1
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Kusumi T, Katakami S, Ishikawa R, Kawahara K, Mullarkey T, Bekkevold JM, Peters JJP, Jones L, Shibata N, Okada M. New Poisson denoising method for pulse-count STEM imaging. Ultramicroscopy 2024; 264:113996. [PMID: 38885602 DOI: 10.1016/j.ultramic.2024.113996] [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: 02/19/2024] [Revised: 05/23/2024] [Accepted: 05/25/2024] [Indexed: 06/20/2024]
Abstract
With the recent progress in the development of detectors in electron microscopy, it has become possible to directly count the number of electrons per pixel, even with a scintillator-type detector, by incorporating a pulse-counting module. To optimize a denoising method for electron counting imaging, in this study, we propose a Poisson denoising method for atomic-resolution scanning transmission electron microscopy images. Our method is based on the Markov random field model and Bayesian inference, and we can reduce the electron dose by a factor of about 15 times or further below. Moreover, we showed that the method of reconstruction from multiple images without integrating them performs better than that from an integrated image.
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Affiliation(s)
- Taichi Kusumi
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Chiba 277-8561, Kashiwa, Japan
| | - Shun Katakami
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Chiba 277-8561, Kashiwa, Japan
| | - Ryo Ishikawa
- Institute of Engineering Innovation, The University of Tokyo, Hongo 7-3-1, Tokyo 113-8656, Bunkyo, Japan.
| | - Kazuaki Kawahara
- Institute of Engineering Innovation, The University of Tokyo, Hongo 7-3-1, Tokyo 113-8656, Bunkyo, Japan
| | - Tiarnan Mullarkey
- School of Physics, Trinity College Dublin, College Green, Dublin 2, D02 PN40, Dublin, Ireland
| | - Julie Marie Bekkevold
- School of Physics, Trinity College Dublin, College Green, Dublin 2, D02 PN40, Dublin, Ireland
| | - Jonathan J P Peters
- School of Physics, Trinity College Dublin, College Green, Dublin 2, D02 PN40, Dublin, Ireland
| | - Lewys Jones
- School of Physics, Trinity College Dublin, College Green, Dublin 2, D02 PN40, Dublin, Ireland
| | - Naoya Shibata
- Institute of Engineering Innovation, The University of Tokyo, Hongo 7-3-1, Tokyo 113-8656, Bunkyo, Japan; Nanostructures Research Laboratory, Japan Fine Ceramics Center, Atsuta Mutsuno 2-4-1, Aichi 456-8587, Nagoya, Japan
| | - Masato Okada
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Chiba 277-8561, Kashiwa, Japan.
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2
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Eliasson H, Erni R. Localization and segmentation of atomic columns in supported nanoparticles for fast scanning transmission electron microscopy. NPJ COMPUTATIONAL MATERIALS 2024; 10:168. [PMID: 39104782 PMCID: PMC11297796 DOI: 10.1038/s41524-024-01360-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 07/21/2024] [Indexed: 08/07/2024]
Abstract
To accurately capture the dynamic behavior of small nanoparticles in scanning transmission electron microscopy, high-quality data and advanced data processing is needed. The fast scan rate required to observe structural dynamics inherently leads to very noisy data where machine learning tools are essential for unbiased analysis. In this study, we develop a workflow based on two U-Net architectures to automatically localize and classify atomic columns at particle-support interfaces. The model is trained on non-physical image simulations, achieves sub-pixel localization precision, high classification accuracy, and generalizes well to experimental data. We test our model on both in situ and ex situ experimental time series recorded at 5 frames per second of small Pt nanoparticles supported on CeO2(111). The processed movies show sub-second dynamics of the nanoparticles and reveal site-specific movement patterns of individual atomic columns.
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Affiliation(s)
- Henrik Eliasson
- Electron Microscopy Center, Empa – Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Rolf Erni
- Electron Microscopy Center, Empa – Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
- Department of Materials, ETH Zürich, CH-8093 Zürich, Switzerland
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3
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Peters JJP, Reed BW, Jimbo Y, Noguchi K, Müller KH, Porter A, Masiel DJ, Jones L. Event-responsive scanning transmission electron microscopy. Science 2024; 385:549-553. [PMID: 39088619 DOI: 10.1126/science.ado8579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 06/17/2024] [Indexed: 08/03/2024]
Abstract
An ever-present limitation of transmission electron microscopy is the damage caused by high-energy electrons interacting with any sample. By reconsidering the fundamentals of imaging, we demonstrate an event-responsive approach to electron microscopy that delivers more information about the sample for a given beam current. Measuring the time to achieve an electron count threshold rather than waiting a predefined constant time improves the information obtained per electron. The microscope was made to respond to these events by blanking the beam, thus reducing the overall dose required. This approach automatically apportions dose to achieve a given signal-to-noise ratio in each pixel, eliminating excess dose that is associated with diminishing returns of information. We demonstrate the wide applicability of our approach to beam-sensitive materials by imaging biological tissue and zeolite.
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Affiliation(s)
- Jonathan J P Peters
- Advanced Microscopy Laboratory, CRANN, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- School of Physics, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- turboTEM Ltd., Dublin, Ireland
| | | | - Yu Jimbo
- JEOL Ltd. Akishima, Tokyo, Japan
| | | | - Karin H Müller
- Faculty of Engineering, Department of Materials, Imperial College London, London, UK
| | - Alexandra Porter
- Faculty of Engineering, Department of Materials, Imperial College London, London, UK
| | | | - Lewys Jones
- Advanced Microscopy Laboratory, CRANN, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- School of Physics, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- turboTEM Ltd., Dublin, Ireland
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4
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Lu C, Chen G, Song W, Chen K, Hee C, Nikan M, Guagliardo P, Bennett CF, Seth P, Iyer KS, Young SG, Qi X, Jiang H. Tool to Resolve Distortions in Elemental and Isotopic Imaging. J Am Chem Soc 2024; 146:20221-20229. [PMID: 38985464 DOI: 10.1021/jacs.4c05384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
Nanoscale secondary ion mass spectrometry (NanoSIMS) makes it possible to visualize elements and isotopes in a wide range of samples at a high resolution. However, the fidelity and quality of NanoSIMS images often suffer from distortions because of a requirement to acquire and integrate multiple image frames. We developed an optical flow-based algorithm tool, NanoSIMS Stabilizer, for all-channel postacquisition registration of images. The NanoSIMS Stabilizer effectively deals with the distortions and artifacts, resulting in a high-resolution visualization of isotope and element distribution. It is open source with an easy-to-use ImageJ plugin and is accompanied by a Python version with GPU acceleration.
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Affiliation(s)
- Chixiang Lu
- Department of Chemistry, The University of Hong Kong, Pok Fu Lam, Hong Kong 999077, P. R. China
| | - Gu Chen
- Department of Chemistry, The University of Hong Kong, Pok Fu Lam, Hong Kong 999077, P. R. China
| | - Wenxin Song
- Departments of Medicine, University of California, Los Angeles, California 90095, United States
| | - Kai Chen
- School of Molecular Sciences, University of Western Australia, Perth 6009, Australia
| | - Charmaine Hee
- School of Molecular Sciences, University of Western Australia, Perth 6009, Australia
| | - Mehran Nikan
- Ionis Pharmaceuticals, Inc., Carlsbad, California 92010, United States
| | - Paul Guagliardo
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth 6009, Australia
| | - C Frank Bennett
- Ionis Pharmaceuticals, Inc., Carlsbad, California 92010, United States
| | - Punit Seth
- Ionis Pharmaceuticals, Inc., Carlsbad, California 92010, United States
| | | | - Stephen G Young
- Departments of Medicine, University of California, Los Angeles, California 90095, United States
- Human Genetics, University of California, Los Angeles, California 90095, United States
| | - Xiaojuan Qi
- Electrical and Electronic Engineering, The University of Hong Kong, Pok Fu Lam, Hong Kong 999077, P. R. China
| | - Haibo Jiang
- Department of Chemistry, The University of Hong Kong, Pok Fu Lam, Hong Kong 999077, P. R. China
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5
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Roccapriore KM, Torsi R, Robinson J, Kalinin S, Ziatdinov M. Dynamic STEM-EELS for single-atom and defect measurement during electron beam transformations. SCIENCE ADVANCES 2024; 10:eadn5899. [PMID: 39018401 PMCID: PMC466940 DOI: 10.1126/sciadv.adn5899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 06/11/2024] [Indexed: 07/19/2024]
Abstract
This study introduces the integration of dynamic computer vision-enabled imaging with electron energy loss spectroscopy (EELS) in scanning transmission electron microscopy (STEM). This approach involves real-time discovery and analysis of atomic structures as they form, allowing us to observe the evolution of material properties at the atomic level, capturing transient states traditional techniques often miss. Rapid object detection and action system enhances the efficiency and accuracy of STEM-EELS by autonomously identifying and targeting only areas of interest. This machine learning (ML)-based approach differs from classical ML in that it must be executed on the fly, not using static data. We apply this technology to V-doped MoS2, uncovering insights into defect formation and evolution under electron beam exposure. This approach opens uncharted avenues for exploring and characterizing materials in dynamic states, offering a pathway to increase our understanding of dynamic phenomena in materials under thermal, chemical, and beam stimuli.
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Affiliation(s)
- Kevin M. Roccapriore
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Riccardo Torsi
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Joshua Robinson
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sergei Kalinin
- Department of Materials Science and Engineering, Institute for Advanced Materials and Manufacturing, University of Tennessee, Knoxville, TN 37996, USA
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Maxim Ziatdinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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6
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Pingen K, Wolff N, Mohammadian Z, Sandström P, Beuer S, von Hauff E, Kienle L, Hultman L, Birch J, Hsiao CL, Hinz AM. III-Nitride Magnetron Sputter Epitaxy on Si: Controlling Morphology, Crystal Quality, and Polarity Using Al Seed Layers. ACS APPLIED MATERIALS & INTERFACES 2024; 16:34294-34302. [PMID: 38886009 PMCID: PMC11231972 DOI: 10.1021/acsami.4c03112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 05/06/2024] [Accepted: 05/10/2024] [Indexed: 06/20/2024]
Abstract
Group III-nitride semiconductors have been subject of intensive research, resulting in the maturing of the material system and adoption of III-nitrides in modern optoelectronics and power electronic devices. Defined film polarity is an important aspect of III-nitride epitaxy as the polarity affects the design of electronic devices. Magnetron sputtering is a novel approach for cost-effective epitaxy of III-nitrides nearing the technological maturity needed for device production; therefore, control of film polarity is an important technological milestone. In this study, we show the impact of Al seeding on the AlN/Si interface and resulting changes in crystal quality, film morphology, and polarity of GaN/AlN stacks grown by magnetron sputter epitaxy. X-ray diffraction measurements demonstrate the improvement of the crystal quality of the AlN and subsequently the GaN film by the Al seeding. Nanoscale structural and chemical investigations using scanning transmission electron microscopy reveal the inversion of the AlN film polarity. It is proposed that N-polar growth induced by Al seeding is related to the formation of a polycrystalline oxygen-rich AlN interlayer partially capped by an atomically thin Si-rich layer at the AlN/Si interface. Complementary aqueous KOH etch studies of GaN/AlN stacks demonstrate that purely metal-polar and N-polar layers can be grown on a macroscopic scale by controlling the amount of Al seeding.
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Affiliation(s)
- Katrin Pingen
- Fraunhofer
Institute for Organic Electronics, Electron Beam and Plasma Technology, Winterbergstrasse 28, D-01277 Dresden, Germany
- Institute
of Solid State Electronics, Technische Universität
Dresden, Mommsenstrasse
15, D-01069 Dresden, Germany
| | - Niklas Wolff
- Synthesis
and Real Structure, Department of Material Science, Kiel University, Kaiserstrasse
2, D-24143 Kiel, Germany
- Kiel
Nano, Surface and Interface Science, Kiel
University, Christian-Albrechts-Platz
4, D-24118 Kiel, Germany
| | - Zahra Mohammadian
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Per Sandström
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Susanne Beuer
- Fraunhofer
Institute for Integrated Systems and Device Technology, Schottkystrasse 10, D-91058 Erlangen, Germany
| | - Elizabeth von Hauff
- Fraunhofer
Institute for Organic Electronics, Electron Beam and Plasma Technology, Winterbergstrasse 28, D-01277 Dresden, Germany
- Institute
of Solid State Electronics, Technische Universität
Dresden, Mommsenstrasse
15, D-01069 Dresden, Germany
| | - Lorenz Kienle
- Synthesis
and Real Structure, Department of Material Science, Kiel University, Kaiserstrasse
2, D-24143 Kiel, Germany
- Kiel
Nano, Surface and Interface Science, Kiel
University, Christian-Albrechts-Platz
4, D-24118 Kiel, Germany
| | - Lars Hultman
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Jens Birch
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Ching-Lien Hsiao
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Alexander M. Hinz
- Fraunhofer
Institute for Organic Electronics, Electron Beam and Plasma Technology, Winterbergstrasse 28, D-01277 Dresden, Germany
- Institute
of Solid State Electronics, Technische Universität
Dresden, Mommsenstrasse
15, D-01069 Dresden, Germany
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7
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Taniguchi H, Watanabe T, Kuwano T, Nakano A, Sato Y, Hagiwara M, Yokota H, Deguchi K. Unconventional Polarization Response in Titanite-Type Oxides due to Hashed Antiferroelectric Domains. ACS NANO 2024; 18:14523-14531. [PMID: 38770881 DOI: 10.1021/acsnano.4c02168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Domains in a crystal, which have crystallographic uniformity and are geometrically segmented, typically arise from various phase transitions. The physical properties within individual domains are inherently the same as those in the homogeneous bulk. As a result, sufficiently large domains have little influence on the bulk properties. However, as the domains decrease in size to the nanoscale, for instance, due to multiple phase instabilities or spatial inhomogeneities, then the materials often acquire exceptional functionalities that are unattainable without these domains. This effect is exemplified by the ultrahigh dielectric and piezoelectric responses observed in ferroelectric oxides with nanoscale polar domains as well as in ferroelectric relaxors with polar nanoclusters. Here, we demonstrate that hashed nanoscale domains in an antiferroelectric material are also capable of boosting dielectric permittivity in an unconventional way. This discovery has been made in an antiferroelectric titanite-type oxide, CaTi(Si1-xGex)O5, in which the permittivity significantly increases when the antiferroelectric order becomes short-range. Our transmission electron microscopy observations have clarified that polar regions simultaneously appear around antiphase boundaries in the antiferroelectric phase of CaTi(Si1-xGex)O5. As the concentration of the antiphase boundary increases, the polar regions become denser and play a crucial role in boosting the permittivity. At the composition of x = 0.5, the value of the permittivity finally reaches double that in the bulk and shows excellent linearity, at least until an electric field of 500 kV/cm is applied. The present findings highlight the promise of domain engineering for boosting the permittivity in antiferroelectrics as a way to develop materials with excellent dielectric properties.
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Affiliation(s)
- Hiroki Taniguchi
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - Takumi Watanabe
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - Taro Kuwano
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - Akitoshi Nakano
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - Yukio Sato
- Research and Education Institute for Semiconductors and Informatics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Manabu Hagiwara
- Department of Applied Chemistry, Keio University, Yokohama 223-8522, Japan
| | - Hiroko Yokota
- School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama 226-8502, Japan
| | - Kazuhiko Deguchi
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
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8
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Kawahara Y, Kobatake S, Kaneko K, Sasaki T, Ohkubo T, Takushima C, Hamada JI. Combined effect of interstitial-substitutional elements on dislocation dynamics in nitrogen-added austenitic stainless steels. Sci Rep 2024; 14:4360. [PMID: 38388633 PMCID: PMC10883984 DOI: 10.1038/s41598-024-54852-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 02/17/2024] [Indexed: 02/24/2024] Open
Abstract
Combined addition of interstitial-substitutional elements has been acknowledged to contribute to the increase in the strengths of steels. For further improvements in mechanical properties, their atomic-scale interaction mechanisms with dislocations are required to be examined. In this study, both high-resolution transmission electron microscopy and atom-probe tomography were used to correlate interstitial-substitutional elements with dislocation characteristics in austenitic stainless steels. Three types of dislocation core structures are identified and associated with their strain fields as well as N and Cr atoms in the N-added steels. It is revealed that N atoms interact elastically with the dislocations, followed by the segregation of Cr atoms via the chemical interaction between N and Cr atoms. This insight significantly improves the understanding of the multiple alloying mechanism in metallic materials such as interstitial alloys and high-entropy alloys.
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Affiliation(s)
- Yasuhito Kawahara
- Department of Materials, Kyushu University, 744 Motooka, Nishi, Fukuoka, 891-0395, Japan.
| | - Shunya Kobatake
- Department of Materials, Kyushu University, 744 Motooka, Nishi, Fukuoka, 891-0395, Japan
| | - Kenji Kaneko
- Department of Materials, Kyushu University, 744 Motooka, Nishi, Fukuoka, 891-0395, Japan
| | - Taisuke Sasaki
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, 305-0047, Japan
| | - Tadakatsu Ohkubo
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, 305-0047, Japan
| | - Chikako Takushima
- Research & Development Center, Nippon Steel Stainless Steel Corporation, 3434 Shimata, Hikari, 743-8550, Japan
| | - Jun-Ichi Hamada
- Research & Development Center, Nippon Steel Stainless Steel Corporation, 3434 Shimata, Hikari, 743-8550, Japan
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9
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Mun J, Sushko PV, Brass E, Zhou C, Kisslinger K, Qu X, Liu M, Zhu Y. Probing Oxidation-Driven Amorphized Surfaces in a Ta(110) Film for Superconducting Qubit. ACS NANO 2024; 18:1126-1136. [PMID: 38147003 DOI: 10.1021/acsnano.3c10740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Recent advances in superconducting qubit technology have led to significant progress in quantum computing, but the challenge of achieving a long coherence time remains. Despite the excellent lifetime performance that tantalum (Ta) based qubits have demonstrated to date, the majority of superconducting qubit systems, including Ta-based qubits, are generally believed to have uncontrolled surface oxidation as the primary source of the two-level system loss in two-dimensional transmon qubits. Therefore, atomic-scale insight into the surface oxidation process is needed to make progress toward a practical quantum processor. In this study, the surface oxidation mechanism of native Ta films and its potential impact on the lifetime of superconducting qubits were investigated using advanced scanning transmission electron microscopy (STEM) techniques combined with density functional theory calculations. The results suggest an atomistic model of the oxidized Ta(110) surface, showing that oxygen atoms tend to penetrate the Ta surface and accumulate between the two outermost Ta atomic planes; oxygen accumulation at the level exceeding a 1:1 O/Ta ratio drives disordering and, eventually, the formation of an amorphous Ta2O5 phase. In addition, we discuss how the formation of a noninsulating ordered TaO1-δ (δ < 0.1) suboxide layer could further contribute to the losses of superconducting qubits. Subsurface oxidation leads to charge redistribution and electric polarization, potentially causing quasiparticle loss and decreased current-carrying capacity, thus affecting superconducting qubit coherence. The findings enhance the comprehension of the realistic factors that might influence the performance of superconducting qubits, thus providing valuable guidance for the development of future quantum computing hardware.
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Affiliation(s)
- Junsik Mun
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Peter V Sushko
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Emma Brass
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Chenyu Zhou
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Kim Kisslinger
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Xiaohui Qu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Mingzhao Liu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Yimei Zhu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
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10
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Şentürk DG, Yu CP, De Backer A, Van Aert S. Atom counting from a combination of two ADF STEM images. Ultramicroscopy 2024; 255:113859. [PMID: 37778104 DOI: 10.1016/j.ultramic.2023.113859] [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: 07/07/2023] [Revised: 09/13/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023]
Abstract
To understand the structure-property relationship of nanostructures, reliably quantifying parameters, such as the number of atoms along the projection direction, is important. Advanced statistical methodologies have made it possible to count the number of atoms for monotype crystalline nanoparticles from a single ADF STEM image. Recent developments enable one to simultaneously acquire multiple ADF STEM images. Here, we present an extended statistics-based method for atom counting from a combination of multiple statistically independent ADF STEM images reconstructed from non-overlapping annular detector collection regions which improves the accuracy and allows one to retrieve precise atom-counts, especially for images acquired with low electron doses and multiple element structures.
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Affiliation(s)
- D G Şentürk
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - C P Yu
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - A De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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11
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Eliasson H, Niu Y, Palmer RE, Grönbeck H, Erni R. Support-facet-dependent morphology of small Pt particles on ceria. NANOSCALE 2023; 15:19091-19098. [PMID: 37929917 DOI: 10.1039/d3nr04701f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Direct atomic scale information on how the structure of supported nanoparticles is affected by the metal-support interaction is rare. Using scanning transmission electron microscopy, we provide direct evidence of a facet-dependent support interaction for Pt nanoparticles on CeO2, governing the dimensionality of small platinum particles. Our findings indicate that particles consisting of less than ∼130 atoms prefer a 3D shape on CeO2(111) facets, while 2D raft structures are favored on CeO2(100) facets. Measurements of stationary particles on both surface facets are supplemented by time resolved measurements following a single particle with atomic resolution as it migrates from CeO2(111) to CeO2(100), undergoing a dimensionality change from 3D to 2D. The intricate transformation mechanism reveals how the 3D particle disassembles and completely wets a neighboring CeO2(100) facet. Density functional theory calculations confirm the structure-trend and reveal the thermodynamic driving force for the migration of small particles. Knowledge of the presented metal-support interactions is crucial to establish structure-function relationships in a range of applications based on supported nanostructures.
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Affiliation(s)
- Henrik Eliasson
- Electron Microscopy Center, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
| | - Yubiao Niu
- Nanomaterials Lab, Faculty of Science and Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, UK
| | - Richard E Palmer
- Nanomaterials Lab, Faculty of Science and Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, UK
| | - Henrik Grönbeck
- Department of Physics and Competence Centre for Catalysis, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Rolf Erni
- Electron Microscopy Center, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
- Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
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12
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Gupta SK, Habib A, Kumar P, Melandsø F, Ahmad A. Automated tilt compensation in acoustic microscopy. J Microsc 2023; 292:90-102. [PMID: 37698414 DOI: 10.1111/jmi.13226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/31/2023] [Accepted: 09/08/2023] [Indexed: 09/13/2023]
Abstract
Scanning acoustic microscopy (SAM) is a potent and nondestructive technique capable of producing three-dimensional topographic and tomographic images of specimens. This is achieved by measuring the differences in time of flight (ToF) of acoustic signals emitted from various regions of the sample. The measurement accuracy of SAM strongly depends on the ToF measurement, which is affected by tilt in either the scanning stage or the sample stage. Hence, compensating for the ToF shift resulting from sample tilt is imperative for obtaining precise topographic and tomographic profiles of the samples in a SAM. In the present work, we propose an automated tilt compensation in ToF of acoustic signal based on proposed curve fitting method. Unlike the conventional method, the proposed approach does not demand manually choosing three separate coordinate points from SAM's time domain data. The effectiveness of the proposed curve fitting method is demonstrated by compensating time shifts in ToF data of a coin due to the presence of tilt. The method is implemented for the correction of different amounts of tilt in the coin corresponding to angles 6.67°, 12.65° and 15.95°. It is observed that the present method can perform time offset correction in the time domain data of SAM with an accuracy of 45 arcsec. The experimental results confirm the effectiveness of the suggested tilt compensation technique in SAM, indicating its potential for future applications.
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Affiliation(s)
- Shubham Kumar Gupta
- Department of Chemical Engineering, Indian Institute of Technology, Guwahati, India
| | - Anowarul Habib
- Department of Physics and Technology, UiT The Arctic University of Norway, Tromso, Norway
| | - Prakhar Kumar
- Department of Electronics Engineering, Indian Institute of Technology, Dhanbad, India
| | - Frank Melandsø
- Department of Physics and Technology, UiT The Arctic University of Norway, Tromso, Norway
| | - Azeem Ahmad
- Department of Physics and Technology, UiT The Arctic University of Norway, Tromso, Norway
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13
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Silinga A, Allen CS, Barthel J, Ophus C, MacLaren I. Measurement of Atomic Modulation Direction Using the Azimuthal Variation of First-Order Laue Zone Electron Diffraction. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1682-1687. [PMID: 37639214 DOI: 10.1093/micmic/ozad089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/12/2023] [Accepted: 08/02/2023] [Indexed: 08/29/2023]
Abstract
We show that diffraction intensity into the first-order Laue zone (FOLZ) of a crystal can have a strong azimuthal dependence, where this FOLZ ring appears solely because of unidirectional atom position modulation. Such a modulation was already known to cause the appearance of elliptical columns in atom-resolution images, but we show that measurement of the angle via four-dimensional scanning transmission electron microscopy (4DSTEM) is far more reliable and allows the measurement of the modulation direction with a precision of about 1° and an accuracy of about 3°. This method could be very powerful in characterizing atomic structures in three dimensions by 4DSTEM, especially in cases where the structure is found only in nanoscale regions or crystals.
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Affiliation(s)
- Aurys Silinga
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Christopher S Allen
- Electron Physical Science Imaging Centre, Diamond Light Source Ltd., Oxford OX11 0DE, UK
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Juri Barthel
- Ernst Ruska-Centre (ER-C 2), Forschungszentrum Jülich GmbH, Jülich 52425, Germany
| | - Colin Ophus
- NCEM, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ian MacLaren
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
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14
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Schönweger G, Wolff N, Islam MR, Gremmel M, Petraru A, Kienle L, Kohlstedt H, Fichtner S. In-Grain Ferroelectric Switching in Sub-5 nm Thin Al 0.74 Sc 0.26 N Films at 1 V. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2302296. [PMID: 37382398 PMCID: PMC10477852 DOI: 10.1002/advs.202302296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/26/2023] [Indexed: 06/30/2023]
Abstract
Analog switching in ferroelectric devices promises neuromorphic computing with the highest energy efficiency if limited device scalability can be overcome. To contribute to a solution, one reports on the ferroelectric switching characteristics of sub-5 nm thin Al0.74 Sc0.26 N films grown on Pt/Ti/SiO2 /Si and epitaxial Pt/GaN/sapphire templates by sputter-deposition. In this context, the study focuses on the following major achievements compared to previously available wurtzite-type ferroelectrics: 1) Record low switching voltages down to 1 V are achieved, which is in a range that can be supplied by standard on-chip voltage sources. 2) Compared to the previously investigated deposition of ultrathin Al1-x Scx N films on epitaxial templates, a significantly larger coercive field (Ec ) to breakdown field ratio is observed for Al0.74 Sc0.26 N films grown on silicon substrates, the technologically most relevant substrate-type. 3) The formation of true ferroelectric domains in wurtzite-type materials is for the first time demonstrated on the atomic scale by scanning transmission electron microscopy (STEM) investigations of a sub-5 nm thin partially switched film. The direct observation of inversion domain boundaries (IDB) within single nm-sized grains supports the theory of a gradual domain-wall driven switching process in wurtzite-type ferroelectrics. Ultimately, this should enable the analog switching necessary for mimicking neuromorphic concepts also in highly scaled devices.
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Affiliation(s)
- Georg Schönweger
- Department of Electrical and Information EngineeringKiel UniversityKaiserstrasse 2D‐24143KielGermany
- Fraunhofer Institute for Silicon Technology (ISIT)Fraunhoferstr. 1D‐25524ItzehoeGermany
| | - Niklas Wolff
- Department of Material ScienceKiel UniversityKaiserstrasse 2D‐24143KielGermany
- Kiel Nano, Surface and Interface Science (KiNSIS)Kiel UniversityChristian‐Albrechts‐Platz 4D‐24118KielGermany
| | - Md Redwanul Islam
- Department of Material ScienceKiel UniversityKaiserstrasse 2D‐24143KielGermany
| | - Maike Gremmel
- Department of Material ScienceKiel UniversityKaiserstrasse 2D‐24143KielGermany
| | - Adrian Petraru
- Department of Electrical and Information EngineeringKiel UniversityKaiserstrasse 2D‐24143KielGermany
| | - Lorenz Kienle
- Department of Material ScienceKiel UniversityKaiserstrasse 2D‐24143KielGermany
- Kiel Nano, Surface and Interface Science (KiNSIS)Kiel UniversityChristian‐Albrechts‐Platz 4D‐24118KielGermany
| | - Hermann Kohlstedt
- Department of Electrical and Information EngineeringKiel UniversityKaiserstrasse 2D‐24143KielGermany
- Kiel Nano, Surface and Interface Science (KiNSIS)Kiel UniversityChristian‐Albrechts‐Platz 4D‐24118KielGermany
| | - Simon Fichtner
- Fraunhofer Institute for Silicon Technology (ISIT)Fraunhoferstr. 1D‐25524ItzehoeGermany
- Department of Material ScienceKiel UniversityKaiserstrasse 2D‐24143KielGermany
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15
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Peters JJP, Mullarkey T, Hedley E, Müller KH, Porter A, Mostaed A, Jones L. Electron counting detectors in scanning transmission electron microscopy via hardware signal processing. Nat Commun 2023; 14:5184. [PMID: 37626044 PMCID: PMC10457289 DOI: 10.1038/s41467-023-40875-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Transmission electron microscopy is a pivotal instrument in materials and biological sciences due to its ability to provide local structural and spectroscopic information on a wide range of materials. However, the electron detectors used in scanning transmission electron microscopy are often unable to provide quantified information, that is the number of electrons impacting the detector, without exhaustive calibration and processing. This results in arbitrary signal values with slow response times that cannot be used for quantification or comparison to simulations. Here we demonstrate and optimise a hardware signal processing approach to augment electron detectors to perform single electron counting.
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Affiliation(s)
- Jonathan J P Peters
- Advanced Microscopy Laboratory (AML), Trinity College Dublin, the University of Dublin, Dublin, Ireland.
- School of Physics, Trinity College Dublin, the University of Dublin, Dublin, Ireland.
| | - Tiarnan Mullarkey
- Advanced Microscopy Laboratory (AML), Trinity College Dublin, the University of Dublin, Dublin, Ireland
- Centre for Doctoral Training in the Advanced Characterisation of Materials, AMBER Centre, Dublin, Ireland
| | - Emma Hedley
- Department of Materials, University of Oxford, Oxford, UK
| | - Karin H Müller
- Faculty of Engineering, Department of Materials, Imperial College London, London, UK
| | - Alexandra Porter
- Faculty of Engineering, Department of Materials, Imperial College London, London, UK
| | - Ali Mostaed
- Department of Materials, University of Oxford, Oxford, UK
| | - Lewys Jones
- Advanced Microscopy Laboratory (AML), Trinity College Dublin, the University of Dublin, Dublin, Ireland
- School of Physics, Trinity College Dublin, the University of Dublin, Dublin, Ireland
- Centre for Doctoral Training in the Advanced Characterisation of Materials, AMBER Centre, Dublin, Ireland
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16
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Iwashimizu C, Haruta M, Nemoto T, Kurata H. Different atomic contrasts in HAADF images and EELS maps of rutile TiO2. Microscopy (Oxf) 2023; 72:353-360. [PMID: 36440709 DOI: 10.1093/jmicro/dfac067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/21/2022] [Accepted: 11/27/2022] [Indexed: 08/05/2023] Open
Abstract
High-angle annular dark-field (HAADF) imaging and elemental mapping at the atomic scale by scanning transmission electron microscopy (STEM) combined with electron energy-loss spectroscopy (EELS) are widely used for material characterization, in which quantitative understanding of the contrast of the image is required. Here, we report an unexpected image contrast in the elemental mapping of rutile TiO2, where the Ti L2,3 map shows an anisotropic elliptical shape that extends along the long axis in the octahedral structure, while the atomic contrast of Ti columns in the HAADF image is almost circular. Multi-slice simulation reveals that unique electron channeling related to the rutile structure and the difference of the potentials between HAADF and EELS cause the different atomic contrasts in the two images.
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Affiliation(s)
- Chisaki Iwashimizu
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Mitsutaka Haruta
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takashi Nemoto
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Hiroki Kurata
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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17
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Mullarkey T, Geever M, Peters JJP, Griffiths I, Nellist PD, Jones L. How Fast is Your Detector? The Effect of Temporal Response on Image Quality. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1402-1408. [PMID: 37488817 DOI: 10.1093/micmic/ozad061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 03/08/2023] [Accepted: 05/13/2023] [Indexed: 07/26/2023]
Abstract
With increasing interest in high-speed imaging, there should be an increased interest in the response times of our scanning transmission electron microscope detectors. Previous works have highlighted and contrasted the performance of various detectors for quantitative compositional or structural studies, but here, we shift the focus to detector temporal response, and the effect this has on captured images. The rise and decay times of eight detectors' single-electron response are reported, as well as measurements of their flatness, roundness, smoothness, and ellipticity. We develop and apply a methodology for incorporating the temporal detector response into simulations, showing that a loss of resolution is apparent in both the images and their Fourier transforms. We conclude that the solid-state detector outperforms the photomultiplier tube-based detectors in all areas bar a slightly less elliptical central hole and is likely the best detector to use for the majority of applications. However, using the tools introduced here, we encourage users to effectively evaluate which detector is most suitable for their experimental needs.
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Affiliation(s)
- Tiarnan Mullarkey
- School of Physics, Trinity College Dublin, College Green, Dublin D02 PN40, Ireland
- Centre for Doctoral Training in the Advanced Characterisation of Materials, AMBER Centre, Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Matthew Geever
- School of Physics, Trinity College Dublin, College Green, Dublin D02 PN40, Ireland
| | - Jonathan J P Peters
- School of Physics, Trinity College Dublin, College Green, Dublin D02 PN40, Ireland
| | - Ian Griffiths
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Peter D Nellist
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Lewys Jones
- School of Physics, Trinity College Dublin, College Green, Dublin D02 PN40, Ireland
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin D02 PN40, Ireland
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18
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Peters JJP, Mullarkey T, Gott JA, Nelson E, Jones L. Interlacing in Atomic Resolution Scanning Transmission Electron Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1373-1379. [PMID: 37488815 DOI: 10.1093/micmic/ozad056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 03/27/2023] [Accepted: 04/24/2023] [Indexed: 07/26/2023]
Abstract
Fast frame rates are desirable in scanning transmission electron microscopy for a number of reasons: controlling electron beam dose, capturing in situ events, or reducing the appearance of scan distortions. While several strategies exist for increasing frame rates, many impact image quality or require investment in advanced scan hardware. Here, we present an interlaced imaging approach to achieve minimal loss of image quality with faster frame rates that can be implemented on many existing scan controllers. We further demonstrate that our interlacing approach provides the best possible strain precision for a given electron dose compared with other contemporary approaches.
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Affiliation(s)
- Jonathan J P Peters
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin D02 DA31, Ireland
- School of Physics, Trinity College Dublin, Dublin D02 E8C0, Ireland
| | - Tiarnan Mullarkey
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin D02 DA31, Ireland
- School of Physics, Trinity College Dublin, Dublin D02 E8C0, Ireland
- Centre for Doctoral Training in the Advanced Characterisation of Materials, AMBER Centre, Trinity College Dublin, Dublin D02 W9K7, Ireland
| | - James A Gott
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
- Advanced Materials Manufacturing Centre (AMMC), Warwick Manufacturing Group (WMG), University of Warwick, Coventry CV4 7AL, UK
| | - Elizabeth Nelson
- School of Physics, Trinity College Dublin, Dublin D02 E8C0, Ireland
| | - Lewys Jones
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin D02 DA31, Ireland
- School of Physics, Trinity College Dublin, Dublin D02 E8C0, Ireland
- Centre for Doctoral Training in the Advanced Characterisation of Materials, AMBER Centre, Trinity College Dublin, Dublin D02 W9K7, Ireland
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19
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De Backer A, Bals S, Van Aert S. A decade of atom-counting in STEM: From the first results toward reliable 3D atomic models from a single projection. Ultramicroscopy 2023; 247:113702. [PMID: 36796120 DOI: 10.1016/j.ultramic.2023.113702] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 02/03/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023]
Abstract
Quantitative structure determination is needed in order to study and understand nanomaterials at the atomic scale. Materials characterisation resulting in precise structural information is a crucial point to understand the structure-property relation of materials. Counting the number of atoms and retrieving the 3D atomic structure of nanoparticles plays an important role here. In this paper, an overview will be given of the atom-counting methodology and its applications over the past decade. The procedure to count the number of atoms will be discussed in detail and it will be shown how the performance of the method can be further improved. Furthermore, advances toward mixed element nanostructures, 3D atomic modelling based on the atom-counting results, and quantifying the nanoparticle dynamics will be highlighted.
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Affiliation(s)
- A De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Bals
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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20
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Fowlie J, Georgescu AB, Suter A, Mundet B, Toulouse C, Jaouen N, Viret M, Domínguez C, Gibert M, Salman Z, Prokscha T, Alexander DTL, Kreisel J, Georges A, Millis AJ, Triscone JM. Metal-insulator transition in composition-tuned nickel oxide films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:304001. [PMID: 37059114 DOI: 10.1088/1361-648x/accd38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/14/2023] [Indexed: 06/19/2023]
Abstract
Thin films of the solid solution Nd1-xLaxNiO3are grown in order to study the expected 0 K phase transitions at a specific composition. We experimentally map out the structural, electronic and magnetic properties as a function ofxand a discontinuous, possibly first order, insulator-metal transition is observed at low temperature whenx= 0.2. Raman spectroscopy and scanning transmission electron microscopy show that this is not associated with a correspondingly discontinuous global structural change. On the other hand, results from density functional theory (DFT) and combined DFT and dynamical mean field theory calculations produce a 0 K first order transition at around this composition. We further estimate the temperature-dependence of the transition from thermodynamic considerations and find that a discontinuous insulator-metal transition can be reproduced theoretically and implies a narrow insulator-metal phase coexistence withx. Finally, muon spin rotation (µSR) measurements suggest that there are non-static magnetic moments in the system that may be understood in the context of the first order nature of the 0 K transition and its associated phase coexistence regime.
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Affiliation(s)
- Jennifer Fowlie
- Department of Applied Physics, Stanford University, Stanford, CA, United States of America
| | - Alexandru B Georgescu
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, United States of America
| | - Andreas Suter
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Bernat Mundet
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
- Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Constance Toulouse
- Department of Physics and Materials Science, University of Luxembourg, 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | | | - Michel Viret
- SPEC, CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Claribel Domínguez
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
| | - Marta Gibert
- Solid State Physics Institute, TU Wien, Vienna, Austria
| | - Zaher Salman
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Thomas Prokscha
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Duncan T L Alexander
- Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jens Kreisel
- Department of Physics and Materials Science, University of Luxembourg, 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Antoine Georges
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
- Center for Computational Quantum Physics, Flatiron Institute, New York, NY, United States of America
- Collège de France, 75005 Paris, France
- Centre de Physique Théorique, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France
| | - Andrew J Millis
- Center for Computational Quantum Physics, Flatiron Institute, New York, NY, United States of America
- Department of Physics, Columbia University, New York, NY, United States of America
| | - Jean-Marc Triscone
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
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21
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Vogel A, Ruiz Caridad A, Nordlander J, Sarott MF, Meier QN, Erni R, Spaldin NA, Trassin M, Rossell MD. Origin of the Critical Thickness in Improper Ferroelectric Thin Films. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18482-18492. [PMID: 36996320 DOI: 10.1021/acsami.3c00412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Improper ferroelectrics are expected to be more robust than conventional ferroelectrics against depolarizing field effects and to exhibit a much-desired absence of critical thickness. Recent studies, however, revealed the loss of ferroelectric response in epitaxial improper ferroelectric thin films. Here, we investigate improper ferroelectric hexagonal YMnO3 thin films and find that the polarization suppression, and hence functionality, in the thinner films is due to oxygen off-stoichiometry. We demonstrate that oxygen vacancies form on the film surfaces to provide the necessary charge to screen the large internal electric field resulting from the positively charged YMnO3 surface layers. Additionally, we show that by modifying the oxygen concentration of the films, the phase transition temperatures can be substantially tuned. We anticipate that our findings are also valid for other ferroelectric oxide films and emphasize the importance of controlling the oxygen content and cation oxidation states in ferroelectrics for their successful integration in nanoscale applications.
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Affiliation(s)
- Alexander Vogel
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | - Alicia Ruiz Caridad
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Johanna Nordlander
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Martin F Sarott
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | - Quintin N Meier
- Université Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Rolf Erni
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Nicola A Spaldin
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | - Morgan Trassin
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | - Marta D Rossell
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
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22
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Ning S, Xu W, Loh L, Lu Z, Bosman M, Zhang F, He Q. An integrated constrained gradient descent (iCGD) protocol to correct scan-positional errors for electron ptychography with high accuracy and precision. Ultramicroscopy 2023; 248:113716. [PMID: 36958156 DOI: 10.1016/j.ultramic.2023.113716] [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: 11/05/2022] [Revised: 02/11/2023] [Accepted: 03/10/2023] [Indexed: 03/13/2023]
Abstract
Correcting scan-positional errors is critical in achieving electron ptychography with both high resolution and high precision. This is a demanding and challenging task due to the sheer number of parameters that need to be optimized. For atomic-resolution ptychographic reconstructions, we found classical refining methods for scan positions not satisfactory due to the inherent entanglement between the object and scan positions, which can produce systematic errors in the results. Here, we propose a new protocol consisting of a series of constrained gradient descent (CGD) methods to achieve better recovery of scan positions. The central idea of these CGD methods is to utilize a priori knowledge about the nature of STEM experiments and add necessary constraints to isolate different types of scan positional errors during the iterative reconstruction process. Each constraint will be introduced with the help of simulated 4D-STEM datasets with known positional errors. Then the integrated constrained gradient decent (iCGD) protocol will be demonstrated using an experimental 4D-STEM dataset of the 1H-MoS2 monolayer. We will show that the iCGD protocol can effectively address the errors of scan positions across the spectrum and help to achieve electron ptychography with high accuracy and precision.
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Affiliation(s)
- Shoucong Ning
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Wenhui Xu
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Harbin Institute of Technology, Harbin 150001, China
| | - Leyi Loh
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Zhen Lu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Michel Bosman
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Fucai Zhang
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Qian He
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore.
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23
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Nordahl G, Jones L, Christiansen EF, Hunnestad KA, Nord M. Correcting for probe wandering by precession path segmentation. Ultramicroscopy 2023; 248:113715. [PMID: 36924599 DOI: 10.1016/j.ultramic.2023.113715] [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: 11/21/2022] [Revised: 02/22/2023] [Accepted: 03/02/2023] [Indexed: 03/11/2023]
Abstract
Precession electron diffraction has in the past few decades become a powerful technique for structure solving, strain analysis, and orientation mapping, to name a few. One of the benefits of precessing the electron beam, is increased reciprocal space resolution, albeit at a loss of spatial resolution due to an effect referred to as 'probe wandering'. Here, a new methodology of precession path segmentation is presented to counteract this effect and increase the resolution in reconstructed virtual images from scanning precession electron diffraction data. By utilizing fast pixelated electron detector technology, multiple frames are recorded for each azimuthal rotation of the beam, allowing for the probe wandering to be corrected in post-acquisition processing. Not only is there an apparent increase in the resolution of the reconstructed images, but probe wandering due to instrument misalignment is reduced, potentially easing an already difficult alignment procedure.
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Affiliation(s)
- Gregory Nordahl
- Department of Physics, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway.
| | - Lewys Jones
- School of Physics, Trinity College Dublin, Dublin 2, Ireland; Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Dublin 2, Ireland
| | - Emil Frang Christiansen
- Department of Physics, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Kasper Aas Hunnestad
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Magnus Nord
- Department of Physics, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
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24
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Kim S, Miyauchi R, Sato Y, Nam H, Fujii I, Ueno S, Kuroiwa Y, Wada S. Piezoelectric Actuation Mechanism Involving Extrinsic Nanodomain Dynamics in Lead-Free Piezoelectrics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208717. [PMID: 36609990 DOI: 10.1002/adma.202208717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/19/2022] [Indexed: 06/17/2023]
Abstract
Piezoelectric materials play a key role in applications, while there are physically open questions. The physical origin of piezoelectricity is understood as the sum of contributions from intrinsic effects on lattice dynamics and those from extrinsic effects on ferroic-domain dynamics, but there is an incomplete understanding that all but intrinsic effects are classified as extrinsic effects. Therefore, the accurate classification of extrinsic effects is important for understanding the physical origin of piezoelectricity. In this work, high-energy synchrotron radiation X-ray diffraction is utilized to measure the response of BiFeO3 -BaTiO3 piezoelectrics and the intrinsic/extrinsic contribution to electric fields. It is found from crystal structure and intrinsic/extrinsic contribution, using the analysis involving structure refinement with various structural model and micromechanics-based calculations, that Bi3+ -ion disordering is important for realization of piezoelectricity and nanodomains. Here, an extrinsic effect on the rearrangement of nanodomains is suggested. The nanodomains, which are formed by the locally distorted structure around the A-site by Bi-ion disordering, can significantly deform the material in the BiFeO3 -BaTiO3 system, which contributes to the piezoelectric actuation mechanism apart from the extrinsic effect on ferroic-domain dynamics. Bi-ion disordering plays an important role in realizing piezoelectricity and nanodomains and can provide essential material design clues to develop next-generation Bi-based lead-free piezoelectric ceramics.
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Affiliation(s)
- Sangwook Kim
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashihiroshima, Hiroshima, 739-8526, Japan
| | - Ryuki Miyauchi
- Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, Fukuoka, 819-0395, Japan
| | - Yukio Sato
- Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, Fukuoka, 819-0395, Japan
| | - Hyunwook Nam
- Graduate Faculty of Interdisciplinary Research, University of Yamanashi, Kofu, Yamanashi, 400-8510, Japan
| | - Ichiro Fujii
- Graduate Faculty of Interdisciplinary Research, University of Yamanashi, Kofu, Yamanashi, 400-8510, Japan
| | - Shintaro Ueno
- Graduate Faculty of Interdisciplinary Research, University of Yamanashi, Kofu, Yamanashi, 400-8510, Japan
| | - Yoshihiro Kuroiwa
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashihiroshima, Hiroshima, 739-8526, Japan
| | - Satoshi Wada
- Graduate Faculty of Interdisciplinary Research, University of Yamanashi, Kofu, Yamanashi, 400-8510, Japan
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25
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Kim D, Kim M, Reidt S, Han H, Baghizadeh A, Zeng P, Choi H, Puigmartí-Luis J, Trassin M, Nelson BJ, Chen XZ, Pané S. Shape-memory effect in twisted ferroic nanocomposites. Nat Commun 2023; 14:750. [PMID: 36765045 PMCID: PMC9918508 DOI: 10.1038/s41467-023-36274-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 01/20/2023] [Indexed: 02/12/2023] Open
Abstract
The shape recovery ability of shape-memory alloys vanishes below a critical size (~50 nm), which prevents their practical applications at the nanoscale. In contrast, ferroic materials, even when scaled down to dimensions of a few nanometers, exhibit actuation strain through domain switching, though the generated strain is modest (~1%). Here, we develop freestanding twisted architectures of nanoscale ferroic oxides showing shape-memory effect with a giant recoverable strain (>8%). The twisted geometrical design amplifies the strain generated during ferroelectric domain switching, which cannot be achieved in bulk ceramics or substrate-bonded thin films. The twisted ferroic nanocomposites allow us to overcome the size limitations in traditional shape-memory alloys and open new avenues in engineering large-stroke shape-memory materials for small-scale actuating devices such as nanorobots and artificial muscle fibrils.
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Affiliation(s)
- Donghoon Kim
- grid.5801.c0000 0001 2156 2780Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, 8092 Zurich, Switzerland
| | - Minsoo Kim
- grid.5801.c0000 0001 2156 2780Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, 8092 Zurich, Switzerland
| | - Steffen Reidt
- grid.410387.9IBM Research Zurich, Säumerstrasse 4, 8803 Rüschilikon, Switzerland
| | - Hyeon Han
- grid.450270.40000 0004 0491 5558Max Plank Institute of Microstructure Physics, 06120 Halle (Saale), Germany
| | - Ali Baghizadeh
- grid.5801.c0000 0001 2156 2780The Scientific Center for Optical and Electron Microscopy (ScopeM), ETH Zurich, 8093 Zurich, Switzerland
| | - Peng Zeng
- grid.5801.c0000 0001 2156 2780The Scientific Center for Optical and Electron Microscopy (ScopeM), ETH Zurich, 8093 Zurich, Switzerland
| | - Hongsoo Choi
- grid.417736.00000 0004 0438 6721Department of Robotics & Mechatronics Engineering, DGIST-ETH Microrobotics Research Center, Daegu Gyeong-buk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Josep Puigmartí-Luis
- grid.5841.80000 0004 1937 0247Departament de Ciència dels Materials i Química Física, Institut de Química Teòrica i Computacional, University of Barcelona (UB), 08028 Barcelona, Spain ,grid.425902.80000 0000 9601 989XInstitució Catalana de Recerca i Estudis Avançats (ICREA); Pg. Lluís Companys 23, Barcelona, 08010 Spain
| | - Morgan Trassin
- grid.5801.c0000 0001 2156 2780Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Bradley J. Nelson
- grid.5801.c0000 0001 2156 2780Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, 8092 Zurich, Switzerland
| | - Xiang-Zhong Chen
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, 8092, Zurich, Switzerland.
| | - Salvador Pané
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, 8092, Zurich, Switzerland.
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26
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Reidy K, Majchrzak PE, Haas B, Thomsen JD, Konečná A, Park E, Klein J, Jones AJH, Volckaert K, Biswas D, Watson MD, Cacho C, Narang P, Koch CT, Ulstrup S, Ross FM, Idrobo JC. Direct Visualization of Subnanometer Variations in the Excitonic Spectra of 2D/3D Semiconductor/Metal Heterostructures. NANO LETTERS 2023; 23:1068-1076. [PMID: 36637381 DOI: 10.1021/acs.nanolett.2c04749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The integration of metallic contacts with two-dimensional (2D) semiconductors is routinely required for the fabrication of nanoscale devices. However, nanometer-scale variations in the 2D/metal interface can drastically alter the local optoelectronic properties. Here, we map local excitonic changes of the 2D semiconductor MoS2 in contact with Au. We utilize a suspended and epitaxially grown 2D/metal platform that allows correlated electron energy-loss spectroscopy (EELS) and angle resolved photoelectron spectroscopy (nanoARPES) mapping. Spatial localization of MoS2 excitons uncovers an additional EELS peak related to the MoS2/Au interface. NanoARPES measurements indicate that Au-S hybridization decreases substantially with distance from the 2D/metal interface, suggesting that the observed EELS peak arises due to dielectric screening of the excitonic Coulomb interaction. Our results suggest that increasing the van der Waals distance could optimize excitonic spectra of mixed-dimensional 2D/3D interfaces and highlight opportunities for Coulomb engineering of exciton energies by the local dielectric environment or moiré engineering.
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Affiliation(s)
- Kate Reidy
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | | | - Benedikt Haas
- Department of Physics & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Joachim Dahl Thomsen
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Andrea Konečná
- Central European Institute of Technology, Brno University of Technology, 61200 Brno, Czech Republic
| | - Eugene Park
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Julian Klein
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alfred J H Jones
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Klara Volckaert
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Deepnarayan Biswas
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Matthew D Watson
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Cephise Cacho
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Prineha Narang
- College of Letters and Science, Physical Sciences, UCLA, Los Angeles, California 90095, United States
| | - Christoph T Koch
- Department of Physics & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Søren Ulstrup
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Juan Carlos Idrobo
- Materials Science and Engineering Department, University of Washington, Seattle, Washington 98195, United States
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27
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Mun J, Ko EK, Kang B, Gil B, Kim CH, Hahn S, Song J, Zhu Y, Sohn C, Noh TW, Kim M. Extended Oxygen Octahedral Tilt Proximity near Oxide Heterostructures. NANO LETTERS 2023; 23:1036-1043. [PMID: 36716295 DOI: 10.1021/acs.nanolett.2c04633] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The oxide interfaces between materials with different structural symmetries have been actively studied due to their novel physical properties. However, the investigation of intriguing interfacial phenomena caused by the oxygen octahedral tilt (OOT) proximity effect has not been fully exploited, as there is still no clear understanding of what determines the proximity length and what the underlying control mechanism is. Here, we achieved scalability of the OOT proximity effect in SrRuO3 (SRO) by epitaxial strain near the SRO/SrTiO3 heterointerface. We demonstrated that the OOT proximity length scale of SRO is extended from 4 unit cells to 14 unit cells by employing advanced scanning transmission electron microscopy. We also suggest that this variation may originate from changes in phonon dispersions due to electron-phonon coupling in SRO. This study will provide in-depth insights into the structural gradients of correlated systems and facilitate potential device applications.
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Affiliation(s)
- Junsik Mun
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul08826, Republic of Korea
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul08826, Republic of Korea
| | - Eun Kyo Ko
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul08826, Republic of Korea
| | - Baekjune Kang
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan44919, Republic of Korea
| | - Byeongjun Gil
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul08826, Republic of Korea
| | - Choong H Kim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul08826, Republic of Korea
| | - Sungsoo Hahn
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul08826, Republic of Korea
| | - Jeongkeun Song
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul08826, Republic of Korea
| | - Yimei Zhu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York11973, United States
| | - Changhee Sohn
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan44919, Republic of Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul08826, Republic of Korea
| | - Miyoung Kim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul08826, Republic of Korea
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul08826, Republic of Korea
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28
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Ronan O, Roy A, Ryan S, Hughes L, Downing C, Jones L, Nicolosi V. Templated Synthesis of SiO 2 Nanotubes for Lithium-Ion Battery Applications: An In Situ (Scanning) Transmission Electron Microscopy Study. ACS OMEGA 2023; 8:925-933. [PMID: 36643545 PMCID: PMC9835544 DOI: 10.1021/acsomega.2c06298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
One of the weaknesses of silicon-based batteries is the rapid deterioration of the charge-storage capacity with increasing cycle numbers. Pure silicon anodes tend to suffer from poor cycling ability due to the pulverization of the crystal structure after repeated charge and discharge cycles. In this work, we present the synthesis of a hollow nanostructured SiO2 material for lithium-ion anode applications to counter this drawback. To improve the understanding of the synthesis route, the crucial synthesis step of removing the ZnO template core is shown using an in situ closed gas-cell sample holder for transmission electron microscopy. A direct visual observation of the removal of the ZnO template from the SiO2 shell is yet to be reported in the literature and is a critical step in understanding the mechanism by which these hollow nanostructures form from their core-shell precursors for future electrode material design. Using this unique technique, observation of dynamic phenomena at the individual particle scale is possible with simultaneous heating in a reactive gas environment. The electrochemical benefits of the hollow morphology are demonstrated with exceptional cycling performance, with capacity increasing with subsequent charge-discharge cycles. This demonstrates the criticality of nanostructured battery materials for the development of next-generation Li+-ion batteries.
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Affiliation(s)
- Oskar Ronan
- Centre
for Research on Adaptive Nanostructures and Nanodevices (CRANN) and
Advanced Materials and Bioengineering Research (AMBER), School of
Chemistry, Trinity College Dublin, DublinDublin 2, Ireland
| | - Ahin Roy
- Materials
Science Centre, Indian Institute of Technology, Kharagpur721302, West Bengal, India
| | - Sean Ryan
- Centre
for Research on Adaptive Nanostructures and Nanodevices (CRANN) and
Advanced Materials and Bioengineering Research (AMBER), School of
Chemistry, Trinity College Dublin, DublinDublin 2, Ireland
| | - Lucia Hughes
- Centre
for Research on Adaptive Nanostructures and Nanodevices (CRANN) and
Advanced Materials and Bioengineering Research (AMBER), School of
Chemistry, Trinity College Dublin, DublinDublin 2, Ireland
| | - Clive Downing
- Advanced
Microscopy Laboratory (AML), and Advanced Materials and Bioengineering
Research (AMBER), Trinity College Dublin, DublinDublin 2, Ireland
| | - Lewys Jones
- School
of Physics, Advanced Microscopy Laboratory (AML), and Advanced Materials
and Bioengineering Research (AMBER), Trinity
College Dublin, DublinDublin 2, Ireland
| | - Valeria Nicolosi
- Centre
for Research on Adaptive Nanostructures and Nanodevices (CRANN) and
Advanced Materials and Bioengineering Research (AMBER), School of
Chemistry, Trinity College Dublin, DublinDublin 2, Ireland
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29
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Pokle A, Weber D, Bianchini M, Janek J, Volz K. Probing the Ni(OH) 2 Precursor for LiNiO 2 at the Atomic Scale: Insights into the Origin of Structural Defect in a Layered Cathode Active Material. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2205508. [PMID: 36433828 DOI: 10.1002/smll.202205508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/17/2022] [Indexed: 06/16/2023]
Abstract
In lithium ion batteries (LIBs), the layered cathode materials of composition LiNi1- x - y Cox Mny O2 are critical for achieving high energy densities. A high nickel content (>80%) provides an attractive balance between high energy density, long lifetime, and low cost. Consequently, Ni-rich layered oxides cathode active materials (CAMs) are in high demand, and the importance of LiNiO2 (LNO) as limiting case, is hence paramount. However, achieving perfect stoichiometry is a challenge resulting in various structural issues, which successively impact physicochemical properties and result in the capacity fade of LIBs. To better understand defect formation in LNO, the role of the Ni(OH)2 precursor morphology in the synthesis of LNO requires in-depth investigation. By employing aberration-corrected scanning transmission electron microscopy, electron energy loss spectroscopy, and precession electron diffraction, a direct observation of defects in the Ni(OH)2 precursor preparedis reported and the ex situ structural evolution from the precursor to the end product is monitored. During synthesis, the layered Ni(OH)2 structure transforms to partially lithiated (non-layered) NiO and finally to layered LNO. The results suggest that the defects observed in commercially relevant CAMs originate to a large extent from the precursors, hence care must be taken in tuning the co-precipitation parameters to synthesize defect-free Ni-rich layered oxides CAMs.
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Affiliation(s)
- Anuj Pokle
- Materials Science Center (WZMW) and Department of Physics, Philipps-University Marburg, 35032, Marburg, Germany
| | - Daniel Weber
- Battery and Electrochemistry Laboratory, Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Matteo Bianchini
- Battery and Electrochemistry Lab (BELLA), BASF SE, Carl-Bosch-Strasse 38, 67056, Ludwigshafen, Germany
| | - Jürgen Janek
- Battery and Electrochemistry Laboratory, Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Institute of Physical Chemistry & Center for Materials Research, Justus-Liebig-University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Kerstin Volz
- Materials Science Center (WZMW) and Department of Physics, Philipps-University Marburg, 35032, Marburg, Germany
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30
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Botifoll M, Pinto-Huguet I, Arbiol J. Machine learning in electron microscopy for advanced nanocharacterization: current developments, available tools and future outlook. NANOSCALE HORIZONS 2022; 7:1427-1477. [PMID: 36239693 DOI: 10.1039/d2nh00377e] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In the last few years, electron microscopy has experienced a new methodological paradigm aimed to fix the bottlenecks and overcome the challenges of its analytical workflow. Machine learning and artificial intelligence are answering this call providing powerful resources towards automation, exploration, and development. In this review, we evaluate the state-of-the-art of machine learning applied to electron microscopy (and obliquely, to materials and nano-sciences). We start from the traditional imaging techniques to reach the newest higher-dimensionality ones, also covering the recent advances in spectroscopy and tomography. Additionally, the present review provides a practical guide for microscopists, and in general for material scientists, but not necessarily advanced machine learning practitioners, to straightforwardly apply the offered set of tools to their own research. To conclude, we explore the state-of-the-art of other disciplines with a broader experience in applying artificial intelligence methods to their research (e.g., high-energy physics, astronomy, Earth sciences, and even robotics, videogames, or marketing and finances), in order to narrow down the incoming future of electron microscopy, its challenges and outlook.
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Affiliation(s)
- Marc Botifoll
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain.
| | - Ivan Pinto-Huguet
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain.
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain.
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
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31
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Mg segregation at inclined facets of pyramidal inversion domains in GaN:Mg. Sci Rep 2022; 12:17987. [PMID: 36289429 PMCID: PMC9606308 DOI: 10.1038/s41598-022-22622-1] [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: 07/12/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022] Open
Abstract
Structural defects in Mg-doped GaN were analyzed using high-resolution scanning transmission electron microscopy combined with electron energy loss spectroscopy. The defects, in the shape of inverted pyramids, appear at high concentrations of incorporated Mg, which also lead to a reduction in free-hole concentration in Mg doped GaN. Detailed analysis pinpoints the arrangement of atoms in and around the defects and verify the presence of a well-defined layer of Mg at all facets, including the inclined facets. Our observations have resulted in a model of the pyramid-shaped defect, including structural displacements and compositional replacements, which is verified by image simulations. Finally, the total concentration of Mg atoms bound to these defects were evaluated, enabling a correlation between inactive and defect-bound dopants.
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32
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Nylund IE, Løndal NS, Walker J, Vullum PE, Einarsrud MA, Grande T. Cation Disorder in Ferroelectric Ba 4M 2Nb 10O 30 (M = Na, K, and Rb) Tetragonal Tungsten Bronzes. Inorg Chem 2022; 61:15540-15546. [PMID: 36137177 PMCID: PMC9533300 DOI: 10.1021/acs.inorgchem.2c02266] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The crystal structure of tetragonal tungsten bronzes,
with the
general formula A12A24C4B12B28O30, is flexible both from a chemical and
structural viewpoint, resulting in a multitude of compositions. The
A1 and A2 lattice sites, with different coordination environments,
are usually regarded to be occupied by two different cations such
as in Ba4Na2Nb10O30 with
Na+ and Ba2+ occupying the A1 and A2 sites,
respectively. Here, we report on a systematic study of the lattice
site occupancy on the A1 and A2 sites in the series Ba4M2Nb10O30 (M = Na, K, and Rb). The
three compounds were synthesized by a two-step solid-state method.
The site occupancy on the A1 and A2 sites were investigated by a combination
of Rietveld refinement of X-ray diffraction patterns and scanning
transmission electron microscopy with simultaneous energy-dispersive
spectroscopy. The two methods demonstrated consistent site occupancy
of the cations on the A1 and A2 sites, rationalized by the variation
in the size of the alkali cations. The cation order–disorder
phenomenology in the tungsten bronzes reported is discussed using
a thermodynamic model of O’Neill and Navrotsky, originally
developed for cation interchange in spinels. In tetragonal tungsten bronzes, with
general formula A12A24C4B12B28O30, the A1 and A2 lattice sites are usually
regarded to be
occupied by two different cations. Here, the site occupancy on the
A1 and A2 sites in the tetragonal tungsten bronzes Ba4M2Nb10O30 (M = Na, K, and Rb) was investigated
by a combination of Rietveld refinement of X-ray diffraction data
and scanning transmission electron microscopy with simultaneous energy-dispersive
spectroscopy, revealing cation intermixing rationalized by the relative
size difference between the two cations.
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Affiliation(s)
- Inger-Emma Nylund
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Nora Statle Løndal
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Julian Walker
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Per Erik Vullum
- Department of Physics, NTNU Norwegian University of Science and Technology, 7491 Trondheim, Norway.,SINTEF Industry, NO-7034 Trondheim, Norway
| | - Mari-Ann Einarsrud
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Tor Grande
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, 7491 Trondheim, Norway
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33
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Akkerman QA, Nguyen TPT, Boehme SC, Montanarella F, Dirin DN, Wechsler P, Beiglböck F, Rainò G, Erni R, Katan C, Even J, Kovalenko MV. Controlling the nucleation and growth kinetics of lead halide perovskite quantum dots. Science 2022; 377:1406-1412. [PMID: 36074820 DOI: 10.1126/science.abq3616] [Citation(s) in RCA: 75] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Colloidal lead halide perovskite (LHP) nanocrystals are of interest as photoluminescent quantum dots (QDs) whose properties depend on the size and shape. They are normally synthesized on subsecond time scales through hard-to-control ionic metathesis reactions. We report a room-temperature synthesis of monodisperse, isolable spheroidal APbBr3 QDs (A=Cs, formamidinium, methylammonium) that are size-tunable from 3 to over 13 nanometers. The kinetics of both nucleation and growth are temporally separated and drastically slowed down by the intricate equilibrium between the precursor (PbBr2) and the A[PbBr3] solute, with the latter serving as a monomer. QDs of all these compositions exhibit up to four excitonic transitions in their linear absorption spectra, and we demonstrate that the size-dependent confinement energy for all transitions is independent of the A-site cation.
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Affiliation(s)
- Quinten A Akkerman
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland.,Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Tan P T Nguyen
- Univ Rennes, ENSCR, INSA Rennes, CNRS, ISCR - UMR 6226, F-35000 Rennes, France
| | - Simon C Boehme
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland.,Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Federico Montanarella
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland.,Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Dmitry N Dirin
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland.,Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Philipp Wechsler
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland
| | - Finn Beiglböck
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Gabriele Rainò
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland.,Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
| | - Rolf Erni
- Electron Microscopy Center, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Claudine Katan
- Univ Rennes, ENSCR, INSA Rennes, CNRS, ISCR - UMR 6226, F-35000 Rennes, France
| | - Jacky Even
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON - UMR 6082, F-35000 Rennes, France
| | - Maksym V Kovalenko
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland.,Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland
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34
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Critical ionic transport across an oxygen-vacancy ordering transition. Nat Commun 2022; 13:5130. [PMID: 36050294 PMCID: PMC9437025 DOI: 10.1038/s41467-022-32826-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 08/17/2022] [Indexed: 11/19/2022] Open
Abstract
Phase transition points can be used to critically reduce the ionic migration activation energy, which is important for realizing high-performance electrolytes at low temperatures. Here, we demonstrate a route toward low-temperature thermionic conduction in solids, by exploiting the critically lowered activation energy associated with oxygen transport in Ca-substituted bismuth ferrite (Bi1-xCaxFeO3-δ) films. Our demonstration relies on the finding that a compositional phase transition occurs by varying Ca doping ratio across xCa ≃ 0.45 between two structural phases with oxygen-vacancy channel ordering along <100> or <110> crystal axis, respectively. Regardless of the atomic-scale irregularity in defect distribution at the doping ratio, the activation energy is largely suppressed to 0.43 eV, compared with ~0.9 eV measured in otherwise rigid phases. From first-principles calculations, we propose that the effective short-range attraction between two positively charged oxygen vacancies sharing lattice deformation not only forms the defect orders but also suppresses the activation energy through concerted hopping. Phase transition points can be used to reduce the ionic migration activation energy. Here, the authors find a lowered activation energy associated with oxygen transport at a compositional phase transition point in Ca-doped bismuth ferrite films.
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35
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Deep learning-based noise filtering toward millisecond order imaging by using scanning transmission electron microscopy. Sci Rep 2022; 12:13462. [PMID: 35931705 PMCID: PMC9356044 DOI: 10.1038/s41598-022-17360-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 07/25/2022] [Indexed: 11/09/2022] Open
Abstract
Application of scanning transmission electron microscopy (STEM) to in situ observation will be essential in the current and emerging data-driven materials science by taking STEM's high affinity with various analytical options into account. As is well known, STEM's image acquisition time needs to be further shortened to capture a targeted phenomenon in real-time as STEM's current temporal resolution is far below the conventional TEM's. However, rapid image acquisition in the millisecond per frame or faster generally causes image distortion, poor electron signals, and unidirectional blurring, which are obstacles for realizing video-rate STEM observation. Here we show an image correction framework integrating deep learning (DL)-based denoising and image distortion correction schemes optimized for STEM rapid image acquisition. By comparing a series of distortion corrected rapid scan images with corresponding regular scan speed images, the trained DL network is shown to remove not only the statistical noise but also the unidirectional blurring. This result demonstrates that rapid as well as high-quality image acquisition by STEM without hardware modification can be established by the DL. The DL-based noise filter could be applied to in-situ observation, such as dislocation activities under external stimuli, with high spatio-temporal resolution.
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36
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Haruta M, Kikkawa J, Kimoto K, Kurata H. Comparison of detection limits of direct-counting CMOS and CCD cameras in EELS experiments. Ultramicroscopy 2022; 240:113577. [PMID: 35728341 DOI: 10.1016/j.ultramic.2022.113577] [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: 02/09/2022] [Revised: 04/18/2022] [Accepted: 06/13/2022] [Indexed: 11/15/2022]
Abstract
The noise performance and the detection limits of a direct-counting complementary metal-oxide semiconductor (CMOS) K2 camera and a charge-coupled device (CCD) camera in electron energy loss spectroscopy (EELS) experiments were evaluated. In the case of a single spectrum acquired at the shortest dwell times (2.5 ms for K2 and 1 μs for CCD), the detection limit, defined as three times the standard deviation of the spectral noise (3σ), was very low (1 e-/channel) in the counting-mode spectrum acquired with the K2 camera compared with that acquired with the CCD camera (5 e-/channel). By contrast, the spectral noise of the K2 camera changed depending on the dwell time because of the multiple read-outs related to its fixed frame rate (400 fps). The spectral noise of the K2 camera was greater than that of the CCD camera when the dwell time was longer than ∼30 ms. Thus, the CCD camera was found to still be useful when detecting a very small number of electrons using a long acquisition time. In the case of an accumulated spectrum obtained by acquiring 10,000 spectra after subtracting the ultra-high-quality dark reference signal, the detection limits per read-out were ∼0.016 and ∼0.025 e-/channel/read-out for the K2 and CCD cameras, respectively. Because both cameras have advantages and disadvantages with respect to their detection limit, speed, and dynamic range, their proper use is important.
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Affiliation(s)
- Mitsutaka Haruta
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
| | - Jun Kikkawa
- Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Koji Kimoto
- Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Hiroki Kurata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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37
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Multilevel polarization switching in ferroelectric thin films. Nat Commun 2022; 13:3159. [PMID: 35672404 PMCID: PMC9174202 DOI: 10.1038/s41467-022-30823-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 05/19/2022] [Indexed: 11/11/2022] Open
Abstract
Ferroic order is characterized by hystereses with two remanent states and therefore inherently binary. The increasing interest in materials showing non-discrete responses, however, calls for a paradigm shift towards continuously tunable remanent ferroic states. Device integration for oxide nanoelectronics furthermore requires this tunability at the nanoscale. Here we demonstrate that we can arbitrarily set the remanent ferroelectric polarization at nanometric dimensions. We accomplish this in ultrathin epitaxial PbZr0.52Ti0.48O3 films featuring a dense pattern of decoupled nanometric 180° domains with a broad coercive-field distribution. This multilevel switching is achieved by driving the system towards the instability at the morphotropic phase boundary. The phase competition near this boundary in combination with epitaxial strain increases the responsiveness to external stimuli and unlocks new degrees of freedom to nano-control the polarization. We highlight the technological benefits of non-binary switching by demonstrating a quasi-continuous tunability of the non-linear optical response and of tunnel electroresistance. Setting any polarization value in ferroelectric thin films is a key step for their implementation in neuromorphic devices. Here, the authors demonstrate continuous modulation of the remanent polarization at the nanoscale in PbZr0.52Ti0.48O3 films.
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38
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Ultra-narrow room-temperature emission from single CsPbBr 3 perovskite quantum dots. Nat Commun 2022; 13:2587. [PMID: 35546149 PMCID: PMC9095639 DOI: 10.1038/s41467-022-30016-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 03/25/2022] [Indexed: 11/29/2022] Open
Abstract
Semiconductor quantum dots have long been considered artificial atoms, but despite the overarching analogies in the strong energy-level quantization and the single-photon emission capability, their emission spectrum is far broader than typical atomic emission lines. Here, by using ab-initio molecular dynamics for simulating exciton-surface-phonon interactions in structurally dynamic CsPbBr3 quantum dots, followed by single quantum dot optical spectroscopy, we demonstrate that emission line-broadening in these quantum dots is primarily governed by the coupling of excitons to low-energy surface phonons. Mild adjustments of the surface chemical composition allow for attaining much smaller emission linewidths of 35−65 meV (vs. initial values of 70–120 meV), which are on par with the best values known for structurally rigid, colloidal II-VI quantum dots (20−60 meV). Ultra-narrow emission at room-temperature is desired for conventional light-emitting devices and paramount for emerging quantum light sources. Narrow emission is desired for light-emitting devices. Here, Kovalenko et al. demonstrate that the emission line-broadening in perovskite quantum dots is dominated by the coupling between excitons and surface phonon modes which can be controlled by minimal surface modifications.
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39
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High-precision atomic-scale strain mapping of nanoparticles from STEM images. Ultramicroscopy 2022; 239:113561. [DOI: 10.1016/j.ultramic.2022.113561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 05/02/2022] [Accepted: 05/21/2022] [Indexed: 11/22/2022]
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40
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Firoozabadi S, Kükelhan P, Beyer A, Lehr J, Volz K. Quantitative composition determination by ADF-STEM at a low angular regime: a combination of EFSTEM and 4DSTEM. Ultramicroscopy 2022; 240:113550. [DOI: 10.1016/j.ultramic.2022.113550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/26/2022] [Accepted: 05/04/2022] [Indexed: 10/18/2022]
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41
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Schwenker E, Kolluru VSC, Guo J, Zhang R, Hu X, Li Q, Paul JT, Hersam MC, Dravid VP, Klie R, Guest JR, Chan MKY. Ingrained: An Automated Framework for Fusing Atomic-Scale Image Simulations into Experiments. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2102960. [PMID: 35384282 DOI: 10.1002/smll.202102960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 12/20/2021] [Indexed: 06/14/2023]
Abstract
To fully leverage the power of image simulation to corroborate and explain patterns and structures in atomic resolution microscopy, an initial correspondence between the simulation and experimental image must be established at the outset of further high accuracy simulations or calculations. Furthermore, if simulation is to be used in context of highly automated processes or high-throughput optimization, the process of finding this correspondence itself must be automated. In this work, "ingrained," an open-source automation framework which solves for this correspondence and fuses atomic resolution image simulations into the experimental images to which they correspond, is introduced. Herein, the overall "ingrained" workflow, focusing on its application to interface structure approximations, and the development of an experimentally rationalized forward model for scanning tunneling microscopy simulation are described.
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Affiliation(s)
- Eric Schwenker
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Venkata Surya Chaitanya Kolluru
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Jinglong Guo
- Department of Physics, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Rui Zhang
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Xiaobing Hu
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Qiucheng Li
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Joshua T Paul
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Vinayak P Dravid
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Robert Klie
- Department of Physics, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Jeffrey R Guest
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Maria K Y Chan
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
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42
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Quigley F, McBean P, O'Donovan P, Peters JJP, Jones L. Cost and Capability Compromises in STEM Instrumentation for Low-Voltage Imaging. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-7. [PMID: 35354509 DOI: 10.1017/s1431927622000277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Low-voltage transmission electron microscopy (≤80 kV) has many applications in imaging beam-sensitive samples, such as metallic nanoparticles, which may become damaged at higher voltages. To improve resolution, spherical aberration can be corrected for in a scanning transmission electron microscope (STEM); however, chromatic aberration may then dominate, limiting the ultimate resolution of the microscope. Using image simulations, we examine how a chromatic aberration corrector, different objective lenses, and different beam energy spreads each affect the image quality of a gold nanoparticle imaged at low voltages in a spherical aberration-corrected STEM. A quantitative analysis of the simulated examples can inform the choice of instrumentation for low-voltage imaging. We here demonstrate a methodology whereby the optimum energy spread to operate a specific STEM can be deduced. This methodology can then be adapted to the specific sample and instrument of the reader, enabling them to make an informed economical choice as to what would be most beneficial for their STEM in the cost-conscious landscape of scientific infrastructure.
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Affiliation(s)
- Frances Quigley
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures & Nanodevices (CRANN), Dublin 2, Ireland
| | - Patrick McBean
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures & Nanodevices (CRANN), Dublin 2, Ireland
| | - Peter O'Donovan
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Jonathan J P Peters
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures & Nanodevices (CRANN), Dublin 2, Ireland
| | - Lewys Jones
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures & Nanodevices (CRANN), Dublin 2, Ireland
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43
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Abstract
Ferroics, especially ferromagnets, can form complex topological spin structures such as vortices1 and skyrmions2,3 when subjected to particular electrical and mechanical boundary conditions. Simple vortex-like, electric-dipole-based topological structures have been observed in dedicated ferroelectric systems, especially ferroelectric-insulator superlattices such as PbTiO3/SrTiO3, which was later shown to be a model system owing to its high depolarizing field4-8. To date, the electric dipole equivalent of ordered magnetic spin lattices driven by the Dzyaloshinskii-Moriya interaction (DMi)9,10 has not been experimentally observed. Here we examine a domain structure in a single PbTiO3 epitaxial layer sandwiched between SrRuO3 electrodes. We observe periodic clockwise and anticlockwise ferroelectric vortices that are modulated by a second ordering along their toroidal core. The resulting topology, supported by calculations, is a labyrinth-like pattern with two orthogonal periodic modulations that form an incommensurate polar crystal that provides a ferroelectric analogue to the recently discovered incommensurate spin crystals in ferromagnetic materials11-13. These findings further blur the border between emergent ferromagnetic and ferroelectric topologies, clearing the way for experimental realization of further electric counterparts of magnetic DMi-driven phases.
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44
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Kohno Y, Seki T, Findlay SD, Ikuhara Y, Shibata N. Real-space visualization of intrinsic magnetic fields of an antiferromagnet. Nature 2022; 602:234-239. [PMID: 35140388 DOI: 10.1038/s41586-021-04254-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/16/2021] [Indexed: 11/09/2022]
Abstract
Characterizing magnetic structures down to atomic dimensions is central to the design and control of nanoscale magnetism in materials and devices. However, real-space visualization of magnetic fields at such dimensions has been extremely challenging. In recent years, atomic-resolution differential phase contrast scanning transmission electron microscopy (DPC STEM)1 has enabled direct imaging of electric field distribution even inside single atoms2. Here we show real-space visualization of magnetic field distribution inside antiferromagnetic haematite (α-Fe2O3) using atomic-resolution DPC STEM in a magnetic-field-free environment3. After removing the phase-shift component due to atomic electric fields and improving the signal-to-noise ratio by unit-cell averaging, real-space visualization of the intrinsic magnetic fields in α-Fe2O3 is realized. These results open a new possibility for real-space characterization of many magnetic structures.
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Affiliation(s)
| | - Takehito Seki
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo, Japan.,PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Scott D Findlay
- School of Physics and Astronomy, Monash University, Melbourne, Victoria, Australia
| | - Yuichi Ikuhara
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo, Japan.,Nanostructures Research Laboratory, Japan Fine Ceramic Center, Nagoya, Japan
| | - Naoya Shibata
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo, Japan. .,Nanostructures Research Laboratory, Japan Fine Ceramic Center, Nagoya, Japan. .,Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo, Japan.
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45
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Wardini JL, Vahidi H, Guo H, Bowman WJ. Probing Multiscale Disorder in Pyrochlore and Related Complex Oxides in the Transmission Electron Microscope: A Review. Front Chem 2021; 9:743025. [PMID: 34917587 PMCID: PMC8668443 DOI: 10.3389/fchem.2021.743025] [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: 07/17/2021] [Accepted: 10/15/2021] [Indexed: 11/13/2022] Open
Abstract
Transmission electron microscopy (TEM), and its counterpart, scanning TEM (STEM), are powerful materials characterization tools capable of probing crystal structure, composition, charge distribution, electronic structure, and bonding down to the atomic scale. Recent (S)TEM instrumentation developments such as electron beam aberration-correction as well as faster and more efficient signal detection systems have given rise to new and more powerful experimental methods, some of which (e.g., 4D-STEM, spectrum-imaging, in situ/operando (S)TEM)) facilitate the capture of high-dimensional datasets that contain spatially-resolved structural, spectroscopic, time- and/or stimulus-dependent information across the sub-angstrom to several micrometer length scale. Thus, through the variety of analysis methods available in the modern (S)TEM and its continual development towards high-dimensional data capture, it is well-suited to the challenge of characterizing isometric mixed-metal oxides such as pyrochlores, fluorites, and other complex oxides that reside on a continuum of chemical and spatial ordering. In this review, we present a suite of imaging and diffraction (S)TEM techniques that are uniquely suited to probe the many types, length-scales, and degrees of disorder in complex oxides, with a focus on disorder common to pyrochlores, fluorites and the expansive library of intermediate structures they may adopt. The application of these techniques to various complex oxides will be reviewed to demonstrate their capabilities and limitations in resolving the continuum of structural and chemical ordering in these systems.
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Affiliation(s)
- Jenna L. Wardini
- Materials Science and Engineering, University of California, Irvine, Irvine, CA, United States
| | - Hasti Vahidi
- Materials Science and Engineering, University of California, Irvine, Irvine, CA, United States
| | - Huiming Guo
- Materials Science and Engineering, University of California, Irvine, Irvine, CA, United States
| | - William J. Bowman
- Materials Science and Engineering, University of California, Irvine, Irvine, CA, United States
- Irvine Materials Research Institute, Irvine, CA, United States
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46
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Zschiesche H, Aygar AM, Langelier B, Szkopek T, Botton GA. Atomic scale chemical ordering in franckeite-a natural van der Waals superlattice. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:055403. [PMID: 34783682 DOI: 10.1088/1361-648x/ac3451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
The mineral franckeite is a naturally occurring van der Waals superlattice which has recently attracted attention for future applications in optoelectronics, biosensors and beyond. Furthermore, its stacking of incommensurately modulated 2D layers, the pseudo tetragonal Q-layer and the pseudo hexagonal H-layer, is an experimentally accessible prototype for the development of synthetic van der Waals materials and of advanced characterization methods to reveal new insights in their structure and chemistry at the atomic scale that is crucial for deep understanding of its properties. While some experimental studies have been undertaken in the past, much is still unknown on the correlation between local atomic structure and chemical composition within the layers. Here we present an investigation of the atomic structure of franckeite using state-of-the-art high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) and atom probe tomography (APT). With atomic-number image contrast in HAADF STEM direct information about both the geometric structure and its chemistry is provided. By imaging samples under different zone axes within the van der Waals plane, we propose refinements to the structure of the Q-layer and H-layer, including several chemical ordering effects that are expected to impact electronic structure calculations. Additionally, we observe and characterize stacking faults which are possible sources of differences between experimentally determined properties and calculations. Furthermore, we demonstrate advantages and discuss current limitations and perspectives of combining TEM and APT for the atomic scale characterization of incommensurately modulated von der Waals materials.
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Affiliation(s)
- Hannes Zschiesche
- McMaster University, Department of Materials Science and Engineering, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada
| | - Ayse Melis Aygar
- McGill University, Department of Electrical and Computer Engineering, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Brian Langelier
- McMaster University, Canadian Center for Electron microscopy, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada
| | - Thomas Szkopek
- McGill University, Department of Electrical and Computer Engineering, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Gianluigi A Botton
- McMaster University, Department of Materials Science and Engineering, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada
- Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, SK S7N 2V3, Canada
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47
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Velazco A, Béché A, Jannis D, Verbeeck J. Reducing electron beam damage through alternative STEM scanning strategies, Part I: Experimental findings. Ultramicroscopy 2021; 232:113398. [PMID: 34655928 DOI: 10.1016/j.ultramic.2021.113398] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/31/2021] [Accepted: 09/20/2021] [Indexed: 12/22/2022]
Abstract
The highly energetic electrons in a transmission electron microscope (TEM) can alter or even completely destroy the structure of samples before sufficient information can be obtained. This is especially problematic in the case of zeolites, organic and biological materials. As this effect depends on both the electron beam and the sample and can involve multiple damage pathways, its study remained difficult and is plagued with irreproducibility issues, circumstantial evidence, rumors, and a general lack of solid data. Here we take on the experimental challenge to investigate the role of the STEM scan pattern on the damage behavior of a commercially available zeolite sample with the clear aim to make our observations as reproducible as possible. We make use of a freely programmable scan engine that gives full control over the tempospatial distribution of the electron probe on the sample and we use its flexibility to obtain multiple repeated experiments under identical conditions comparing the difference in beam damage between a conventional raster scan pattern and a newly proposed interleaved scan pattern that provides exactly the same dose and dose rate and visits exactly the same scan points. We observe a significant difference in beam damage for both patterns with up to 11 % reduction in damage (measured from mass loss). These observations demonstrate without doubt that electron dose, dose rate and acceleration voltage are not the only parameters affecting beam damage in (S)TEM experiments and invite the community to rethink beam damage as an unavoidable consequence of applied electron dose.
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Affiliation(s)
- A Velazco
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - A Béché
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - D Jannis
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - J Verbeeck
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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Wang B, Bagués N, Liu T, Kawakami RK, McComb DW. Extracting weak magnetic contrast from complex background contrast in plan-view FeGe thin films. Ultramicroscopy 2021; 232:113395. [PMID: 34653891 DOI: 10.1016/j.ultramic.2021.113395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/07/2021] [Accepted: 09/20/2021] [Indexed: 11/29/2022]
Abstract
The desire to design and build skyrmion-based devices has led to the need to characterize magnetic textures in thin films of functional materials. This can usually be achieved through the Lorentz transmission electron microscopy (LTEM) and the Lorentz scanning transmission electron microscopy (LSTEM) in thin film cross-section and single crystal specimens. However, direct imaging of the magnetic texture in plan-view samples of thin (< 50 nm) films has proved to be challenging due to the complex "background" contrast associated with the microstructure and defects, as well as contributions from bending of the specimens. Using a mechanically polished 35 nm plan-view FeGe thin film, we have explored three methods to extract magnetic contrast from the complex background contrast observed; (1) background subtraction in defocused LTEM images, (2) frequency filtered CoM-DPC reconstructed from LSTEM datasets and 3) registration of 4D-STEM datasets acquired at different tilt angles. Using these methods, we have successfully implemented real space imaging of both the helical phase and skyrmion phase. The ability to understand nanoscale magnetic behavior from plan-view thin films is a fundamental step towards development of highly integrated spin electronics.
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Affiliation(s)
- Binbin Wang
- Department of Materials Science and Engineering, The Ohio State University, OH 43210, United States; Center for Electron Microscopy and Analysis, The Ohio State University, OH 43212, United States.
| | - Núria Bagués
- Center for Electron Microscopy and Analysis, The Ohio State University, OH 43212, United States
| | - Tao Liu
- Department of Physics, The Ohio State University, OH 43212, United States
| | - Roland K Kawakami
- Department of Physics, The Ohio State University, OH 43212, United States
| | - David W McComb
- Department of Materials Science and Engineering, The Ohio State University, OH 43210, United States; Center for Electron Microscopy and Analysis, The Ohio State University, OH 43212, United States.
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Vogel A, Sarott MF, Campanini M, Trassin M, Rossell MD. Monitoring Electrical Biasing of Pb(Zr 0.2Ti 0.8)O 3 Ferroelectric Thin Films In Situ by DPC-STEM Imaging. MATERIALS (BASEL, SWITZERLAND) 2021; 14:4749. [PMID: 34443272 PMCID: PMC8400982 DOI: 10.3390/ma14164749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 11/17/2022]
Abstract
Increased data storage densities are required for the next generation of nonvolatile random access memories and data storage devices based on ferroelectric materials. Yet, with intensified miniaturization, these devices face a loss of their ferroelectric properties. Therefore, a full microscopic understanding of the impact of the nanoscale defects on the ferroelectric switching dynamics is crucial. However, collecting real-time data at the atomic and nanoscale remains very challenging. In this work, we explore the ferroelectric response of a Pb(Zr0.2Ti0.8)O3 thin film ferroelectric capacitor to electrical biasing in situ in the transmission electron microscope. Using a combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and differential phase contrast (DPC)-STEM imaging we unveil the structural and polarization state of the ferroelectric thin film, integrated into a capacitor architecture, before and during biasing. Thus, we can correlate real-time changes in the DPC signal with the presence of misfit dislocations and ferroelastic domains. A reduction in the domain wall velocity of 24% is measured in defective regions of the film when compared to predominantly defect-free regions.
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Affiliation(s)
- Alexander Vogel
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Material Science and Technology, 8600 Dübendorf, Switzerland;
| | - Martin F. Sarott
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland; (M.F.S.); (M.T.)
| | - Marco Campanini
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Material Science and Technology, 8600 Dübendorf, Switzerland;
| | - Morgan Trassin
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland; (M.F.S.); (M.T.)
| | - Marta D. Rossell
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Material Science and Technology, 8600 Dübendorf, Switzerland;
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