ELECTRONIC TRANSPORT IN WINDING CHAINS

We study the electronic transport properties of quasi-one-dimensional winding chains with random loops by an exact self-consistent recursion method. We obtain groups of states with very long localization length s which can lead to high values of the conductance. The energy distrib ution of these states causes unusual transport properties, similar to the behavior found near a metal-insulator transition. Our results demo nstrate the importance of the winding structures for explaining the pr operties of highly conducting polymers since the obtained temperature and magnetic-field dependences of the conductance in the presence of l ow loop density show good agreement with recent experimental results.