Surface-plasmon excitation during aloof scattering of low-energy electrons in micropores in a thin metal foil

Interaction of charged particles with surface plasmons in cylindrical channels in solids

“…The observation of multiple plasmon-loss peaks in these cases should be expected ͑note by comparison that only single plasmon peaks with small intensities have been observed in experiments with larger capillary radii͒. 7,8 The dependence of the stopping force with the 0 value is indicated in Fig. 5, for the case aϭ10 a.u.…”

“…[2][3][4] In experiments with electrons, the excitation of surface plasmons may be studied through the analysis of the multiple energy-loss peaks that appear in the spectrum of the inelastically reflected particles. 5,6 Previous experiments of plasmon excitation in aloof scattering during transmission through micropores in thin metal foils ͑with channel radii of nm͒ have also been reported, 7,8 and several theoretical studies dealing with the energy loss of charged particles in cylindrical cavities have been published. [9][10][11] In these papers, the energy-loss process has been described in a classical way, but the importance of the underlying mechanism of surface-plasmon excitation may be inferred from the results.…”

Image potential in scanning transmission electron microscopy

“…Martinos and Economou [125] studied the plasmon excitations in cylindrical surfaces by electrons describing circular orbits around cylinders, moved by axial magnetic ®elds. Warmack et al [126] obtained the ®rst energy loss spectrum in microchannels of 20±200 nm drilled in metallic ®lms and Chu et al [127] provided the estimate of the energy loss probability of electrons moving in cylindrical channels in the non-relativistic approximation, to account for the energy loss suered by electrons in particle accelerators. Interest in the cylindrical geometry increased in the 1980s, due to the ability shown by the STEM electron beam to drill holes and lines of nanometre size in ®lms of about 100 nm thick of inorganic materials [128±130], such as alumina or aluminium¯uoride.…”

Theory of surface plasmons and surface-plasmon polaritons

“…Conversely, valence-electron excitations provide information about the surface structure with a resolution of the order of several nanometers. One advantage of valence EELS is that it provides a strong signal, even for non-penetrating trajectories (the so-called aloof beam energy loss spectroscopy [337,338]), and generates less specimen damage [135].…”