TY - JOUR
T1 - Crossover from incoherent to coherent phonon scattering in epitaxial oxide superlattices
JF - Nature Materials
Y1 - 2014/
SP - 168
EP - 172
A1 - J. Ravichandran
A1 - A.K. Yadav
A1 - R. Cheaito
A1 - P.B. Rossen
A1 - A. Soukiassian
A1 - S.J. Suresha
A1 - J.C. Duda
A1 - B.M. Foley
A1 - C.-H. Lee
A1 - Y. Zhu
A1 - A.W. Lichtenberger
A1 - J.E. Moore
A1 - D.A. Muller
A1 - D.G. Schlom
A1 - P.E. Hopkins
A1 - A. Majumdar
A1 - Ramamoorthy Ramesh
A1 - M.A. Zurbuchen
KW - Article
KW - Calcium compounds
KW - calcium derivative
KW - Chemical
KW - chemical model
KW - chemistry
KW - Collective excitations
KW - Computer simulation
KW - crystallization
KW - density functional theory
KW - Epitaxial growth
KW - Interface density
KW - Interference effects
KW - Lattice thermal conductivity
KW - Macroscopic properties
KW - Materials testing
KW - models
KW - oxide
KW - Oxide superlattices
KW - oxides
KW - Perovskite
KW - Perovskite oxides
KW - Phonon scattering
KW - Phonons
KW - radiation
KW - Radiation scattering
KW - scattering
KW - Thermal conductivity
KW - Thermoelectrics
KW - titanium
AB - 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. © 2014 Macmillan Publishers Limited. All rights reserved.
VL - 13
N1 - cited By 226
ER -
TY - JOUR
T1 - Tuning the electronic effective mass in double-doped SrTiO3
JF - Physical Review B - Condensed Matter and Materials Physics
Y1 - 2011/
A1 - J. Ravichandran
A1 - W. Siemons
A1 - M.L. Scullin
A1 - S. Mukerjee
A1 - M. Huijben
A1 - J.E. Moore
A1 - A. Majumdar
A1 - Ramamoorthy Ramesh
AB - We elucidate the relationship between effective mass and carrier concentration in an oxide semiconductor controlled by a double-doping mechanism. In this model oxide system, Sr1-xLaxTiO 3-δ, we can tune the effective mass ranging from 6 to 20m e as a function of filling (carrier concentration) and the scattering mechanism, which are dependent on the chosen lanthanum- and oxygen-vacancy concentrations. The effective mass values were calculated from the Boltzmann transport equation using the measured transport properties of thin films of Sr1-xLaxTiO3-δ. We show that the effective mass decreases with carrier concentration in this large-band-gap, low-mobility oxide, and this behavior is contrary to the traditional high-mobility, small-effective-mass semiconductors. © 2011 The American Physical Society.
VL - 83
N1 - cited By 22
ER -