Spectral Properties of High-Tc Cuprates via a Cluster-Perturbation Approach

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Angular-resolved photoemission data on half-filled doped cuprate materials are compared with an exact-diagonalization analysis of the three-band Hubbard model, which is extended to the infinite lattice by means of a perturbation in the intercluster hopping (cluster perturbation theory). A study of the band dispersion and spectral weight of the insulating cuprate Sr₂CuO₂Cl₂ allows us to fix a consistent parameter set, which turns out to be appropriate at finite dopings as well. In the overdoped regime, our results for the spectral weight and for the Fermi surface give a good description of the experimental data on Bi₂Sr₂CaCu₂O₈₊δ. In particular, the Fermi surface is hole-like and centered around k=(π,π). Finally, we introduce a hopping between two layers and address the issue of bilayer splitting.