HAL : hal-00409391, version 2

arXiv : 0908.1018

DOI : 10.1103/PhysRevB.80.184510

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Physical Review B 80 (2008) 184510

Versions disponibles :

v1 (07-08-2009)

v2 (02-12-2009)

Non-equilibrium supercurrent through a quantum dot: current harmonics and proximity effect due to a normal metal lead

Thibaut Jonckheere 1, Alex Zazunov 2, K. Bayandin 1, 3, Vitaly Shumeiko 1, 4, Thierry Martin 1

(23/11/2008)

We consider a Hamiltonian model for a quantum dot which is placed between two superconducting leads with a constant bias imposed between these leads. Using the non-equilibrium Keldysh technique, we focus on the subgap current, where it is known that multiple Andreev reflections (MAR) are responsible for charge transfer through the dot. Attention is put on the DC current and on the first harmonics of the supercurrent. Varying the energy and width of the resonant level on the dot, we first investigate a cross-over from a quantum dot regime to a quantum point contact regime when there is zero coupling to the normal probe. We then study the effect on the supercurrent of the normal probe which is attached to the dot. This normal probe is understood to lead to dephasing, or alternatively to induce reverse proximity effect. We describe the full crossover from zero dephasing to the incoherent case. We also compute the Josephson current in the presence of the normal lead, and find it in excellent agreement with the values of the non-equlibrium current extrapolated at zero voltage.

1 :	Centre de Physique Théorique (CPT)
	CNRS : FR2291 – Université de Provence - Aix-Marseille I – Université de la Méditerranée - Aix-Marseille II – Université Sud Toulon Var
2 :	Institut fur Theoretische Physik
	Heinrich-Heine-Universitat
3 :	Landau Institue for Theoretical Physics
	Landau Institute for Theoretical Physics
4 :	Chalmers University of Technology (Chalmers)
	Chalmers University of Technology

Domaine

:

Physique/Matière Condensée/Systèmes mésoscopiques et effet Hall quantique

Mots Clés : Josephon effect – Multiple Andreev Reflection – Quantum dot – Proximity effect – Tunneling

hal-00409391, version 2

http://hal.archives-ouvertes.fr/hal-00409391

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Contributeur : Thibaut Jonckheere <>

Soumis le : Mercredi 2 Décembre 2009, 16:28:05

Dernière modification le : Mercredi 2 Décembre 2009, 16:29:11