Extended states in 1-D Anderson chain diluted by periodic disorder

In this work, we generalize the periodic random Anderson model, because instead of using constant site energies between disordered sites, we dilute the Anderson lattice by means of(P - 1) site energies given by an arbitrary periodic function epsilon (l) =f(l) =f(l + P), I = 2, 3,..., P, where P is the period of the Anderson lattice. Using a block decimation scheme, we analytically find the mathematical conditions for the appearing of delocalized states with critical energies E,. In addition, we find some of the symmetries associated to the function f(l) which allows the propagation of extended electronic waves through our generalized model. (C) 2001 Elsevier Science B.V. All rights reserved.