Evidence for saturation of channel transmission from conductance fluctuations in atomic-size point contacts

TL;DR

This paper reports the observation of conductance fluctuation suppression in atomic gold contacts near integer multiples of the conductance quantum, indicating channel saturation effects in atomic-scale conductance.

Contribution

It provides experimental evidence and a theoretical interpretation of conductance channel saturation in atomic-size contacts, a novel insight into quantum conductance behavior.

Findings

Suppression of conductance fluctuations near integer conductance quanta

Evidence of fully transmitted channels in atomic contacts

Support for the Landauer-Büttiker model in atomic conductance

Abstract

The conductance of atomic size contacts has a small, random, voltage dependent component analogous to conductance fluctuations observed in diffusive wires (UCF). A new effect is observed in gold contacts, consisting of a marked suppression of these fluctuations when the conductance of the contact is close to integer multiples of the conductance quantum. Using a model based on the Landauer-Buettiker formalism we interpret this effect as evidence that the conductance tends to be built up from fully transmitted (i.e., saturated) channels plus a single, which is partially transmitted.