Renormalization approach for transport and electronic properties of conducting polymers

By means of the renormalization approach, we have developed a map that allows us to investigate transport and electronic properties in polyaniline chains in terms of an effective lattice. This lattice may contain impurities of two kinds: the first has the form of a couple of sites (dimer) with the same or different site energies according to the symmetry of the rings of the polymer it simulates; the other can occur without constraint in the number of sites involved. In the case of more sophisticated descriptions of the polymer, the dimer model can be inadequate and impurities of four sites have to be introduced in the map. We compare the results for the scattering properties of a single impurity with those of a finite sample of the chain, and we show the dependence of the results on the energies assigned to the carbon and nitrogen atoms of the polymer.