Evidence for compact cooperatively rearranging regions in a supercooled liquid

TL;DR

This study uses molecular dynamics simulations to reveal that in supercooled liquids, structural relaxation is delayed due to collective particle movements within compact regions, indicating cooperatively rearranging regions.

Contribution

It provides evidence for the existence of compact cooperatively rearranging regions in supercooled liquids through analysis of kinetic energy fluctuations.

Findings

Structural relaxation delays under cooling.

Collective particle movements preserve structural correlations.

Evidence supports compact cooperatively rearranging regions.

Abstract

We examine structural relaxation in a supercooled glass-forming liquid simulated by NVE molecular dynamics. Time correlations of the total kinetic energy fluctuations are used as a comprehensive measure of the system's approach to the ergodic equilibrium. We find that, under cooling, the total structural relaxation becomes delayed as compared with the decay of the component of the intermediate scattering function corresponding to the main peak of the structure factor. This observation can be explained by collective movements of particles preserving many-body structural correlations within compact 3D cooperatively rearranging regions.