Electronic theory for superconductivity in : Triplet pairing due to spin-fluctuation exchange
Institut für Theoretische Physik, Freie
Universität Berlin D-14195 Berlin, Germany
2 Physics Department, Kazan State University - 420008 Kazan, Russia
Accepted: 2 April 2002
Using a Hubbard Hamiltonian for the three electronic bands crossing the Fermi level in , we calculate the band structure and spin susceptibility in quantitative agreement with nuclear magnetic resonance (NMR) and inelastic neutron scattering (INS) experiments. The susceptibility has two peaks at due to the nesting Fermi surface properties and at due to the tendency towards ferromagnetism. Applying spin-fluctuation exchange theory as in layered cuprates we determine from , electronic dispersions, and Fermi surface topology that superconductivity in consists of triplet pairing. Using we can exclude s- and d-wave symmetry for the superconducting order parameter. Furthermore, within our analysis and approximations we find that the order parameter will have a node between neighboring -planes and that in the -plane -wave and p-wave symmetry are close in energy.
PACS: 74.20.Mn – Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) / 74.25.-q – General properties; correlations between physical properties in normal and superconducting states / 74.25.Ha – Magnetic properties
© EDP Sciences, 2002