https://doi.org/10.1140/epjb/e2013-31157-6
Regular Article
On the theory of superconductivity in the extended Hubbard model
Spin-fluctuation pairing
1 Joint Institute for Nuclear
Research, 141980
Dubna,
Russia
2 Max-Planck-Institut für Physik
komplexer Systeme, 01187
Dresden,
Germany
3 Rutgers University,
08854
New Jersey,
USA
a e-mail: plakida@theor.jinr.ru
Received:
27
December
2012
Received in final form:
17
January
2013
Published online:
25
March
2013
A microscopic theory of superconductivity in the extended Hubbard model which takes into account the intersite Coulomb repulsion and electron-phonon interaction is developed in the limit of strong correlations. The Dyson equation for normal and pair Green functions expressed in terms of the Hubbard operators is derived. The self-energy is obtained in the noncrossing approximation. In the normal state, antiferromagnetic short-range correlations result in the electronic spectrum with a narrow bandwidth. We calculate superconducting Tc by taking into account the pairing mediated by charge and spin fluctuations and phonons. We found the d-wave pairing with high-Tc mediated by spin fluctuations induced by the strong kinematic interaction for the Hubbard operators. Contributions to the d-wave pairing coming from the intersite Coulomb repulsion and phonons turned out to be small.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2013