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Cao Y, Tang YL, Zhu YL, Wang Y, Liu N, Zou MJ, Liu J, Feng YP, Geng WR, Ma XL. Achieving High-Temperature Multiferroism by Atomic Architecture. ACS APPLIED MATERIALS & INTERFACES 2023; 15:3163-3171. [PMID: 36621962 DOI: 10.1021/acsami.2c20122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Materials with multiple order parameters, typically, in which ferroelectricity and magnetism are coupled, are illuminative for next-generation multifunctional electronics. However, searching for such single-phase multiferroics is challenging owing to antagonistic orbital occupancy and chemical bonding requirements for polarity and magnetism. Appropriate multiferroic candidates have been proposed, but their practical implementation is impeded by the low working temperature, weak coupling between ferroic orders, or antiparallel spin alignment in magnetic sublattices. Here, we report a family of single-phase multiferroic materials in which high-temperature magnetism and voltage-switchable ferroelectricity are coupled. Using pulsed laser deposition, we have fabricated single-crystalline thin films incorporating a uniformly percolated open-shell dn framework, which are composed of Fe cations with B-site occupancy and exhibit long-range spin ordering into the displacive ferroelectric PbTiO3 lattice, as demonstrated by atomically resolved chemical analysis. The tetragonal polar Pb(Ti1-x,Fex)O3 (PFT(x), x ≤ 0.10) family exhibits a switchable ferroelectric nature and magnetic interaction with a moderate coercive field of around 300 Oe at room temperature. Notably, the magnetic order even persists above 500 K, which is higher than already reported potential multiferroic candidates until now. Our strategy of merging a spin-ordered sublattice into inherent ferroelectrics via atomic occupancy engineering provides an available pathway for highly thermally stable multiferroic and spintronic applications.
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Affiliation(s)
- Yi Cao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Yin-Lian Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Yujia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Nan Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Min-Jie Zou
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiaqi Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yan-Peng Feng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wan-Rong Geng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiu-Liang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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2
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Saleem MS, Chen Q, Shepelin NA, Dolabella S, Rossell MD, Zhang X, Kronawitter CX, La Mattina F, Braun A. The Role of Strain in Proton Conduction in Multi-Oriented BaZr 0.9Y 0.1O 3-δ Thin Film. ACS APPLIED MATERIALS & INTERFACES 2022; 14:55915-55924. [PMID: 36508578 DOI: 10.1021/acsami.2c12657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Within the emerging field of proton-conducting fuel cells, BaZr0.9Y0.1O3-δ (BZY10) is an attractive material due to its high conductivity and stability. The fundamentals of conduction in sintered pellets and thin films heterostructures have been explored in several studies; however, the role of crystallographic orientation, grains, and grain boundaries is poorly understood for proton conduction. This article reports proton conduction in a self-assembled multi-oriented BZY10 thin film grown on top of a (110) NdGaO3 substrate. The multiple orientations are composed of different lattices, which provide a platform to study the lattice-dependent conductivity through different orientations in the vicinity of grain boundary between them and the substrate. The crystalline stacking of each orientation is confirmed by X-ray diffraction analysis and scanning transmission electron microscopy. The transport measurements are carried out under different gas atmospheres. The highest conductivity of 3.08 × 10-3 S cm-1 at 400 °C is found under a wet H2 environment together with an increased lattice parameter of 4.208 Å, while under O2 and Ar environments, the film shows lower conductivity and lattice parameter. Our findings not only demonstrate the role of crystal lattice for conduction properties but also illustrate the importance of self-assembled strategies to achieve high proton conduction in BZY10 thin films.
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Affiliation(s)
- Muhammad Shahrukh Saleem
- Laboratory for High Performance Ceramics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf8600, Switzerland
| | - Qianli Chen
- University of Michigan─Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai200240, China
| | - Nick A Shepelin
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institut, Villigen PSI5232, Switzerland
| | - Simone Dolabella
- Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf8600, Switzerland
| | - Marta D Rossell
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf8600, Switzerland
| | - Xuhai Zhang
- Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing, 211189, China
| | - Coleman X Kronawitter
- Department of Chemical Engineering, University of California, Davis, Davis, California95616, United States
| | - Fabio La Mattina
- Laboratory for Transport at Nanoscale Interfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf8600, Switzerland
| | - Artur Braun
- Laboratory for High Performance Ceramics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf8600, Switzerland
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3
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Diaz C, Valenzuela ML, Laguna-Bercero MÁ. Solid-State Preparation of Metal and Metal Oxides Nanostructures and Their Application in Environmental Remediation. Int J Mol Sci 2022; 23:ijms23031093. [PMID: 35163017 PMCID: PMC8835339 DOI: 10.3390/ijms23031093] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 02/01/2023] Open
Abstract
Nanomaterials have attracted much attention over the last decades due to their very different properties compared to those of bulk equivalents, such as a large surface-to-volume ratio, the size-dependent optical, physical, and magnetic properties. A number of solution fabrication methods have been developed for the synthesis of metal and metal oxides nanoparticles, but few solid-state methods have been reported. The application of nanostructured materials to electronic solid-state devices or to high-temperature technology requires, however, adequate solid-state methods for obtaining nanostructured materials. In this review, we discuss some of the main current methods of obtaining nanomaterials in solid state, and also we summarize the obtaining of nanomaterials using a new general method in solid state. This new solid-state method to prepare metals and metallic oxides nanostructures start with the preparation of the macromolecular complexes chitosan·Xn and PS-co-4-PVP·MXn as precursors (X = anion accompanying the cationic metal, n = is the subscript, which indicates the number of anions in the formula of the metal salt and PS-co-4-PVP = poly(styrene-co-4-vinylpyridine)). Then, the solid-state pyrolysis under air and at 800 °C affords nanoparticles of M°, MxOy depending on the nature of the metal. Metallic nanoparticles are obtained for noble metals such as Au, while the respective metal oxide is obtained for transition, representative, and lanthanide metals. Size and morphology depend on the nature of the polymer as well as on the spacing of the metals within the polymeric chain. Noticeably in the case of TiO2, anatase or rutile phases can be tuned by the nature of the Ti salts coordinated in the macromolecular polymer. A mechanism for the formation of nanoparticles is outlined on the basis of TG/DSC data. Some applications such as photocatalytic degradation of methylene by different metal oxides obtained by the presented solid-state method are also described. A brief review of the main solid-state methods to prepare nanoparticles is also outlined in the introduction. Some challenges to further development of these materials and methods are finally discussed.
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Affiliation(s)
- Carlos Diaz
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Ñuñoa, Casilla 653, Santiago 7800003, Chile
- Correspondence:
| | - Maria Luisa Valenzuela
- Instituto de Ciencias Químicas Aplicadas, Grupo de Investigación en Energía y Procesos Sustentables, Facultad de Ingeniería, Universidad Autónoma de Chile, Av. El Llano Subercaseaux 2801, Santiago 8900000, Chile;
| | - Miguel Á. Laguna-Bercero
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza C/Pedro Cerbuna 12, 50009 Zaragoza, Spain;
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4
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Eom K, Yu M, Seo J, Yang D, Lee H, Lee JW, Irvin P, Oh SH, Levy J, Eom CB. Electronically reconfigurable complex oxide heterostructure freestanding membranes. SCIENCE ADVANCES 2021; 7:7/33/eabh1284. [PMID: 34389541 PMCID: PMC8363151 DOI: 10.1126/sciadv.abh1284] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 06/24/2021] [Indexed: 05/28/2023]
Abstract
In recent years, lanthanum aluminate/strontium titanate (LAO/STO) heterointerfaces have been used to create a growing family of nanoelectronic devices based on nanoscale control of LAO/STO metal-to-insulator transition. The properties of these devices are wide-ranging, but they are restricted by nature of the underlying thick STO substrate. Here, single-crystal freestanding membranes based on LAO/STO heterostructures were fabricated, which can be directly integrated with other materials via van der Waals stacking. The key properties of LAO/STO are preserved when LAO/STO membranes are formed. Conductive atomic force microscope lithography is shown to successfully create reversible patterns of nanoscale conducting regions, which survive to millikelvin temperatures. The ability to form reconfigurable conducting nanostructures on LAO/STO membranes opens opportunities to integrate a variety of nanoelectronics with silicon-based architectures and flexible, magnetic, or superconducting materials.
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Affiliation(s)
- Kitae Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Muqing Yu
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jinsol Seo
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Dengyu Yang
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Hyungwoo Lee
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jung-Woo Lee
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Patrick Irvin
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Sang Ho Oh
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Jeremy Levy
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Chang-Beom Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
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5
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Sahoo P, Gupta B, Chandra Sahoo R, Vankayala K, Ramakrishna Matte HSS. Solution Processing of Topochemically Converted Layered WO 3 for Multifunctional Applications. Chemistry 2021; 27:11326-11334. [PMID: 34019316 DOI: 10.1002/chem.202100751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Indexed: 11/10/2022]
Abstract
Solution processing of nanomaterials is a promising technique for use in various applications owing to its simplicity and scalability. However, the studies on liquid-phase exfoliation (LPE) of tungsten oxide (WO3 ) are limited, unlike others, by a lack of commercial availability of bulk WO3 with layered structures. Herein, a one-step topochemical synthesis approach to obtain bulk layered WO3 from commercially available layered tungsten disulfide (WS2 ) by optimizing various parameters like reaction time and temperature is reported. Detailed microscopic and spectroscopic techniques confirmed the conversion process. Further, LPE was carried out on topochemically converted bulk layered WO3 in 22 different solvents; among the solvents studied, the propan-2-ol/water (1 : 1) co-solvent system appeared to be the best. This indicates that the possible values of surface tension and Hansen solubility parameters for bulk WO3 could be close to that of the co-solvent system. The obtained WO3 dispersions in a low-boiling-point solvent enable thin films of various thickness to be fabricated by using spray coating. The obtained thin films were used as active materials in supercapacitors without any conductive additives/binders and exhibited an areal capacitance of 31.7 mF cm-2 at 5 mV s-1 . Photo-electrochemical measurements revealed that these thin films can also be used as photoanodes for photo-electrochemical water oxidation.
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Affiliation(s)
- Priyabrata Sahoo
- Energy Materials Laboratory, Centre for Nano and Soft Matter Sciences (CeNS), Arkavathi Campus, Survey No.7, Shivanapura, Dasanapura Hobli, Bangalore, 562162, India.,Manipal Academy of Higher Education, Manipal, 576104, India
| | - Bikesh Gupta
- Energy Materials Laboratory, Centre for Nano and Soft Matter Sciences (CeNS), Arkavathi Campus, Survey No.7, Shivanapura, Dasanapura Hobli, Bangalore, 562162, India
| | - Ramesh Chandra Sahoo
- Energy Materials Laboratory, Centre for Nano and Soft Matter Sciences (CeNS), Arkavathi Campus, Survey No.7, Shivanapura, Dasanapura Hobli, Bangalore, 562162, India.,Manipal Academy of Higher Education, Manipal, 576104, India
| | - Kiran Vankayala
- Department of Chemistry, Birla Institute of Technology & Science, Pilani, K. K. Birla Goa campus, Goa, 403726, India
| | - H S S Ramakrishna Matte
- Energy Materials Laboratory, Centre for Nano and Soft Matter Sciences (CeNS), Arkavathi Campus, Survey No.7, Shivanapura, Dasanapura Hobli, Bangalore, 562162, India
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6
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Orvis T, Cao T, Surendran M, Kumarasubramanian H, Thind AS, Cunniff A, Mishra R, Ravichandran J. Direct Observation and Control of Surface Termination in Perovskite Oxide Heterostructures. NANO LETTERS 2021; 21:4160-4166. [PMID: 33974439 DOI: 10.1021/acs.nanolett.0c04818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Interfacial behavior of quantum materials leads to emergent phenomena such as quantum phase transitions and metastable functional phases. Probes for in situ and real time surface-sensitive characterization are critical for control during epitaxial synthesis of heterostructures. Termination switching in complex oxides has been studied using a variety of probes, often ex situ; however, direct in situ observation of this phenomena during growth is rare. To address this, we establish in situ and real time Auger electron spectroscopy for pulsed laser deposition with reflection high energy electron diffraction, providing structural and compositional surface information during film deposition. Using this capability, we show the direct observation and control of surface termination in heterostructures of SrTiO3 and SrRuO3. Density-functional-theory calculations capture the energetics and stability of the observed structures, elucidating their electronic behavior. This work demonstrates an exciting approach to monitor and control the composition of materials at the atomic scale for control over emergent phenomena and potential applications.
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Affiliation(s)
- Thomas Orvis
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089, United States
- Core Center for Excellence in Nano Imaging, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089, United States
| | - Tengfei Cao
- Department of Mechanical Engineering & Materials Science, and Institute of Materials Science & Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Mythili Surendran
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089, United States
- Core Center for Excellence in Nano Imaging, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089, United States
| | - Harish Kumarasubramanian
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089, United States
| | - Arashdeep Singh Thind
- Department of Mechanical Engineering & Materials Science, and Institute of Materials Science & Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Austin Cunniff
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089, United States
| | - Rohan Mishra
- Department of Mechanical Engineering & Materials Science, and Institute of Materials Science & Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Jayakanth Ravichandran
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089, United States
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089, United States
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7
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Fu G, Li W, Zhang JY, Li M, Li C, Li N, He Q, Xi S, Qi D, MacManus-Driscoll JL, Cheng J, Zhang KH. Facilitating the Deprotonation of OH to O through Fe 4+ -Induced States in Perovskite LaNiO 3 Enables a Fast Oxygen Evolution Reaction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2006930. [PMID: 33656259 DOI: 10.1002/smll.202006930] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/01/2021] [Indexed: 06/12/2023]
Abstract
Aliovalent doping is widely adopted to tune the electronic structure of transition-metal oxides for design of low-cost, active electrocatalysts. Here, using single-crystalline thin films as model electrocatalysts, the structure-activity relationship of Fe states doping in perovskite LaNiO3 for oxygen evolution reaction (OER) is studied. Fe4+ state is found to be crucial for enhancing the OER activity of LaNiO3 , dramatically increasing the activity by six times, while Fe3+ has negligible effect. Spectroscopic studies and DFT calculations indicate Fe4+ states enhance the degree of Ni/Fe 3d and O 2p hybridization, and meanwhile produce down-shift of the unoccupied density of states towards lower energies. Such electronic features reduce the energy barrier for interfacial electron transfer for water oxidization by 0.2 eV. Further theoretical calculations and H/D isotope experiments reveal the electronic states associated with Fe4+ -O2- -Ni3+ configuration accelerate the deprotonation of *OH to *O (rate-determining step), and thus facilitate fast OER kinetics.
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Affiliation(s)
- Gaoliang Fu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P.R. China
| | - Weiwei Li
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
- MIIT Key Laboratory of Aerospace Information Materials and Physics, College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, China
| | - Jia-Ye Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P.R. China
| | - Mengsha Li
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Block EA, #03-09, Singapore, 117575, Singapore
| | - Changjian Li
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Block EA, #03-09, Singapore, 117575, Singapore
| | - Ning Li
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Block EA, #03-09, Singapore, 117575, Singapore
| | - Qian He
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Block EA, #03-09, Singapore, 117575, Singapore
| | - Shibo Xi
- Institute of Chemical and Engineering Sciences A*STAR, 1 Pesek Road, Singapore, 627833, Singapore
| | - Dongchen Qi
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland, 4001, Australia
| | - Judith L MacManus-Driscoll
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Jun Cheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P.R. China
| | - Kelvin Hongliang Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P.R. China
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Baraik K, Bhakar A, Srihari V, Bhaumik I, Mukherjee C, Gupta M, Yadav AK, Tiwari P, Phase DM, Jha SN, Singh SD, Ganguli T. Structural, optical and electronic properties of Ni 1-x Co x O in the complete composition range. RSC Adv 2020; 10:43497-43507. [PMID: 35519712 PMCID: PMC9058517 DOI: 10.1039/d0ra09128f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 11/11/2020] [Indexed: 11/21/2022] Open
Abstract
Crystallographic and electronic structures of phase pure ternary solid solutions of Ni1−xCoxO (x = 0 to 1) have been studied using XRD, EXAFS and XAS measurements. The lattice parameter of the cubic rock-salt (RS) Ni1−xCoxO solid solutions increases linearly with increasing Co content and follows Vegard's law, in the complete composition range. A linear increase in the bond lengths (Ni/Co–O, Ni–Ni and Ni–Co) with “x”, closely following the bond lengths determined from virtual crystal approximation (VCA), is observed, which implies that there is only a minimal local distortion of the lattice in the mixed crystal. The optical gap of the ternary solid solution determined from diffuse reflectivity measurements shows neither a linear variation with Co composition nor bowing, as observed in many ternary semiconductors. This trend in the variation of optical gaps is explained by probing the conduction band using XAS at the O K-edge. We have observed that the variation in the onset energy of the conduction band edge with “x” is very similar to the variation in the optical gap with “x”, thus clearly indicating the dominant role played by the conduction band position in determining the optical gap. The variation in the intensities of the pre-edge peak in the XANES spectra measured at Ni and Co K-edges, and the L1/2 peak in XAS spectra measured at Ni and Co L-edges, is found to depend on the unoccupied O 2p-metal-(Ni/Co) 3d hybridized states and the bond lengths. The optical gap of Ni1−xCoxO solid solutions neither varies linearly with Co composition nor shows any bowing in the complete composition range. The nature of this variation of the gap is governed by the position of conduction band edge.![]()
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Affiliation(s)
- Kiran Baraik
- Synchrotrons Utilisation Section, RRCAT Indore 452013 India .,Homi Bhabha National Institute Anushakti Nagar Mumbai 400094 India
| | - Ashok Bhakar
- Synchrotrons Utilisation Section, RRCAT Indore 452013 India .,Homi Bhabha National Institute Anushakti Nagar Mumbai 400094 India
| | - V Srihari
- High Pressure and Synchrotron Radiation Physics Division, BARC India
| | - Indranil Bhaumik
- Laser and Functional Materials Division, RRCAT Indore 452013 India.,Homi Bhabha National Institute Anushakti Nagar Mumbai 400094 India
| | - C Mukherjee
- Laser Technology Division, RRCAT Indore 452013 India.,Homi Bhabha National Institute Anushakti Nagar Mumbai 400094 India
| | | | - A K Yadav
- Atomic and Molecular Physics Division, BARC India
| | - Pragya Tiwari
- Synchrotrons Utilisation Section, RRCAT Indore 452013 India
| | | | - S N Jha
- Atomic and Molecular Physics Division, BARC India
| | - S D Singh
- Synchrotrons Utilisation Section, RRCAT Indore 452013 India .,Homi Bhabha National Institute Anushakti Nagar Mumbai 400094 India
| | - Tapas Ganguli
- Synchrotrons Utilisation Section, RRCAT Indore 452013 India .,Homi Bhabha National Institute Anushakti Nagar Mumbai 400094 India
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9
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Knez D, Dražić G, Chaluvadi SK, Orgiani P, Fabris S, Panaccione G, Rossi G, Ciancio R. Unveiling Oxygen Vacancy Superstructures in Reduced Anatase Thin Films. NANO LETTERS 2020; 20:6444-6451. [PMID: 32794711 DOI: 10.1021/acs.nanolett.0c02125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Oxygen vacancies are known to play a crucial role in tuning the physical properties and technological applications of titanium dioxide TiO2. Over the last decades, defects in substoichiometric TiO2 have been commonly associated with the formation of TinO2n-x Magnéli phases, which are extended planar defects originating from crystallographic shear planes. By combining advanced transmission electron microscopy techniques, electron energy-loss spectroscopy and atomistic simulations, we reach new understanding of the oxygen vacancy induced structural modulations in anatase, ruling out the earlier shear-plane model. Structural modulations are instead shown to be due to the formation of oxygen vacancy superstructures that extend periodically inside the films, preserving the crystalline order of anatase. Elucidating the structure of oxygen defects in anatase is a crucial step for improving the functionalities of such material system and to engineer devices with targeted properties.
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Affiliation(s)
- Daniel Knez
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Goran Dražić
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
| | - Sandeep Kumar Chaluvadi
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Pasquale Orgiani
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Stefano Fabris
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Giorgio Rossi
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
- Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
| | - Regina Ciancio
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
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10
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Yi D, Yu P, Chen YC, Lee HH, He Q, Chu YH, Ramesh R. Tailoring Magnetoelectric Coupling in BiFeO 3 /La 0.7 Sr 0.3 MnO 3 Heterostructure through the Interface Engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806335. [PMID: 30663174 DOI: 10.1002/adma.201806335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/15/2018] [Indexed: 06/09/2023]
Abstract
Electric field control of magnetism ultimately opens up the possibility of reducing energy consumption of memory and logic devices. Electric control of magnetization and exchange bias are demonstrated in all-oxide heterostructures of BiFeO3 (BFO) and La0.7 Sr0.3 MnO3 (LSMO). However, the role of the polar heterointerface on magnetoelectric (ME) coupling is not fully explored. Here, the ME coupling in BFO/LSMO heterostructures with two types of interfaces, achieved by exploiting the interface engineering at the atomic scale, is investigated. It is shown that both magnetization and exchange bias are reversibly controlled by switching the ferroelectric polarization of BFO. Intriguingly, distinctly different modulation behaviors that depend on the interfacial atomic sequence are observed. These results provide new insights into the underlying physics of ME coupling in the model system. This study highlights that designing interface at the atomic scale is of general importance for functional spintronic devices.
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Affiliation(s)
- Di Yi
- Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Pu Yu
- State Key Laboratory for Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Hsin-Hua Lee
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Qing He
- Department of Physics, Durham University, Durham, DH1 3LE, UK
| | - Ying-Hao Chu
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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11
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Huang Z, Renshaw Wang X, Rusydi A, Chen J, Yang H, Venkatesan T. Interface Engineering and Emergent Phenomena in Oxide Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802439. [PMID: 30133012 DOI: 10.1002/adma.201802439] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/06/2018] [Indexed: 06/08/2023]
Abstract
Complex oxide interfaces have mesmerized the scientific community in the last decade due to the possibility of creating tunable novel multifunctionalities, which are possible owing to the strong interaction among charge, spin, orbital, and structural degrees of freedom. Artificial interfacial modifications, which include defects, formal polarization, structural symmetry breaking, and interlayer interaction, have led to novel properties in various complex oxide heterostructures. These emergent phenomena not only serve as a platform for investigating strong electronic correlations in low-dimensional systems but also provide potentials for exploring next-generation electronic devices with high functionality. Herein, some recently developed strategies in engineering functional oxide interfaces and their emergent properties are reviewed.
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Affiliation(s)
- Zhen Huang
- NUSNNI-NanoCore, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Xiao Renshaw Wang
- NUSNNI-NanoCore, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Andrivo Rusydi
- NUSNNI-NanoCore, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Jingsheng Chen
- NUSNNI-NanoCore, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Hyunsoo Yang
- NUSNNI-NanoCore, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Thirumalai Venkatesan
- NUSNNI-NanoCore, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
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12
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Pai YY, Tylan-Tyler A, Irvin P, Levy J. Physics of SrTiO 3-based heterostructures and nanostructures: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:036503. [PMID: 29424362 DOI: 10.1088/1361-6633/aa892d] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This review provides a summary of the rich physics expressed within SrTiO3-based heterostructures and nanostructures. The intended audience is researchers who are working in the field of oxides, but also those with different backgrounds (e.g., semiconductor nanostructures). After reviewing the relevant properties of SrTiO3 itself, we will then discuss the basics of SrTiO3-based heterostructures, how they can be grown, and how devices are typically fabricated. Next, we will cover the physics of these heterostructures, including their phase diagram and coupling between the various degrees of freedom. Finally, we will review the rich landscape of quantum transport phenomena, as well as the devices that elicit them.
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Affiliation(s)
- Yun-Yi Pai
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, United States of America. Pittsburgh Quantum Institute, Pittsburgh, PA 15260, United States of America
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13
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Bano A, Gaur NK. Interfacial Coupling Effect on Electron Transport in MoS 2/SrTiO 3 Heterostructure: An Ab-initio Study. Sci Rep 2018; 8:714. [PMID: 29335594 PMCID: PMC5768749 DOI: 10.1038/s41598-017-18984-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 12/15/2017] [Indexed: 11/24/2022] Open
Abstract
A variety of theoretical and experimental works have reported several potential applications of MoS2 monolayer based heterostructures (HSs) such as light emitting diodes, photodetectors and field effect transistors etc. In the present work, we have theoretically performed as a model case study, MoS2 monolayer deposited over insulating SrTiO3 (001) to study the band alignment at TiO2 termination. The interfacial characteristics are found to be highly dependent on the interface termination. With an insulating oxide material, a significant band gap (0.85eV) is found in MoS2/TiO2 interface heterostructure (HS). A unique electronic band profile with an indirect band gap (0.67eV) is observed in MoS2 monolayer when confined in a cubic environment of SrTiO3 (STO). Adsorption analysis showed the chemisorption of MoS2 on the surface of STO substrate with TiO2 termination which is justified by the charge density calculations that shows the existence of covalent bonding at the interface. The fabrication of HS of such materials paves the path for developing the unprecedented 2D materials with exciting properties such as semiconducting devices, thermoelectric and optoelectronic applications.
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Affiliation(s)
- Amreen Bano
- Department of Physics, Barkatullah University, Bhopal, 462026, India.
| | - N K Gaur
- Department of Physics, Barkatullah University, Bhopal, 462026, India
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14
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Chopdekar RV, Malik VK, Kane AM, Mehta A, Arenholz E, Takamura Y. Engineered superlattices with crossover from decoupled to synthetic ferromagnetic behavior. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:015805. [PMID: 29144279 DOI: 10.1088/1361-648x/aa9b13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The extent of interfacial charge transfer and the resulting impact on magnetic interactions were investigated as a function of sublayer thickness in La0.7Sr0.3MnO3/La0.7Sr0.3CoO3 ferromagnetic superlattices. Element-specific soft x-ray magnetic spectroscopy reveals that the electronic structure is altered within 5-6 unit cells of the chemical interface, and can lead to a synthetic ferromagnet with strong magnetic coupling between the sublayers. The saturation magnetization and coercivity depends sensitively on the sublayer thickness due to the length scale of this interfacial effect. For larger sublayer thicknesses, the La0.7Sr0.3MnO3 and La0.7Sr0.3CoO3 sublayers are magnetically decoupled, displaying two independent magnetic transitions with little sublayer thickness dependence. These results demonstrate how interfacial phenomena at perovskite oxide interfaces can be used to tailor their functional properties at the atomic scale.
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Affiliation(s)
- Rajesh V Chopdekar
- Department of Materials Science and Engineering, University of California, Davis, Davis, CA 95616, United States of America
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15
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Chen C, Yin D, Inoue K, Lichtenberg F, Ma X, Ikuhara Y, Bednorz JG. Atomic-Scale Origin of the Quasi-One-Dimensional Metallic Conductivity in Strontium Niobates with Perovskite-Related Layered Structures. ACS NANO 2017; 11:12519-12525. [PMID: 29190071 DOI: 10.1021/acsnano.7b06619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The quasi-one-dimensional (1D) metallic conductivity of the perovskite-related SrnNbnO3n+2 compounds is of continuing fundamental physical interest as well as being important for developing advanced electronic devices. The SrnNbnO3n+2 compounds can be derived by introducing additional oxygen into the SrNbO3 perovskite. However, the physical origin for the transition of electrical properties from the three-dimensional (3D) isotropic conductivity in SrNbO3 to the quasi-1D metallic conductivity in SrnNbnO3n+2 requires more in-depth clarification. Here we combine advanced transmission electron microscopy with atomistic first-principles calculations to unambiguously determine the atomic and electronic structures of the SrnNbnO3n+2 compounds and reveal the underlying mechanism for their quasi-1D metallic conductivity. We demonstrate that the local electrical conductivity in the SrnNbnO3n+2 compounds directly depends on the configuration of the NbO6 octahedra in local regions. These findings will shed light on the realization of two-dimensional (2D) electrical conductivity from a bulk material, namely by segmenting a 3D conductor into a stack of 2D conducting thin layers.
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Affiliation(s)
- Chunlin Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016, China
- Advanced Institute for Materials Research, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Deqiang Yin
- Advanced Institute for Materials Research, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- College of Aerospace Engineering, Chongqing University , Chongqing 400044, China
| | - Kazutoshi Inoue
- Advanced Institute for Materials Research, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | | | - Xiuliang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016, China
| | - Yuichi Ikuhara
- Advanced Institute for Materials Research, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Institute of Engineering Innovation, The University of Tokyo , 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramics Center , 2-4-1 Mutsuno, Atsuta, Nagoya 456-8587, Japan
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16
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Wang L, Kim R, Kim Y, Kim CH, Hwang S, Cho MR, Shin YJ, Das S, Kim JR, Kalinin SV, Kim M, Yang SM, Noh TW. Electronic-Reconstruction-Enhanced Tunneling Conductance at Terrace Edges of Ultrathin Oxide Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1702001. [PMID: 29024168 DOI: 10.1002/adma.201702001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 09/06/2017] [Indexed: 06/07/2023]
Abstract
Quantum mechanical tunneling of electrons across ultrathin insulating oxide barriers has been studied extensively for decades due to its great potential in electronic-device applications. In the few-nanometers-thick epitaxial oxide films, atomic-scale structural imperfections, such as the ubiquitously existed one-unit-cell-high terrace edges, can dramatically affect the tunneling probability and device performance. However, the underlying physics has not been investigated adequately. Here, taking ultrathin BaTiO3 films as a model system, an intrinsic tunneling-conductance enhancement is reported near the terrace edges. Scanning-probe-microscopy results demonstrate the existence of highly conductive regions (tens of nanometers wide) near the terrace edges. First-principles calculations suggest that the terrace-edge geometry can trigger an electronic reconstruction, which reduces the effective tunneling barrier width locally. Furthermore, such tunneling-conductance enhancement can be discovered in other transition metal oxides and controlled by surface-termination engineering. The controllable electronic reconstruction can facilitate the implementation of oxide electronic devices and discovery of exotic low-dimensional quantum phases.
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Affiliation(s)
- Lingfei Wang
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Rokyeon Kim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yoonkoo Kim
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Choong H Kim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sangwoon Hwang
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Myung Rae Cho
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yeong Jae Shin
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Saikat Das
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jeong Rae Kim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sergei V Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Miyoung Kim
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sang Mo Yang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Department of Physics, Sookmyung Women's University, Seoul, 04310, Republic of Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
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17
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Shin YJ, Wang L, Kim Y, Nahm HH, Lee D, Kim JR, Yang SM, Yoon JG, Chung JS, Kim M, Chang SH, Noh TW. Oxygen Partial Pressure during Pulsed Laser Deposition: Deterministic Role on Thermodynamic Stability of Atomic Termination Sequence at SrRuO 3/BaTiO 3 Interface. ACS APPLIED MATERIALS & INTERFACES 2017; 9:27305-27312. [PMID: 28731326 DOI: 10.1021/acsami.7b07813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
With recent trends on miniaturizing oxide-based devices, the need for atomic-scale control of surface/interface structures by pulsed laser deposition (PLD) has increased. In particular, realizing uniform atomic termination at the surface/interface is highly desirable. However, a lack of understanding on the surface formation mechanism in PLD has limited a deliberate control of surface/interface atomic stacking sequences. Here, taking the prototypical SrRuO3/BaTiO3/SrRuO3 (SRO/BTO/SRO) heterostructure as a model system, we investigated the formation of different interfacial termination sequences (BaO-RuO2 or TiO2-SrO) with oxygen partial pressure (PO2) during PLD. We found that a uniform SrO-TiO2 termination sequence at the SRO/BTO interface can be achieved by lowering the PO2 to 5 mTorr, regardless of the total background gas pressure (Ptotal), growth mode, or growth rate. Our results indicate that the thermodynamic stability of the BTO surface at the low-energy kinetics stage of PLD can play an important role in surface/interface termination formation. This work paves the way for realizing termination engineering in functional oxide heterostructures.
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Affiliation(s)
- Yeong Jae Shin
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) , Seoul 08826, Republic of Korea
| | - Lingfei Wang
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) , Seoul 08826, Republic of Korea
| | | | - Ho-Hyun Nahm
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) , Seoul 08826, Republic of Korea
| | - Daesu Lee
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) , Seoul 08826, Republic of Korea
| | - Jeong Rae Kim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) , Seoul 08826, Republic of Korea
| | - Sang Mo Yang
- Department of Physics, Sookmyung Women's University , Seoul 04310, Republic of Korea
| | - Jong-Gul Yoon
- Department of Physics, University of Suwon , Hwaseong, Gyunggi-do 18323, Republic of Korea
| | - Jin-Seok Chung
- Department of Physics, Soongsil University , Seoul 06978, Republic of Korea
| | | | - Seo Hyoung Chang
- Department of Physics, Chung-Ang University , Seoul 06974, Republic of Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) , Seoul 08826, Republic of Korea
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18
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Zhang KHL, Wu R, Tang F, Li W, Oropeza FE, Qiao L, Lazarov VK, Du Y, Payne DJ, MacManus-Driscoll JL, Blamire MG. Electronic Structure and Band Alignment at the NiO and SrTiO 3 p-n Heterojunctions. ACS APPLIED MATERIALS & INTERFACES 2017; 9:26549-26555. [PMID: 28695740 DOI: 10.1021/acsami.7b06025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Understanding the energetics at the interface, including the alignment of valence and conduction bands, built-in potentials, and ionic and electronic reconstructions, is an important challenge in designing oxide interfaces that have controllable multifunctionalities for novel (opto-)electronic devices. In this work, we report detailed investigations on the heterointerface of wide-band-gap p-type NiO and n-type SrTiO3 (STO). We show that despite a large lattice mismatch (∼7%) and dissimilar crystal structure, high-quality NiO and Li-doped NiO (LNO) thin films can be epitaxially grown on STO(001) substrates through a domain-matching epitaxy mechanism. X-ray photoelectron spectroscopy studies indicate that NiO/STO heterojunctions form a type II "staggered" band alignment. In addition, a large built-in potential of up to 0.97 eV was observed at the interface of LNO and Nb-doped STO (NbSTO). The LNO/NbSTO p-n heterojunctions exhibit not only a large rectification ratio of 2 × 103 but also a large ideality factor of 4.3. The NiO/STO p-n heterojunctions have important implications for applications in photocatalysis and photodetectors as the interface provides favorable energetics for facile separation and transport of photogenerated electrons and holes.
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Affiliation(s)
- Kelvin H L Zhang
- Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
| | - Rui Wu
- Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
| | - Fengzai Tang
- Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
| | - Weiwei Li
- Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
| | - Freddy E Oropeza
- Department of Materials, Imperial College London , Exhibition Road, London SW7 2AZ, U.K
| | - Liang Qiao
- School of Materials, The University of Manchester , Manchester M13 9PL, U.K
| | - Vlado K Lazarov
- Department of Physics, University of York , Heslington, York YO10 5DD, U.K
| | - Yingge Du
- Physical Sciences Division, Physical & Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - David J Payne
- Department of Materials, Imperial College London , Exhibition Road, London SW7 2AZ, U.K
| | - Judith L MacManus-Driscoll
- Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
| | - Mark G Blamire
- Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K
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19
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Sarkar S, Saha S, Motapothula MR, Patra A, Cao BC, Prakash S, Cong CX, Mathew S, Ghosh S, Yu T, Venkatesan T. Magneto-Optical Study of Defect Induced Sharp Photoluminescence in LaAlO3 and SrTiO3. Sci Rep 2016; 6:33145. [PMID: 27619076 PMCID: PMC5020611 DOI: 10.1038/srep33145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 08/19/2016] [Indexed: 11/09/2022] Open
Abstract
Strongly correlated electronic systems such as Transition Metal Oxides often possess various mid-gap states originating from intrinsic defects in these materials. In this paper, we investigate an extremely sharp Photoluminescence (PL) transition originating from such defect states in two widely used perovskites, LaAlO3 and SrTiO3. A detailed study of the PL as a function of temperature and magnetic field has been conducted to understand the behavior and origin of the transition involved. The temperature dependence of the PL peak position for SrTiO3 is observed to be opposite to that in LaAlO3. Our results reveal the presence of a spin/orbital character in these transitions which is evident from the splitting of these defect energy levels under a high magnetic field. These PL transitions have the potential for enabling non-contact thermal and field sensors.
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Affiliation(s)
- Soumya Sarkar
- NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, National University of Singapore, 117456, Singapore
| | - Surajit Saha
- NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.,Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore
| | - M R Motapothula
- NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.,Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore
| | - Abhijeet Patra
- NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore
| | - Bing-Chen Cao
- Division of Physics and Applied Physics, School of Physics and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Saurav Prakash
- NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, National University of Singapore, 117456, Singapore
| | - Chun Xiao Cong
- Division of Physics and Applied Physics, School of Physics and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Sinu Mathew
- NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore
| | - Siddhartha Ghosh
- NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore
| | - Ting Yu
- Division of Physics and Applied Physics, School of Physics and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - T Venkatesan
- NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, National University of Singapore, 117456, Singapore.,Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.,Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore.,Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
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20
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Atomic scale imaging of competing polar states in a Ruddlesden-Popper layered oxide. Nat Commun 2016; 7:12572. [PMID: 27578622 PMCID: PMC5013660 DOI: 10.1038/ncomms12572] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 07/14/2016] [Indexed: 12/03/2022] Open
Abstract
Layered complex oxides offer an unusually rich materials platform for emergent phenomena through many built-in design knobs such as varied topologies, chemical ordering schemes and geometric tuning of the structure. A multitude of polar phases are predicted to compete in Ruddlesden–Popper (RP), An+1BnO3n+1, thin films by tuning layer dimension (n) and strain; however, direct atomic-scale evidence for such competing states is currently absent. Using aberration-corrected scanning transmission electron microscopy with sub-Ångstrom resolution in Srn+1TinO3n+1 thin films, we demonstrate the coexistence of antiferroelectric, ferroelectric and new ordered and low-symmetry phases. We also directly image the atomic rumpling of the rock salt layer, a critical feature in RP structures that is responsible for the competing phases; exceptional quantitative agreement between electron microscopy and density functional theory is demonstrated. The study shows that layered topologies can enable multifunctionality through highly competitive phases exhibiting diverse phenomena in a single structure. Competing phases in layered complex oxides are believed to be relevant for emergent phenomena, which still await to be witnessed. Here, Stone et al. report direct atomic-scale imaging of a multitude of polar phases in Ruddlesden-Popper oxide thin films, exhibiting diverse phenomena in a single structure.
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21
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Hong X. Emerging ferroelectric transistors with nanoscale channel materials: the possibilities, the limitations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:103003. [PMID: 26881391 DOI: 10.1088/0953-8984/28/10/103003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Combining the nonvolatile, locally switchable polarization field of a ferroelectric thin film with a nanoscale electronic material in a field effect transistor structure offers the opportunity to examine and control a rich variety of mesoscopic phenomena and interface coupling. It is also possible to introduce new phases and functionalities into these hybrid systems through rational design. This paper reviews two rapidly progressing branches in the field of ferroelectric transistors, which employ two distinct classes of nanoscale electronic materials as the conducting channel, the two-dimensional (2D) electron gas graphene and the strongly correlated transition metal oxide thin films. The topics covered include the basic device physics, novel phenomena emerging in the hybrid systems, critical mechanisms that control the magnitude and stability of the field effect modulation and the mobility of the channel material, potential device applications, and the performance limitations of these devices due to the complex interface interactions and challenges in achieving controlled materials properties. Possible future directions for this field are also outlined, including local ferroelectric gate control via nanoscale domain patterning and incorporating other emergent materials in this device concept, such as the simple binary ferroelectrics, layered 2D transition metal dichalcogenides, and the 4d and 5d heavy metal compounds with strong spin-orbit coupling.
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Affiliation(s)
- Xia Hong
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience University of Nebraska-Lincoln, Lincoln, NE 68588, USA
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22
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Okada T, Shimizu K, Yamakami T. An inorganic anionic polymer filter disc: direct crystallization of a layered silicate nanosheet on a glass fiber filter. RSC Adv 2016. [DOI: 10.1039/c5ra25626g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cation-exchangeable layered silicate nanosheet fine crystals covered thoroughly a commercially available silica fiber filter paper through hydrothermal reactions with LiF, MgCl2 and urea.
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Affiliation(s)
- Tomohiko Okada
- Department of Chemistry and Material Engineering
- Faculty of Engineering
- Shinshu University
- Nagano 380-8553
- Japan
| | - Kei Shimizu
- Department of Chemistry and Material Engineering
- Faculty of Engineering
- Shinshu University
- Nagano 380-8553
- Japan
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23
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Vaz CAF, Staub U. Magnetoelectronics--electric field control of magnetism in the solid state. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:500301. [PMID: 26613520 DOI: 10.1088/0953-8984/27/50/500301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- C A F Vaz
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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24
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Quackenbush NF, Paik H, Woicik JC, Arena DA, Schlom DG, Piper LFJ. X-Ray Spectroscopy of Ultra-Thin Oxide/Oxide Heteroepitaxial Films: A Case Study of Single-Nanometer VO2/TiO2. MATERIALS 2015; 8:5452-5466. [PMID: 28793516 PMCID: PMC5455529 DOI: 10.3390/ma8085255] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 08/12/2015] [Accepted: 08/14/2015] [Indexed: 11/23/2022]
Abstract
Epitaxial ultra-thin oxide films can support large percent level strains well beyond their bulk counterparts, thereby enabling strain-engineering in oxides that can tailor various phenomena. At these reduced dimensions (typically < 10 nm), contributions from the substrate can dwarf the signal from the epilayer, making it difficult to distinguish the properties of the epilayer from the bulk. This is especially true for oxide on oxide systems. Here, we have employed a combination of hard X-ray photoelectron spectroscopy (HAXPES) and angular soft X-ray absorption spectroscopy (XAS) to study epitaxial VO2/TiO2 (100) films ranging from 7.5 to 1 nm. We observe a low-temperature (300 K) insulating phase with evidence of vanadium-vanadium (V-V) dimers and a high-temperature (400 K) metallic phase absent of V-V dimers irrespective of film thickness. Our results confirm that the metal insulator transition can exist at atomic dimensions and that biaxial strain can still be used to control the temperature of its transition when the interfaces are atomically sharp. More generally, our case study highlights the benefits of using non-destructive XAS and HAXPES to extract out information regarding the interfacial quality of the epilayers and spectroscopic signatures associated with exotic phenomena at these dimensions.
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Affiliation(s)
- Nicholas F Quackenbush
- Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA.
| | - Hanjong Paik
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
| | - Joseph C Woicik
- Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Dario A Arena
- National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, NY 11973, 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.
| | - Louis F J Piper
- Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA.
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25
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Vaz CAF, Walker FJ, Ahn CH, Ismail-Beigi S. Intrinsic interfacial phenomena in manganite heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:123001. [PMID: 25721578 DOI: 10.1088/0953-8984/27/12/123001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We review recent advances in our understanding of interfacial phenomena that emerge when dissimilar materials are brought together at atomically sharp and coherent interfaces. In particular, we focus on phenomena that are intrinsic to the interface and review recent work carried out on perovskite manganites interfaces, a class of complex oxides whose rich electronic properties have proven to be a useful playground for the discovery and prediction of novel phenomena.
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Affiliation(s)
- C A F Vaz
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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26
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Li G, Varga T, Yan P, Wang Z, Wang C, Chambers SA, Du Y. Crystallographic dependence of photocatalytic activity of WO3thin films prepared by molecular beam epitaxy. Phys Chem Chem Phys 2015; 17:15119-23. [DOI: 10.1039/c5cp01344e] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The (111) surface of WO3is found to have the highest photocatalytic reactivity, followed by (110) and (001).
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Affiliation(s)
- Guoqiang Li
- Fundamental & Computational Sciences Directorate
- Pacific Northwest National Laboratory
- Richland
- USA
- Key Laboratory of Photovoltaic Materials of Henan Province
| | - Tamas Varga
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Pengfei Yan
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Zhiguo Wang
- Department of Applied Physics
- University of Electronic Science and Technology of China
- Chengdu
- P. R. China
| | - Chongmin Wang
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Scott A. Chambers
- Fundamental & Computational Sciences Directorate
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Yingge Du
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
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27
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Carretero-Genevrier A, Drisko GL, Grosso D, Boissiere C, Sanchez C. Mesoscopically structured nanocrystalline metal oxide thin films. NANOSCALE 2014; 6:14025-14043. [PMID: 25224841 DOI: 10.1039/c4nr02909g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This review describes the main successful strategies that are used to grow mesostructured nanocrystalline metal oxide and SiO₂ films via deposition of sol-gel derived solutions. In addition to the typical physicochemical forces to be considered during crystallization, mesoporous thin films are also affected by the substrate-film relationship and the mesostructure. The substrate can influence the crystallization temperature and the obtained crystallographic orientation due to the interfacial energies and the lattice mismatch. The mesostructure can influence the crystallite orientation, and affects nucleation and growth behavior due to the wall thickness and pore curvature. Three main methods are presented and discussed: templated mesoporosity followed by thermally induced crystallization, mesostructuration of already crystallized metal oxide nanobuilding units and substrate-directed crystallization with an emphasis on very recent results concerning epitaxially grown piezoelectric structured α-quartz films via crystallization of amorphous structured SiO₂ thin films.
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Affiliation(s)
- Adrian Carretero-Genevrier
- Institut des Nanotechnologies de Lyon (INL) CNRS - Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France
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28
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De Angelis F, Di Valentin C, Fantacci S, Vittadini A, Selloni A. Theoretical Studies on Anatase and Less Common TiO2 Phases: Bulk, Surfaces, and Nanomaterials. Chem Rev 2014; 114:9708-53. [DOI: 10.1021/cr500055q] [Citation(s) in RCA: 321] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Filippo De Angelis
- Computational
Laboratory for Hybrid Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Molecolari, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Cristiana Di Valentin
- Dipartimento
di Scienza dei Materiali, Università di Milano-Bicocca, I-20125 Milano, Italy
| | - Simona Fantacci
- Computational
Laboratory for Hybrid Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Molecolari, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Andrea Vittadini
- Istituto
CNR per l’Energetica e le Interfasi (IENI), c/o Dipartimento
di Scienze Chimiche, Universita’ di Padova, I-35131 Padova, Italy
| | - Annabella Selloni
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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29
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Lee JH, Selloni A. TiO2/ferroelectric heterostructures as dynamic polarization-promoted catalysts for photochemical and electrochemical oxidation of water. PHYSICAL REVIEW LETTERS 2014; 112:196102. [PMID: 24877949 DOI: 10.1103/physrevlett.112.196102] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Indexed: 06/03/2023]
Abstract
Using first-principles density functional theory calculations, we explore the chemical activity of epitaxial heterostructures of TiO2 anatase on strained polar SrTiO3 films focusing on the oxygen evolution reaction (OER), the bottleneck of water splitting. Our results show that the reactivity of the TiO2 surface is tuned by electric dipoles dynamically induced by the adsorbed species during the intermediate steps of the reaction while the initial and final steps remain unaffected. Compared to the OER on unsupported TiO2, the combined effects of the dynamically induced dipoles and epitaxial strain strongly reduce rate-limiting thermodynamic barriers and significantly improve the efficiency of the reaction.
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Affiliation(s)
- Jun Hee Lee
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Annabella Selloni
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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30
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Rice WD, Ambwani P, Bombeck M, Thompson JD, Haugstad G, Leighton C, Crooker SA. Persistent optically induced magnetism in oxygen-deficient strontium titanate. NATURE MATERIALS 2014; 13:481-487. [PMID: 24658116 DOI: 10.1038/nmat3914] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 02/12/2014] [Indexed: 06/03/2023]
Abstract
Strontium titanate (SrTiO3) is a foundational material in the emerging field of complex oxide electronics. Although its bulk electronic and optical properties are rich and have been studied for decades, SrTiO3 has recently become a renewed focus of materials research catalysed in part by the discovery of superconductivity and magnetism at interfaces between SrTiO3 and other non-magnetic oxides. Here we illustrate a new aspect to the phenomenology of magnetism in SrTiO3 by reporting the observation of an optically induced and persistent magnetization in slightly oxygen-deficient bulk SrTiO3-δ crystals using magnetic circular dichroism (MCD) spectroscopy and SQUID magnetometry. This zero-field magnetization appears below ~18 K, persists for hours below 10 K, and is tunable by means of the polarization and wavelength of sub-bandgap (400-500 nm) light. These effects occur only in crystals containing oxygen vacancies, revealing a detailed interplay between magnetism, lattice defects, and light in an archetypal complex oxide material.
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Affiliation(s)
- W D Rice
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - P Ambwani
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - M Bombeck
- Experimentelle Physik 2, Technische Universität Dortmund, D-44227 Dortmund, Germany
| | - J D Thompson
- Materials Physics and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - G Haugstad
- Characterization Facility, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - C Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - S A Crooker
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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31
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Li W, Zhao R, Tang R, Chen A, Zhang W, Lu X, Wang H, Yang H. Vertical-interface-manipulated conduction behavior in nanocomposite oxide thin films. ACS APPLIED MATERIALS & INTERFACES 2014; 6:5356-5361. [PMID: 24689868 DOI: 10.1021/am5001129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Vertically aligned nanocomposites with vertical interfaces are a novel concept that show powerful advantages over conventional nanocomposites with lateral interfaces. However, significant obstacles to a systematic understanding of vertical interfaces still remain. Here, heteroepitaxial (BaTiO3)0.5:(Sm2O3)0.5 nanocomposite thin films have been fabricated and the conduction behaviors have been investigated. A spontaneous phase ordering with clear vertical interfaces has been found in the composite films. Because of the structural discontinuity as well as a large strain generated at the interfaces, the vertical interfaces are revealed to become the sinks to attract oxygen vacancies. The accumulated oxygen vacancies contributed to a largely reduced leakage current and a different leakage mechanism in the composite films compared to that of the pure BaTiO3 film. The present work represents a methodology to manipulate functionalities by designing configuration of the interfaces in oxide thin films.
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Affiliation(s)
- Weiwei Li
- School of Physical Science and Technology & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
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32
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Pal J, Smerieri M, Celasco E, Savio L, Vattuone L, Rocca M. Morphology of monolayer MgO films on Ag(100): switching from corrugated islands to extended flat terraces. PHYSICAL REVIEW LETTERS 2014; 112:126102. [PMID: 24724662 DOI: 10.1103/physrevlett.112.126102] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Indexed: 05/28/2023]
Abstract
The ability to engineer nearly perfect ultrathin oxide layers, up to the limit of monolayer thickness, is a key issue for nanotechnological applications. Here we face the difficult and important case of ultrathin MgO films on Ag(100), for which no extended and well-ordered layers could thus far be produced in the monolayer limit. We demonstrate that their final morphology depends not only on the usual growth parameters (crystal temperature, metal flux, and oxygen partial pressure), but also on aftergrowth treatments controlling so far neglected thermodynamics constraints. We thus succeed in tuning the shape of the oxide films from irregular, nanometer-sized, monolayer-thick islands to slightly larger, perfectly squared, bilayer islands, to extended monolayers limited apparently only by substrate steps.
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Affiliation(s)
- Jagriti Pal
- IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Marco Smerieri
- IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Edvige Celasco
- IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Letizia Savio
- IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Luca Vattuone
- IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Mario Rocca
- IMEM-CNR, UOS Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
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33
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Xie Y, Scafetta MD, Sichel-Tissot RJ, Moon EJ, Devlin RC, Wu H, Krick AL, May SJ. Control of functional responses via reversible oxygen loss in La₁-xSrxFeO₃-δ films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:1434-1438. [PMID: 24734299 DOI: 10.1002/adma.201304374] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
La0.3 Sr0.7 FeO3-δ films undergo dramatic changes in electronic and optical properties due to reversible oxygen loss induced by low-temperature heating. This mechanism to control the functional properties may serve as a platform for new devices or sensors in which external stimuli are used to dynamically control the composition of complex oxide heterostructures.
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34
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Chen YZ, Bovet N, Kasama T, Gao WW, Yazdi S, Ma C, Pryds N, Linderoth S. Room temperature formation of high-mobility two-dimensional electron gases at crystalline complex oxide interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:1462-1467. [PMID: 24338762 DOI: 10.1002/adma.201304634] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Indexed: 06/03/2023]
Abstract
Well-controlled sub-unit-cell layer-bylayer epitaxial growth of spinel alumina is achieved at room temperature on a TiO2 -terminated SrTiO3 single-crystalline substrate. By tailoring the interface redox reaction, 2D electron gases with mobilities exceeding 3000 cm 2 V(-1) s(-1) are achieved at this novel oxide interface.
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Affiliation(s)
- Y Z Chen
- Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, 4000, Roskilde, Denmark
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35
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Lee JS, Jang J. Hetero-structured semiconductor nanomaterials for photocatalytic applications. J IND ENG CHEM 2014. [DOI: 10.1016/j.jiec.2013.11.050] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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36
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Havelia S, Wang S, Balasubramaniam KR, Schultz AM, Rohrer GS, Salvador PA. Combinatorial substrate epitaxy: a new approach to growth of complex metastable compounds. CrystEngComm 2013. [DOI: 10.1039/c3ce40469b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Lee SW, Liu Y, Heo J, Gordon RG. Creation and control of two-dimensional electron gas using Al-based amorphous oxides/SrTiO₃ heterostructures grown by atomic layer deposition. NANO LETTERS 2012; 12:4775-4783. [PMID: 22908907 DOI: 10.1021/nl302214x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The formation of a two-dimensional electron gas (2-DEG) using SrTiO(3) (STO)-based heterostructures provides promising opportunities in oxide electronics. We realized the formation of 2-DEG using several amorphous layers grown by the atomic layer deposition (ALD) technique at 300 °C which is a process compatible with mass production and thereby can provide the realization of potential applications. We found that the amorphous LaAlO(3) (LAO) layer grown by the ALD process can generate 2-DEG (∼1 × 10(13)/cm(2)) with an electron mobility of 4-5 cm(2)/V·s. A much higher electron mobility was observed at lower temperatures. More remarkably, amorphous YAlO(3) (YAO) and Al(2)O(3) layers, which are not polar-perovskite-structured oxides, can create 2-DEG as well. 2-DEG was created by means of the important role of trimethylaluminum, Me(3)Al, as a reducing agent for STO during LAO and YAO ALD as well as the Al(2)O(3) ALD process at 300 °C. The deposited oxide layer also plays an essential role as a catalyst that enables Me(3)Al to reduce the STO. The electrons were localized very near to the STO surface, and the source of carriers was explained based on the oxygen vacancies generated in the STO substrate.
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Affiliation(s)
- Sang Woon Lee
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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38
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Vaz CAF. Electric field control of magnetism in multiferroic heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:333201. [PMID: 22824827 DOI: 10.1088/0953-8984/24/33/333201] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We review the recent developments in the electric field control of magnetism in multiferroic heterostructures, which consist of heterogeneous materials systems where a magnetoelectric coupling is engineered between magnetic and ferroelectric components. The magnetoelectric coupling in these composite systems is interfacial in origin, and can arise from elastic strain, charge, and exchange bias interactions, with different characteristic responses and functionalities. Moreover, charge transport phenomena in multiferroic heterostructures, where both magnetic and ferroelectric order parameters are used to control charge transport, suggest new possibilities to control the conduction paths of the electron spin, with potential for device applications.
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Affiliation(s)
- C A F Vaz
- SwissFEL, Paul Scherrer Institut, Villigen PSI, Switzerland.
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39
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Over H. Surface Chemistry of Ruthenium Dioxide in Heterogeneous Catalysis and Electrocatalysis: From Fundamental to Applied Research. Chem Rev 2012; 112:3356-426. [DOI: 10.1021/cr200247n] [Citation(s) in RCA: 509] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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40
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Kaspar TC, Bowden ME, Varga T, Wang CM, Shutthanandan V, Joly AG, Wirth BD, Kurtz RJ. Structural characterization of epitaxial Cr(x)Mo(1-x) alloy thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:095001. [PMID: 22274988 DOI: 10.1088/0953-8984/24/9/095001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
To develop a model system containing regularly spaced misfit dislocations for studies of the radiation resistance of nanoscale defects, epitaxial thin films of Cr, Mo, and Cr(x)Mo(1-x) alloys were deposited on MgO(001) by molecular beam epitaxy. Film compositions were chosen to vary the lattice mismatch with MgO. The film structure was investigated by x-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) and scanning transmission electron microscopy (STEM). Epitaxial films with reasonably high crystalline quality and abrupt interfaces were achieved at a relatively low deposition temperature, as confirmed by STEM. However, it was found by XRD and RBS in the channeling geometry that increasing the Mo content of the CrMo alloy films degraded the crystalline quality, despite the improved lattice match with MgO. XRD rocking curve data indicated that regions of different crystalline order may be present within the films with higher Mo content. This is tentatively ascribed to spinodal decomposition into Cr-rich and Mo-rich regions, as predicted by the Cr(x)Mo(1-x) phase diagram.
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Affiliation(s)
- T C Kaspar
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, USA.
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41
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Ciancio R, Carlino E, Aruta C, Maccariello D, Granozio FM, Scotti di Uccio U. Nanostructure of buried interface layers in TiO₂ anatase thin films grown on LaAlO₃ and SrTiO₃ substrates. NANOSCALE 2012; 4:91-94. [PMID: 22024736 DOI: 10.1039/c1nr11015b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
TiO(2) anatase thin films grown by pulsed laser deposition are investigated by high resolution transmission electron microscopy and high angle annular dark field scanning transmission electron microscopy. The analyses provide evidence of a peculiar growth mode of anatase on LaAlO(3) and SrTiO(3) characterized by the formation of an epitaxial layer at the film/substrate interface, due to cationic diffusion from the substrate into the film region. Pure TiO(2) anatase growth occurs in both specimens above a critical thickness of about 20 nm. The microstructural and chemical characterization of the samples is presented and discussed in the framework of oxide interface engineering.
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Affiliation(s)
- Regina Ciancio
- CNR-IOM TASC, Area Science Park, Basovizza S.S. 14 Km 163.5, 34149 Trieste, Italy.
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42
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Qin L, Zhu Q, Li G, Liu F, Pan Q. Controlled fabrication of flower–like ZnO–Fe2O3 nanostructured films with excellent lithium storage properties through a partly sacrificed template method. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm30277b] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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44
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Chen Y, Pryds N, Kleibeuker JE, Koster G, Sun J, Stamate E, Shen B, Rijnders G, Linderoth S. Metallic and insulating interfaces of amorphous SrTiO₃-based oxide heterostructures. NANO LETTERS 2011; 11:3774-3778. [PMID: 21823637 DOI: 10.1021/nl201821j] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The conductance confined at the interface of complex oxide heterostructures provides new opportunities to explore nanoelectronic as well as nanoionic devices. Herein we show that metallic interfaces can be realized in SrTiO(3)-based heterostructures with various insulating overlayers of amorphous LaAlO(3), SrTiO(3), and yttria-stabilized zirconia films. On the other hand, samples of amorphous La(7/8)Sr(1/8)MnO(3) films on SrTiO(3) substrates remain insulating. The interfacial conductivity results from the formation of oxygen vacancies near the interface, suggesting that the redox reactions on the surface of SrTiO(3) substrates play an important role.
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Affiliation(s)
- Yunzhong Chen
- Fuel Cells and Solid State Chemistry Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde, Denmark.
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45
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Lu X, Kim Y, Goetze S, Li X, Dong S, Werner P, Alexe M, Hesse D. Magnetoelectric coupling in ordered arrays of multilayered heteroepitaxial BaTiO₃/CoFe₂O₄ nanodots. NANO LETTERS 2011; 11:3202-3206. [PMID: 21749120 DOI: 10.1021/nl201443h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fully epitaxial BaTiO(3)/CoFe(2)O(4) ferroelectric/ferromagnetic multilayered nanodot arrays, a new type of magnetoelectric (ME) nanocomposite with both horizontal and vertical orderings, were fabricated via a stencil-derived direct epitaxy technique. By reducing the clamping effect, ferroelectric domain modification and distinct magnetization change proportional to different interfacial area around the BaTiO(3) phase transition temperatures were found, which may pave the way to quantitative introducing of ME coupling at nanoscale and build high density multistate memory devices.
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Affiliation(s)
- Xiaoli Lu
- Max Planck Institute of Microstructure Physics, D-06120 Halle (Saale), Germany.
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Radović M, Salluzzo M, Ristić Z, Di Capua R, Lampis N, Vaglio R, Granozio FM. In situ investigation of the early stage of TiO2 epitaxy on (001) SrTiO3. J Chem Phys 2011; 135:034705. [DOI: 10.1063/1.3613637] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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47
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Maksymovych P, Pan M, Yu P, Ramesh R, Baddorf AP, Kalinin SV. Scaling and disorder analysis of local I-V curves from ferroelectric thin films of lead zirconate titanate. NANOTECHNOLOGY 2011; 22:254031. [PMID: 21572199 DOI: 10.1088/0957-4484/22/25/254031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Differential analysis of current-voltage characteristics, obtained on the surface of epitaxial films of ferroelectric lead zirconate titanate (Pb(Zr(0.2)Ti(0.8))O(3)) using scanning probe microscopy, was combined with spatially resolved mapping of variations in local conductance to differentiate between candidate mechanisms of local electronic transport and the origin of disorder. Within the assumed approximations, electron transport was inferred to be determined by two mechanisms depending on the magnitude of applied bias, with the low-bias range dominated by the trap-assisted Fowler-Nordheim tunneling through the interface and the high-bias range limited by the hopping conduction through the bulk. Phenomenological analysis of the I-V curves has further revealed that the transition between the low- and high-bias regimes is manifested both in the strength of variations within the I-V curves sampled across the surface, as well as the spatial distribution of conductance. Spatial variations were concluded to originate primarily from the heterogeneity of the interfacial electronic barrier height with an additional small contribution from random changes in the tip-contact geometry.
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Affiliation(s)
- Peter Maksymovych
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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Patzke GR, Zhou Y, Kontic R, Conrad F. Oxidische Nanomaterialien: Von der Synthese über den Mechanismus zur technologischen Innovation. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201000235] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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49
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Patzke GR, Zhou Y, Kontic R, Conrad F. Oxide Nanomaterials: Synthetic Developments, Mechanistic Studies, and Technological Innovations. Angew Chem Int Ed Engl 2010; 50:826-59. [DOI: 10.1002/anie.201000235] [Citation(s) in RCA: 306] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Indexed: 11/07/2022]
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50
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Konstantinović Z, Santiso J, Balcells L, Martínez B. Kinetic versus strain formation of self-organized nanoholes in manganite thin films. NANOTECHNOLOGY 2010; 21:465601. [PMID: 20972308 DOI: 10.1088/0957-4484/21/46/465601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report on the formation of self-organized rows of pits in highly epitaxial La(2/3)Sr(1/3)MnO(3) thin films on top of substrates having different structural misfits by rf magnetron sputtering. The best-defined pits form in coherently grown films at a low misfit irrespective of its nature (tensile or compressive stress). It is also found that the pit rows align along the step edges, which indicates in-phase growth instability with the step edges, irrespective of the misfit. However, out-of-phase pit rows are also found when the terrace width increases due to a decrease of the miscut angle. Pit's volume scales inversely with the lattice mismatch suggesting that structural strain alone does not favor the formation of pits. The formation of pits is analyzed within a thermodynamic model.
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Affiliation(s)
- Z Konstantinović
- Instituto de Ciencia de Materiales de Barcelona (ICMAB-CSIC), Bellaterra, Spain.
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