Interchain coupling induced localization/delocalization in coupled one-dimensional ordered and disordered chains

A different type of system with coupled ordered-disordered chains has given rise to considerable interest recently, as it has a variety of applications in nanostructures and biological systems such as DNA molecules. We investigate the localization/delocalization of coupled one-dimensional systems composed of one disordered chain (chain I) and another ordered chain (chain II), focusing on the interplay among the disorder, correlation, and interchain coupling. We find that for systems where chain I exhibits uncorrelated disorder, charge transport in chain I (II) is enhanced (suppressed), as the disorder in chain I leads to the localization of all states in both chains. However, for chain I with hopping amplitude t(1) and long-range correlated disorder (with power-law spectral density and disorder strength W), we find there is a localization/delocalization transition for the case W <= 4t(1), induced by interchain coupling. For W > 4t(1), we find there is a quantum-phase transition at finite interchain coupling V-c: The interchain coupling induces appearance of two channels of extended states for V > V-c while there is only one channel of extended states for V < V-c.