Site correlation, anomalous diffusion, and enhancement of the localization length

Herein we study the effects on Anderson localization of correlations in the energy distribution of the sites of a tight-binding Hamiltonian. The lattice correlations are introduced by means of classical maps generating anomalous diffusion, that have recently been found to account for the correlated disorder of ‘‘biological’’ lattices. We show that the enhancement of localization length takes place on a much wider band of energies than in the case of the random-dimer model if the random walk on the site energies of the tight-binding Hamiltonian is determined by the joint action of short- and long-range correlations. © 1996 The American Physical Society.