Strain mediated interaction of adatom dimers

TL;DR

This paper extends a substrate strain interaction model to include adatom dimers, revealing anisotropic stress effects and their dependence on substrate elastic properties, impacting the understanding of adatom structure formation.

Contribution

It introduces a model for adatom dimer interactions mediated by substrate strain, accounting for anisotropic stress and elastic anisotropy effects.

Findings

Interactions are strongly angle dependent.

Dimers create anisotropic stress due to bond stretching.

Elastic anisotropy influences adatom interactions.

Abstract

An earlier model for substrate strain mediated interactions between monomer adatoms is extended to the interaction of monomers with dimers and the interaction of dimers. While monomers (sitting on high symmetric sites) are supposed to create isotropic stress on the substrate, dimers would create anisotropic stress caused by stretching their bond. Resulting interactions are strongly angle dependent and also reflect the elastic anisotropy of the substrate. The applicability of a continuum elastic model and its limitations are discussed. Consequences for modelling adatom structures are sketched without detailed analysis.