Ab initioapproach for gap plasmonics

Abstract

Gap plasmonics deals with the properties of surface plasmons in the narrow region between two metallic nanoparticles forming the gap. For sub-nanometer gap distances electrons can tunnel between the nanoparticles leading to the emergence of novel charge transfer plasmons. These are conveniently described within the quantum corrected model by introducing an artificial material with a tunnel conductivity inside the gap region. Here we develop a methodology for computing such tunnel conductivities within the first-principles framework of density functional theory, and apply our approach to a jellium model representative for sodium. We show that the frequency dependence of the tunnel conductivity at infrared and optical frequencies can be significantly more complicated than previously thought.

Distinguishable Plasmonic Nanoparticle and Gap Mode Properties in a Silver Nanoparticle on a Gold Film System Using Three-Dimensional FDTD Simulations

“…Furthermore, by optical characterizations, it is possible to interpret the SPR of plasmonic nanomaterials based upon their geometrical parameters, surrounding dielectric medium, composition, spatial arrangements, and so on. Generally, sizeable local-field enhancements can be generated in plasmonic nanostructures based on three dynamic plasmonic designs: (i) plasmonic nanostructures which are self-tunable based on carrier control; (ii) tunable dielectric environments; and (iii) nanostructures with tunable gap sizes [ 23 , 24 , 25 , 26 , 27 ]. Of these, plasmonic nanostructures with tunable gap sizes have attracted potential interest because of dramatic electromagnetic near-field confinement and enhancement in the nanogap, which have been called hot-spots [ 27 , 28 , 29 , 30 , 31 , 32 ].…”

Modifying Plasmonic-Field Enhancement and Resonance Characteristics of Spherical Nanoparticles on Metallic Film: Effects of Faceting Spherical Nanoparticle Morphology

“…A plasmonic nanostructure's choice of material, size, morphology, shape, and surface modification significantly affects various SPR optical properties [2,5,6]. The LSPR properties (e.g., extinction, scattering or absorption spectra) and near field enhancement generated in the plasmonic nanostructures come down to three major structural designs: tunable dielectric-control nanostructures, nanostructures with tunable gaps, and nanostructures self-tunable by charge carrier [22][23][24]. Of these designs, the most attractive one for applications in the fields of active optical signal control, plasmonic sensing, and tunable surface enhanced Raman spectroscopy (SERS) is for plasmonic nanostructures with tunable gaps.…”

Electrical control of the light absorption in quantum-well functionalized junctions between thin metallic films

“…In particular, for metals with high conduction electron density, the optical response of the system is determined by the nonlocal response and dynamical screening. Only few studies of PAT based on the time dependent density functional theory (TDDFT) and incorporating many-body effects at full-quantum level have been reported so far [35][36][37][38][39][40]. However, to the best of our knowledge, the issue of active control has not yet been addressed.…”