Conductance and current noise of a superconductor/ferromagnet quantum point contact

Audrey Cottet and Wolfgang Belzig
Phys. Rev. B 77, 064517 – Published 26 February 2008

Abstract

We study the conductance and current noise of a superconductor/ferromagnet (S/F) single-channel quantum point contact (QPC) as a function of the QPC bias voltage using a scattering approach. We show that the spin dependence of interfacial phase shifts (SDIPS) acquired by electrons upon scattering by the QPC can strongly modify these signals. For a weakly transparent contact, the SDIPS induces subgap resonances in the conductance and differential Fano factor curves of the QPC. For high transparencies, these resonances are smoothed, but the shape of the signals remains extremely sensitive to the SDIPS. We show that noise measurements could help to gain more information on the device, e.g., in cases where the SDIPS modifies qualitatively the differential Fano factor of the QPC, but not the conductance.

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  • Received 2 November 2007

DOI:https://doi.org/10.1103/PhysRevB.77.064517

©2008 American Physical Society

Authors & Affiliations

Audrey Cottet

  • Laboratoire de Physique Théorique et Hautes Énergies, Universités Paris 6 et 7, CNRS, UMR 7589, 4 place Jussieu, F-75252 Paris Cedex 05, France

Wolfgang Belzig

  • Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany

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Issue

Vol. 77, Iss. 6 — 1 February 2008

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