title: Crossover from incoherent to coherent phonon scattering in epitaxial oxide superlattices.
abstract: 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.
authors: 1] Applied Science and Technology Graduate Group, University of California, Berkeley, California 94720, USA [2] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [3] [4].
authors: Jayakanth
authors: J
authors: Ravichandran
authors: 1] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA [3].
authors: Ajay K
authors: AK
authors: Yadav
authors: 1] Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, USA [2].
authors: Ramez
authors: R
authors: Cheaito
authors: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors: Pim B
authors: PB
authors: Rossen
authors: Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA.
authors: Arsen
authors: A
authors: Soukiassian
authors: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors: S J
authors: SJ
authors: Suresha
authors: Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, USA.
authors: John C
authors: JC
authors: Duda
authors: Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, USA.
authors: Brian M
authors: BM
authors: Foley
authors: Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA.
authors: Che-Hui
authors: CH
authors: Lee
authors: School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
authors: Ye
authors: Y
authors: Zhu
authors: Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904, USA.
authors: Arthur W
authors: AW
authors: Lichtenberger
authors: 1] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2] Department of Physics, University of California, Berkeley, California 94720, USA.
authors: Joel E
authors: JE
authors: Moore
authors: 1] School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA [2] Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA.
authors: David A
authors: 0000000341290473
authors: DA
authors: Muller
authors: 1] Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA [2] Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA.
authors: Darrell G
authors: DG
authors: Schlom
authors: Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, USA.
authors: Patrick E
authors: PE
authors: Hopkins
authors: ARPA-E, US Department of Energy, 1000 Independence Avenue, Washington DC 20585, USA.
authors: Arun
authors: A
authors: Majumdar
authors: 1] Applied Science and Technology Graduate Group, University of California, Berkeley, California 94720, USA [2] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [3] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA [4] Department of Physics, University of California, Berkeley, California 94720, USA [5] Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors: Ramamoorthy
authors: R
authors: Ramesh
authors: 1] Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA [2] Western Institute of Nanoelectronics, Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA [3] California NanoSystems Institute, University of California, Los Angeles, California 90095, USA.
authors: Mark A
authors: MA
authors: Zurbuchen
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D003198:Computer Simulation; D003460:Crystallization; D008422:Materials Testing; D008956:Models, Chemical; D010087:Oxides / Q000737:chemistry*; D012542:Scattering, Radiation; D013814:Thermal Conductivity; D014025:Titanium / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D010087:Oxides; C059910:perovskite; D014025:Titanium