Momentum Broadening in the Interlayer Pair-Tunneling Model of High-T C Superconductivity

Abstract

We investigate how momentum broadening of the interlayer pairing kernel in the interlayer pair tunneling model of high-T c superconductivity affects the critical temperature T c and the zero-temperature gap function. We consider constant as well as k-dependent intralayer pairing kernels. For a sign-changing gap, the variation of T c with broadening is slightly enhanced compared to a gap of constant sign. We identify the amount of broadening that will destroy the sharp k-space features of the gap obtained with a k-diagonal interlayer tunneling, explaining our results in terms of Fermi surface features of the gap. The parameter controlling this amount of k-space broadening is T J /t, where T J is the interlayer tunneling matrix element and t is the bandwidth parameter of the normal state intralayer motion.