Electron-vibration interaction in single-molecule junctions: from contact to tunneling regime

TL;DR

This study investigates how electron-vibration interactions affect conductance in single-molecule junctions, revealing a crossover behavior consistent with single-channel models through conductance and shot noise measurements.

Contribution

It provides experimental evidence linking conductance crossover to transmission channels in single-molecule junctions, confirming theoretical predictions.

Findings

Crossover from conductance enhancement to reduction observed

Transmission probability at crossover is approximately 0.51

At least two conduction channels are present across the junction

Abstract

Point contact spectroscopy on a H2O molecule bridging Pt electrodes reveals a clear crossover between enhancement and reduction of the conductance due to electron-vibration interaction. As single channel models predict such a crossover at transmission probability of t=0.5, we used shot noise measurements to analyze the transmission and observed at least two channels across the junction where the dominant channel has t=0.51+/-0.01 transmission probability at the crossover conductance, which is consistent with the predictions for single-channel models.