Existence of delocalized states in two interpenetrated 1-D diluted Anderson chains

In this Letter we introduce a new model of a diluted Anderson model, which is a non-trivial generalization of a previous work of Late and Onell (Physi ca B 299 (2001) 173), because every Anderson impurity is surrounded by two different sets of site energies, generated by two different periodic functi ons epsilon (i) = f(i), i =2,...,(l(1) + 1), and epsilon (k) = h(k),k = (l( 1) + 1),..., (l(1) + l(2) + 2). Thus, this disordered model has two interpe netrating Anderson lattices with the same periodicity P = (l(1) + l(2) + 2) , where l(1) and l(2) are the numbers of impurities on each diluting set. I n addition, the distance between two consecutive Anderson impurities altern ates between l(1) and l(2) values, apparently breaking the spatial correlat ion, which produces delocalized states when the disorder is diluted in a pe riodical form. Using the block decimation scheme, we demonstrate the existe nce of exactly (l(1) + l(2)) Critical energy values for which this disorder ed system presents delocalized slates. (C) 2001 Elsevier Science B.V, All r ights reserved.