BIPOLARON-IMPURITY INTERACTION IN CONDUCTING POLYMERS

We consider the interaction of localized and delocalized bipolarons (B Ps) with charged and local impurities in conducting polymers. At low t emperatures the bound state of a BP at the impurity is asymmetric and doubly degenerate with respect to the dipole moment's direction. This results in a low frequency absorption and in linear temperature depend ence of the specific heat. The results agree qualitatively with experi mental data on doped (CH)x. At high temperatures we calculated the mea n free path and the localization length l(c). We show that at curtain resonance energies of BP l(c) increases up to complete delocalization.