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.