Excitation of surface and volume plasmons in a metal nanosphere by fast electrons

Journal Article · Tue Mar 15 00:00:00 EDT 2016 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4944395· OSTI ID:22599025

Kostin, V. A.; Pavlichenko, I. A. ^[1]

---

1. University of Nizhny Novgorod, Nizhny Novgorod 603950 (Russian Federation)

Collective multipole oscillations (surface and volume plasmons) excited in a metal nanosphere by moving electron and corresponding inelastic scattering spectra are studied based on the hydrodynamic approach. Along with the bulk (dielectric) losses traditionally taken into account, the surface and radiative ones are also considered as the physical mechanisms responsible for the plasmon damping. The second and third mechanisms are found to be essential for the surface plasmons (at small or large cluster radii, respectively) and depend very differently on the multipole mode order. The differential equations are obtained which describe the temporal evolution of every particular mode as that one of a linear oscillator excited by the given external force, and the electron energy loss spectra are calculated. The changes in spectrum shape with the impact parameter and with the electron passage time are analyzed; the first of them is found to be in good enough agreement with the data of scanning transmission electron microscopy experiments. It is shown that, in the general case, a pronounced contribution to the formation of the loss spectrum is given by the both surface and volume plasmons with low and high multipole indices. In particular, at long electron passage time, the integral (averaged over the impact parameter) loss spectrum which is calculated for the free-electron cluster model contains two main peaks: a broad peak from merging of many high-order multipole resonances of the surface plasmons and a narrower peak of nearly the same height from merged volume plasmons excited by the electrons that travel through the central region of the cluster. Comparatively complex dependences of the calculated excitation coefficients and damping constants of various plasmons on the order of the excited multipole result in wide diversity of possible types of the loss spectrum even for the same cluster material and should be taken into account in interpretation of corresponding electron energy loss spectroscopy experiments.

• OSTI ID: 22599025
• Journal Information: Physics of Plasmas, Vol. 23, Issue 3; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CLUSTER MODEL
DIELECTRIC MATERIALS
DIFFERENTIAL EQUATIONS
ELECTRONS
ENERGY LOSSES
ENERGY-LOSS SPECTROSCOPY
EXCITATION
IMPACT PARAMETER
INELASTIC SCATTERING
METALS
OSCILLATORS
PEAKS
PLASMONS
RESONANCE
SPECTRA
SURFACES
TRANSMISSION ELECTRON MICROSCOPY
TRANSPORT THEORY