Superconductivity from repulsion: Ginzburg-Landau phenomenology of cuprates

We develop Ginzburg-Landau approach to the problem of superconducting pairing with large momentum under screened Coulomb repulsion (eta_K-pairing). Two-component order parameter arising in this scheme can be associated with charge and orbital current degrees of freedom of the relative motion of eta_K-pair corresponding to superconducting and orbital antiferromagnetic ordered states, respectively. All basic features of the phase diagram of cuprate superconductors result directly from the eta_K-pairing concept.