Subgap structure in the conductance of a three-terminal Josephson junction

Andreas H. Pfeffer (1) , Jean Eudes Duvauchelle (1) , Hervé Courtois (2) , Régis Mélin (3) , Denis Feinberg (3) , Francois Lefloch (1)

1 LaTEQS - Laboratoire de Transport Electronique Quantique et Supraconductivité
2 NEEL - QuNES - Nano-Electronique Quantique et Spectroscopie
3 NEEL - ThQC - Théorie Quantique des Circuits

Three-terminal superconductor (S)-normalmetal (N)-superconductor (S) Josephson junctions are investigated. In a geometry where a T-shape normal metal is connected to three superconducting reservoirs, new subgap structures appear in the differential resistance for specific combinations of the superconductor chemical potentials. Those correspond to a correlated motion of Cooper pairs within the device that persist well above the Thouless energy and is consistent with the prediction of quartets formed by two entangled Cooper pairs. A simplified nonequilibrium Keldysh-Green's function calculation is presented that supports this interpretation.

Mots clés: Mesoscopic superconductivity; Andreev reflection; Josephson junctions

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

Andreas H. Pfeffer, Jean Eudes Duvauchelle, Hervé Courtois, Régis Mélin, Denis Feinberg, et al.. Subgap structure in the conductance of a three-terminal Josephson junction. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2014, 90 (7), pp.075401. ⟨10.1103/PhysRevB.90.075401⟩. ⟨cea-01054613⟩