# Conductance channels of a platform molecule on Au(111) probed with shot noise

## TL;DR

This study investigates the conductance channels of a single molecule on gold using shot noise measurements, revealing electron transmission characteristics and molecular electronic structure insights.

## Contribution

It provides experimental shot noise data and theoretical analysis showing that TOTA+ molecules conduct via a single spin-degenerate channel without unpaired electrons.

## Key findings

- Shot noise is reduced compared to Poisson noise.
- Transport occurs through a single spin-degenerate channel.
- Molecular orbitals involved are the lowest unoccupied orbitals.

## Abstract

The shot noise of the current $I$ through junctions to single trioxatriangulenium cations (TOTA$^+$) on Au(111) is measured with a low temperature scanning tunneling microscope using Au tips. The noise is significantly reduced compared to the Poisson noise power of $2eI$ and varies linearly with the junction conductance. The data are consistent with electron transmission through a single spin-degenerate transport channel and show that TOTA$^+$ in a Au contact does not acquire an unpaired electron. Ab initio calculations reproduce the observations and show that the current involves the lowest unoccupied orbital of the molecule and tip states close to the Fermi level.