Superconducting quantum interference at the atomic scale

doi:10.1038/s41567-022-01644-6

Superconducting quantum interference at the atomic scale

2022-07-04

15

OA

AI

Annica M. Black‐Schaffer

DOI：10.1038/s41567-022-01644-6

Original

Original request for help

Save

Abstract

En 中文

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 pi-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 pi 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. Continuously changing the coupling between a magnetic impurity and a superconductor allows the observation of the reversal of supercurrent flow at the atomic scale.

Keywords:

LOCAL ELECTRONIC-STRUCTURE

JOSEPHSON CURRENT

COULOMB-BLOCKADE

PAIRING SYMMETRY

IMPURITY

STATES

Superconducting quantum interference at the atomic scale

Abstract

Journal

Organization