Ion interactions with carbon nanotubes in dielectric media

We extend the two-fluid, two-dimensional hydrodynamic model, describing the collective response of a multiwalled carbon nanotube, to include solid dielectric media embedded inside, or surrounding the nanotube. In the case of aluminum, we study plasmon hybridization in the UV range and find that the nanotube's low-energy, quasiacoustic pi plasmons are remarkably stable, whereas the shift of the high-energy sigma+pi plasmons strongly depends on the gap between the nanotube and the aluminum boundary. Moreover, we study the stopping force on fast ions moving inside nanotubes encapsulated in channels of insulating, amorphous carbon, and metallic materials, with special attention paid to nickel. Finally, our study of the dynamical image potential for fast ions shows that a nanotube will effectively shield the influence of an embedded nickel wire.