Momentum- and space-resolved high-resolution electron energy loss spectroscopy of individual single-wall carbon nanotubes

The ability to probe the electronic structure of individual nano-objects at high energy resolution using momentum- and space-resolved electron energy loss spectroscopy in the scanning transmission electron microscope is demonstrated through the observation of confinement of the π plasmon in individual single-wall carbon nanotubes. While confinement perpendicular to the tube axis was identified for all investigated tubes, a variable degree of confinement parallel to the tube axis was attributed to the concentration of topological defects. Spatially resolved valence loss spectra allowed for the identification of a loss peak attributed to a chirality-dependent radial interband transition. Furthermore, the importance of a careful consideration of loss peak momentum dispersions for the interpretation of spatially resolved valence loss spectra is discussed.