The metallic state in conjugated polymers and single-walled carbon nanotube
s: is studied by dielectric spectroscopy (8-600 GHz). We have found an intr
iguing correlation between scattering time (tau) and plasma frequency (omeg
a (p)):tau (proportional to)omega (-1.3)(p). This relation conflicts with t
he usually applied models that only consider disorder. Based on the observe
d parallels with doped semiconductors, we argue that the interchain couplin
g t(perpendicular to) plays a role comparable to the doping level and that
the unusual free-carrier dynamics in the metallic state can be explained wh
en including the role of t(perpendicular to) in the conventional models.