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Crossover from incoherent to coherent phonon scattering in epitaxial oxide superlattices

TitleCrossover from incoherent to coherent phonon scattering in epitaxial oxide superlattices
Publication TypeJournal Article
Year of Publication2014
AuthorsRavichandran, Jayakanth, Ajay K. Yadav, Ramez Cheaito, Pim B. Rossen, Arsen Soukiassian, S. J. Suresha, John C. Duda, Brian M. Foley, Che-Hui Lee, Ye Zhu, Arthur W. Lichtenberger, Joel E. Moore, David A. Muller, Darrell G. Schlom, Patrick E. Hopkins, Arun Majumdar, Ramamoorthy Ramesh, and Mark A. Zurbuchen
JournalNature Materials
Date PublishedFebruary 2014
ISBN Number1476-1122

Elementary particles such as electrons or photons are frequent subjects of wave-nature-driven investigations, unlike collective excitations such as phonons. The demonstration of wave–particle crossover, in terms of macroscopic properties, is crucial to the understanding and application of the wave behaviour of matter. We present an unambiguous demonstration of the theoretically predicted crossover from diffuse (particle-like) to specular (wave-like) phonon scattering in epitaxial oxide superlattices, manifested by a minimum in lattice thermal conductivity as a function of interface density. We do so by synthesizing superlattices of electrically insulating perovskite oxides and systematically varying the interface density, with unit-cell precision, using two different epitaxial-growth techniques. These observations open up opportunities for studies on the wave nature of phonons, particularly phonon interference effects, using oxide superlattices as model systems, with extensive applications in thermoelectrics and thermal management.

Short TitleNat Mater