Single Photon Emission from a Plasmonic Light Source Driven by a Local Field-Induced Coulomb Blockade

TL;DR

This paper demonstrates nanoscale quantum control by generating single photon emission from a plasmonic source driven by a Coulomb blockade effect in a C60 molecular film, combining experimental STM-induced luminescence with theoretical electronic structure calculations.

Contribution

It introduces a novel mechanism for single photon emission via electric field-induced Coulomb blockade through split-off states in a plasmonic system, supported by experimental and theoretical analysis.

Findings

Single photon emission with sub-nanosecond lifetime observed.

Good agreement between experimental results and tight-binding calculations.

Coulomb blockade via split-off states enables controlled quantum emission.

Abstract

A hallmark of quantum control is the ability to manipulate quantum emission at the nanoscale. Through scanning tunneling microscopy induced luminescence (STML) we are able to generate plasmonic light originating from inelastic tunneling processes that occur in a few-nanometer thick molecular film of C$_{60}$ deposited on Ag(111). Single photon emission, not of excitonic origin, occurs with a 1/$e$ lifetime of a tenth of a nanosecond or less, as shown through Hanbury Brown and Twiss photon intensity interferometry. We have performed tight-binding calculations of the electronic structure for the combined Ag-C$_{60}$-tip system and obtained good agreement with experiment. The tunneling happens through electric field induced split-off states below the C$_{60}$ LUMO band, which leads to a Coulomb blockade effect and single photon emission. The use of split-off states is shown to be a general technique that has special relevance for narrowband materials with a large bandgap.