Acousto-optical phonon excitation in cubic piezoelectric slabs and crystal growth orientation effects

Morten Willatzen, Lars Duggen

    Research output: Contribution to journalJournal articleResearchpeer-review

    428 Downloads (Pure)


    In this paper we investigate theoretically the influence of piezoelectric coupling on phonon dispersion relations. Specifically we solve dispersion relations for a fully coupled zinc-blende freestanding quantum well for different orientations of the crystal unit cell. It is shown that the phonon mode density in GaAs can change by a factor of approximately 2–3 at qx a = 1 for different crystal-growth directions relative to the slab thickness direction. In particular, it is found that optical and acoustic phonon modes are always piezoelectrically coupled, independent of the crystal-growth direction, and will be jointly excited by electrical stimulus. We demonstrate this for an electrically excited freestanding slab for two cases of high-symmetry crystal-growth directions and finally show the impact of the Drude model for permittivity on the phonon dispersion. In particular, it is verified that the piezoelectric effect leads to a drastically enhanced coupling of acoustic and optical phonon modes and increase in the local phonon density of states near the plasma frequency where the permittivity approaches zero.
    Original languageEnglish
    Article number035310
    JournalPhysical Review B
    Issue number3
    Number of pages9
    Publication statusPublished - 2017


    Dive into the research topics of 'Acousto-optical phonon excitation in cubic piezoelectric slabs and crystal growth orientation effects'. Together they form a unique fingerprint.

    Cite this