Single atom adhesion in optimized gold nanojunctions

TL;DR

This paper investigates single atom interactions in gold nanojunctions, revealing how atomic contact transitions relate to elastic properties, with implications for understanding atomic-scale contact mechanics.

Contribution

It introduces a simple elastic model that explains atomic contact transitions and apex atom interactions in gold nanojunctions, based on experimental data.

Findings

Elasticity of electrodes ranges from 5 to 32 N/m.

Transitions between contact and tunnelling regimes are explained by the model.

A change in slope in tunnelling regime indicates apex atom interaction.

Abstract

We study the interaction between single apex atoms in a metallic contact, using the break junction geometry. By carefully 'training' our samples, we create stable junctions in which no further atomic reorganization takes place. This allows us to study the relation between the so-called jump out of contact (from contact to tunnelling regime) and jump to contact (from tunnelling to contact regime) in detail. Our data can be fully understood within a relatively simple elastic model, where the elasticity k of the electrodes is the only free parameter. We find 5 < k < 32 N/m. Furthermore, the interaction between the two apex atoms on both electrodes, observed as a change of slope in the tunnelling regime, is accounted for by the same model.