Metallic conductivity of highly doped poly(3,4-ethylenedioxythiophene)

The temperature dependences of the conductivity sigma(T) and magnetoconductivity (MC) of poly(3,4-ethylenedioxythiophene), PEDOT, doped with PF6, BF4, and CF3SO3 have been studied down to 1.2 K. The transition in sigma(T) from negative to positive temperature coefficient of resistivity, TCR, has been found below 10 K for samples with rho(r) = rho(1.4 K)/rho(291 K) approximate to 1.5-2.8. For negative and positive TCR the cr(T) is isotropic and similar to T-1/2. The MC is negative, isotropic and similar to H-2 and H-1/2 at row and high magnetic field respectively. The results are explained as resulting of the dominant influence of electron-electron interactions on the sigma(T).