Resonant scattering in random-polymer chains with inversely symmetric impurities

In the frame of the tight-binding approximation, we study the electronic transport and delocalization in one-dimensional random-polymer chains, where the impurity clusters are randomly distributed in the host monatomic chain and the impurity atoms possess inverse symmetry in each cluster. As an example, the asymmetric trimer case is presented first. The resonant energy is obtained analytically, which has been demonstrated by the numerical calculation on the electronic transmission. According to the zero Lyapunov exponent at the resonant energy, we confirm that electronic delocalization, indeed, exists in the model. Moreover, the undecayed electronic wave functions are shown near the resonant energy. Thereafter, we generalize the asymmetric trimer model to a polymer one with inversely symmetric impurities. The electronic delocalization and resonant scattering have been found in this generalized polymer model. The result is beyond the common viewpoint that the internal mirror symmetry in the defects is the necessary condition for the presence of delocaliztion in such correlated systems. The polymer model presented here may provide a way to make different types of polymers with high electronic conductivity.