We investigated surface plasmon (SP) waves in the junction of a scanning tunneling microscope (STM). The SP waves were generated on a 45-nm thin Au film and their near-field was locally probed by the tip of the STM. The temporal structure of the observed tunneling current signal revealed information on the physical mechanisms which regulate the interaction of the electric fields in play. We estimated the magnitude of the local electric field enhancement on surface nanostructures by taking advantage of the nonlinearity of the tunneling junction. The mapping of the plasmon field to the surface topography delivers experimental evidence for the localization of SP waves in narrow gaps of a few nanometers width and/or at grain boundaries. The results gained can directly be utilized (e.g., in the development of nanoscale geometries for high-energy electron sources where electrons are accelerated in the electric field of surface plasmons).
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - May 25 2011|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics