Localised and delocalized charge transport in single-wall carbon-nanotube mats

We measured the complex dielectric constant in mats of single-wall carbon n anotubes between 2.7 K and 300 K up to 0.5 THz. The data are well understoo d in a Drude approach with a negligible temperature dependence of the plasm a frequency omega(p) and scattering time tau with an additional contributio n of localized charges. The dielectric properties resemble those of the bes t "metallic" polypyrroles and polyanilines. The absence of metallic islands makes the mats a relevant piece in the puzzle of the interpretation of tau and omega(p) in these polymers.