BCS VERSUS JOSEPHSON PAIR HOPPING BETWEEN THE CUO2 LAYERS IN HIGH-TC SUPERCONDUCTORS

We start with the two-dimensional (2D) scattering matrix for two electrons of opposite spin and momentum, accounting for the fluctuating pair correlations in a single CuO2 layer, and consider the interlayer pair hopping by (a) BCS scattering out of the layer and (b) Josephson tunneling between layers. The experimental 3D transition temperature Tc is found as a function of the interlayer BCS coupling parameter and the Josephson-tunneling matrix element. We discuss the relative importance of both of these transfer mechanisms for the Y and Tl compounds. © 1990 The American Physical Society.