Amine-Gold Linked Single-Molecule Junctions: Experiment and Theory

TL;DR

This study combines extensive experimental measurements and theoretical calculations to analyze conductance in amine-gold single-molecule junctions, revealing the influence of local structure and the limitations of DFT.

Contribution

It provides a comprehensive experimental dataset and compares it with DFT calculations, highlighting the role of many-electron effects in conductance predictions.

Findings

Experimental conductance peak at 0.0064 G₀ with 40% width

DFT calculations show similar conductance spread across geometries

Calculated conductance overestimates experimental values by a factor of seven

Abstract

The measured conductance distribution for single molecule benzenediamine-gold junctions, based on 59,000 individual conductance traces recorded while breaking a gold point contact in solution, has a clear peak at 0.0064 G$_{0}$ with a width of $\pm$ 40%. Conductance calculations based on density functional theory (DFT) for 15 distinct junction geometries show a similar spread. Differences in local structure have a limited influence on conductance because the amine-Au bonding motif is well-defined and flexible. The average calculated conductance (0.046 G$_{0}$) is seven times larger than experiment, suggesting the importance of many-electron corrections beyond DFT.