Proximity fingerprint of s±-superconductivity
Materials Science Division, Argonne National Laboratory - Argonne, IL 60439, USA
Accepted: 6 September 2011
We suggest a straightforward and unambiguous test to identify possible opposite signs of the superconducting order parameter in different bands proposed for iron-based superconductors (s±-state). We consider the proximity effect in a weakly coupled sandwich composed of a s±-superconductor and a thin layer of the s-wave superconductor. In such system the s-wave order parameter is coupled differently with different s±-gaps and it typically aligns with one of these gaps. This forces the other s±-gap to be anti-aligned with the s-wave gap. In such situation the aligned band induces a peak in the s-wave density of states (DoS), while the anti-aligned band induces a dip. Observation of such contact-induced negative feature in the s-wave DoS would provide a definite proof for s±-superconductivity.
PACS: 74.45.+c – Proximity effects; Andreev reflection; SN and SNS junctions / 74.70.Xa – Pnictides and chalcogenides / 74.20.Rp – Pairing symmetries (other than s-wave)
© EPLA, 2011