Ostwald ripening of faceted two-dimensional islands

TL;DR

This paper investigates the Ostwald ripening process of two-dimensional islands on crystal surfaces using kinetic Monte Carlo simulations, revealing unique coarsening behaviors related to island shape and size.

Contribution

It introduces a detailed simulation study showing how large bond energies lead to square-shaped islands and altered coarsening kinetics, supported by Becker–Döring equations.

Findings

Square-shaped islands at large bond energies change coarsening dynamics

Coarsening proceeds through 'magic' sizes of square or rectangular islands

Wagner's law is approached after a long transient period

Abstract

We study Ostwald ripening of two-dimensional adatom and advacancy islands on a crystal surface by means of kinetic Monte Carlo simulations. At large bond energies the islands are square-shaped, which qualitatively changes the coarsening kinetics. The Gibbs--Thomson chemical potential is violated: the coarsening proceeds through a sequence of `magic' sizes corresponding to square or rectangular islands. The coarsening becomes attachment-limited, but Wagner's asymptotic law is reached after a very long transient time. The unusual coarsening kinetics obtained in Monte Carlo simulations are well described by the Becker--D\"oring equations of nucleation kinetics. These equations can be applied to a wide range of coarsening problems.