D. Bormann et P. Bernier, LOW-TEMPERATURE SINGULARITY OF THE ELECTRICAL-CONDUCTIVITY IN POTASSIUM-DOPED POLYACETYLENE, Synthetic metals, 84(1-3), 1997, pp. 907-908
We present the temperature dependence of the electrical conductivity o
f highly potassium doped polyacetylene. While the conductivity sigma o
f these systems usually decreases when T decreases, we show that it is
possible to observe an increase of sigma for decreasing temperatures
when T < 7 K. The Sheng model is able to explain the behaviour of the
conductivity for T > 10 K but it diverges from our data for T < 10 K.
Highly potassium doped polyacetylene behaves like a metal for 4.2 K <
T < 10 K and we demonstrate that a model of disordered metal correctly
fits our results. This study gives an interpretation for the electric
al conductivity behaviour in the whole temperature range 4.2 K - 300 K
and shows the importance of the: intrinsic disorder of the polymer in
the observation of the singularity at low temperature.