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MacManus-Driscoll JL, Wu R, Li W. Interface-related phenomena in epitaxial complex oxide ferroics across different thin film platforms: opportunities and challenges. MATERIALS HORIZONS 2023; 10:1060-1086. [PMID: 36815609 PMCID: PMC10068909 DOI: 10.1039/d2mh01527g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Interfaces in complex oxides give rise to fascinating new physical phenomena arising from the interconnected spin, lattice, charge and orbital degrees of freedom. Most commonly, interfaces are engineered in epitaxial superlattice films. Of growing interest also are epitaxial vertically aligned nanocomposite films where interfaces form by self-assembly. These two thin film forms offer different capabilities for materials tuning and have been explored largely separately from one another. Ferroics (ferroelectric, ferromagnetic, multiferroic) are among the most fascinating phenomena to be manipulated using interface effects. Hence, in this review we compare and contrast the ferroic properties that arise in these two different film forms, highlighting exemplary materials combinations which demonstrate novel, enhanced and/or emergent ferroic functionalities. We discuss the origins of the observed functionalities and propose where knowledge can be translated from one materials form to another, to potentially produce new functionalities. Finally, for the two different film forms we present a perspective on underexplored/emerging research directions.
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Affiliation(s)
| | - Rui Wu
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK.
- Spin-X Institute, School of Physics and Optoelectronics, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou 511442, China
| | - Weiwei Li
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK.
- MIIT Key Laboratory of Aerospace Information Materials and Physics, State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China
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Fan S, Das H, Rébola A, Smith KA, Mundy J, Brooks C, Holtz ME, Muller DA, Fennie CJ, Ramesh R, Schlom DG, McGill S, Musfeldt JL. Site-specific spectroscopic measurement of spin and charge in (LuFeO 3) m/(LuFe 2O 4) 1 multiferroic superlattices. Nat Commun 2020; 11:5582. [PMID: 33149138 PMCID: PMC7642375 DOI: 10.1038/s41467-020-19285-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 10/07/2020] [Indexed: 11/09/2022] Open
Abstract
Interface materials offer a means to achieve electrical control of ferrimagnetism at room temperature as was recently demonstrated in (LuFeO3)m/(LuFe2O4)1 superlattices. A challenge to understanding the inner workings of these complex magnetoelectric multiferroics is the multitude of distinct Fe centres and their associated environments. This is because macroscopic techniques characterize average responses rather than the role of individual iron centres. Here, we combine optical absorption, magnetic circular dichroism and first-principles calculations to uncover the origin of high-temperature magnetism in these superlattices and the charge-ordering pattern in the m = 3 member. In a significant conceptual advance, interface spectra establish how Lu-layer distortion selectively enhances the Fe2+ → Fe3+ charge-transfer contribution in the spin-up channel, strengthens the exchange interactions and increases the Curie temperature. Comparison of predicted and measured spectra also identifies a non-polar charge ordering arrangement in the LuFe2O4 layer. This site-specific spectroscopic approach opens the door to understanding engineered materials with multiple metal centres and strong entanglement.
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Affiliation(s)
- Shiyu Fan
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA
| | - Hena Das
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Midori-ku, 4259 Nagatesuta, Yokohama, Kanagawa, 226-8503, Japan
- Tokyo Tech World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
| | - Alejandro Rébola
- Instituto de Física Rosario-CONICET, Boulevard 27 de Febrero 210 bis, 2000, Rosario, Argentina
| | - Kevin A Smith
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | - Julia Mundy
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Charles Brooks
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Megan E Holtz
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA
| | - Craig J Fennie
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA
| | - Stephen McGill
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Janice L Musfeldt
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA.
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
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Park J, Mangeri J, Zhang Q, Yusuf MH, Pateras A, Dawber M, Holt MV, Heinonen OG, Nakhmanson S, Evans PG. Domain alignment within ferroelectric/dielectric PbTiO 3/SrTiO 3 superlattice nanostructures. NANOSCALE 2018; 10:3262-3271. [PMID: 29384166 DOI: 10.1039/c7nr07203a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The ferroelectric domain pattern within lithographically defined PbTiO3/SrTiO3 ferroelectric/dielectric heteroepitaxial superlattice nanostructures is strongly influenced by the edges of the structures. Synchrotron X-ray nanobeam diffraction reveals that the spontaneously formed 180° ferroelectric stripe domains exhibited by such superlattices adopt a configuration in rectangular nanostructures in which domain walls are aligned with long patterned edges. The angular distribution of X-ray diffuse scattering intensity from nanodomains indicates that domains are aligned within an angular range of approximately 20° with respect to the edges. Computational studies based on a time-dependent Landau-Ginzburg-Devonshire model show that the preferred direction of the alignment results from lowering of the bulk and electrostrictive contributions to the free energy of the system due to the release of the lateral mechanical constraint. This unexpected alignment appears to be intrinsic and not a result of distortions or defects caused by the patterning process. Our work demonstrates how nanostructuring and patterning of heteroepitaxial superlattices allow for pathways to create and control ferroelectric structures that may appear counterintuitive.
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Affiliation(s)
- Joonkyu Park
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Liu S, Zhang C, Zhu M, He Q, Chakhalian J, Liu X, Borisevich A, Wang X, Xiao M. Polar phase transitions in heteroepitaxial stabilized La 0.5Y 0.5AlO 3 thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:405401. [PMID: 28741594 DOI: 10.1088/1361-648x/aa81ea] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report on the fabrication of epitaxial La0.5Y0.5AlO3 ultrathin films on (001) LaAlO3 substrates. Structural characterizations by scanning transmission electron microscopy and x-ray diffraction confirm the high quality of the film with a - b + c - AlO6 octahedral tilt pattern. Unlike either of the nonpolar parent compound, LaAlO3 and YAlO3, second harmonic generation measurements on the thin films suggest a nonpolar-polar phase transition at T c near 500 K, and a polar-polar phase transition at T a near 160 K. By fitting the angular dependence of the second harmonic intensities, we further propose that the two polar structures can be assigned to the Pmc2 1 and Pmn2 1 space group, while the high temperature nonpolar structure belongs to the Pbnm space group.
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Affiliation(s)
- Shenghua Liu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
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Zhu XN, Gao TT, Xu X, Liang WZ, Lin Y, Chen C, Chen XM. Piezoelectric and Dielectric Properties of Multilayered BaTiO3/(Ba,Ca)TiO3/CaTiO3 Thin Films. ACS APPLIED MATERIALS & INTERFACES 2016; 8:22309-22315. [PMID: 27514235 DOI: 10.1021/acsami.6b05469] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Highly oriented multilayered BaTiO3-(Ba,Ca)TiO3-CaTiO3 thin films were fabricated on Nb-doped (001) SrTiO3 (Nb:STO) substrates by pulsed laser deposition. The configurations of multilayered BaTiO3-(Ba,Ca)TiO3-CaTiO3 thin films are designed with the thickness ratio of 1:1:1 and 2:1:1 and total thickness ∼300 nm. Microstructural characterization by X-ray diffraction indicates that the as-deposited thin films are highly c-axis oriented and large in-plane strain is determined in BaTiO3 and CaTiO3 layers. Piezoresponse force microscopy (PFM) studies reveal an intense in-plane polarization component, whereas the out-of-plane shows inferior phase contrast. The optimized combination is found to be the BaTiO3-(Ba0.85Ca0.15)TiO3-CaTiO3 structure with combination ratio 2:1:1, which displays the largest domain switching amplitude under DC electric field, the largest room-temperature dielectric constant ∼646, a small dielectric loss of 0.03, and the largest dielectric tunability of ∼50% at 400 kV/cm. These results suggest that the enhanced dielectric and tunability performance are greatly associated with the large in-plane polarization component and domain switching.
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Affiliation(s)
- Xiao Na Zhu
- Laboratory of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China
- Department of Physics and Astronomy, University of Texas at San Antonio , Texas 78249, United States
| | - Ting Ting Gao
- Laboratory of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Xing Xu
- Department of Physics and Astronomy, University of Texas at San Antonio , Texas 78249, United States
| | - Wei Zheng Liang
- State Key Laboratory of Electronic Thin films and Integrated Devices, University of Electronic Science and Technology of China , Chengdu, Sichuan 610054, China
| | - Yuan Lin
- State Key Laboratory of Electronic Thin films and Integrated Devices, University of Electronic Science and Technology of China , Chengdu, Sichuan 610054, China
| | - Chonglin Chen
- Department of Physics and Astronomy, University of Texas at San Antonio , Texas 78249, United States
| | - Xiang Ming Chen
- Laboratory of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China
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Hong S, Nakhmanson SM, Fong DD. Screening mechanisms at polar oxide heterointerfaces. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:076501. [PMID: 27308889 DOI: 10.1088/0034-4885/79/7/076501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The interfaces of polar oxide heterostructures can display electronic properties unique from the oxides they border, as they require screening from either internal or external sources of charge. The screening mechanism depends on a variety of factors, including the band structure at the interface, the presence of point defects or adsorbates, whether or not the oxide is ferroelectric, and whether or not an external field is applied. In this review, we discuss both theoretical and experimental aspects of different screening mechanisms, giving special emphasis to ways in which the mechanism can be altered to provide novel or tunable functionalities. We begin with a theoretical introduction to the problem and highlight recent progress in understanding the impact of point defects on polar interfaces. Different case studies are then discussed, for both the high thickness regime, where interfaces must be screened and each interface can be considered separately, and the low thickness regime, where the degree and nature of screening can be manipulated and the interfaces are close enough to interact. We end with a brief outlook toward new developments in this rapidly progressing field.
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Affiliation(s)
- Seungbum Hong
- Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA. Department of Materials Science & Engineering, KAIST, Daejeon 305-701, Korea
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Fang YW, Ding HC, Tong WY, Zhu WJ, Shen X, Gong SJ, Wan XG, Duan CG. First-principles studies of multiferroic and magnetoelectric materials. Sci Bull (Beijing) 2015. [DOI: 10.1007/s11434-014-0628-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Bonnet N, Marzari N. Static dielectric permittivity of ice from first principles. PHYSICAL REVIEW LETTERS 2014; 113:245501. [PMID: 25541777 DOI: 10.1103/physrevlett.113.245501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Indexed: 06/04/2023]
Abstract
The static permittivity of ice is computed from first principles as a function of the electric field, together with the generalized Kirkwood factor. The molecular dipole in ice is unambiguously obtained by an original method combining a slab approach and Berry phase calculations, and the fluctuations of the polarization are sampled by Monte Carlo runs using first-principles model Hamiltonians for different proton configurations. Common approximations in the exchange-correlation functionals overestimate the dielectric permittivity and enhance ferroelectric configurations and the Kirkwood factor, whereas dielectric saturation effects compare well with experiment.
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Affiliation(s)
- Nicéphore Bonnet
- Department of Materials Science and Engineering, MIT, Cambridge, Massachusetts 02139, USA
| | - Nicola Marzari
- Theory and Simulation of Materials (THEOS), École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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Gao YC, Duan CG, Tang XD, Hu ZG, Yang P, Zhu Z, Chu J. A first-principles study on the intrinsic asymmetric ferroelectricity of the SrTiO3-BaTiO3-CaTiO3 tricolor superlattice at the nanoscale. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:165901. [PMID: 23552107 DOI: 10.1088/0953-8984/25/16/165901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report a systematic theoretical study on the ferroelectric behavior of ultrathin three-component ferroelectric films, e.g., CaTiO3-BaTiO3-SrTiO3, sandwiched between electrodes. Using first-principles calculations we demonstrate that such structures have intrinsic asymmetric ferroelectricity which is robust even at the nanoscale. In addition, there exists a certain relationship between the polarization directions and geometric stacking sequences of the superlattices. Specifically, the lowest energy states always have polarizations pointing from CaTiO3 via BaTiO3 to SrTiO3, while the sequence in the metastable states is SrTiO3-BaTiO3-CaTiO3. Therefore we were able to distinguish one ferroelectric state from its opposite state by means of their geometric stackings along the polarization directions. Besides this, band alignment analysis reveals that such structures are well behaved at the metal/ferroelectric interface, confirming the credibility and reliability of our first-principles calculation. Our finding may suggest a controllable and unambiguous way to build ferroelectric and multiferroic tunnel junctions.
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Affiliation(s)
- Yong-Chao Gao
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200062, People's Republic of China
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Bristowe NC, Littlewood PB, Artacho E. The net charge at interfaces between insulators. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:081001. [PMID: 21411891 DOI: 10.1088/0953-8984/23/8/081001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The issue of the net charge at insulating oxide interfaces is briefly reviewed with the ambition of dispelling myths of such charges being affected by covalency and related charge density effects. For electrostatic analysis purposes, the net charge at such interfaces is defined by the counting of discrete electrons and core ion charges, and by the definition of the reference polarization of the separate, unperturbed bulk materials. The arguments are illustrated for the case of a thin film of LaAlO(3) over SrTiO(3) in the absence of free carriers, for which the net charge is exactly 0.5e per interface formula unit, if the polarization response in both materials is referred to zero bulk values. Further consequences of the argument are extracted for structural and chemical alterations of such interfaces, in which internal rearrangements are distinguished from extrinsic alterations (changes of stoichiometry, redox processes), only the latter affecting the interfacial net charge. The arguments are reviewed alongside the proposal of Stengel and Vanderbilt (2009 Phys. Rev. B 80 241103) of using formal polarization values instead of net interfacial charges, based on the interface theorem of Vanderbilt and King-Smith (1993 Phys. Rev. B 48 4442-55). Implications for non-centrosymmetric materials are discussed, as well as for interfaces for which the charge mismatch is an integer number of polarization quanta.
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Affiliation(s)
- N C Bristowe
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK.
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Jo JY, Sichel RJ, Lee HN, Nakhmanson SM, Dufresne EM, Evans PG. Piezoelectricity in the dielectric component of nanoscale dielectric-ferroelectric superlattices. PHYSICAL REVIEW LETTERS 2010; 104:207601. [PMID: 20867066 DOI: 10.1103/physrevlett.104.207601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Indexed: 05/29/2023]
Abstract
The origin of the functional properties of complex oxide superlattices can be resolved using time-resolved synchrotron x-ray diffraction into contributions from the component layers making up the repeating unit. The CaTiO3 layers of a CaTiO3/BaTiO3 superlattice have a piezoelectric response to an applied electric field, consistent with a large continuous polarization throughout the superlattice. The overall piezoelectric coefficient at large strains, 54 pm/V, agrees with first-principles predictions in which a tetragonal symmetry is imposed on the superlattice by the SrTiO3 substrate.
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Affiliation(s)
- Ji Young Jo
- Department of Materials Science and Engineering and Materials Science Program, University of Wisconsin, Madison, Wisconsin 53706, USA
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Stengel M, Vanderbilt D, Spaldin NA. Enhancement of ferroelectricity at metal-oxide interfaces. NATURE MATERIALS 2009; 8:392-7. [PMID: 19377465 DOI: 10.1038/nmat2429] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Accepted: 03/18/2009] [Indexed: 05/10/2023]
Abstract
The development of ultrathin ferroelectric capacitors for use in memory applications has been hampered by depolarization effects arising from the electrode-film interfaces. These can be characterized in terms of a reduced interface capacitance, or equivalently an 'effective dead layer' in contact with the electrode. Here, by performing first-principles calculations on four capacitor structures based on BaTiO(3) and PbTiO(3), we determine the intrinsic interfacial effects responsible for destabilizing the ferroelectric state in ultrathin-film devices. Although it has been widely believed that these are governed by the electronic screening properties at the interface, we show that they also depend crucially on the local chemical environment through the force constants of the metal oxide bonds. In particular, in the case of interfaces formed between AO-terminated perovskites and simple metals, we demonstrate a novel mechanism of interfacial ferroelectricity that produces an overall enhancement of the ferroelectric instability of the film, rather than its suppression as is usually assumed. The resulting 'negative dead layer' suggests a route to thin-film ferroelectric devices that are free of deleterious size effects.
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Affiliation(s)
- Massimiliano Stengel
- Materials Department, University of California, Santa Barbara, California 93106-5050, USA
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