Frictional drag between quantum wells mediated by phonon exchange

M.C. Bønsager, Karsten Flensberg, Ben Yu-Kuang Hu, A.H. MacDonald

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    Abstract

    We use the Kubo formalism to evaluate the contribution of acoustic-phonon exchange to the frictional drag between nearby two-dimensional electron systems. In the case of free phonons, we find a divergent drag rate (tau(D)(-l)). However, tau(D)(-l) becomes finite when phonon scattering from either lattice imperfections or electronic excitations is accounted for. In the case of GaAs quantum wells, we find that for a phonon mean free path l(ph) smaller than a critical value, imperfection scattering dominates and the drag rate varies as ln(l(ph)/d) over many orders of magnitude of the layer separation d. When l(ph) exceeds the critical value, the drag rate is dominated by coupling through an electron-phonon collective mode localized in the vicinity of the electron layers. We argue that the coupled electron-phonon mode may be observable for realistic parameters. Our theory is in good agreement with experimental results for the temperature, density, and d dependence of the drag rate.
    Original languageEnglish
    JournalPhysical Review B
    Volume57
    Issue number12
    Pages (from-to)7085-7102
    ISSN2469-9950
    DOIs
    Publication statusPublished - 1998

    Bibliographical note

    Copyright (1998) by the American Physical Society.

    Keywords

    • SYSTEMS
    • MONTE-CARLO
    • ELECTRON-ELECTRON-SCATTERING
    • MUTUAL DRAG
    • HOLE TRANSPORT
    • PARALLEL 2-DIMENSIONAL GASES
    • HETEROSTRUCTURES
    • COULOMB DRAG
    • LAYERS
    • SPATIALLY SEPARATED ELECTRON

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