D.C. Josephson transport by quartets and other Andreev resonances in superconducting bijunctions

27th International Conference on Low Temperature Physics

Mélin, R.^1 ; Feinberg, D.^1 ; Courtois, H.^1 ; Padurariu, C.^1 ; Pfeffer, A.^2 ; Duvauchelle, J.E.^2 ; Lefloch, F.^2 ; Jonckheere, T.^3 ; Rech, J.^3 ; Martin, T.^3 ; Doucot, B.^4

Université Grenoble-Alpes, Institut Néel, CNRS, Grenoble, France^1

SPSMS/LaTEQS, UMR-E 9001, Université Grenoble-Alpes, Grenoble, France^2

Aix-Marseille Université, Université de Toulon, UMR 7332, Marseille

13288, France^3

Laboratoire de Physique Théorique et des Hautes Energies, CNRS UMR 7589, Universités Paris 6 et 7, 4 Place Jussieu, Paris Cedex 05

75252, France^4

关键词: Aluminum-copper;    Andreev reflection;    Applied voltages;    Cooper pair;    Energy-conserving;    Josephson current;    Metallic regions;    Non-equilibrium Green's function;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/5/052006/pdf
DOI  :  10.1088/1742-6596/568/5/052006

来源: IOP

【 摘 要 】

Bijunctions are three-terminal Josephson junctions where three superconductors are connected by a single weak link made of a metallic region or of quantum dots. Biasing two of the superconductors with commensurate voltages yields Andreev resonances that produce d.c. Josephson currents made of correlated Cooper pairs. For instance with applied voltages (0, V, - V), quartets formed by two entangled Cooper pairs are emitted by one reservoir towards the two others. Theory involving non-equilibrium Green's functions reveal the microsopic mechanism at play, e.g multiple coherent Andreev reflections that provide an energy-conserving and fully coherent channel. Recent experiments on diffusive Aluminum-Copper bijunctions show transport anomalies that are interpreted in terms of quartet resonances.