Hole pairing induced by antiferromagnetic spin fluctuations

The revolutionary discovery of high Tc superconductivity in oxide compounds has stimulated great efforts towards its theoretical interpretation. Apart from the conventional electron-phonon interaction, a large number of different mechanisms have been proposed including the resonating valence bond (RVB), charge transfer excitons, coupling to antiferromagnetic (AF) spin configurations, and many others. In this paper we study the effective interaction between two holes seen as defects on an AF background mediated by spin fluctuations (exchange of virtual spin waves) in the random phase approximation. We find that this effective interaction favours triplet pairing in the antiparallel configuration (S = 1, Sz = 0) and does not favour the singlet pairing. Moreover, this effective interaction is found to persist even if the AF long range order is switched off. 26 refs