MAGNETORESISTANCE OF RANDOM DOUBLE-CHAIN SYSTEMS

The transport properties of double-chain systems with random interchai n couplings in the presence of a magnetic field are studied theoretica lly by the use of an exact self-consistent recursion method and the La ndauer's formula. Each of the chains is either pure or doped with impu rities. Our results show that the magnetic field has either a delocali zation or localization effect on electronic states depending on the ty pe of the topological configuration of the system. Some structures exh ibit a high positive magnetoresistance. The calculated magnetic-held a nd temperature dependence of the conductance are compared with experim ental data of highly conducting polymers.