Piezoelectric coefficients and spontaneous polarization of ScAlN

Miguel Caro (Corresponding Author), Siyuan Zhang, Tommi Riekkinen, Markku Ylilammi, Michelle Moram, Olga Lopez-Acevedo, Jyrki Molarius, Tomi Laurila

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    76 Citations (Scopus)

    Abstract

    We present a computational study of spontaneous polarization and piezoelectricity in ScxAl1?xN alloys in the compositional range from x = 0 to x = 0.5, obtained in the context of density functional theory and the Berry-phase theory of electric polarization using large periodic supercells. We report composition-dependent values of piezoelectric coefficients eij , piezoelectric moduli dij and elastic constants Cij . The theoretical findings are complemented with experimental measurement of e33 for a series of sputtered ScAlN films carried out with a piezoelectric resonator. The rapid increase with Sc content of the piezoelectric response reported in previous studies is confirmed for the available data. A detailed description of the full methodology required to calculate the piezoelectric properties of ScAlN, with application to other complex alloys, is presented. In particular, we find that the large amount of internal strain present in ScAlN and its intricate relation with electric polarization make configurational sampling and the use of large supercells at different compositions necessary in order to accurately derive the piezoelectric response of the material.
    Original languageEnglish
    Article number245901
    JournalJournal of Physics: Condensed Matter
    Volume27
    Issue number24
    DOIs
    Publication statusPublished - 2015
    MoE publication typeA1 Journal article-refereed

    Keywords

    • ScAIN
    • piezoelectricity
    • nitride
    • berry phase
    • polarization

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    Caro, M., Zhang, S., Riekkinen, T., Ylilammi, M., Moram, M., Lopez-Acevedo, O., Molarius, J., & Laurila, T. (2015). Piezoelectric coefficients and spontaneous polarization of ScAlN. Journal of Physics: Condensed Matter, 27(24), [245901]. https://doi.org/10.1088/0953-8984/27/24/245901