Predicted energy-loss spectrum of low-dimensional plasmons in a metallic strip monolayer on a semiconductor surface

Abstract

In view of high-resolution electron-energy-loss spectroscopy, we predict the energy-loss spectrum of lowdimensional ͑LD͒ plasmons in a metallic strip monolayer on a semiconductor surface. By means of the time-dependent local density approximation, we calculate the dynamical response of our electron system to some typical trajectories of a probe electron incident on the surface along the strip. As shown in our previous work, the energy dispersion of the LD plasmons is composed of a series of dispersion branches where the node number in oscillation of the induced electron density across the strip increases one by one with ascending energy. These branches can produce a series of loss peaks in the spectrum. The branch of the two-node modes gives rise to an outstanding loss peak, and the branches of the zero-node modes ͑symmetric edge plasmons͒ and the four-node modes also create significant loss peaks, when the intersection of the scattering plane with the surface plane runs around the center line of the strip region. The branch of the one-node modes ͑antisym-metric edge plasmons͒ yields a remarkable loss peak, when the intersection runs just near one of the strip edges. These loss peaks should actually be observed in the spectrum, if there are a sufficient number of strip regions in a surface area illuminated by an electron beam.

Plasmons in Pb nanowire arrays on Si(557): Between one and two dimensions

“…For the analysis of broad strips, where several subbands are occupied, we referred to some previous results using the time-dependent local density approximation. 38,39 The quasi-1D fit shows very good agreement with the dispersion data as a function of k and demonstrates the 1D character of the plasmon dispersion. The one-dimensional electron concentration, N 1D , and the effective electron mass, m * , are variable parameters for the plasmon dispersion.…”

The influence of electron confinement, quantum size effects, and film morphology on the dispersion and the damping of plasmonic modes in Ag and Au thin films

“…Thus, Ag/Si(1 1 1) is a model system for investigating the behaviour of the collective modes as a function of the growth mechanism of the film. For the ffiffiffi 3 p  ffiffiffi 3 p R30°-Ag/Si(1 1 1) surface a two-dimensional (2D) plasmon (characterized by a square-root dependence on q || ) has been reported in several experimental [235][236][237][238] and theoretical [239][240][241] studies. A 2D plasmon (or sheet plasmon) is a collective excitation in which the oscillating charge density distribution is strictly confined to a 2D space ( Fig.…”

“…Data for the 2D surface state gave N 2D = 1.9Á10 13 cm À2 and m ⁄ = 0.24 m e where m e is the mass of electrons [238]. (1 1 1).…”

Low-energy plasmons in quantum-well and surface states of metallic thin films

“…[59][60][61][62][63][64][65][66][67] One can see in Fig. 6 that surface excitation spectra evaluated in the jellium model are rather featureless in this low-energy domain compared to Fig.…”