Distribution of conduction channels in nanoscale contacts: Evolution towards the diffusive limit

TL;DR

This study experimentally investigates conduction channel distributions in nanoscale lead contacts, revealing a tendency towards diffusive behavior even in very small contacts, influenced by lead's band structure rather than disorder.

Contribution

It provides the first experimental analysis of conduction channels in nanoscale contacts, linking band structure effects to diffusive-like conduction behavior.

Findings

Channels tend toward the diffusive limit even in small contacts

Partially open channels are significant due to band structure effects

Behavior occurs without atomic disorder influence

Abstract

We present an experimental determination of the conduction channel distribution in lead nanoscale contacts with total conductances ranging from 1 to 15 G0, where G0=2e2/h. It is found that even for contacts having a cross section much smaller than the mean free path the distribution tends to be remarkably close to the universal diffusive limit. With the help of theoretical calculations we show that this behavior can be associated with the specific band structure of lead which produces a significant contribution of partially open channels even in the absence of atomic disorder. Published in Europhysics Letters, http://www.edpsciences.org/articles/epl/abs/2005/11/epl8748/epl8748.html