The influence of low-energy excitations on the metallic conductivity of perchlorate doped polyacetylene

The nature of low-temperature conductivity for stretch oriented perchlorate doped polyacetylene (PA) films is considered. It is concluded that the con ductivity behavior is, in particular, related to a strong inelastic electro n scattering by low-energy vibrational excitations which becomes important due to the influence of glassy properties on the polymer structure. The obs erved negative magnetoresistance (MR) is attributed to weak localization, w hich at higher temperature is suppressed by a strong inelastic scattering o f electrons by low-energy vibrational excitations typical for glasses. The possible influence of inelastic scattering by lattice vibrations typical fo r clean metals or by quasilocal harmonic vibrations typical for glasses on the metallic conductivity at higher temperature is discussed. (C) 2001 Else vier Science B.V. All rights reserved.