Details

Autor(en) / Beteiligte

• Ko, Wonhee
• Lado, Jose L.
• Maksymovych, Petro

Titel

Noncontact Andreev Reflection as a Direct Probe of Superconductivity on the Atomic Scale

Ist Teil von

• Nano letters, 2022-05, Vol.22 (10), p.4042-4048

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Direct detection of superconductivity has long been a key strength of point-contact Andreev reflection. However, its applicability to atomic-scale imaging is limited by the mechanical contact of the Andreev probe. To this end, we present a new method to probe Andreev reflection in a tunnel junction, leveraging tunneling spectroscopy and junction tunability to achieve quantitative detection of Andreev scattering. This method enables unambiguous assignment of superconducting origins of current-carrying excitations, as well as detection of higher order Andreev processes in atomic-scale junctions. We furthermore revealed distinct sensitivity of Andreev reflection to natural defects, such as step edges, even in classical superconductors. The methodology opens a new path to nano- and atomic-scale imaging of superconducting properties, including disordered superconductors and proximity to phase transitions.