Role of electronic structure in photoassisted transport through atomic-sized contacts

TL;DR

This paper theoretically investigates how laser irradiation affects quantum transport in atomic-sized metallic contacts, revealing that electronic structure influences whether conductance is enhanced or diminished by radiation.

Contribution

It provides a new theoretical framework for understanding photoassisted transport in atomic contacts, emphasizing the role of electronic structure and frequency dependence.

Findings

Radiation can either increase or decrease conductance depending on material and frequency.

Electronic structure critically influences the effect of laser irradiation on conductance.

The study offers insights into controlling nanoscale transport with optical fields.

Abstract

We study theoretically quantum transport through laser-irradiated metallic atomic-sized contacts. The radiation field is treated classically, assuming its effect to be the generation of an ac voltage over the contact. We derive an expression for the dc current and compute the linear conductance in one-atom thick contacts as a function of the ac frequency, concentrating on the role played by electronic structure. In particular, we present results for three materials (Al, Pt, and Au) with very different electronic structures. It is shown that, depending on the frequency and the metal, the radiation can either enhance or diminish the conductance. This can be intuitively understood in terms of the energy dependence of the transmission of the contacts in the absence of radiation.