Electrical Conduction of Poly-Acetylene under High Pressure

The thermal activation energy of the electrical conduction in the polyacetylene powder was measured as a function of pressure in the temperature range from room to liquid nitrogen temperature. The thermal activation energy of 0.27 eV at atmospheric pressure decreased to 0.17 eV at 100 kbar. Contrary to the expectation, the pre-exponential factor of the conductivity did not change at all. These results suggest that for this material the energy gap changes with pressure, while the probability of the carrier transfer between molecules does not change with the pressure.