title: Tracking Optical Welding through Groove Modes in Plasmonic Nanocavities.
abstract: We report the light-induced formation of conductive links across nanometer-wide insulating gaps. These are realized by incorporating spacers of molecules or 2D monolayers inside a gold plasmonic nanoparticle-on-mirror (NPoM) geometry. Laser irradiation of individual NPoMs controllably reshapes and tunes the plasmonic system, in some cases forming conductive bridges between particle and substrate, which shorts the nanometer-wide plasmonic gaps geometrically and electronically. Dark-field spectroscopy monitors the bridge formation in situ, revealing strong plasmonic mode mixing dominated by clear anticrossings. Finite difference time domain simulations confirm this spectral evolution, which gives insights into the metal filament formation. A simple analytic cavity model describes the observed plasmonic mode hybridization between tightly confined plasmonic cavity modes and a radiative antenna mode sustained in the NPoM. Our results show how optics can reveal the properties of electrical transport across well-defined metallic nanogaps to study and develop technologies such as resistive memory devices (memristors).
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Mertens
authors.affiliation: Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, and Donostia International Physics Center (DIPC), Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastian, Spain.|Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Demetriadou
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: R W
authors.initials: RW
authors.lastname: Bowman
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: F
authors.initials: F
authors.lastname: Benz
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: M-E
authors.initials: ME
authors.lastname: Kleemann
authors.affiliation: Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, and Donostia International Physics Center (DIPC), Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastian, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Tserkezis
authors.affiliation: Pillar of Engineering Product Development, Singapore University of Technology and Design , Singapore 138682, Singapore.
authors.forename: Y
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Pillar of Engineering Product Development, Singapore University of Technology and Design , Singapore 138682, Singapore.
authors.forename: H Y
authors.initials: HY
authors.lastname: Yang
authors.affiliation: Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: O
authors.initials: O
authors.lastname: Hess
authors.affiliation: Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, and Donostia International Physics Center (DIPC), Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastian, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Aizpurua
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: J J
authors.initials: JJ
authors.lastname: Baumberg
keywords: 2D materials; Plasmonic nanocavities; light-induced plasmonic welding; nanoparticle on mirror; plasmonic hybridisation; tuneable plasmonics