Effect of attractions on correlation length scales in a glass-forming liquid

TL;DR

This study uses molecular dynamics simulations to explore how attractions influence dynamic heterogeneity and correlation length scales in a weakly frustrated glass-forming liquid, revealing that bond orientational order alone cannot fully explain dynamic heterogeneity.

Contribution

It demonstrates that attractions significantly impact dynamic heterogeneity and correlation lengths, but have limited effect on bond orientational order, challenging its role as a sole structural signature.

Findings

Attractions strongly affect relaxation dynamics and dynamic heterogeneity.

Bond orientational order shows limited influence from attractions.

Static correlation length scales are affected similarly to thermodynamic properties.

Abstract

There is growing evidence that slow dynamics and dynamic heterogeneity possess structural signatures in glass-forming liquids. However, even in the weakly frustrated glass-forming liquids, whether or not the dynamic heterogeneity has a structural origin is a matter of debate. Via molecular dynamics simulation, we present a study of examining the connection between dynamic heterogeneity and bond orientational order in a weakly frustrated glass-forming liquid in two dimensions by taking advantage of assessing the effect of attractions on the correlation length scales. We find that attractions can strongly affect relaxation dynamics, dynamic heterogeneity and the associated dynamic correlation length of the liquid, but their influence on bond orientational order and the associated static correlation length shows a manner reminiscent of the effect of attractions on the thermodynamics of liquids. This implies that the growth of bond orientational order and static correlation length scale might be merely a manifestation of favoring the configurational entropy in weakly frustrated glass-forming liquids. Thus, our results lead strong evidence that bond orientational order cannot provide a complete description of dynamic heterogeneity even in weakly frustrated glass-forming systems.