A REALISTIC MICROSCOPIC THEORY FOR THE HIGH-TC CUPRATES

The electronic structure of the high-T(c) cuprates is worked out by decomposing the orbitals around the Fermi level into ''large-U'' and ''small-U'' components. The large- U orbitals are treated by the ''slave-fermion'' method, the small-U orbitals by a mean-field approach, and the hybridization between them is then worked out. It turns out that hopping energy binds the spin and the charge of the large- U orbitals. The state so obtained is either antiferromagnetic, or paramagnetic with antiferromagnetic fluctuations and with violation of parity. Two types of charge carriers are predicted: (i) spinless polarons with a very small bandwidth, explaining the anomalous thermoelectric power, the mid-infrared peak, lattice anomalies, etc.; (ii) anomalous carriers of both charge and spin, explaining ''marginal-Fermi-liquid'' behavior and deviations from it, anomalous relaxation time, the systematic behavior of the resistivity, the Hall constant, the Hall angle, etc.