Andreev reflection spectroscopy in strongly paired superconductors

Abstract

One of the challenges in the pursuit of solid state BEC superconductors is the need for unambiguous experimental signatures. Here, the authors propose a new signature, relying on Andreev reflection, which distinguishes BEC from BCS superconductors. They demonstrate that, in a standard tunneling spectroscopy setup, a BEC superconductor exhibits suppressed Andreev reflection; however, if the tunneling barrier becomes a potential well, then appreciable Andreev reflection can be revived. Their predictions can be probed in various architectures that are also discussed.

Topics & Concepts