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 (ηK-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 ηK-pair corresponding to superconducting and orbital antiferromagnetic ordered states, respectively. All basic features of the phase diagram of cuprate superconductors result directly from the ηK-pairing concept.