Tight-binding quantum network with cosine modulations: electronic localization and delocalization

Localization phenomena of non-interacting electrons are critically investigated in a quantum network where site energies and/or hopping integrals are correlated in the form of Aubry-Andre-Harper (AAH) model. In presence of diagonal hopping between neighboring strands of the network an energy zone, consists of extended and localized states, appears whose width can be adjusted by tuning the physical parameters describing the system. It gives an important signature towards the detection of mobility edge which we justify by analyzing the energy band spectra. Finally, we study the interplay between the diagonal and off-diagonal disorders, and explore the robust delocalizing effect. Our analysis may lead to important aspects of electronic localization in coupled AAH chains.