FALICOV-KIMBALL MODEL AND ITS RELATION TO THE HUBBARD-MODEL - STUDIESON CLUSTERS

Ground-state properties of the asymmetric Hubbard model are studied on one-dimensional clusters (rings) with N = 6, 8, and 10 sites. The gro und-state energy, correlation functions, and phase diagrams are determ ined for various sets of model parameters. Computations are performed both by exact diagonalization (for N = 6) and by an approximate method by which correlation effects can be examined on larger clusters than exact diagonalization allows. In the Limiting cases (one limit corresp onds to the spinless Falicov-Kimball model and the other to the Hubbar d model) our results agree quite well with those obtained analytically for infinite systems.