INTERLAYER PAIRINGS IN THE JOSEPHSON-COUPLED LAYERED SUPERCONDUCTORS

The general expression of the effective pairing Hamiltonian is propose d to obtain the multicomponent Ginzburg-Landau free energy functional for strongly anisotropic layered superconductors. The effective Hamilt onian contains an intralayer pairing interaction as well as all possib le interlayer pairing potentials. It is shown that the problem with ma ny order parameters can be reduced to the problem with two order param eters which characterize the effective intralayer and effective interl ayer pairings, The interlayer interaction (V) over tilde(0), which cor responds to the coherently hopping of pairs from one layer to the near est neighboring layers, renormalizes the Josephson tunneling strength for an intralayer effective order parameter. Mixing of two order param eters is characterized by the Lifschitz invariant in the free energy f unctional. The Lifschitz invariant is enhanced due to the interlayer p airing potential V-01 which represents an interaction of two particles on the layer with scattering one of them into the nearest neighboring layers. The interlayer interaction V-01, also stabilizes the mixing o f two-order parameters. Since in the absence of V-01 the Lifschitz inv ariant vanishes for a half-filled band of two-dimensional electrons in a layer. The transition temperature T-c to the superconducting state and upper critical magnetic field H-c2 are calculated. Effects of all possible interlayer pairing interactions on T-c and H-c2 an studied. ( C) 1998 Elsevier Science B.V.