Melting a copper cluster: Critical droplet theory

TL;DR

This paper investigates the melting process of a copper cluster through simulations and applies critical droplet theory to explain the thermodynamics of phase transition, revealing how the transition width scales with cluster size.

Contribution

It introduces a detailed simulation of copper cluster melting and applies critical droplet theory to interpret the thermodynamics of the transition.

Findings

Faceted crystal surfaces pre-melt at low temperatures

Melted regions form a liquid envelope with a crystalline nucleus

Transition width scales as particle number to the power -1/4

Abstract

We simulate the melting of a 71 A diameter cluster of Cu. At low temperatures the crystal exhibits facets. With increasing temperatures the open facets pre-melt, the melted regions coalesce into a liquid envelope containing a crystalline nucleus, and the nucleus finally goes unstable to the supercooled liquid. Using critical droplet theory and experimental data for Cu, we explain the thermodynamics of the coexistence region. The width of the transition scales as (Number of particles) to the power (-1/4).