Defect-induced perturbations of atomic monolayers on solid surfaces

TL;DR

This paper investigates how various defects, such as steps and AFM tips, cause long-range morphological changes in atomic monolayers on solid surfaces using a Frenkel-Kontorova model.

Contribution

It introduces a model to analyze defect-induced perturbations and calculates density profiles and forces for different defect geometries.

Findings

Defects induce long-range morphological changes in monolayers.

The model predicts density variations around defects.

Additional forces on AFM tips due to monolayer perturbations.

Abstract

We study long-range morphological changes in atomic monolayers on solid substrates induced by different types of defects; e.g., by monoatomic steps in the surface, or by the tip of an atomic force microscope (AFM), placed at some distance above the substrate. Representing the monolayer in terms of a suitably extended Frenkel-Kontorova-type model, we calculate the defect-induced density profiles for several possible geometries. In case of an AFM tip, we also determine the extra force exerted on the tip due to the tip-induced de-homogenization of the monolayer.