Multipair dc Josephson resonances in a biased all-superconducting bijunction

Thibaut Jonckheere (1, 2, 3, 4) , Jérôme Rech (2, 3, 4) , Thierry Martin (2, 3, 4) , Benoît Douçot (5) , Denis Feinberg (6) , Régis Mélin (6)

1 CPT - E6 Nanophysique
2 CPT - Centre de Physique Théorique - UMR 7332
3 AMU - Aix Marseille Université
4 UTLN - Université de Toulon
5 LPTHE - Laboratoire de Physique Théorique et Hautes Energies
6 NEEL - ThQC - Théorie Quantique des Circuits

An all-superconducting bijunction consists of a central superconductor contacted to two lateral superconductors, such that nonlocal crossed Andreev reflection is operating. Then new correlated transport channels for the Cooper pairs appear in addition to those of separated conventional Josephson junctions. We study this system in a configuration where the superconductors are connected through gate-controllable quantum dots. Multipair phase-coherent resonances and phase-dependent multiple Andreev reflections are both obtained when the voltages of the lateral superconductors are commensurate, and they add to the usual local dissipative transport due to quasiparticles. The two-pair resonance (quartets) as well as some other higher order multipair resonances are π shifted at low voltage. Dot control can be used to dramatically enhance the multipair current when the voltages are resonant with the dot levels.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Thibaut Jonckheere, Jérôme Rech, Thierry Martin, Benoît Douçot, Denis Feinberg, et al.. Multipair dc Josephson resonances in a biased all-superconducting bijunction. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2013, 87 (21), pp.214501. ⟨10.1103/PhysRevB.87.214501⟩. ⟨hal-00830387⟩