamming in glass-forming liquids, challenging previous assumptions about force chains.

Findings

No peak in force distribution at the glass transition temperature.

Localized particles experience lower forces, mobile particles experience higher forces.

Potential link between force chains and string-like motion in glasses.

Abstract

The relationship between spatially heterogeneous dynamics (SHD) and jamming is studied in a glass-forming binary Lennard-Jones system via molecular dynamics simulations. It has been suggested that the probability distribution of interparticle forces $P(F)$ develops a peak at the glass transition temperature $T_g$, and that the large force inhomogeneities, responsible for structural arrest in granular materials, are related to dynamical heterogeneities in supercooled liquids that form glasses. It has been further suggested that ``force chains'' present in granular materials may exist in supercooled liquids, and may provide an order parameter for the glass transition. Our goal is to investigate the extent to which the forces experienced by particles in a glass-forming liquid are related to SHD, and compare these forces to those observed in granular materials and other glass-forming systems. We find no peak in $P(F)$ at any temperature in our system, even below $T_g$. We also find that particles that have been localized for a long time are less likely to experience high relative force and that mobile particles experience higher relative forces at shorter time scales, indicating a correlation between pairwise forces and particle mobility. We also discuss a possible relationship between force chains found here and the development of string-like motion found in other glass-forming liquids.