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First-principles calculation of electroacoustic properties of wurtzite (Al,Sc)N

 
: Urban, D.F.; Ambacher, Oliver; Elsässer, C.

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Volltext (PDF; )

Physical Review. B 103 (2021), Nr.11, Art. 115204, 13 S.
ISSN: 0163-1829
ISSN: 1098-0121
ISSN: 0556-2805
ISSN: 2469-9950
ISSN: 2469-9969
Englisch
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IWM ()
Fraunhofer IAF ()
elasticity; first-principles; calculations; piezoelectricity; disordered alloys; piezoelectrics; Wurtzite; density functional calculation

Abstract
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. 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 term s of an element-specific analysis of bond lengths and bond angles.

: http://publica.fraunhofer.de/dokumente/N-633401.html