ANDERSON LOCALIZATION FOR SUBLATTICE MODELS

A new universality class for the Anderson-localization behaviour is established. It is represented by a particular class of the Anderson model where all random variables or regular matrix transfer elements connect only points of different sublattices. For the band centre an effective field theory based on the replica trick with manifold GL(4m, C)/U(4m) is derived. From an epsilon expansion a trivial beta function indicating extended states at the band centre in two dimensions is obtained. Due to the nonvanishing zeta function the density of states is enhanced for d > 2 and diverges as d approaches 2. For nonzero energies the sublattice restriction does not modify the symmetry group. The energy dependence of several quantities related to one- and two-particle Green functions is given in a crude approximation.