Finding <i>T</i>_c in an attractive-<i>U </i>Hubbard-metallic bilayer system.

An intriguing route to higher temperature superconductivity is via coupling layers of different material properties. From a model standpoint, others have shown coupling layers with a large pairing scale, and weak superfluid stiffness to a metal can recover part of the mean-field transition temperature when coupled to a thin metallic film. But how general is this result? We examine this question by studying a bilayer system comprised of an attractive Hubbard layer and a metallic layer coupled with an interlayer hopping using the dynamical cluster approximation. Focusing on the regime where the interaction magnitude is comparable to the electronic bandwidth, we find that coupling between the layers suppresses T_c and that the transition evolves from a Kosterlitz-Thouless type to a logarithmic BCS (mean-field) type transition. We will discuss the reasons for this suppression and potential future directions.