Structure and metastability of superheated Al(111)

TL;DR

This study uses molecular dynamics to explore the superheating and melting behavior of the Al(111) surface, revealing how superheating precedes rapid melting and analyzing the transition with kinetic models.

Contribution

It provides detailed molecular-dynamics insights into superheating phenomena and the melting transition of Al(111), including structural and thermodynamic properties.

Findings

Al(111) surface can be superheated above its melting point

Melting occurs rapidly after superheating within a narrow temperature range

Surface stress and vibrational amplitudes show characteristic temperature dependence

Abstract

The high-temperature properties of the Al(111) surface are studied by molecular-dynamics simulation. This surface does not melt below the bulk melting point, but can be superheated. Superheating of metal surfaces has been recently observed in several experiments. A molecular-dynamics study of the structural properties reveals how after going through the superheating regime melting occurs over the whole crystal in a narrow temperature range. The temperature dependence of the surface stress, the mean-square vibrational amplitudes and the anomalous outward expansion of the distance between two top layers are calculated. A transition from superheated to liquid state is analyzed using kinetic description for the formation of liquid nuclei by the Fokker-Planck equation and conservation of heat at the liquid-solid interface.