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Tsang CS, Zheng X, Ly TH, Zhao J. Recent progresses in transmission electron microscopy studies of two-dimensional ferroelectrics. Micron 2024; 185:103678. [PMID: 38941681 DOI: 10.1016/j.micron.2024.103678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/03/2024] [Accepted: 06/13/2024] [Indexed: 06/30/2024]
Abstract
The rich potential of two-dimensional materials endows them with superior properties suitable for a wide range of applications, thereby attracting substantial interest across various fields. The ongoing trend towards device miniaturization aligns with the development of materials at progressively smaller scales, aiming to achieve higher integration density in electronics. In the realm of nano-scaling ferroelectric phenomena, numerous new two-dimensional ferroelectric materials have been predicted theoretically and subsequently validated through experimental confirmation. However, the capabilities of conventional tools, such as electrical measurements, are limited in providing a comprehensive investigation into the intrinsic origins of ferroelectricity and its interactions with structural factors. These factors include stacking, doping, functionalization, and defects. Consequently, the progress of potential applications, such as high-density memory devices, energy conversion systems, sensing technologies, catalysis, and more, is impeded. In this paper, we present a review of recent research that employs advanced transmission electron microscopy (TEM) techniques for the direct visualization and analysis of ferroelectric domains, domain walls, and other crucial features at the atomic level within two-dimensional materials. We discuss the essential interplay between structural characteristics and ferroelectric properties on the nanoscale, which facilitates understanding of the complex relationships governing their behavior. By doing so, we aim to pave the way for future innovative applications in this field.
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Affiliation(s)
- Chi Shing Tsang
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong, China
| | - Xiaodong Zheng
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Thuc Hue Ly
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong, China; Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China; City University of Hong Kong Shenzhen Research Institute, Shenzhen, China.
| | - Jiong Zhao
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China; The Research Institute for Advanced Manufacturing, The Hong Kong polytechnic University, Hong Kong, China.
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2
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Rehman F, Ahmad P, Rahman AU, Alharthi AI, Khalid A, Faruque MRI, Shah AH, Alotaibi MA, Ali H, Osman H, Khandaker MU. Solid state synthesis of lead-free Sm-doped Na 0.5Bi 4.5Ti 4O 15 ceramics for enhanced dielectric and electrical properties. Heliyon 2024; 10:e33606. [PMID: 39040251 PMCID: PMC11261011 DOI: 10.1016/j.heliyon.2024.e33606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/22/2024] [Accepted: 06/24/2024] [Indexed: 07/24/2024] Open
Abstract
Here we report the synthesis of Sm-doped Na0.5Bi4.5Ti4O15 (Na0.5Sm0.5Bi4Ti4O15) lead-free ceramics via a conventional solid-state technique. Investigations of Na0.5Bi4.5Ti4O15 (NBT) and Na0.5Sm0.5Bi4.5Ti4O15 (NSBT) ceramics were demonstrated in detail to understand the composition-based structure-property of Aurivillius compounds and related functional material. Dielectric properties for frequency and temperature in a wide range were analyzed. The conduction activation energy values of NSBT ceramics are obtained to be 1.40 eV, whereas, the NBT ceramics get the value to be 1.31 eV. At higher temperatures, the conduction activation energy value of NSBT ceramics is 1.32 eV for both frequencies of 100 Hz and 1 kHz, whereas, for NBT compounds, the calculated value is 1.27 eV for both frequencies. The simulation performed on the impedance data for capacitive and resistance elements shows well-fitting curves which indicates a single relaxation behavior in the material. Similarly, the AC-conductivity data were analyzed which gives different conduction processes and relaxation activation energies in the NSBT ceramics.
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Affiliation(s)
- Fida Rehman
- Department of Physics, Khushal Khan Khattak University, Karak, KP, Pakistan
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Pervaiz Ahmad
- Department of Physics, University of Azad Jammu and Kashmir, 13100, Muzaffarabad, Pakistan
- Department of Physics, College of Science and Humanities in Al-Kharj, Prince Sattam bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia
| | - Atta Ur Rahman
- Department of Physics, Khushal Khan Khattak University, Karak, KP, Pakistan
| | - Abdulrahman I. Alharthi
- Department of Chemistry, College of Science and Humanities, Prince Sattam Bin Abdulaziz University, P.O. Box 173, Al-Kharj, 11942, Saudi Arabia
| | - Awais Khalid
- Department of Physics, College of Science and Humanities in Al-Kharj, Prince Sattam bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia
| | | | - Abdul Hakim Shah
- Department of Physics, Khushal Khan Khattak University, Karak, KP, Pakistan
| | - Mshari A. Alotaibi
- Department of Chemistry, College of Science and Humanities, Prince Sattam Bin Abdulaziz University, P.O. Box 173, Al-Kharj, 11942, Saudi Arabia
| | - Hazrat Ali
- Department of Physics, Abbottabad University of Science & Technology, Havelian, KP, Pakistan
| | - Hamid Osman
- Department of Radiological Sciences, College of Applied Medical Sciences, Taif University, 21944, Taif, Saudi Arabia
| | - Mayeen Uddin Khandaker
- Applied Physics and Radiation Technologies Group, CCDCU, School of Engineering and Technology, Sunway University, Bandar Sunway, 47500, Selangor, Malaysia
- Faculty of Graduate Studies, Daffodil International University, Daffodil Smart City, Birulia, Savar, Dhaka, 1216, Bangladesh
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3
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Sun Q, Zhou X, Liu X, Yuan Y, Sun L, Wang D, Xue F, Luo H, Zhang D, Sun J. Quasi-Zero-Dimensional Ferroelectric Polarization Charges-Coupled Resistance Switching with High-Current Density in Ultrascaled Semiconductors. NANO LETTERS 2024; 24:975-982. [PMID: 38189647 DOI: 10.1021/acs.nanolett.3c04378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Ferroelectric memristors hold immense promise for advanced memory and neuromorphic computing. However, they face limitations due to low readout current density in conventional designs with low-conductive ferroelectric channels, especially at the nanoscale. Here, we report a ferroelectric-mediated memristor utilizing a 2D MoS2 nanoribbon channel with an ultrascaled cross-sectional area of <1000 nm2, defined by a ferroelectric BaTiO3 nanoribbon stacked on top. Strikingly, the Schottky barrier at the MoS2 contact can be effectively tuned by the charge transfers coupled with quasi-zero-dimensional polarization charges formed at the two ends of the nanoribbon, which results in distinctive resistance switching accompanied by multiple negative differential resistance showing the high-current density of >104 A/cm2. The associated space charges in BaTiO3 are minimized to ∼3.7% of the polarization charges, preserving nonvolatile polarization. This achievement establishes ferroelectric-mediated nanoscale semiconductor memristors with high readout current density as promising candidates for memory and highly energy-efficient in-memory computing applications.
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Affiliation(s)
- Qi Sun
- School of Physics, Central South University, Changsha, 410083, Hunan, China
| | - Xuefan Zhou
- State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, Hunan, China
| | - Xiaochi Liu
- School of Physics, Central South University, Changsha, 410083, Hunan, China
| | - Yahua Yuan
- School of Physics, Central South University, Changsha, 410083, Hunan, China
| | - Linfeng Sun
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Ding Wang
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, School of Micro-Nano Electronics, Zhejiang University, Hangzhou 311215, China
| | - Fei Xue
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, School of Micro-Nano Electronics, Zhejiang University, Hangzhou 311215, China
| | - Hang Luo
- State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, Hunan, China
| | - Dou Zhang
- State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, Hunan, China
| | - Jian Sun
- School of Physics, Central South University, Changsha, 410083, Hunan, China
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4
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Wu Q, Wang K, Simpson A, Hao Y, Wang J, Li D, Hong X. Electrode Effect on Ferroelectricity in Free-Standing Membranes of PbZr 0.2Ti 0.8O 3. ACS NANOSCIENCE AU 2023; 3:482-490. [PMID: 38144704 PMCID: PMC10740143 DOI: 10.1021/acsnanoscienceau.3c00032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 09/30/2023] [Accepted: 10/02/2023] [Indexed: 12/26/2023]
Abstract
We report the effects of screening capacity, surface roughness, and interfacial epitaxy of the bottom electrodes on the polarization switching, domain wall (DW) roughness, and ferroelectric Curie temperature (TC) of PbZr0.2Ti0.8O3 (PZT)-based free-standing membranes. Singe crystalline 10-50 nm (001) PZT and PZT/La0.67Sr0.33MnO3 (LSMO) membranes are prepared on Au, correlated oxide LSMO, and two-dimensional (2D) semiconductor MoS2 base layers. Switching the polarization of PZT yields nonvolatile current modulation in the MoS2 channel at room temperature, with an on/off ratio of up to 2 × 105 and no apparent decay for more than 3 days. Piezoresponse force microscopy studies show that the coercive field Ec for the PZT membranes varies from 0.75 to 3.0 MV cm-1 on different base layers and exhibits strong polarization asymmetry. The PZT/LSMO membranes exhibit significantly smaller Ec, with the samples transferred on LSMO showing symmetric Ec of about -0.26/+0.28 MV cm-1, smaller than that of epitaxial PZT films. The DW roughness exponent ζ points to 2D random bond disorder dominated DW roughening (ζ = 0.31) at room temperature. Upon thermal quench at progressively higher temperatures, ζ values for PZT membranes on Au and LSMO approach the theoretical value for 1D random bond disorder (ζ = 2/3), while samples on MoS2 exhibits thermal roughening (ζ = 1/2). The PZT membranes on Au, LSMO, and MoS2 show TC of about 763 ± 12, 725 ± 25, and 588 ± 12 °C, respectively, well exceeding the bulk value. Our study reveals the complex interplay between the electrostatic and mechanical boundary conditions in determining ferroelectricity in free-standing PZT membranes, providing important material parameters for the functional design of PZT-based flexible nanoelectronics.
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Affiliation(s)
- Qiuchen Wu
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Kun Wang
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Alyssa Simpson
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Yifei Hao
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Jia Wang
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Dawei Li
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Xia Hong
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
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5
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Zhou T, Zhai T, Shen H, Wang J, Min R, Ma K, Zhang G. Strategies for enhancing performance of perovskite bismuth ferrite photocatalysts (BiFeO 3): A comprehensive review. CHEMOSPHERE 2023; 339:139678. [PMID: 37527742 DOI: 10.1016/j.chemosphere.2023.139678] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/08/2023] [Accepted: 07/28/2023] [Indexed: 08/03/2023]
Abstract
Organic pollutants pose a significant threat to water safety, and their degradation is of paramount importance. Photocatalytic technology has emerged as a promising approach for environmental remediation, and Bismuth ferrite (BiFeO3) has been shown to exhibit remarkable potential for photocatalytic degradation of water pollutants, with its excellent crystal structure properties and visible light photocatalytic activity. This review presents an overview of the crystal properties and photocatalytic mechanism of perovskite bismuth ferrite (BiFeO3), as well as a summary of various strategies for enhancing its efficiency in photocatalytic degradation of organic pollutants. These strategies include pure phase preparation, microscopic modulation, composite modification of BiFeO3, and the integration of Fenton-like reactions and external field-assisted methods to improve its photocatalytic performance. The review emphasizes the impact of each strategy on photocatalytic enhancement. By providing comprehensive strategies for improving the efficiency of BiFeO3 photocatalysis, this review inspires new insights for efficient degradation of organic pollutants using BiFeO3 photocatalysis and contributes to the development of photocatalysis in environmental remediation.
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Affiliation(s)
- Tianhong Zhou
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Tianjiao Zhai
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Huidong Shen
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Jinyi Wang
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Rui Min
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Kai Ma
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Guozhen Zhang
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou, 730070, China.
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6
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Ran K, Barthel J, Jin L, Park D, Buchheit A, Neuhaus K, Baumann S, Meulenberg WA, Mayer J. Direct Visualization of Distorted Twin Boundaries in Ce-Doped GdFeO 3. NANO LETTERS 2023; 23:2945-2951. [PMID: 36972518 DOI: 10.1021/acs.nanolett.3c00318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Utilizing advanced transmission electron microscopy (TEM), the structure at the (110)-type twin boundary (TB) of Ce-doped GdFeO3 (C-GFO) has been investigated with picometer precision. Such a TB is promising to generate local ferroelectricity within a paraelectric system, while precise knowledge about its structure is still largely missing. In this work, a direct measurement of the cation off-centering with respect to the neighboring oxygen is enabled by integrated differential phase contrast (iDPC) imaging, and up to 30 pm Gd off-centering is highly localized at the TB. Further electron energy loss spectroscopy (EELS) analysis demonstrates a slight accumulation of oxygen vacancies at the TB, a self-balanced behavior of Ce at the Gd sites, and a mixed occupation of Fe2+ and Fe3+ at the Fe sites. Our results provide an informative picture with atomic details at the TB of C-GFO, which is indispensable to further push the potential of grain boundary engineering.
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Affiliation(s)
- Ke Ran
- Central Facility for Electron Microscopy GFE, RWTH Aachen University, 52074 Aachen, Germany
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons ER-C, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Juri Barthel
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons ER-C, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Lei Jin
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons ER-C, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Daesung Park
- Physikalisch-Technische Bundesanstalt PTB, 38116 Braunschweig, Germany
| | - Annika Buchheit
- Institute of Energy and Climate Research IEK-12, Forschungszentrum Jülich GmbH, 48149 Münster, Germany
| | - Kerstin Neuhaus
- Institute of Energy and Climate Research IEK-12, Forschungszentrum Jülich GmbH, 48149 Münster, Germany
| | - Stefan Baumann
- Institute of Energy and Climate Research IEK-1, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Wilhelm A Meulenberg
- Institute of Energy and Climate Research IEK-1, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Faculty of Science and Technology, Inorganic Membranes, University of Twente, 7500 AE Enschede, The Netherlands
| | - Joachim Mayer
- Central Facility for Electron Microscopy GFE, RWTH Aachen University, 52074 Aachen, Germany
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons ER-C, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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7
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Lawrence RA, Ramasse QM, Holsgrove KM, Sando D, Cazorla C, Valanoor N, Arredondo MA. Effects of Multiple Local Environments on Electron Energy Loss Spectra of Epitaxial Perovskite Interfaces. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:21453-21466. [PMID: 36582487 PMCID: PMC9791663 DOI: 10.1021/acs.jpcc.2c06879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/15/2022] [Indexed: 06/17/2023]
Abstract
The role of local chemical environments in the electron energy loss spectra of complex multiferroic oxides was studied using computational and experimental techniques. The evolution of the O K-edge across an interface between bismuth ferrite (BFO) and lanthanum strontium manganate (LSMO) was considered through spectral averaging over crystallographically equivalent positions to capture the periodicity of the local O environments. Computational techniques were used to investigate the contribution of individual atomic environments to the overall spectrum, and the role of doping and strain was considered. Chemical variation, even at the low level, was found to have a major impact on the spectral features, whereas strain only induced a small chemical shift to the edge onset energy. Through a combination of these methods, it was possible to explain experimentally observed effects such as spectral flattening near the interface as the combination of spectral responses from multiple local atomic environments.
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Affiliation(s)
- Robert A. Lawrence
- Department
of Physics, University of York, Heslington, North YorkshireYO10 5DD, United Kingdom
| | - Quentin M. Ramasse
- SuperSTEM
Laboratory, SciTech Daresbury Campus, DaresburyWA4 4AD, United Kingdom
- School
of Chemical and Process Engineering and School of Physics and Astronomy, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - Kristina M. Holsgrove
- School
of Mathematics and Physics, Queen’s
University Belfast, BelfastBT7 1NN, Northern Ireland, United Kingdom
| | - Daniel Sando
- School
of Physical and Chemical Sciences, University
of Canterbury, ChristChurch8140, New Zealand
| | - Claudio Cazorla
- Departament
de Fisica, Universitat Politecnica de Catalunya, BarcelonaE-08034, Catalonia, Spain
| | - Nagarajan Valanoor
- School
of Materials Science and Engineering, University
of New South Wales, Sydney, NSW2052, Australia
| | - Miryam A. Arredondo
- School
of Mathematics and Physics, Queen’s
University Belfast, BelfastBT7 1NN, Northern Ireland, United Kingdom
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8
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Ziatdinov M, Ghosh A, Wong CY, Kalinin SV. AtomAI framework for deep learning analysis of image and spectroscopy data in electron and scanning probe microscopy. NAT MACH INTELL 2022. [DOI: 10.1038/s42256-022-00555-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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9
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Chen X, Liu C, Hua Z, Ma N. Ferroelectric Polarization and Oxygen Vacancy Synergistically Induced an Ultrasensitive and Fast Humidity Sensor for Multifunctional Applications. ACS APPLIED MATERIALS & INTERFACES 2022; 14:49965-49974. [PMID: 36285769 DOI: 10.1021/acsami.2c14332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
With the arrival of the Internet of Things and artificial intelligence, humidity sensors monitoring water emissions from human metabolism have attracted great attention in the fields of smart wearable devices and noncontact human-machine interaction. However, their application is seriously limited by the trade-off between the sensitivity and response speed for traditional humidity sensors. Herein, to overcome it, a self-powered high performance humidity sensor is developed on the basis of the electric-poled and oxygen vacancy-rich BiFeO3 (BFO) ferroelectric material. The synergistic effect of ferroelectric polarization and oxygen vacancy provides a strong driving force and active adsorption sites for an abundance of OH/H2O adsorption, resulting in an ultrahigh response (∼104) and ultrafast response/recovery speed (∼84/376 ms). Benefiting from its promising advantages, the wearable humidity sensor can accurately record the respiration rate/depth and recognize different human respiratory behaviors in real-time. Importantly, by utilizing the moisture from mouth-blowing and skin, the sensors are successfully applied to noncontact control of a robotic car, noncontact switch, and noncontact interface for visualization applications. This work provides an effective strategy for developing excellent humidity sensors that meet the requirement of noncontact interaction for next-generation intelligent electronics.
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Affiliation(s)
- Xinyi Chen
- CAS Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai201899, China
- Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin300401, China
| | - Cheng Liu
- School of Naval Architecture Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai200240, China
| | - Zhongqiu Hua
- Electronic College, Peking University, Beijing100871, China
| | - Nan Ma
- CAS Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai201899, China
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10
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Liu P, Miao J, Liu Q, Xu Z, Wu Y, Meng K, Xu X, Jiang Y. Large non-volatile modulation of perpendicular magnetic anisotropy in Pb (Zr0.2Ti0.8) O3/SrRuO3. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Recent trends and morphology mechanisms of rare-earth based BiFeO3 nano perovskites with excellent photocatalytic performances. J RARE EARTH 2022. [DOI: 10.1016/j.jre.2022.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Ren Z, Ruan L, Yin L, Akkiraju K, Giordano L, Liu Z, Li S, Ye Z, Li S, Yang H, Wang Y, Tian H, Liu G, Shao-Horn Y, Han G. Surface Oxygen Vacancies Confined by Ferroelectric Polarization for Tunable CO Oxidation Kinetics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2202072. [PMID: 35580350 DOI: 10.1002/adma.202202072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 05/13/2022] [Indexed: 06/15/2023]
Abstract
Surface oxygen vacancies have been widely discussed to be crucial for tailoring the activity of various chemical reactions from CO, NO, to water oxidation by using oxide-supported catalysts. However, the real role and potential function of surface oxygen vacancies in the reaction remains unclear because of their very short lifetime. Here, it is reported that surface oxygen vacancies can be well confined electrostatically for a polarization screening near the perimeter interface between Pt {111} nanocrystals and the negative polar surface (001) of ferroelectric PbTiO3. Strikingly, such a catalyst demonstrates a tunable catalytic CO oxidation kinetics from 200 °C to near room temperature by increasing the O2 gas pressure, accompanied by the conversion curve from a hysteresis-free loop to one with hysteresis. The combination of reaction kinetics, electronic energy loss spectroscopy (EELS) analysis, and density functional theory (DFT) calculations, indicates that the oxygen vacancies stabilized by the negative polar surface are the active sites for O2 adsorption as a rate-determining step, and then dissociated O moves to the surface of the Pt nanocrystals for oxidizing adsorbed CO. The results open a new pathway for tunable catalytic activity of CO oxidation.
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Affiliation(s)
- Zhaohui Ren
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
- Research Center for Intelligent Sensing, Zhejiang Lab, Hangzhou, 311100, China
| | - Luoyuan Ruan
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
- Research Center for Sensing Materials and Devices, Zhejiang Lab, Hangzhou, 311121, China
| | - Lichang Yin
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Karthik Akkiraju
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Livia Giordano
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Zhongran Liu
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Shi Li
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zixing Ye
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Songda Li
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Hangsheng Yang
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Yong Wang
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - He Tian
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
- School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, 450052, China
| | - Gang Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Yang Shao-Horn
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Gaorong Han
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
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13
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Ding Y, Yang J, Ji Y, Guo Q, Li X, Wang L, Meng Y, Shen X, Yao Y, Yu R. Several factors influencing energy‐loss near‐edge structure calculations using Wien2k. J Microsc 2022; 287:61-68. [DOI: 10.1111/jmi.13111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 05/02/2022] [Accepted: 05/10/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Yifan Ding
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Physics Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Junkai Yang
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Physics Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Yu Ji
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Physics Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Qinwen Guo
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Physics Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Xiangfei Li
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Physics Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Luyao Wang
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Physics Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Ying Meng
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Physics Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Xi Shen
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Yuan Yao
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Richeng Yu
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Physics Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
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14
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Wu PC, Wei CC, Zhong Q, Ho SZ, Liou YD, Liu YC, Chiu CC, Tzeng WY, Chang KE, Chang YW, Zheng J, Chang CF, Tu CM, Chen TM, Luo CW, Huang R, Duan CG, Chen YC, Kuo CY, Yang JC. Twisted oxide lateral homostructures with conjunction tunability. Nat Commun 2022; 13:2565. [PMID: 35538081 PMCID: PMC9090740 DOI: 10.1038/s41467-022-30321-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 04/13/2022] [Indexed: 11/28/2022] Open
Abstract
Epitaxial growth is of significant importance over the past decades, given it has been the key process of modern technology for delivering high-quality thin films. For conventional heteroepitaxy, the selection of proper single crystal substrates not only facilitates the integration of different materials but also fulfills interface and strain engineering upon a wide spectrum of functionalities. Nevertheless, the lattice structure, regularity and crystalline orientation are determined once a specific substrate is chosen. Here, we reveal the growth of twisted oxide lateral homostructure with controllable in-plane conjunctions. The twisted lateral homostructures with atomically sharp interfaces can be composed of epitaxial "blocks" with different crystalline orientations, ferroic orders and phases. We further demonstrate that this approach is universal for fabricating various complex systems, in which the unconventional physical properties can be artificially manipulated. Our results establish an efficient pathway towards twisted lateral homostructures, adding additional degrees of freedom to design epitaxial films.
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Affiliation(s)
- Ping-Chun Wu
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Chia-Chun Wei
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Qilan Zhong
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, 200241, Shanghai, China
| | - Sheng-Zhu Ho
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Yi-De Liou
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Yu-Chen Liu
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Chun-Chien Chiu
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Wen-Yen Tzeng
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Kuo-En Chang
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Yao-Wen Chang
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Junding Zheng
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, 200241, Shanghai, China
| | - Chun-Fu Chang
- Max-Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Chien-Ming Tu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Tse-Ming Chen
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Chih-Wei Luo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Rong Huang
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, 200241, Shanghai, China
| | - Chun-Gang Duan
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, 200241, Shanghai, China
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Chang-Yang Kuo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Jan-Chi Yang
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan.
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, 70101, Taiwan.
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15
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Su L, Huyan H, Sarkar A, Gao W, Yan X, Addiego C, Kruk R, Hahn H, Pan X. Direct observation of elemental fluctuation and oxygen octahedral distortion-dependent charge distribution in high entropy oxides. Nat Commun 2022; 13:2358. [PMID: 35487934 PMCID: PMC9055071 DOI: 10.1038/s41467-022-30018-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 03/04/2022] [Indexed: 11/30/2022] Open
Abstract
The enhanced compositional flexibility to incorporate multiple-principal cations in high entropy oxides (HEOs) offers the opportunity to expand boundaries for accessible compositions and unconventional properties in oxides. Attractive functionalities have been reported in some bulk HEOs, which are attributed to the long-range compositional homogeneity, lattice distortion, and local chemical bonding characteristics in materials. However, the intricate details of local composition fluctuation, metal-oxygen bond distortion and covalency are difficult to visualize experimentally, especially on the atomic scale. Here, we study the atomic structure-chemical bonding-property correlations in a series of perovskite-HEOs utilizing the recently developed four-dimensional scanning transmission electron microscopy techniques which enables to determine the structure, chemical bonding, electric field, and charge density on the atomic scale. The existence of compositional fluctuations along with significant composition-dependent distortion of metal-oxygen bonds is observed. Consequently, distinct variations of metal-oxygen bonding covalency are shown by the real-space charge-density distribution maps with sub-ångström resolution. The observed atomic features not only provide a realistic picture of the local physico-chemistry of chemically complex HEOs but can also be directly correlated to their distinctive magneto-electronic properties.
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Affiliation(s)
- Lei Su
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
| | - Huaixun Huyan
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
| | - Abhishek Sarkar
- KIT-TUD-Joint Research Laboratory Nanomaterials, Technical University Darmstadt, 64287, Darmstadt, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Wenpei Gao
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
| | - Xingxu Yan
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
| | - Christopher Addiego
- Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA
| | - Robert Kruk
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Horst Hahn
- KIT-TUD-Joint Research Laboratory Nanomaterials, Technical University Darmstadt, 64287, Darmstadt, Germany.
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany.
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA.
- Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA.
- Irvine Materials Research Institute, University of California, Irvine, CA, 92697, USA.
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16
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Mazza AR, Skoropata E, Sharma Y, Lapano J, Heitmann TW, Musico BL, Keppens V, Gai Z, Freeland JW, Charlton TR, Brahlek M, Moreo A, Dagotto E, Ward TZ. Designing Magnetism in High Entropy Oxides. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200391. [PMID: 35150081 PMCID: PMC8981892 DOI: 10.1002/advs.202200391] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Indexed: 06/14/2023]
Abstract
In magnetic systems, spin and exchange disorder can provide access to quantum criticality, frustration, and spin dynamics, but broad tunability of these responses and a deeper understanding of strong limit disorder are lacking. Here, it is demonstrated that high entropy oxides present a previously unexplored route to designing materials in which the presence of strong local compositional disorder may be exploited to generate tunable magnetic behaviors-from macroscopically ordered states to frustration-driven dynamic spin interactions. Single-crystal La(Cr0.2 Mn0.2 Fe0.2 Co0.2 Ni0.2 )O3 films are used as a model system hosting a magnetic sublattice with a high degree of microstate disorder in the form of site-to-site spin and exchange type inhomogeneity. A classical Heisenberg model simplified to represent the highest probability microstates well describes how compositionally disordered systems can paradoxically host magnetic uniformity and demonstrates a path toward continuous control over ordering types and critical temperatures. Model-predicted materials are synthesized and found to possess an incipient quantum critical point when magnetic ordering types are designed to be in direct competition, this leads to highly controllable exchange bias behaviors previously accessible only in intentionally designed bilayer heterojunctions.
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Affiliation(s)
- Alessandro R. Mazza
- Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Elizabeth Skoropata
- Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Yogesh Sharma
- Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- Center for Integrated NanotechnologiesLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Jason Lapano
- Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Thomas W. Heitmann
- University of Missouri Research ReactorThe University of MissouriColumbiaMO65211USA
| | - Brianna L. Musico
- Department of Materials Science and EngineeringUniversity of TennesseeKnoxvilleTN37996‐4545USA
| | - Veerle Keppens
- Department of Materials Science and EngineeringUniversity of TennesseeKnoxvilleTN37996‐4545USA
| | - Zheng Gai
- Center for Nanophase Materials SciencesOak Ridge National LaboratoryOak RidgeTN37831USA
| | - John W. Freeland
- Advanced Photon SourceArgonne National LaboratoryLemontIL60439USA
| | | | - Matthew Brahlek
- Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Adriana Moreo
- Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- Department of Physics and AstronomyUniversity of TennesseeKnoxvilleTN37996USA
| | - Elbio Dagotto
- Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
- Department of Physics and AstronomyUniversity of TennesseeKnoxvilleTN37996USA
| | - Thomas Z. Ward
- Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
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17
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Zhang Q, Meng F, Gao A, Li X, Jin Q, Lin S, Chen S, Shang T, Zhang X, Guo H, Wang C, Jin K, Wang X, Su D, Gu L, Guo EJ. Dynamics of Anisotropic Oxygen-Ion Migration in Strained Cobaltites. NANO LETTERS 2021; 21:10507-10515. [PMID: 34870440 DOI: 10.1021/acs.nanolett.1c04057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Orientation control of the oxygen vacancy channel (OVC) is highly desirable for tailoring oxygen diffusion as it serves as a fast transport channel in ion conductors, which is widely exploited in solid-state fuel cells, catalysts, and ion-batteries. Direct observation of oxygen-ion hopping toward preferential vacant sites is a key to clarifying migration pathways. Here we report anisotropic oxygen-ion migration mediated by strain in ultrathin cobaltites via in situ thermal activation in atomic-resolved transmission electron microscopy. Oxygen migration pathways are constructed on the basis of the atomic structure during the OVC switching, which is manifested as the vertical-to-horizontal OVC switching under tensile strain but the horizontal-to-diagonal switching under compression. We evaluate the topotactic structural changes to the OVC, determine the crucial role of the tolerance factor for OVC stability, and establish the strain-dependent phase diagram. Our work provides a practical guide for engineering OVC orientation that is applicable to ionic-oxide electronics.
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Affiliation(s)
- Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Yangtze River Delta Physics Research Center Co. Ltd., Liyang 213300, China
| | - Fanqi Meng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ang Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinyan Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiao Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shan Lin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shengru Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tongtong Shang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xing Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Haizhong Guo
- School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
| | - Can Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Kuijuan Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Xuefeng Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Dong Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Er-Jia Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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18
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Ma X, Li X, Su C, Zhu M, Miao J, Guan D, Zhou W, Shao Z. Interface engineered perovskite oxides for enhanced catalytic oxidation: The vital role of lattice oxygen. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116944] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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19
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Petralanda U, Kruse M, Simons H, Olsen T. Oxygen Vacancies Nucleate Charged Domain Walls in Ferroelectrics. PHYSICAL REVIEW LETTERS 2021; 127:117601. [PMID: 34558956 DOI: 10.1103/physrevlett.127.117601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 06/25/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
We study the influence of oxygen vacancies on the formation of charged 180° domain walls in ferroelectric BaTiO_{3} using first principles calculations. We show that it is favorable for vacancies to assemble in crystallographic planes, and that such clustering is accompanied by the formation of a charged domain wall. The domain wall has negative bound charge, which compensates the nominal positive charge of the vacancies and leads to a vanishing density of free charge at the wall. This is in contrast to the positively charged domain walls, which are nearly completely compensated by free charge from the bulk. The results thus explain the experimentally observed difference in electronic conductivity of the two types of domain walls, as well as the generic prevalence of charged domain walls in ferroelectrics. Moreover, the explicit demonstration of vacancy driven domain wall formation implies that specific charged domain wall configurations may be realized by bottom-up design for use in domain wall based information processing.
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Affiliation(s)
- Urko Petralanda
- Computational Atomic-Scale Materials Design (CAMD), Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Mads Kruse
- Computational Atomic-Scale Materials Design (CAMD), Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Hugh Simons
- Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Thomas Olsen
- Computational Atomic-Scale Materials Design (CAMD), Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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20
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Ghimire G, Dhakal KP, Choi W, Esthete YA, Kim SJ, Tran TT, Lee H, Yang H, Duong DL, Kim YM, Kim J. Doping-Mediated Lattice Engineering of Monolayer ReS 2 for Modulating In-Plane Anisotropy of Optical and Transport Properties. ACS NANO 2021; 15:13770-13780. [PMID: 34296605 DOI: 10.1021/acsnano.1c05316] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
ReS2 exhibits strong anisotropic optical and electrical responses originating from the asymmetric lattice. Here, we show that the anisotropy of monolayer (1L) ReS2 in optical scattering and electrical transport can be practically erased by lattice engineering via lithium (Li) treatment. Scanning transmission electron microscopy revealed that significant strain is induced in the lattice of Li-treated 1L-ReS2, due to high-density electron doping and the resultant formation of continuous tiling of nanodomains with randomly rotating orientations of 60°, which produced a nearly isotropic response of polarized Raman scattering and absorption of Li-treated 1L-ReS2. With Li treatment, the in-plane conductance of 1L-ReS2 increased by an order of magnitude, and its angle dependence became negligible. Our result that the asymmetric phase was converted into the isotropic phase by electron injection could significantly expand the optoelectronic applications of polymorphic two-dimensional transition metal dichalcogenides.
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Affiliation(s)
- Ganesh Ghimire
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Krishna P Dhakal
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Wooseon Choi
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yonas Assefa Esthete
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seon Je Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Trang Thu Tran
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyoyoung Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Heejun Yang
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Dinh Loc Duong
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
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21
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Chen J, Zhang Z, Luo L, Lu Y, Song C, Cheng D, Chen X, Li W, Ren Z, Wang J, Tian H, Zhang Z, Han G. Reversible magnetism transition at ferroelectric oxide heterointerface. Sci Bull (Beijing) 2020; 65:2094-2099. [PMID: 36732962 DOI: 10.1016/j.scib.2020.09.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/11/2020] [Accepted: 09/01/2020] [Indexed: 02/04/2023]
Abstract
Oxide heterointerface is a platform to create unprecedented two-dimensional electron gas, superconductivity and ferromagnetism, arising from a polar discontinuity at the interface. In particular, the ability to tune these intriguing effects paves a way to elucidate their fundamental physics and to develop novel electronic/magnetic devices. In this work, we report for the first time that a ferroelectric polarization screening at SrTiO3/PbTiO3 interface is able to drive an electronic construction of Ti atom, giving rise to room-temperature ferromagnetism. Surprisingly, such ferromagnetism can be switched to antiferromagnetism by applying a magnetic field, which is reversible. A coupling of itinerant electrons with local moments at interfacial Ti 3d orbital was proposed to explain the magnetism. The localization of the itinerant electrons under a magnetic field is responsible for the suppression of magnetism. These findings provide new insights into interfacial magnetism and their control by magnetic field relevant interfacial electrons promising for device applications.
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Affiliation(s)
- Jialu Chen
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China
| | - Zijun Zhang
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China; Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Liang Luo
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory-USDOE, Ames, IA 50011, USA
| | - Yunhao Lu
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Cheng Song
- Key Laboratory of Advanced Materials (Ministry of Education), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Di Cheng
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory-USDOE, Ames, IA 50011, USA
| | - Xing Chen
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China; Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Wei Li
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China
| | - Zhaohui Ren
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China.
| | - Jigang Wang
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory-USDOE, Ames, IA 50011, USA.
| | - He Tian
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China; Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
| | - Ze Zhang
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China; Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Gaorong Han
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China.
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22
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Oxley MP, Yin J, Borodinov N, Somnath S, Ziatdinov M, Lupini AR, Jesse S, Vasudevan RK, Kalinin SV. Deep learning of interface structures from simulated 4D STEM data: cation intermixing vs. roughening. MACHINE LEARNING-SCIENCE AND TECHNOLOGY 2020. [DOI: 10.1088/2632-2153/aba32d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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23
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Wen Z, Wu D. Ferroelectric Tunnel Junctions: Modulations on the Potential Barrier. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1904123. [PMID: 31583775 DOI: 10.1002/adma.201904123] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/16/2019] [Indexed: 06/10/2023]
Abstract
Recently, ferroelectric tunnel junctions (FTJs) have attracted considerable attention for potential applications in next-generation memories, owing to attractive advantages such as high-density of data storage, nondestructive readout, fast write/read access, and low energy consumption. Herein, recent progress regarding FTJ devices is reviewed with an emphasis on the modulation of the potential barrier. Electronic and ionic approaches that modulate the ferroelectric barriers themselves and/or induce extra barriers in electrodes or at ferroelectric/electrode interfaces are discussed with the enhancement of memory performance. Emerging physics, such as nanoscale ferroelectricity, resonant tunneling, and interfacial metallization, and the applications of FTJs in nonvolatile data storage, neuromorphic synapse emulation, and electromagnetic multistate memory are summarized. Finally, challenges and perspectives of FTJ devices are underlined.
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Affiliation(s)
- Zheng Wen
- College of Physics and Center for Marine Observation and Communications, Qingdao University, Qingdao, 266071, China
- Collaborative Innovation Center for Advanced Materials, Nanjing University, Nanjing, 210093, China
| | - Di Wu
- National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, Jiangsu Key Laboratory of Artificial Functional Materials and Collaborative Innovation Center for Advanced Materials, Nanjing University, Nanjing, 210093, China
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24
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Choi M, Ibrahim IAM, Kim K, Koo JY, Kim SJ, Son JW, Han JW, Lee W. Engineering of Charged Defects at Perovskite Oxide Surfaces for Exceptionally Stable Solid Oxide Fuel Cell Electrodes. ACS APPLIED MATERIALS & INTERFACES 2020; 12:21494-21504. [PMID: 32315147 DOI: 10.1021/acsami.9b21919] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Cation segregation, particularly Sr segregation, toward a perovskite surface has a significant effect on the performance degradation of a solid oxide cell (solid oxide electrolysis/fuel cell). Among the number of key reasons generating the instability of perovskite oxide, surface-accumulated positively charged defects (oxygen vacancy, Vo··) have been considered as the most crucial drivers in strongly attracting negatively charged defects (SrA - site') toward the surface. Herein, we demonstrate the effects of a heterointerface on the redistribution of both positively and negatively charged defects for a reduction of Vo·· at a perovskite surface. We took Sm0.5Sr0.5CoO3-δ (SSC) as a model perovskite film and coated Gd0.1Ce0.9O2-δ (GDC) additionally onto the SSC film to create a heterointerface (GDC/SSC), resulting in an ∼11-fold reduction in a degradation rate of ∼8% at 650 °C and ∼10-fold higher surface exchange (kq) than a bare SSC film after 150 h at 650 °C. Using X-ray photoelectron spectroscopy and electron energy loss spectroscopy, we revealed a decrease in positively charged defects of Vo·· and transferred electrons in an SSC film at the GDC/SSC heterointerface, resulting in a suppression of negatively charged Sr (SrSm') segregation. Finally, the energetic behavior, including the charge transfer phenomenon, O p-band center, and oxygen vacancy formation energy calculated using the density functional theory, verified the effects of the heterointerface on the redistribution of the charged defects, resulting in a remarkable impact on the stability of perovskite oxide at elevated temperatures.
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Affiliation(s)
- Mingi Choi
- School of Mechanical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, South Korea
| | - Ismail A M Ibrahim
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, South Korea
- Department of Chemistry, Faculty of Science, Helwan University, Cairo 11795, Egypt
| | - Kyeounghak Kim
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, South Korea
| | - Ja Yang Koo
- School of Mechanical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, South Korea
| | - Seo Ju Kim
- School of Mechanical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, South Korea
| | - Ji-Won Son
- Center for Energy Materials Research, Korea Institute of Science and Technology (KIST), Seoul 02792, South Korea
| | - Jeong Woo Han
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, South Korea
| | - Wonyoung Lee
- School of Mechanical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, South Korea
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25
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Mundet B, Hartman ST, Guzman R, Idrobo JC, Obradors X, Puig T, Mishra R, Gázquez J. Local strain-driven migration of oxygen vacancies to apical sites in YBa 2Cu 3O 7-x. NANOSCALE 2020; 12:5922-5931. [PMID: 32108218 DOI: 10.1039/d0nr00666a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
It is well known that in the high-temperature superconductor YBa2Cu3O7-x (YBCO), oxygen vacancies (VO) control the carrier concentration, its critical current density and transition temperature. In this work, it is revealed that VO also allows the accommodation of local strain fields caused by large-scale defects within the crystal. We show that the nanoscale strain associated with Y2Ba4Cu8O16 (Y124) intergrowths-that are common defects in YBCO-strongly affect the venue and concentration of VO. Local probe measurements in conjunction with density-functional-theory calculations indicate a strain-driven reordering of VO from the commonly observed CuO chains towards the bridging apical sites located in the BaO plane and bind directly to the superconducting CuO2 planes. Our findings have strong implications on the physical properties of the YBCO, as the presence of apical VO alters the transfer of carriers to the CuO2 planes, confirmed by changes in the Cu and O core-loss edge probed using electron energy loss spectroscopy, and creates structural changes that affect the Cu-O bonds in the superconducting planes. In addition, the revelation of apical VO also has implications on modulating critical current densities and enhancing vortex pinning.
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Affiliation(s)
- Bernat Mundet
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Steven T Hartman
- Institute of Materials Science and Engineering, Washington University in St Louis, St Louis, Missouri 63130, USA
| | - Roger Guzman
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Juan C Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Xavier Obradors
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Teresa Puig
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Rohan Mishra
- Department of Mechanical Engineering and Materials Science, Washington University in St Louis, St Louis, Missouri 63130, USA.
| | - Jaume Gázquez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain.
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26
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Moore K, Conroy M, Bangert U. Rapid polarization mapping in ferroelectrics using Fourier masking. J Microsc 2020; 279:222-228. [PMID: 32043577 DOI: 10.1111/jmi.12876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 02/04/2020] [Accepted: 02/06/2020] [Indexed: 11/26/2022]
Abstract
Ferroelectric materials, and more specifically ferroelectric domain walls (DWs) have become an area of intense research in recent years. Novel physical phenomena have been discovered at these nanoscale topological polarization discontinuities by mapping out the polarization in each atomic unit cell around the DW in a scanning transmission electron microscope (STEM). However, identifying these features requires an understanding of the polarization in the overall domain structure of the TEM sample, which is often a time-consuming process. Here, a fast method of polarization mapping in the TEM is presented, which can be applied to a range of ferroelectric materials. Due to the coupling of polarization to spontaneous strain, we can isolate different strain states and demonstrate the fast mapping of the domain structure in ferroelectric lead titanate (PTO). The method only requires a high-resolution TEM or STEM image and is less sensitive to zone axis or local strain effects, which may affect other techniques. Thus, it is easily applicable to in-situ experiments. The complimentary benefits of Fourier masking with more advanced mapping strategies and its application to other materials are discussed. These results imply that Fourier masked polarization mapping will be a useful tool for electron microscopists in streamlining their analysis of ferroelectric TEM samples. LAY DESCRIPTION: This paper addresses a problem that often occurs when looking at a ferroelectric material in the Transmission Electron Microscope (TEM). Ferroelectric samples are interesting because they form tiny areas inside themselves with arrow of charge in each one. The thinner the sample, the smaller these regions, called "domains" become. These arrows of charge point in different directions in each domain of the sample. The boundary where these domains meet have interesting properties to study in a TEM but it's important to figure out which way the arrows point in the domains around the boundary. What causes the arrows in the different domains is tiny shifts of different atoms in unit cell away from their neutral position, usually because they're being squeezed by pressure from the domains nearby. The problem is that these tiny atoms moving are difficult to measure and see where the charged arrow is pointing, often it's hard to know how many different domains are even in the sample and where they begin. This paper discusses a method called "Fourier masking" to quickly see what's going on in the overall TEM sample, where the domains are and roughly where the arrows point. It does this by looking at the spacings of the atoms from a magnification where you can just about see the lines of atoms. In lead titanate the unit cell is a rectangle and the arrow always points in line with the long side of the rectangle. The Fourier masking lets you see which direction the long side of the rectangular unit cell is pointing in different parts of your TEM image. The big advantage is that it takes about two minutes to do and uses software that almost every TEM already has. That lets the TEM user quickly know where the domains are in their TEM samples and roughly which way the arrows of charge are pointing. Then they can choose the most interesting features focus on for higher resolution analysis.
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Affiliation(s)
- K Moore
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - M Conroy
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - U Bangert
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
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27
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Fu G, Li W, Cao H, Chen X, Wang S, Luo L, Wu M, Tian H, Ren Z, Han G. Polarization screening-induced epitaxial growth and interfacial magnetism of BiFeO 3/PbTiO 3nanoplates. CrystEngComm 2020. [DOI: 10.1039/c9ce01862j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Single-crystal BiFeO3/PbTiO3nanoplates have been synthesizedviaa hydrothermal method, where BFO films selectively grew on the negative polar surface of PTO with a saturation thickness of about 18–20 nm and a room-temperature ferromagnetism.
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28
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Yang N, Ren ZQ, Hu CZ, Guan Z, Tian BB, Zhong N, Xiang PH, Duan CG, Chu JH. Ultra-wide temperature electronic synapses based on self-rectifying ferroelectric memristors. NANOTECHNOLOGY 2019; 30:464001. [PMID: 31422955 DOI: 10.1088/1361-6528/ab3c3d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Memristors have been intensively studied in recent years as promising building blocks for next-generation nonvolatile memory, artificial neural networks and brain-inspired computing systems. However, most memristors cannot simultaneously function in extremely low and high temperatures, limiting their use for many harsh environment applications. Here, we demonstrate that the memristors based on high-Curie temperature ferroelectrics can resolve these issues. Excellent synaptic learning and memory functions can be achieved in BiFeO3 (BFO)-based ferroelectric memristors in an ultra-wide temperature range. Correlation between electronic transport and ferroelectric properties is established by the coincidence of resistance and ferroelectricity switch and the direct visualization of local current and domain distributions. The interfacial barrier modification by the reversal of ferroelectric polarization leads to a robust resistance switching behavior. Various synaptic functions including long-term potentiation/depression, consecutive potentiation/depression and spike-timing dependent plasticity have been realized in the BFO ferroelectric memristors over an extremely wide temperature range of -170 °C ∼ 300 °C, which even can be extended to 500 °C due to the robust ferroelectricity of BFO at high temperatures. Our findings illustrate that the BFO ferroelectric memristors are promising candidates for ultra-wide temperature electronic synapse in extreme or harsh environments.
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Affiliation(s)
- Nan Yang
- Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronics, East China Normal University, Shanghai 200241, People's Republic of China
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29
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Du K, Zhang M, Dai C, Zhou ZN, Xie YW, Ren ZH, Tian H, Chen LQ, Van Tendeloo G, Zhang Z. Manipulating topological transformations of polar structures through real-time observation of the dynamic polarization evolution. Nat Commun 2019; 10:4864. [PMID: 31653843 PMCID: PMC6814840 DOI: 10.1038/s41467-019-12864-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 09/30/2019] [Indexed: 12/01/2022] Open
Abstract
Topological structures based on controllable ferroelectric or ferromagnetic domain configurations offer the opportunity to develop microelectronic devices such as high-density memories. Despite the increasing experimental and theoretical insights into various domain structures (such as polar spirals, polar wave, polar vortex) over the past decade, manipulating the topological transformations of polar structures and comprehensively understanding its underlying mechanism remains lacking. By conducting an in-situ non-contact bias technique, here we systematically investigate the real-time topological transformations of polar structures in PbTiO3/SrTiO3 multilayers at an atomic level. The procedure of vortex pair splitting and the transformation from polar vortex to polar wave and out-of-plane polarization are observed step by step. Furthermore, the redistribution of charge in various topological structures has been demonstrated under an external bias. This provides new insights for the symbiosis of polar and charge and offers an opportunity for a new generation of microelectronic devices. Direct observation of the dynamic evolution of polar domain structures at atomic level remains challenging. Here, the authors report the observation of real-time topological transformations of polar structures in PbTiO3/SrTiO3 multilayers.
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Affiliation(s)
- K Du
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - M Zhang
- Department of Physics, Zhejiang University, Hangzhou, 310027, China
| | - C Dai
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, 16802, USA
| | - Z N Zhou
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Y W Xie
- Department of Physics, Zhejiang University, Hangzhou, 310027, China
| | - Z H Ren
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - H Tian
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China. .,State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - L Q Chen
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, 16802, USA
| | - Gustaaf Van Tendeloo
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium.,Nanostructure Research Centre (NRC) Wuhan University of Technology, Wuhan, 430070, China
| | - Z Zhang
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China. .,State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
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30
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Agar JC, Naul B, Pandya S, van der Walt S, Maher J, Ren Y, Chen LQ, Kalinin SV, Vasudevan RK, Cao Y, Bloom JS, Martin LW. Revealing ferroelectric switching character using deep recurrent neural networks. Nat Commun 2019; 10:4809. [PMID: 31641122 PMCID: PMC6805893 DOI: 10.1038/s41467-019-12750-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 09/18/2019] [Indexed: 11/22/2022] Open
Abstract
The ability to manipulate domains underpins function in applications of ferroelectrics. While there have been demonstrations of controlled nanoscale manipulation of domain structures to drive emergent properties, such approaches lack an internal feedback loop required for automatic manipulation. Here, using a deep sequence-to-sequence autoencoder we automate the extraction of latent features of nanoscale ferroelectric switching from piezoresponse force spectroscopy of tensile-strained PbZr0.2Ti0.8O3 with a hierarchical domain structure. We identify characteristic behavior in the piezoresponse and cantilever resonance hysteresis loops, which allows for the classification and quantification of nanoscale-switching mechanisms. Specifically, we identify elastic hardening events which are associated with the nucleation and growth of charged domain walls. This work demonstrates the efficacy of unsupervised neural networks in learning features of a material’s physical response from nanoscale multichannel hyperspectral imagery and provides new capabilities in leveraging in operando spectroscopies that could enable the automated manipulation of nanoscale structures in materials. The scale and dimensionality of imaging data means information is commonly overlooked. Here, using recurrent neural networks we understand temporal dependencies in hyperspectral imagery, enabling the observation of differences in ferroelectric switching mechanisms in PbZr0.2Ti0.8O3 thin films due to formation of charged domain walls.
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Affiliation(s)
- Joshua C Agar
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA, 18015, USA.
| | - Brett Naul
- Department of Astronomy, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Shishir Pandya
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Stefan van der Walt
- Berkeley Institute of Data Science, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Joshua Maher
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Yao Ren
- Department of Materials Science and Engineering, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, 16802-5006, USA
| | - Sergei V Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Rama K Vasudevan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Ye Cao
- Department of Materials Science and Engineering, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Joshua S Bloom
- Department of Astronomy, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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31
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Zachman MJ, Hachtel JA, Idrobo JC, Chi M. Emerging Electron Microscopy Techniques for Probing Functional Interfaces in Energy Materials. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902993] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Michael J. Zachman
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Jordan A. Hachtel
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Miaofang Chi
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
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32
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Zachman MJ, Hachtel JA, Idrobo JC, Chi M. Emerging Electron Microscopy Techniques for Probing Functional Interfaces in Energy Materials. Angew Chem Int Ed Engl 2019; 59:1384-1396. [PMID: 31081976 DOI: 10.1002/anie.201902993] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/01/2019] [Indexed: 11/10/2022]
Abstract
Interfaces play a fundamental role in many areas of chemistry. However, their localized nature requires characterization techniques with high spatial resolution in order to fully understand their structure and properties. State-of-the-art atomic resolution or in situ scanning transmission electron microscopy and electron energy-loss spectroscopy are indispensable tools for characterizing the local structure and chemistry of materials with single-atom resolution, but they are not able to measure many properties that dictate function, such as vibrational modes or charge transfer, and are limited to room-temperature samples containing no liquids. Here, we outline emerging electron microscopy techniques that are allowing these limitations to be overcome and highlight several recent studies that were enabled by these techniques. We then provide a vision for how these techniques can be paired with each other and with in situ methods to deliver new insights into the static and dynamic behavior of functional interfaces.
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Affiliation(s)
- Michael J Zachman
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Miaofang Chi
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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33
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Gao W, Addiego C, Wang H, Yan X, Hou Y, Ji D, Heikes C, Zhang Y, Li L, Huyan H, Blum T, Aoki T, Nie Y, Schlom DG, Wu R, Pan X. Real-space charge-density imaging with sub-ångström resolution by four-dimensional electron microscopy. Nature 2019; 575:480-484. [DOI: 10.1038/s41586-019-1649-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 08/06/2019] [Indexed: 11/09/2022]
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34
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Li L, Cheng X, Blum T, Huyan H, Zhang Y, Heikes C, Yan X, Gadre C, Aoki T, Xu M, Xie L, Hong Z, Adamo C, Schlom DG, Chen LQ, Pan X. Observation of Strong Polarization Enhancement in Ferroelectric Tunnel Junctions. NANO LETTERS 2019; 19:6812-6818. [PMID: 31508969 DOI: 10.1021/acs.nanolett.9b01878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ferroelectric heterostructures, with capability of storing data at ultrahigh densities, could act as the platform for next-generation memories. The development of new device paradigms has been hampered by the long-standing notion of inevitable ferroelectricity suppression under reduced dimensions. Despite recent experimental observation of stable polarized states in ferroelectric ultrathin films, the out-of-plane polarization components in these films are strongly attenuated compared to thicker films, implying a degradation of device performance in electronic miniaturization processes. Here, in a model system of BiFeO3/La0.7Sr0.3MnO3, we report observation of a dramatic out-of-plane polarization enhancement that occurs with decreasing film thickness. Our electron microscopy analysis coupled with phase-field simulations reveals a polarization-enhancement mechanism that is dominated by the accumulation of oxygen vacancies at interfacial layers. The results shed light on the interplay between polarization and defects in nanoscale ferroelectrics and suggest a route to enhance functionality in oxide devices.
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Affiliation(s)
- Linze Li
- Department of Chemical Engineering and Materials Science , University of California - Irvine , Irvine , California 92697 , United States
| | - Xiaoxing Cheng
- Department of Materials Science and Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Thomas Blum
- Department of Physics and Astronomy , University of California - Irvine , Irvine , California 92697 , United States
| | - Huaixun Huyan
- Department of Chemical Engineering and Materials Science , University of California - Irvine , Irvine , California 92697 , United States
| | - Yi Zhang
- Department of Chemical Engineering and Materials Science , University of California - Irvine , Irvine , California 92697 , United States
| | - Colin Heikes
- NIST Center for Neutron Research , National Institute of Standards and Technology , Gaithersburg , Maryland 20899 , United States
| | - Xingxu Yan
- Department of Chemical Engineering and Materials Science , University of California - Irvine , Irvine , California 92697 , United States
| | - Chaitanya Gadre
- Department of Physics and Astronomy , University of California - Irvine , Irvine , California 92697 , United States
| | - Toshihiro Aoki
- Irvine Materials Research Institute (IMRI) , University of California - Irvine , Irvine , California 92697 , United States
| | - Mingjie Xu
- Irvine Materials Research Institute (IMRI) , University of California - Irvine , Irvine , California 92697 , United States
| | - Lin Xie
- National Laboratory of Solid State Microstructures and College of Engineering and Applied Sciences , Nanjing University , Nanjing , Jiangsu 210093 , China
| | - Zijian Hong
- Department of Materials Science and Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Carolina Adamo
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14853 , United States
| | - Darrell G Schlom
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14853 , United States
- Kavli Institute at Cornell for Nanoscale Science , Ithaca , New York 14853 , United States
| | - Long-Qing Chen
- Department of Materials Science and Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science , University of California - Irvine , Irvine , California 92697 , United States
- Department of Physics and Astronomy , University of California - Irvine , Irvine , California 92697 , United States
- Irvine Materials Research Institute (IMRI) , University of California - Irvine , Irvine , California 92697 , United States
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35
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Wang ZJ, Bai Y. Resistive Switching Behavior in Ferroelectric Heterostructures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1805088. [PMID: 30773808 DOI: 10.1002/smll.201805088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 01/18/2019] [Indexed: 06/09/2023]
Abstract
Resistive random-access memory (RRAM) is a promising candidate for next-generation nonvolatile random-access memory protocols. The information storage in RRAM is realized by the resistive switching (RS) effect. The RS behavior of ferroelectric heterostructures is mainly controlled by polarization-dominated and defect-dominated mechanisms. Under certain conditions, these two mechanisms can have synergistic effects on RS behavior. Therefore, RS performance can be effectively improved by optimizing ferroelectricity, conductivity, and interfacial structures. Many methods have been studied to improve the RS performance of ferroelectric heterostructures. Typical approaches include doping elements into the ferroelectric layer, controlling the oxygen vacancy concentration and optimizing the thickness of the ferroelectric layer, and constructing an insertion layer at the interface. Here, the mechanism of RS behavior in ferroelectric heterostructures is briefly introduced, and the methods used to improve RS performance in recent years are summarized. Finally, existing problems in this field are identified, and future development trends are highlighted.
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Affiliation(s)
- Zhan Jie Wang
- School of Material Science and Engineering, Shenyang University of Technology, Shenyang, 110870, China
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Yu Bai
- School of Material Science and Engineering, Shenyang University of Technology, Shenyang, 110870, China
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
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36
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Li M, Tang C, Paudel TR, Song D, Lü W, Han K, Huang Z, Zeng S, Renshaw Wang X, Yang P, Chen J, Venkatesan T, Tsymbal EY, Li C, Pennycook SJ. Controlling the Magnetic Properties of LaMnO 3 /SrTiO 3 Heterostructures by Stoichiometry and Electronic Reconstruction: Atomic-Scale Evidence. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1901386. [PMID: 31099075 DOI: 10.1002/adma.201901386] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/10/2019] [Indexed: 06/09/2023]
Abstract
Interface-driven magnetic effects and phenomena associated with spin-orbit coupling and intrinsic symmetry breaking are of importance for fundamental physics and device applications. How interfaces affect the interplay between charge, spin, orbital, and lattice degrees of freedom is the key to boosting device performance. In LaMnO3 /SrTiO3 (LMO/STO) polar-nonpolar heterostructures, electronic reconstruction leads to an antiferromagnetic to ferromagnetic transition, making them viable for spin filter applications. The interfacial electronic structure plays a critical role in the understanding of the microscopic origins of the observed magnetic phase transition, from antiferromagnetic at 5 unit cells (ucs) of LMO or below to ferromagnetic at 6 ucs or above, yet such a study is missing. Here, an atomic scale understanding of LMO/STO ambipolar ferromagnetism is offered by quantifying the interface charge distribution and performing first-principles density functional theory (DFT) calculations across this abrupt magnetic transition. It is found that the electronic reconstruction is confined within the first 3 ucs of LMO from the interface, and more importantly, it is robust against oxygen nonstoichiometry. When restoring stoichiometry, an enhanced ferromagnetic insulating state in LMO films with a thickness as thin as 2 nm (5 uc) is achieved, making LMO readily applicable as barriers in spin filters.
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Affiliation(s)
- Mengsha Li
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Chunhua Tang
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Tula R Paudel
- Department of Physics and Astronomy and Nebraska, Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA
| | - Dongsheng Song
- NUSNNI-Nanocore, National University of Singapore, Singapore, 117411, Singapore
| | - Weiming Lü
- Spintronics Institute, University of Jinan, Jinan, 250022, China
- Condensed Matter Science and Technology Institute and Department of Physics, Harbin Institute of Technology, Harbin, 150001, China
| | - Kun Han
- NUSNNI-Nanocore, National University of Singapore, Singapore, 117411, Singapore
| | - Zhen Huang
- NUSNNI-Nanocore, National University of Singapore, Singapore, 117411, Singapore
| | - Shengwei Zeng
- NUSNNI-Nanocore, National University of Singapore, Singapore, 117411, Singapore
| | - Xiao Renshaw Wang
- School of Physical and Mathematical Sciences and School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Ping Yang
- Singapore Synchrotron Light Source National University of Singapore 5 Research Link, Singapore, 117603, Singapore
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | | | - Evgeny Y Tsymbal
- Department of Physics and Astronomy and Nebraska, Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA
| | - Changjian Li
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Stephen John Pennycook
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
- NUSNNI-Nanocore, National University of Singapore, Singapore, 117411, Singapore
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Wang H, Chi X, Liu Z, Yoong H, Tao L, Xiao J, Guo R, Wang J, Dong Z, Yang P, Sun CJ, Li C, Yan X, Wang J, Chow GM, Tsymbal EY, Tian H, Chen J. Atomic-Scale Control of Magnetism at the Titanite-Manganite Interfaces. NANO LETTERS 2019; 19:3057-3065. [PMID: 30964306 DOI: 10.1021/acs.nanolett.9b00441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Complex oxide thin-film heterostructures often exhibit magnetic properties different from those known for bulk constituents. This is due to the altered local structural and electronic environment at the interfaces, which affects the exchange coupling and magnetic ordering. The emergent magnetism at oxide interfaces can be controlled by ferroelectric polarization and has a strong effect on spin-dependent transport properties of oxide heterostructures, including magnetic and ferroelectric tunnel junctions. Here, using prototype La2/3Sr1/3MnO3/BaTiO3 heterostructures, we demonstrate that ferroelectric polarization of BaTiO3 controls the orbital hybridization and magnetism at heterointerfaces. We observe changes in the enhanced orbital occupancy and significant charge redistribution across the heterointerfaces, affecting the spin and orbital magnetic moments of the interfacial Mn and Ti atoms. Importantly, we find that the exchange coupling between Mn and Ti atoms across the interface is tuned by ferroelectric polarization from ferromagnetic to antiferromagnetic. Our findings provide a viable route to electrically control complex magnetic configurations at artificial multiferroic interfaces, taking a step toward low-power spintronics.
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Affiliation(s)
- Han Wang
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - Xiao Chi
- Department of Physics , National University of Singapore , 2 Science Drive 3 , 117542 Singapore
- Singapore Synchrotron Light Source (SSLS) , National University of Singapore , 117603 Singapore
| | - ZhongRan Liu
- Center of Electron Microscope, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering , Zhejiang University , Hangzhou 310027 , China
| | - HerngYau Yoong
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - LingLing Tao
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience , University of Nebraska , Lincoln , Nebraska 68588-0299 , United States
| | - JuanXiu Xiao
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - Rui Guo
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - JingXian Wang
- School of Materials Science and Engineering , Nanyang Technological University , 639798 Singapore
| | - ZhiLi Dong
- School of Materials Science and Engineering , Nanyang Technological University , 639798 Singapore
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS) , National University of Singapore , 117603 Singapore
| | - Cheng-Jun Sun
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - ChangJian Li
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - XiaoBing Yan
- College of Electron and Information Engineering , Hebei University , Baoding 071002 , China
| | - John Wang
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - Gan Moog Chow
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience , University of Nebraska , Lincoln , Nebraska 68588-0299 , United States
| | - He Tian
- Center of Electron Microscope, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Jingsheng Chen
- Department of Materials Science and Engineering , National University of Singapore , 117575 Singapore
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Short range biaxial strain relief mechanism within epitaxially grown BiFeO 3. Sci Rep 2019; 9:6715. [PMID: 31040305 PMCID: PMC6491549 DOI: 10.1038/s41598-019-42998-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/10/2019] [Indexed: 11/30/2022] Open
Abstract
Lattice mismatch-induced biaxial strain effect on the crystal structure and growth mechanism is investigated for the BiFeO3 films grown on La0.6Sr0.4MnO3/SrTiO3 and YAlO3 substrates. Nano-beam electron diffraction, structure factor calculation and x-ray reciprocal space mapping unambiguously confirm that the crystal structure within both of the BiFeO3 thin films is rhombohedral by showing the rhombohedral signature Bragg’s reflections. Further investigation with atomic resolution scanning transmission electron microscopy reveals that while the ~1.0% of the lattice mismatch found in the BiFeO3 grown on La0.6Sr0.4MnO3/SrTiO3 is exerted as biaxial in-plane compressive strain with atomistically coherent interface, the ~6.8% of the lattice mismatch found in the BiFeO3 grown on YAlO3 is relaxed at the interface by introducing dislocations. The present result demonstrates the importance of: (1) identification of the epitaxial relationship between BFO and its substrate material to quantitatively evaluate the amount of the lattice strain within BFO film and (2) the atomistically coherent BFO/substrate interface for the lattice mismatch to exert the lattice strain.
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Chen C, Wang C, Cai X, Xu C, Li C, Zhou J, Luo Z, Fan Z, Qin M, Zeng M, Lu X, Gao X, Kentsch U, Yang P, Zhou G, Wang N, Zhu Y, Zhou S, Chen D, Liu JM. Controllable defect driven symmetry change and domain structure evolution in BiFeO 3 with enhanced tetragonality. NANOSCALE 2019; 11:8110-8118. [PMID: 30984948 DOI: 10.1039/c9nr00932a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Defect engineering has been a powerful tool to enable the creation of exotic phases and the discovery of intriguing phenomena in ferroelectric oxides. However, the accurate control of the concentration of defects remains a big challenge. In this work, ion implantation, which can provide controllable point defects, allows us to produce a controlled defect driven true super-tetragonal (T) phase with a single-domain-state in ferroelectric BiFeO3 thin films. This point-defect engineering is found to drive the phase transition from the as-grown mixed rhombohedral-like (R) and tetragonal-like (MC) phase to true tetragonal (T) symmetry and induce the stripe multi-nanodomains to a single domain state. By further increasing the injected dose of the He ion, we demonstrate an enhanced tetragonality super-tetragonal (super-T) phase with the largest c/a ratio of ∼1.3 that has ever been experimentally achieved in BiFeO3. A combination of the morphology change and domain evolution further confirms that the mixed R/MC phase structure transforms to the single-domain-state true tetragonal phase. Moreover, the re-emergence of the R phase and in-plane nanoscale multi-domains after heat treatment reveal the memory effect and reversible phase transition and domain evolution. Our findings demonstrate the reversible control of R-Mc-T-super T symmetry changes (leading to the creation of true T phase BiFeO3 with enhanced tetragonality) and multidomain-single domain structure evolution through controllable defect engineering. This work also provides a pathway to generate large tetragonality (or c/a ratio) that could be extended to other ferroelectric material systems (such as PbTiO3, BaTiO3 and HfO2) which might lead to strong polarization enhancement.
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Affiliation(s)
- Chao Chen
- Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China.
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40
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Ferroelectrics with a controlled oxygen-vacancy distribution by design. Sci Rep 2019; 9:4225. [PMID: 30862877 PMCID: PMC6414602 DOI: 10.1038/s41598-019-40717-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/22/2019] [Indexed: 11/21/2022] Open
Abstract
Controlling and manipulating defects in materials provides an extra degree of freedom not only for enhancing physical properties but also for introducing additional functionalities. In ferroelectric oxides, an accumulation of point defects at specific boundaries often deteriorates a polarization-switching capability, but on the one hand, delivers interface-driven phenomena. At present, it remains challenging to control oxygen vacancies at will to achieve a desirable defect structure. Here, we report a practical route to designing oxygen-vacancy distributions by exploiting the interaction with transition-metal dopants. Our thin-film experiments combined with ab-initio theoretical calculations for BiFeO3 demonstrate that isovalent dopants such as Mn3+ with a partly or fully electron-occupied eg state can trap oxygen vacancies, leading to a robust polarization switching. Our approach to controlling oxygen vacancy distributions by harnessing the vacancy-trapping capability of isovalent transition-metal cations will realize the full potential of switchable polarization in ferroelectric perovskite oxides.
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41
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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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42
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Zheng D, Zhang J, Wang Y, Wang Z, Zheng W, Li D, Zhang L, Jin C, Li P, Zhang X, Bai H. Ferroelectric Field Effect Tuned Giant Electroresistance in La 0.67Sr 0.33MnO 3/BaTiO 3 Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2018; 10:40328-40334. [PMID: 30370759 DOI: 10.1021/acsami.8b15498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The mediation of metastable state has been approved to be a promising tool to achieve giant modulations of the physical properties in artificial structures. In this work, the metastable state La0.67Sr0.33MnO3 (LSMO) films with the coexistence of two phases were fabricated on the tensile ferroelectric BaTiO3 (BTO) substrates. Upon application of pulse electric fields to the BTO substrates, the oxygen vacancies and charge redistribute and result in giant and volatile electroresistance (∼230%) and normal and nonvolatile electroresistance (∼5%) in the LSMO films, respectively. The observation of binary resistance states is very interesting and totally unexpected because only a normal electroresistance has been reported in the similar LSMO/piezoelectric structures previously. Here, we attribute the binary state performance to the model of oxygen redistribution and charge accumulation/depletion modulated by the ferroelectric field effect. The oxygen redistribution strongly affects the double exchange interaction in the LSMO layer, which leads to the giant and volatile electroresistance. This work indicates that the mediation of metastable states by electric field is a promising way to enrich the physical properties in artificial structures.
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Affiliation(s)
- Dongxing Zheng
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, School of Science , Tianjin University , Tianjin 300072 , China
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering (PSE) Division , Thuwal 23955-6900 , Saudi Arabia
| | - Junwei Zhang
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering (PSE) Division , Thuwal 23955-6900 , Saudi Arabia
- Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University , Lanzhou University , Lanzhou 730000 , P. R. China
| | - Yuchen Wang
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, School of Science , Tianjin University , Tianjin 300072 , China
| | - Zeyang Wang
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, School of Science , Tianjin University , Tianjin 300072 , China
| | - Wanchao Zheng
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, School of Science , Tianjin University , Tianjin 300072 , China
| | - Dong Li
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, School of Science , Tianjin University , Tianjin 300072 , China
| | - Linxing Zhang
- Institute of Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Chao Jin
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, School of Science , Tianjin University , Tianjin 300072 , China
| | - Peng Li
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering (PSE) Division , Thuwal 23955-6900 , Saudi Arabia
| | - Xixiang Zhang
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering (PSE) Division , Thuwal 23955-6900 , Saudi Arabia
| | - Haili Bai
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, School of Science , Tianjin University , Tianjin 300072 , China
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43
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Zhang N, Zhu Y, Li D, Pan D, Tang Y, Han M, Ma J, Wu B, Zhang Z, Ma X. Oxygen Vacancy Ordering Modulation of Magnetic Anisotropy in Strained LaCoO 3- x Thin Films. ACS APPLIED MATERIALS & INTERFACES 2018; 10:38230-38238. [PMID: 30339014 DOI: 10.1021/acsami.8b13674] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Oxygen vacancy configurations and concentration are coupled with the magnetic, electronic, and transport properties of perovskite oxides, and manipulating the physical properties by tuning the vacancy structures of thin films is crucial for applications in many functional devices. In this study, we report a direct atomic resolution observation of the preferred orientation of vacancy ordering structure in the epitaxial LaCoO3- x (LCO) thin films under various strains from large compressive to large tensile strain utilizing scanning transmission electron microscopy (STEM). Under compressive strains, the oxygen vacancy ordering prefers to be along the planes parallel to the heterointerface. Changing the strains from compressive to tensile, the oxygen vacancy planes turn to be perpendicular to the heterointerface. Aberration-corrected STEM images, electron diffractions, and X-ray diffraction combined with X-ray photoelectron spectroscopy demonstrate that the vacancy concentration increases with increasing misfit strains and vacancy distribution is more ordered and homogeneous. The temperature-dependent magnetization curves show the Curie temperature increases, displaying a positive correlation with the misfit strains. With change in the strain from compressive to tensile, anisotropy fields vary and show large values under tensile strains. It is proposed that oxygen vacancy concentration and preferred ordering planes are responsible for the enhanced magnetic properties of LCO films. Our results have realized a controllable preparation of oxygen vacancy ordering structures via strains and thus provide an effective method to regulate and optimize the physical properties such as magnetic properties by strain engineering.
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Affiliation(s)
- Ningbin Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
- School of Material Science and Engineering , University of Science and Technology of China , 230026 Hefei , China
| | - Yinlian Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
| | - Da Li
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
| | - Desheng Pan
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
- School of Material Science and Engineering , University of Science and Technology of China , 230026 Hefei , China
| | - Yunlong Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
| | - Mengjiao Han
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
| | - Jinyuan Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
- State Key Lab of Advanced Processing and Recycling on Non-ferrous Metals , Lanzhou University of Technology , Langongping Road 287 , 730050 Lanzhou , China
| | - Bo Wu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
- School of Material Science and Engineering , University of Science and Technology of China , 230026 Hefei , China
| | - Zhidong Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
| | - Xiuliang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Wenhua Road 72 , 110016 Shenyang , China
- State Key Lab of Advanced Processing and Recycling on Non-ferrous Metals , Lanzhou University of Technology , Langongping Road 287 , 730050 Lanzhou , China
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44
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Ren Z, Wu M, Chen X, Li W, Li M, Wang F, Tian H, Chen J, Xie Y, Mai J, Li X, Lu X, Lu Y, Zhang H, Van Tendeloo G, Zhang Z, Han G. Electrostatic Force-Driven Oxide Heteroepitaxy for Interface Control. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707017. [PMID: 30080288 DOI: 10.1002/adma.201707017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 07/05/2018] [Indexed: 06/08/2023]
Abstract
Oxide heterostructure interfaces create a platform to induce intriguing electric and magnetic functionalities for possible future devices. A general approach to control growth and interface structure of oxide heterostructures will offer a great opportunity for understanding and manipulating the functionalities. Here, it is reported that an electrostatic force, originating from a polar ferroelectric surface, can be used to drive oxide heteroepitaxy, giving rise to an atomically sharp and coherent interface by using a low-temperature solution method. These heterostructures adopt a fascinating selective growth, and show a saturation thickness and the reconstructed interface with concentrated charges accumulation. The ferroelectric polarization screening, developing from a solid-liquid interface to the heterostructure interface, is decisive for the specific growth. At the interface, a charge transfer and accumulation take place for electrical compensation. The facile approach presented here can be extremely useful for controlling oxide heteroepitaxy and producing intriguing interface functionality via electrostatic engineering.
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Affiliation(s)
- Zhaohui Ren
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou, 310027, China
| | - Mengjiao Wu
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou, 310027, China
| | - Xing Chen
- Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Wei Li
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou, 310027, China
| | - Ming Li
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou, 310027, China
| | - Fang Wang
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou, 310027, China
| | - He Tian
- Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Junze Chen
- School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Yanwu Xie
- Department of Physics, Zhejiang University, Hangzhou, 310027, China
| | - Jiangquan Mai
- Department of Physics, Chinese University of Hong Kong, Hong Kong, 999077, China
| | - Xiang Li
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou, 310027, China
| | - Xinhui Lu
- Department of Physics, Chinese University of Hong Kong, Hong Kong, 999077, China
| | - Yunhao Lu
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou, 310027, China
| | - Hua Zhang
- School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Gustaaf Van Tendeloo
- EMAT, University of Antwerp, B-2020, Antwerp, Belgium
- Nanostructure Research Center, Wuhan University of Technology, 430074, Wuhan, China
| | - Ze Zhang
- Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Gaorong Han
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou, 310027, China
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45
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Klyukin K, Tao LL, Tsymbal EY, Alexandrov V. Defect-Assisted Tunneling Electroresistance in Ferroelectric Tunnel Junctions. PHYSICAL REVIEW LETTERS 2018; 121:056601. [PMID: 30118295 DOI: 10.1103/physrevlett.121.056601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/27/2018] [Indexed: 06/08/2023]
Abstract
Recent experimental results have demonstrated ferroelectricity in thin films of SrTiO_{3} induced by antisite Ti_{Sr} defects. This opens a possibility to use SrTiO_{3} as a barrier layer in ferroelectric tunnel junctions (FTJs)-emerging electronic devices promising for applications in nanoelectronics. Here using density functional theory combined with quantum-transport calculations applied to a prototypical Pt/SrTiO_{3}/Pt FTJ, we demonstrate that the localized in-gap energy states produced by the antisite Ti_{Sr} defects are responsible for the enhanced electron tunneling conductance which can be controlled by ferroelectric polarization. Our tight-binding modeling, which takes into account multiple defects, shows that the predicted defect-assisted tunneling electroresistance effect is greatly amplified when the defect energy levels are brought to the Fermi energy by one of the polarization states. Our results have implications for FTJs based on conventional ferroelectric barriers with defects and can be employed for the design of new types of FTJs with enhanced performance.
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Affiliation(s)
- Konstantin Klyukin
- Department of Chemical and Biomolecular Engineering, University of Nebraska, Lincoln, Nebraska 68588, USA
| | - L L Tao
- Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588, USA
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588, USA
- Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA
| | - Vitaly Alexandrov
- Department of Chemical and Biomolecular Engineering, University of Nebraska, Lincoln, Nebraska 68588, USA
- Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA
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46
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Gao P, Yang S, Ishikawa R, Li N, Feng B, Kumamoto A, Shibata N, Yu P, Ikuhara Y. Atomic-Scale Measurement of Flexoelectric Polarization at SrTiO_{3} Dislocations. PHYSICAL REVIEW LETTERS 2018; 120:267601. [PMID: 30004731 DOI: 10.1103/physrevlett.120.267601] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/06/2018] [Indexed: 05/27/2023]
Abstract
Owing to the broken translational symmetry at dislocations, a strain gradient naturally exists around the dislocation cores and can significantly influence the electrical and mechanical properties. We use aberration corrected scanning transmission electron microscopy to directly measure the flexoelectric polarization (∼28 μC cm^{-2}) at dislocation cores in SrTiO_{3}. The polarization charges can interact with the nonstoichiometric dislocation cores and thus impact the electrical activities. Our findings can help us to understand the properties of dislocations in perovskite, providing new insights into the design of new devices via defect engineering such as bicrystal fabrication and thin film growth.
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Affiliation(s)
- Peng Gao
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Shuzhen Yang
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tshinghua University, Beijing 100084, China
| | - Ryo Ishikawa
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Ning Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Bin Feng
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Akihito Kumamoto
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Naoya Shibata
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Pu Yu
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tshinghua University, Beijing 100084, China
| | - Yuichi Ikuhara
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, Nagoya 456-8587, Japan
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
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47
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Symmetry mismatch-driven perpendicular magnetic anisotropy for perovskite/brownmillerite heterostructures. Nat Commun 2018; 9:1923. [PMID: 29765023 PMCID: PMC5953968 DOI: 10.1038/s41467-018-04304-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 04/18/2018] [Indexed: 12/22/2022] Open
Abstract
Grouping different transition metal oxides together by interface engineering is an important route toward emergent phenomenon. While most of the previous works focused on the interface effects in perovskite/perovskite heterostructures, here we reported on a symmetry mismatch-driven spin reorientation toward perpendicular magnetic anisotropy in perovskite/brownmillerite heterostructures, which is scarcely seen in tensile perovskite/perovskite heterostructures. We show that alternately stacking perovskite La2/3Sr1/3MnO3 and brownmillerite LaCoO2.5 causes a strong interface reconstruction due to symmetry discontinuity at interface: neighboring MnO6 octahedra and CoO4 tetrahedra at the perovskite/brownmillerite interface cooperatively relax in a manner that is unavailable for perovskite/perovskite interface, leading to distinct orbital reconstructions and thus the perpendicular magnetic anisotropy. Moreover, the perpendicular magnetic anisotropy is robust, with an anisotropy constant two orders of magnitude greater than the in-plane anisotropy of the perovskite/perovskite interface. The present work demonstrates the great potential of symmetry engineering in designing artificial materials on demand. Complex oxide heterostructures exhibit multifunctional behaviour that could be used in a range of device applications. Here, the authors observe that reconstruction at oxide perovskite/brownmillerite interfaces leads to perpendicular magnetic spin orientation, with potential use in spintronic devices.
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48
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Mesopores induced zero thermal expansion in single-crystal ferroelectrics. Nat Commun 2018; 9:1638. [PMID: 29692407 PMCID: PMC5915410 DOI: 10.1038/s41467-018-04113-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 04/05/2018] [Indexed: 11/25/2022] Open
Abstract
For many decades, zero thermal expansion materials have been the focus of numerous investigations because of their intriguing physical properties and potential applications in high-precision instruments. Different strategies, such as composites, solid solution and doping, have been developed as promising approaches to obtain zero thermal expansion materials. However, microstructure controlled zero thermal expansion behavior via interface or surface has not been realized. Here we report the observation of an impressive zero thermal expansion (volumetric thermal expansion coefficient, −1.41 × 10−6 K−1, 293–623 K) in single-crystal ferroelectric PbTiO3 fibers with large-scale faceted and enclosed mesopores. The zero thermal expansion behavior is attributed to a synergetic effect of positive thermal expansion near the mesopores due to the oxygen-based polarization screening and negative thermal expansion from an intrinsic ferroelectricity. Our results show that a fascinating surface construction in negative thermal expansion ferroelectric materials could be a promising strategy to realize zero thermal expansion. Zero thermal expansion materials—often composites of negative and positive coefficient materials—are needed for applications that see large temperature changes. Here, the authors demonstrate that polarization around pores in single-phase mesoporous lead titanate can be used to tune thermal expansion to near zero.
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49
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Jia C, Li J, Yang G, Chen Y, Zhang W. Ferroelectric Field Effect Induced Asymmetric Resistive Switching Effect in BaTiO 3/Nb:SrTiO 3 Epitaxial Heterojunctions. NANOSCALE RESEARCH LETTERS 2018; 13:102. [PMID: 29654517 PMCID: PMC5899076 DOI: 10.1186/s11671-018-2513-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/05/2018] [Indexed: 06/08/2023]
Abstract
Asymmetric resistive switching processes were observed in BaTiO3/Nb:SrTiO3 epitaxial heterojunctions. The SET switching time from the high-resistance state to low-resistance state is in the range of 10 ns under + 8 V bias, while the RESET switching time from the low-resistance state to high-resistance state is in the range of 105 ns under - 8 V bias. The ferroelectric polarization screening controlled by electrons and oxygen vacancies at the BaTiO3/Nb:SrTiO3 heterointerface is proposed to understand this switching time difference. This switch with fast SET and slow RESET transition may have potential applications in some special regions.
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Affiliation(s)
- Caihong Jia
- Henan Key Laboratory of Photovoltaic Materials, Laboratory of Low-Dimensional Materials Science, School of Physics and Electronics, Henan University, Kaifeng, 475004 People’s Republic of China
| | - Jiachen Li
- Henan Key Laboratory of Photovoltaic Materials, Laboratory of Low-Dimensional Materials Science, School of Physics and Electronics, Henan University, Kaifeng, 475004 People’s Republic of China
| | - Guang Yang
- Henan Key Laboratory of Photovoltaic Materials, Laboratory of Low-Dimensional Materials Science, School of Physics and Electronics, Henan University, Kaifeng, 475004 People’s Republic of China
| | - Yonghai Chen
- Key Laboratory of Semiconductor Materials, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 People’s Republic of China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Weifeng Zhang
- Henan Key Laboratory of Photovoltaic Materials, Laboratory of Low-Dimensional Materials Science, School of Physics and Electronics, Henan University, Kaifeng, 475004 People’s Republic of China
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50
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Li L, Cheng X, Jokisaari JR, Gao P, Britson J, Adamo C, Heikes C, Schlom DG, Chen LQ, Pan X. Defect-Induced Hedgehog Polarization States in Multiferroics. PHYSICAL REVIEW LETTERS 2018; 120:137602. [PMID: 29694202 DOI: 10.1103/physrevlett.120.137602] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Indexed: 06/08/2023]
Abstract
Continuous developments in nanotechnology require new approaches to materials synthesis that can produce novel functional structures. Here, we show that nanoscale defects, such as nonstoichiometric nanoregions (NSNRs), can act as nano-building blocks for creating complex electrical polarization structures in the prototypical multiferroic BiFeO_{3}. An array of charged NSNRs are produced in BiFeO_{3} thin films by tuning the substrate temperature during film growth. Atomic-scale scanning transmission electron microscopy imaging reveals exotic polarization rotation patterns around these NSNRs. These polarization patterns resemble hedgehog or vortex topologies and can cause local changes in lattice symmetries leading to mixed-phase structures resembling the morphotropic phase boundary with high piezoelectricity. Phase-field simulations indicate that the observed polarization configurations are mainly induced by charged states at the NSNRs. Engineering defects thus may provide a new route for developing ferroelectric- or multiferroic-based nanodevices.
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Affiliation(s)
- Linze Li
- Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697, USA
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Xiaoxing Cheng
- Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, USA
| | - Jacob R Jokisaari
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Peng Gao
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Jason Britson
- Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, USA
| | - Carolina Adamo
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Colin Heikes
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, USA
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California-Irvine, Irvine, California 92697, USA
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