A new perspective on the Animalu nonlocal pairing model of high-Tc superconductivity is reported, currently stressing the possible interband (Cu3d-02p) charge transfer matrix (t). The mean-field Suhl-Matthias-Walker-type Hamiltonian obtained reveals hybrid and nonhybrid Cooper-pair wavefunctions, the latter manifesting anomalous splitting of quasiparticle energy. This result, presently interpreted as the Jahn-Teller (JT) effect, is briefly discussed in the context of data on the Cu-O bond length. In our brief Green’s function analysis, an approximate t-dependence of the nonlocal pair potential (Vij, i ≠ j) and a semi-empirical expression for the JT stabilisation energy (EJT), which we believe to be new, are presented. Numerical estimates of EJT for YBa2Cu3O6.9 compare well with photoemission data. Normal state energies obtained in the model are in excellent qualitative or quantitative agreement with the Mott-Hubbard picture, results from the Gutzwiller approximation of the Emery model and Ohkawa’s breathing mode scheme for the copper ceramic oxides.
Physica C Superconductivity 02/1996; 258(1-2):30-40. DOI:10.1016/0921-4534(95)00412-2