Doping-dependent quasiparticle band structure in cuprate superconductors

We present an exact diagonalization study of the single-particle spectral function in the so-called t-t|IH-t{''}-J model in two dimensions. As a key result, we find that hole doping leads to a major reconstruction of the quasiparticle band structure near ({π},0): whereas for the undoped system the quasiparticle states near ({π},0) are deep below the top of the band near ({π}/2,{π}/2), hole doping shifts these states up to EF, resulting in extended flat band regions close to EF and around ({π},0).