date:Katholieke Univ Leuven, Vaste Stof Fys & Magnetisme Lab, B-3001 Louvain, Belgium; Sofia Univ St Kliment Ohridski, Fac Phys, Dept Theoret Phys, BG-1164 Sofia, Bulgaria
A detailed Linear Combination of Atomic Orbitals (LCAO) tight-binding model is developed for the layered High-Temperature Superconductor (HTSC) cuprates. The band structure of these materials is described using a sigma-band Hamiltonian employing Cu4s, Cu3d(x)(-y)(2)(2), O2p(x) and O2p(y) atomic orbitals. The Fermi level and the shape of the resulting Fermi surface are fitted to recent Angle Resolved Photon Emission Spectroscopy (ARPES) data to realistically determine the dispersion in the conduction band. Electron-electron interactions and, ultimately, Cooper pairing are obtained by introducing a Heitler-London, two-electron exchange between adjacent orbitals within the CuO2 plane. Finally, using the LCAO wavefunctions determined by the band structure fit, the Bardeen-Cooper-Schrieffer (BCS) type kernel is derived for interatomic exchange.