Symmetry and anisotropy of the superconducting gap in layered cuprates: Analysis of experiments on photoemission and the influence of defects on the critical temperature
Krasheninnikov A. V., Opyonov L. A. , Elesin V. F.
The anisotropy parameter χ, which appears in the formula for the critical temperature Tc as a function of the concentration of defects, is calculated on the basis of the results of experimental studies of the Fermi surface and superconducting gap Δ in high-rc superconductors by the method of angle-resolved photoemission spectroscopy. It is shown that the assumption of anisotropic s-pairing makes it possible to correlate the strong angular dependence of Δ in the a — b plane with the relatively weak sensitivity of Tc to atomic disordering. In this case ^«=0.1, which is an order of magnitude less than in the case of i/-pairing (χ= 1) and strongly anisotropic s-pairing (χ^ 1). © 1995