Superconducting quantum interference at the atomic scale

Abstract A single spin in a Josephson junction can reverse the flow of supercurrent by changing sign superconducting phase difference across it. At mesoscopic length scales, these π-junctions are employed various applications, such as finding pairing symmetry underlying superconductor, well quantum computing. atomic scale, counterpart tunnel is known Yu–Shiba–Rusinov state. Observation reversal that setting has so far remained elusive. Here we demonstrate 0 to π transition through state continuously change impurity–superconductor coupling. We detect critical current exploiting second transport channel reference analogy interference device, which provides our scanning tunnelling microscope with required sensitivity. The measured signature and allows its characterization high resolution.