Energy spectrometry of electrons ejected from dynamic quantum dots driven up a potential slope by a surface acoustic wave

ORAL

Abstract

Surface acoustic waves (SAWs) in a GaAs/AlGaAs heterostructure generate an electrostatic wave which propagates at the sound velocity. This potential wave is capable of collecting electrons from a 2D electron gas (2DEG) and transporting them through a depleted channel. The SAW minima form a continuous series of dynamic quantum dots, each transporting a controllable number of electrons along the channel. The confinement of the electrons in each dot increases as the potential rises along the channel, ejecting electrons one-by-one back into the 2DEG above the Fermi energy. These electrons can travel several microns before thermalising. We measure their energy spectrum using a variable potential barrier upstream as the channel is squeezed by split gates, and correlate this with the SAW-driven current along the channel.

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Authors

  • C.J.B. Ford

    • University of Cambridge
    • Cavendish Laboratory, University of Cambridge, UK

  • Matthew Benesh

    • University of Cambridge

  • S.K. Son

    • University of Cambridge
    • Cavendish Laboratory, University of Cambridge, UK

  • Masaya Kataoka

    • NPL, UK

  • C.H.W. Barnes

    • University of Cambridge
    • Cavendish Laboratory, University of Cambridge, UK

  • Robert McNeil

    • University of Cambridge

  • J.P. Griffiths

    • University of Cambridge
    • Cavendish Laboratory, University of Cambridge, UK

  • G.A.C. Jones

    • University of Cambridge
    • Cavendish Laboratory, University of Cambridge, UK

  • I. Farrer

    • University of Cambridge
    • Cavendish Laboratory, University of Cambridge, UK

  • D.A. Ritchie

    • University of Cambridge
    • Cavendish Laboratory, University of Cambridge, UK