Schimmel, T. and Denninger, G. and Riess, W. and Voit, J. and Schwoerer, M. and Schoepe, Wilfried and Naarmann, H.
High-θ polyacetylene: DC conductivity between 14 mK and 300 K.
Synthetic Metals 28 (3), D11-D18.
Highly stretch-oriented polyacetylene (6.5:1) yields conductivities σ of typically 20 000–100 000 Ω−1cm−1 at room temperature when highly doped with iodine. Between T = 300 K and T = 14 mK, σ decreases monotonically by about a factor of 5 for fresh samples. Above 400 mK the temperature dependence for fresh samples is fitted by the SHENG formula and can be interpreted within a phenomenological model. On fresh samples, MONTGOMERY measurements of the conductivities parallel (σı) and perpendicular (σσ) to the stretching axis show a temperature independent anisotropy A=σı/σσ of about 25 indicating a common limiting mechanism for both, σı and σσ. Deliberate oxygen ageing drastically changes σ(T) and results in a temperature dependence of A.