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

Abstract

We study the electroacoustic properties of aluminum scandium nitride crystals Al${}_{1-x}$Sc${}_x$N 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 $0\le x\le 50$ %. 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 function of Sc content in terms of an element specific analysis of bond lengths and bond angles.

14 pages, 13 figures

References in corpus (3)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Spontaneous polarization and piezoelectric constants of III-V nitrides
• Origin of the anomalous piezoelectric response in wurtzite Sc${}_x$Al${}_{1-x}$N alloys

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• High Mobility Multiple-Channel AlScN/GaN Heterostructures
• Ku-Band AlScn-On-Diamond SAW Resonators with Phase Velocity above 8600 m/s