Metallic nature of heavily doped polyacetylene derivatives: Thermopower

Abstract

Metallic thermopower data on ${\mathrm{FeCl}}_{3}$-doped polyacetylene are presented. We compare the results with the data on iodine- and ${\mathrm{AsF}}_{5}$-doped polyacetylene in the heavily doped regime. General features of the results are consistent with those of a simple metal. However, details are different. We interpret these differences as originating from the different coupling strengths between the metallic chain and the dopant in each polyacetylene derivative. The disorder induced by the dopant ion seems to be more important than the three-dimensional interchain coupling. Thus, the charge-transport mechanism may be quasi one dimensional at the high-concentration limit.