| Spin fluctuation pairing in strongly correlated electronic systems |
September, 20 (2006) at 12am Nikolay Plakida A problem of superconducting pairing mediated by repulsion is discussed. At first, a phenomenological approach is considered and then a microscopic theory in the strong correlation limit within the Hubbard model is presented. By using the Hubbard operator technique, a Dyson equation is derived and solved in the self-consistent Born approximation for the self-energy. It is demonstrated that there are two channels in the pairing: the antiferromagnetic exchange mediated by interband hopping and the spin-fluctuation pairing caused by kinematic interaction in the intraband hopping. The theory is applied to study the copper-oxide superconductors, in particular, T_c dependence on the hole concentration, lattice constants (or pressure) and an oxygen isotope shift are discussed. |