Influence of adatom interactions on second layer nucleation

TL;DR

This paper develops a theoretical framework incorporating adatom interactions, such as ring barriers and cluster binding energies, into second layer nucleation during epitaxial growth, validated by simulations and applied to experimental data.

Contribution

It introduces a master equation-based theory for adatom interactions in second layer nucleation, enhancing understanding of epitaxial growth processes.

Findings

The theory accurately predicts nucleation behavior with adatom interactions.

Simulation results agree with the theoretical model.

Reanalysis of experiments yields refined step edge barrier values.

Abstract

We develop a theory for the inclusion of adatom interactions in second layer nucleation occurring in epitaxial growth. The interactions considered are due to ring barriers between pairs of adatoms and binding energies of unstable clusters. The theory is based on a master equation, which describes the time development of microscopic states that are specified by cluster configurations on top of an island. The transition rates are derived by scaling arguments and tested against kinetic Monte-Carlo simulations. As an application we reanalyze experiments to determine the step edge barrier for Ag/Pt(111).