DIAGRAMMATIC SELF-CONSISTENT THEORY OF ANDERSON LOCALIZATION FOR THE TIGHT-BINDING MODEL

A self-consistent theory of the frequency dependent diffusion coefficient for the Anderson localization problem is presented within the tight-bonding model of noninteracting electrons on a lattice with randomly distributed on-site energy levels. The theory uses a diagrammatic expansion in terms of (extended) Bloch states and is found to be equivalent to the expansion in terms of (localized) Wannier states which was derived earlier by Kroha, Kopp and Wölfle. No adjustable parameters enter the theory. The localization length is calculated in 1, 2 and 3 dimensions as well as the frequency dependent conductivity and the phase diagram of localization in 3 dimensions for various types of disorder distributions. The validity of a universal scaling function of the length dependent conductance derived from this theory is discussed in the strong coupling region. Quantitative agreement with results from numerical diagonalization of finite systems demonstrates that the self-consistent treatment of cooperon contributions is sufficient to explain the phase diagram of localization and suggests that the system may be well described by a one-parameter scaling theory in certain regions of the phase diagram, if one is not too close to the transition point. © 1990.