Superconducting quantum interference at the atomic scale

A single spin in a Josephson junction can reverse the flow of the supercurrent by changing the sign of the superconducting phase difference across it. At mesoscopic length scales, these π-junctions are employed in various applications, such as finding the pairing symmetry of the underlying supercond...

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Bibliographic Details
Authors: Karan, Sujoy, Huang, Haonan, Padurariu, Ciprian, Kubala, Björn, Theiler, Andreas, Black-Schaffer, Annica M., Morras Gutiérrez, Gonzalo, Levy-Yeyati Mizrahi, Alfredo, Cuevas Rodríguez, Juan Carlos, Ankerhold, Joachim, Kern, Klaus, Ast, Christian R.
Format: article
Publication Date:2022
Country:España
Institution:Universidad Autónoma de Madrid
Repository:Biblos-e Archivo. Repositorio Institucional de la UAM
Language:English
OAI Identifier:oai:repositorio.uam.es:10486/715710
Online Access:http://hdl.handle.net/10486/715710
https://dx.doi.org/10.1038/s41567-022-01644-6
Access Level:Open access
Keyword:Superconducting quantum
Atomic scale
Yu–Shiba–Rusinov state
Josephson junction
Física
Description
Summary:A single spin in a Josephson junction can reverse the flow of the supercurrent by changing the sign of the superconducting phase difference across it. At mesoscopic length scales, these π-junctions are employed in various applications, such as finding the pairing symmetry of the underlying superconductor, as well as quantum computing. At the atomic scale, the counterpart of a single spin in a superconducting tunnel junction is known as a Yu–Shiba–Rusinov state. Observation of the supercurrent reversal in that setting has so far remained elusive. Here we demonstrate such a 0 to π transition of a Josephson junction through a Yu–Shiba–Rusinov state as we continuously change the impurity–superconductor coupling. We detect the sign change in the critical current by exploiting a second transport channel as reference in analogy to a superconducting quantum interference device, which provides our scanning tunnelling microscope with the required phase sensitivity. The measured change in the Josephson current is a signature of the quantum phase transition and allows its characterization with high resolution