Tunable nonadiabatic excitation in a single-electron quantum dot

ORAL

Abstract

We report observation of nonadiabatic excitation of single electrons in a quantum dot. We have developed a way of measuring the excitation spectrum of the quantum dot formed in a tunable-barrier single-electron pump. When the confinement potential is deformed at sub-nanosecond timescales, electrons are excited to states with higher back-tunneling rates leading to a measureable reduction in the pumped current. In the presence of a perpendicular magnetic field we have observed that these states follow a Fock-Darwin spectrum. Our experiments demonstrate a simple model system to study nonadiabatic processes of quantum particles.

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Authors

  • J.D. Fletcher

    • National Physical Laboratory
    • National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom

  • M. Kataoka

    • National Physical Laboratory
    • National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom
    • University of Cambridge

  • P. See

    • National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom

  • S.P. Giblin

    • National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom

  • T.J.B.M. Janssen

    • National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom

  • J.P. Griffiths

    • Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK

  • G.A.C. Jones

    • Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK

  • I. Farrer

    • Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK

  • D.A. Ritchie

    • Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK