title: Electron-energy loss study of nonlocal effects in connected plasmonic nanoprisms.
abstract: We investigate the emergence of nonlocal effects in plasmonic nanostructures through electron-energy loss spectroscopy. To theoretically describe the spatial dispersion in the metal permittivity, we develop a full three-dimensional nonlocal hydrodynamic solution of Maxwell's equations in frequency domain that implements the electron beam as a line current source. We use our numerical approach to perform an exhaustive analysis of the impact of nonlocality in the plasmonic response of single triangular prisms and connected bowtie dimers. Our results demonstrate the complexity of the interplay between nonlocal and geometric effects taking place in these structures. We show the different sensitivities to both effects of the various plasmonic modes supported by these systems. Finally, we present an experimental electron-energy loss study on gold nanoprisms connected by bridges as narrow as 1.6 nm. The comparison with our theoretical predictions enables us to reveal in a phenomenological fashion the enhancement of absorption damping that occurs in these atomistic junctions due to quantum confinement and grain boundary electron scattering.
authors.affiliation: Department of Physics, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Aeneas
authors.initials: A
authors.lastname: Wiener
authors.forename: Huigao
authors.initials: H
authors.lastname: Duan
authors.forename: Michel
authors.initials: M
authors.lastname: Bosman
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Horsfield
authors.forename: John B
authors.initials: JB
authors.lastname: Pendry
authors.forename: Joel K W
authors.initials: JK
authors.lastname: Yang
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Maier
authors.forename: Antonio I
authors.initials: AI
authors.lastname: Fernández-Domínguez
mesh_terms: D003198:Computer Simulation; D004579:Electron Transport; D004735:Energy Transfer; D008027:Light; D008962:Models, Theoretical; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000379:methods*