PRESSURE-INDUCED METALLIC RESISTIVITY OF PF6- DOPED POLY(3-METHYLTHIOPHENE)

Electrical resistivity of poly(3-methylthiophene) doped with PF6- has been studied under pressure up to 13 kbar using a self-clamped berylli um-copper pressure cell. Application of the pressure induces a metalli c temperature dependence in resistivity at low temperatures. Below abo ut 4 K, T-1/2 dependence in electrical conductivity was observed, whic h can be explained taking the electron-electron interaction in a disor dered system into account. We show that the extended heterogeneous mod el by Kaiser and Graham gives a good fit to the temperature dependence of the conductivity at low temperatures in the whole range of the pre ssure applied. (C) 1998 Elsevier Science S.A.