We study the k dependence of the gap function of a bilayer superconductor, using standard mean-field techniques applied to a two-dimensional extended Hubbard model, in the presence of coherent interlayer pair-tunneling and quenched coherent single-particle tunneling. The intralayer pairing potential thus defined is expandable in a finite number (5) of basis functions for the irreducible representations of the point-grqup of the perfectly square lattice C-4 nu This gives rise to a competition between s- and d-wave symmetry, as the chemical potential is increased from the bottom to the top of a realistic band for most cuprates. It allows for mixed-symmetry paired state at temperatures below T-c, but never at T-c on a square lattice. Inclusion of the interlayer pair tunneling into the effective pairing potential leads to highly nontrivial k-space structures, such as pronounced maxima along the Fermi line not seen in the absence of interlayer pair tunneling. We show how such a gap structure evolves with temperature and with band filling, and how it affects various observables. In particular, a nonuniversal value of the normalized jump in the specific heat at T-c will be evidenced, at variance with the conventional universal BCS result. [S0163-1829(99)03502-X].
|Titolo:||Sharp k-space features in the order parameter within the interlayer pair-tunneling mechanism of high-T-c, superconductivity|
|Autori interni:||SIRINGO, Fabio|
ANGILELLA, Giuseppe Gioacchino Neil
|Data di pubblicazione:||1999|
|Rivista:||PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS|
|Appare nelle tipologie:||1.1 Articolo in rivista|