Optical Probe of Quantum Shot Noise Reduction at a Single-Atom Contact

TL;DR

This study investigates light emission from a silver junction at atomic scale, revealing nonlinear intensity behavior related to quantum conductance and noise characteristics at optical frequencies.

Contribution

It provides new insights into quantum shot noise and optical emission mechanisms at single-atom contacts using a scanning tunneling microscope.

Findings

Light intensity varies nonlinearly with conductance.

Minimum emission occurs near the conductance quantum.

Emission linked to current noise in open transport channels.

Abstract

Visible and infra-red light emitted at a Ag-Ag(111) junction has been investigated from tunneling to single atom contact conditions with a scanning tunneling microscope. The light intensity varies in a highly nonlinear fashion with the conductance of the junction and exhibits a minimum at conductances close to the conductance quantum. The data are interpreted in terms of current noise at optical frequencies, which is characteristic of partially open transport channels.