Modelling impurity-assisted chain creation in noble-metal break junctions

TL;DR

This paper extends a chain formation model to include impurities in noble-metal break junctions, showing how impurities like H, C, O, and N influence chain stability and formation probability.

Contribution

The authors generalize an existing model to account for zigzag transition-metal chains with impurities, providing material-specific parameters from first-principles calculations.

Findings

Impurities significantly alter the binding properties of noble-metal chains.

Impurity-induced bond strengthening enhances chain formation probability.

Zigzag bond formation is promoted by impurities, aiding chain stability.

Abstract

In this work we present the generalization of the model for chain formation in break-junctions, introduced by Thiess {\it et al.} [\onlinecite{Alex08}], to zigzag transition-metal chains with $s$ and $p$ impurities. We apply this extended model to study the producibility trends for noble-metal chains with impurities, often present in break junction experiments, namely, Cu, Ag and Au chains with H, C, O and N adatoms. Providing the material-specific parameters for our model from systematic full-potential linearized augmented plane-wave first-principles calculations, we find that the presence of such impurities crucially affects the binding properties of the noble-metal chains. We reveal that both, the impurity-induced bond strengthening and the formation of zigzag bonds, can lead to a significantly enhanced probability for chain formation in break junctions.