A STUDY OF LOCALIZATION IN A MODEL SUPERLATTICE WITH 3-DIMENSIONAL DISORDER DISTRIBUTION

We study a microscopic model for a disordered superlattice system, which simulates the effect of intrinsic alloy fluctuation on localization in alloy superlattices. Numerical investigation of scaling behavior of the localiza-tion length shows that excitations along and perpendicular to the super-lattice axis undergo a localization transition at a nonzero critical disorder. Therefore, we contend that for localization, the alloy superlattices should be viewed as a 3-dimensional anisotropic material. At the transition, the localization length diverges with critical exponent v = 1.2 t 0.2. We expect that the model belongs to the same universality class as the 3 dimensional isotropic Anderson model. 0 1997 Elsevier Science Ltd. All rights reserved Recently, much attention [l-6] has been paid to the study of the localization transition in anisotropic materials. It seems now that there is general agreement that the critical disorder at which the localization transition takes plac