VietNam 2013 

IXth Rencontres du Vietnam
Quy-Nhon, August 4-10, 2013

 QNplage

 Nanophysics: from fundamentals to applications

(the return)

 

Wednesday 7
Hybrid's

› 14:00 - 14:20 (20min)
When electrons perform in quartets
Régis Mélin  1, *@  , Thibaut Jonckheere  2@  , Jérôme Rech  2@  , Axel Freyn  1@  , Thierry Martin  2@  , Benoît Douçot  3@  , Denis Feinberg  1@  
1 : Institut Néel  (NEEL)  -  Website
CNRS : UPR2940, Université Joseph Fourier - Grenoble I, Institut National Polytechnique de Grenoble - INPG, Institut National Polytechnique de Grenoble (INPG)
25 avenue des Martyrs - BP 166 38042 GRENOBLE CEDEX 9 -  France
2 : Centre de Physique Théorique  (CPT)  -  Website
CNRS : UMR7332, Aix Marseille Université, Aix-Marseille Université
CNRS Luminy case 907 13288 Marseille cedex 9 -  France
3 : Laboratoire de Physique Théorique et Hautes Energies  (LPTHE)  -  Website
CNRS : UMR7589, Université Paris VI - Pierre et Marie Curie, Université Paris VII - Paris Diderot
4 place Jussieu Paris -  France
* : Corresponding author

In a Sa-S-Sb bijunction, double crossed Andreev reflection simultaneously produces two Cooper pairs, one in each junction if the interfaces are within coherence length of S. This amounts to producing nonlocal quartets in the superconductors Sa and Sb. Dc quartet current in a junction biased at voltages (V,-V,0) has been predicted to be due to the synchronization of the ac Josephson oscillations. Special attention will be paid to the theory of those quartet and higher order resonances in connection with experimental results obtained in Grenoble in a diffusive three-terminal normal-superconducting trijunction. Those experiments confirm the existence of nonlocal quartets. The microscopic theory succeeds in explaining why the nonlocal quartet resonances appear even if V is large compared to the Thouless energy. These experiments requires advocating a quartet term in the phase Hamiltonian of a RSJ triode, from which the experimentally observed satellite resonances are also obtained. It will be also shown that a giant signal of quartets can be obtained in double quantum dots because the gate voltages offer the possilibility to tune the quartet mode at resonance. In addition, above resonance, phase-sensitive-MAR provide a new channel correlating the pair and quasi-particle currents.



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