Los Alamos National Laboratory - Los Alamos, NM 87545, USA
2 Centro Atómico Bariloche and Instituto Balseiro - S. C. de Bariloche, Argentina
Accepted: 3 March 2000
A t-J–like model for inhomogeneous superconductivity of cuprate oxides is presented, in which local anisotropic magnetic terms are essential. We show that this model predicts pairing, consistent with experiments, and argue how the macroscopic phase-coherent state gradually grows upon lowering of the temperature. We show that appropriate inhomogeneities are essential in order to have significant pair binding in the thermodynamic limit. Particularly, local breaking of SU(2) spin symmetry is an efficient mechanism for inducing pairing of two holes, as well as explaining the magnetic scattering properties. We also discuss the connection of the resulting inhomogeneity-induced superconductivity to recent experimental evidence for a linear relation between magnetic incommensurability and the superconducting transition temperature, as a function of doping.
PACS: 74.20.-z – Theories and models of superconducting state / 74.20.Mn – Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) / 71.27.+a – Strongly correlated electron systems; heavy fermions
© EDP Sciences, 2000