SKM 2023 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 11: Functional Materials: Performance, Reliability and Degradation
MM 11.2: Vortrag
Montag, 27. März 2023, 17:15–17:30, SCH A 215
First-principles calculation of electroacoustic properties of wurtzite (Al,Sc)N — •Daniel F. Urban1, Oliver Ambacher2, and Christian Elsässer1 — 1Fraunhofer Institute for Mechanics of Materials IWM, Freiburg, Germany — 2INATECH–Department of Sustainable Systems Engineering, University Freiburg, Germany
We study the electroacoustic properties of aluminum scandium nitride crystals Al1−xScxN with the metastable wurtzite structure by means of first-principles calculations based on density functional theory [1]. We extract the material property data relevant for electroacoustic device design, namely the full tensors of elastic and piezoelectric constants. Atomistic models were constructed and analyzed for a variety of Sc concentrations 0≤ x≤50%. The functional dependence of the material properties on the scandium concentration was extracted by fitting the data obtained from an averaging procedure for different disordered atomic configurations. We give an explanation of the observed elastic softening and the extraordinary increase in piezoelectric response as a function of Sc content in terms of an element specific analysis of bond lengths and bond angles.
[1] D. F. Urban, O. Ambacher, and C. Elsässer, Phys. Rev. B 103, 115204 (2021)