Precursor configurations and post-rupture evolution of Ag-CO-Ag single-molecule junctions

TL;DR

This study combines experimental correlation analysis and first-principles theory to investigate the structure, formation, and post-rupture evolution of Ag-CO-Ag single-molecule junctions, revealing precursor configurations and re-establishment of molecular bonds.

Contribution

It introduces a novel correlation analysis approach and confirms findings with ab initio simulations, advancing understanding of molecular junction dynamics.

Findings

CO binds parallel to Ag contact before junction formation

Additional conductance channels appear with CO presence

Molecular configuration is re-established after rupture

Abstract

Experimental correlation analysis and first-principles theory are used to probe the structure and evolution of Ag-CO-Ag single-molecule junctions, both before the formation, and after the rupture of the junctions. Two dimensional correlation histograms and conditional histograms demonstrate that prior to the single-molecule bridge configuration the CO molecule is already bound parallel to the Ag single-atom contact. This molecular precursor configuration is accompanied by the opening of additional conductance channels compared to the single-channel transport in pure Ag monoatomic junctions. To investigate the post-rupture evolution of the junction we introduce a cross-correlation analysis between the opening and the subsequent closing conductance traces. This analysis implies that the molecule is bound rigidly to the apex of one electrode, and so the same single-molecule configuration is re-established as the junction is closed. The experimental results are confirmed by ab initio simulations of the evolution of contact geometries, transmission eigenvalues and scattering wavefunctions.