Influence of chopped laser light onto the electronic transport through atomic-sized contacts

TL;DR

This study examines how laser irradiation affects the electrical conductance of gold nanocontacts, revealing reversible conductance changes up to 200% influenced by various laser parameters and physical mechanisms.

Contribution

It provides new insights into the effects of laser light on atomic-scale contacts, identifying key factors and ruling out thermal expansion as the main mechanism.

Findings

Conductance can increase by up to 200% under laser irradiation.

Reversible conductance changes depend on laser wavelength, intensity, and position.

Thermal expansion is not the primary cause of conductance enhancement.

Abstract

This article reports on the influence of laser irradiation onto the electrical conductance of gold nanocontacts established with the mechanically controllable breakjunction technique (MCB). We concentrate here on the study of reversible conductance changes which can be as high as 200%. We investigate the dependence on the initial conductance of the contacts, the wavelength, the intensity and position of the laser spot with respect to the sample. Under most conditions an enhancement of the conductance is observed. We discuss several physical mechanisms which might contribute to the observed effect including thermal expansion, rectification and photon-assisted transport. We conclude that thermal expansion is not the dominating one.