Cooperative motion in equilibrium phases across two-dimension melting in pure and disordered systems

TL;DR

This paper investigates particle dynamics during 2D melting in pure and disordered systems, revealing cooperative string-like motions at low temperatures that influence relaxation and correlations in equilibrium phases.

Contribution

It uncovers the presence of cooperative motion in equilibrium 2D phases, including pure systems, and explores how impurities affect these dynamics and correlations.

Findings

String-like cooperative motion observed at low temperatures.

Impurities impact spatiotemporal correlations.

Cooperative motion causes slow relaxation and departure from diffusion.

Abstract

We uncover the dynamics of particles with Gaussian core interactions across melting in pure and disordered two-dimensional (2D) systems. Intriguing signatures of cooperative motion of particles in string-like paths are found at low temperatures. Such a motion, while common to glasses and supercooled liquids, are realized here in traditional equilibrium phases, including in pure systems. We explore the interplay of such motion and impurities and report their repercussions on spatiotemporal correlations. In particular, cooperative motion seems to cause a departure from the diffusive dynamics, causing slow relaxation.