Theory of Superconductor—Normal-Metal Interfaces

Abstract

The superconducting properties of the clean superconductor---normal-metal interface are calculated assuming a constant BCS potential $\ensuremath{\Delta}(x)$ in the superconductor and zero potential in the normal metal. We evaluate the local electronic density of states, which is measured in the tunneling experiments, and find the magnitude of the interference-effect oscillations. The BCS potential is recalculated and is believed to be nearly self-consistent. The pair amplitude $〈{\ensuremath{\psi}}^{+}(x){\ensuremath{\psi}}^{+}(x) 〉$ and the potential oscillate $\ensuremath{\alpha} cos(\frac{x}{\ensuremath{\xi}})$ in the normal metal. We suggest a Josephson tunneling experiment to measure the pair amplitude.