Plasmons in nanoscale metal junctions: optical rectification and thermometry

TL;DR

This paper investigates nanoscale metal junctions by combining electronic transport and optical measurements to understand plasmon-induced effects, local electric fields, and temperature variations at the nanometer scale.

Contribution

It introduces a method to simultaneously measure electronic and optical responses in nanoscale junctions, revealing detailed insights into plasmonic and thermal processes.

Findings

Determined the optical frequency potential difference from photocurrents.

Measured local electric field enhancements within the junction.

Inferred local vibrational and electronic temperatures from Raman emission.

Abstract

We use simultaneous electronic transport and optical characterization measurements to reveal new information about electronic and optical processes in nanoscale junctions fabricated by electromigration. Comparing electronic tunneling and photocurrents allows us to infer the optical frequency potential difference produced by the plasmon response of the junction. Together with the measured tunneling conductance, we can then determine the locally enhanced electric field within the junction. In similar structures containing molecules, anti-Stokes and Stokes Raman emission allow us to infer the effective local vibrational and electronic temperatures as a function of DC current, examining heating and dissipation on the nanometer scale.