Mesoscopic proximity effect probed through superconducting contacts

Abstract

We investigate the properties of complex mesoscopic superconducting-normal hybrid devices, Andreev-Interferometers in the case, where the current is proped through a superconducting tunneling contact whereas the proximity effect is generated by a transparent SN-interface. We show within the quasiclassical Green's functions technique, how the fundamental SNIS-element of the such structures can be mapped onto an effective S$^\prime$IS-junction, where S$^\prime$ is the proximised material with an effective energy gap $E_g<\Delta$. We propose the Andreev-Interferometer, where $E_g$ can be tuned by an external phase $\phi$ and displays maxima at 0 mod $2\pi$ and minima at $\pi$ mod $2\pi$. This leads to peculiar current-phase-relations We propose an experiment to verify our predictions and show, how our results are consistent with recent, unexplained experimental results.