Potassium intercalated bundles of single-wall carbon nanotubes: electronicstructure and optical properties

We present electron energy-loss spectroscopic measurements of potassium int ercalated bundles of single-wall carbon nanotubes. The loss function at low momentum transfer can be simulated within a simple Drude-Lorentz model, in dicating that all of the nanotubes were driven metallic by intercalation. F rom the value of the unscreened plasma energy (1.85 eV) and the damping (0. 4 eV), a lower limit for the optically derived conductivity of the fully in tercalated material of 1200 S cm(-1) is found. This indicates an effective mass 3.5 times greater than that in the analogous graphite intercalation co mpound. (C) 1999 Elsevier Science Ltd. All rights reserved.