Mean Field Green Function Solution of the Two-Band Hubbard Model in Cuprates

The paper discusses the generalized mean field solution of the Green function matrix of the effective two-band two-dimensional Hubbard model of the high-Tc superconductivity in cuprates, as recently modified to include appropriate boundary conditions at zero doping. Two main results are found. (i) Hybridization of normal state energy levels preserves the center of gravity of the unhybridized levels. (ii) Hybridization of superconducting state energy levels displaces the center of gravity of the unhybridized normal levels. The whole spectrum is displaced towards lower frequencies.

high-Tc superconductivity, cuprates, two-band Hubbard model, Green function, mean field approximation