Public exhibit for demonstrating the quantum of electrical conductance

TL;DR

This paper introduces a durable, public-friendly setup that visually demonstrates the quantum of electrical conductance by allowing users to manually thin a gold wire and observe conductance steps in real time.

Contribution

It presents a novel, maintenance-free demonstration setup for illustrating quantum conductance in a public educational setting.

Findings

Observation of step-like conductance decreases during wire thinning

Detection of a single-atom contact with conductance near the quantum value

Setup operates continuously with minimal maintenance

Abstract

We present a new robust setup that explains and demonstrates the quantum of electrical conductance for a general audience and which is continuously available in a public space. The setup allows users to manually thin a gold wire of several atoms in diameter while monitoring its conductance in real time. During the experiment, a characteristic step-like conductance decrease due to rearrangements of atoms in the cross-section of the wire is observed. Just before the wire breaks, a contact consisting of a single atom with a characteristic conductance close to the quantum of conductance can be maintained up to several seconds. The setup is operated full-time, needs practically no maintenance and is used on different educational levels.