Conductivity and magnetoconductivity below 1 K in films of poly(3,4-ethylenedioxythiophene) doped with CF3SO3

The temperature dependence of the electrical conductivity sigma(T) acid the magnetoconductivity sigma(B,T) of poly(3,4-ethylenedioxythiophene) (PEDOT) films heavily doped with CF3SO3 has been measured down to T = 150 mK in magnetic fields up to B = 9 T. It is shown that, below 1 K, sigma(T) alpha In T and sigma(B,T) depends significantly on the orientation of B parallel or perpendicular to the film surface. These facts are interpreted as a manifestation of two-dimensional character of electron transport in highly doped PEDOT films because of the possible formation of strongly graphitized layers with plane structure of polymer chains or fibrils. (C) 1998 Elsevier Science S.A. All rights reserved.