Non-solitonic conductivity in polyacetylene

Abstract Systematic investigations of the temperature dependences of the d.c. and microwave conductivity of polyacetylene doped with various species are reported. These results are discussed within a model where the measured quantities are a superposition of different conduction mechanisms. At low dopant concentrations carrier hopping between localized defect states dominates, while at high doping levels only the inter-fibrillar contact resistances are important. In an intermediate doping region the prevailing contribution to the conductivity is carrier tunnelling between highly conducting parts of the sample separated by less-conducting zones. There seems to be no doping regime in which carrier transport via mobile conjugational defects (solitons) plays a detectable role.