Electron structure and electron-phonon interaction in the strongly correlated electron system of cuprates
S.G. Ovchinnikov, V.A. Gavrichkov, M.M. Korshunov, and E.I. Shneyder
L.V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Sciences Krasnoyarsk 660036, Russia
Received August 22, 2005
The generalized tight-binding method presents a practical realization of the scheme that describes quasiparticles in strongly correlated electron system and consists of exact intra-cell diagonalization of the model Hamiltonian and perturbative treatment of the inter-cell hoppings. In present paper this method and its ab initio modification applied to undoped and weakly doped HTSC cuprates. Results are in very good agreement with the experimental ARPES data on various compounds. Starting with multiband p—d model the realistic effective low-energy Hamiltonian of
strongly correlated electrons interacting with spin fluctuations and phonons is derived both for hole and electron doped systems. Without electron—phonon interaction the pure magnetic mechanism of pairing does not provide the correct value of Tc even for single-layer La2–xSrxCuO4 and
Nd2–xCexCuO4.PACS: 74.72.-h - Cuprate superconductors (high-Tc and insulating parent compounds) 74.20.Mn - Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) 74.25.Jb - Electronic structure 74.25.Kc - Phonons
Key words: strongly correlated electron system, elektron–phonon interaction HTSP cuprates.