Pair-pair interactions as a mechanism for high-Tc superconductivity
Abstract
The mutual interaction between Cooper pairs is proposed as a mechanism for the superconducting state. Above Tc, pre-existing but fluctuating Cooper pairs give rise to the unconventional pseudogap (PG) state, well-characterized by experiment. At the critical temperature, the pair-pair interaction induces a Bose-like condensation of these preformed pairs leading to the superconducting (SC) state. Below Tc, both the condensation energy and the pair-pair interaction β are proportional to the condensate density Noc(T), whereas the usual Fermi-level spectral gap p is independent of temperature. The new order parameter β(T), can be followed as a function of temperature, carrier concentration and disorder - i.e. the phase diagrams. The complexity of the cuprates, revealed by the large number of parameters, is a consequence of the coupling of quasiparticles to Cooper-pair excitations. The latter interpretation is strongly supported by the observed quasiparticle spectral function.