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Shan S, Zhang Z, Volz S, Chen J. Phonon mode at interface and its impact on interfacial thermal transport. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:423001. [PMID: 38968932 DOI: 10.1088/1361-648x/ad5fd7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 07/05/2024] [Indexed: 07/07/2024]
Abstract
Due to the minimization and integration of micro/nano-devices, the high density of interfaces becomes a significant challenge in various applications. Phonon modes at interface resulting from the mismatch between inhomogeneous functional counterparts are crucial for interfacial thermal transport and overall thermal management of micro/nano-devices, making it a topic of great research interest recently. Here, we comprehensively review the recent advances on the theoretical and experimental investigations of interfacial phonon mode and its impact on interfacial thermal transport. Firstly, we summarize the recent progresses of the theoretical and experimental characterization of interfacial phonon modes at various interfaces, along with the overview of the development of diverse methodologies. Then, the impact of interfacial phonon modes on interfacial thermal transport process are discussed from the normal modal decomposition and inelastic scattering mechanisms. Meanwhile, we examine various factors influencing the interfacial phonon modes and interfacial thermal transport, including temperature, interface roughness, interfacial mass gradient, interfacial disorder, and so on. Finally, an outlook is provided for future studies. This review provides a fundamental understanding of interfacial phonon modes and their impact on interfacial thermal transport, which would be beneficial for the exploration and optimization of thermal management in various micro/nano-devices with high density interfaces.
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Affiliation(s)
- Shuyue Shan
- Center for Phononics and Thermal Energy Science, China-EU Joint Lab for Nanophononics, MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Zhongwei Zhang
- Center for Phononics and Thermal Energy Science, China-EU Joint Lab for Nanophononics, MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Sebastian Volz
- Laboratory for Integrated Micro and Mechatronic Systems, CNRS-IIS UMI 2820, The University of Tokyo, Tokyo 153-8505, Japan
| | - Jie Chen
- Center for Phononics and Thermal Energy Science, China-EU Joint Lab for Nanophononics, MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
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2
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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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3
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Di Giulio V, Akerboom E, Polman A, García de Abajo FJ. Toward Optimum Coupling between Free Electrons and Confined Optical Modes. ACS NANO 2024; 18:14255-14275. [PMID: 38775711 PMCID: PMC11155252 DOI: 10.1021/acsnano.3c12977] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/10/2024] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Free electrons are excellent tools to probe and manipulate nanoscale optical fields with emerging applications in ultrafast spectromicroscopy and quantum metrology. However, advances in this field are hindered by the small probability associated with the excitation of single optical modes by individual free electrons. Here, we theoretically investigate the scaling properties of the electron-driven excitation probability for a wide variety of optical modes including plasmons in metallic nanostructures and Mie resonances in dielectric cavities, spanning a broad spectral range that extends from the ultraviolet to the infrared region. The highest probabilities for the direct generation of three-dimensionally confined modes are observed at low electron and mode energies in small structures, with order-unity (∼100%) coupling demanding the use of <100 eV electrons interacting with eV polaritons confined down to tens of nanometers in space. Electronic transitions in artificial atoms also emerge as practical systems to realize strong coupling to few-eV free electrons. In contrast, conventional dielectric cavities reach a maximum probability in the few-percent range. In addition, we show that waveguide modes can be generated with higher-than-unity efficiency by phase-matched interaction with grazing electrons, suggesting a practical method to create multiple excitations of a localized optical mode by an individual electron through funneling the so-generated propagating photons into a confining cavity─an alternative approach to direct electron-cavity interaction. Our work provides a roadmap to optimize electron-photon coupling with potential applications in electron spectromicroscopy as well as nonlinear and quantum optics at the nanoscale.
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Affiliation(s)
- Valerio Di Giulio
- The
Barcelona Institute of Science and Technology, Institut de Ciencies Fotoniques-ICFO, 08860 Castelldefels (Barcelona), Spain
| | - Evelijn Akerboom
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Albert Polman
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - F. Javier García de Abajo
- The
Barcelona Institute of Science and Technology, Institut de Ciencies Fotoniques-ICFO, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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4
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Bugnet M, Löffler S, Ederer M, Kepaptsoglou DM, Ramasse QM. Current opinion on the prospect of mapping electronic orbitals in the transmission electron microscope: State of the art, challenges and perspectives. J Microsc 2024. [PMID: 38818951 DOI: 10.1111/jmi.13321] [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: 02/05/2024] [Revised: 05/03/2024] [Accepted: 05/08/2024] [Indexed: 06/01/2024]
Abstract
The concept of electronic orbitals has enabled the understanding of a wide range of physical and chemical properties of solids through the definition of, for example, chemical bonding between atoms. In the transmission electron microscope, which is one of the most used and powerful analytical tools for high-spatial-resolution analysis of solids, the accessible quantity is the local distribution of electronic states. However, the interpretation of electronic state maps at atomic resolution in terms of electronic orbitals is far from obvious, not always possible, and often remains a major hurdle preventing a better understanding of the properties of the system of interest. In this review, the current state of the art of the experimental aspects for electronic state mapping and its interpretation as electronic orbitals is presented, considering approaches that rely on elastic and inelastic scattering, in real and reciprocal spaces. This work goes beyond resolving spectral variations between adjacent atomic columns, as it aims at providing deeper information about, for example, the spatial or momentum distributions of the states involved. The advantages and disadvantages of existing experimental approaches are discussed, while the challenges to overcome and future perspectives are explored in an effort to establish the current state of knowledge in this field. The aims of this review are also to foster the interest of the scientific community and to trigger a global effort to further enhance the current analytical capabilities of transmission electron microscopy for chemical bonding and electronic structure analysis.
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Affiliation(s)
- M Bugnet
- CNRS, INSA Lyon, Université Claude Bernard Lyon 1, MATEIS, UMR 5510, Villeurbanne, France
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, UK
- School of Chemical and Process Engineering, University of Leeds, Leeds, UK
| | - S Löffler
- University Service Centre for Transmission Electron Microscopy, TU Wien, Wien, Austria
| | - M Ederer
- University Service Centre for Transmission Electron Microscopy, TU Wien, Wien, Austria
| | - D M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, UK
- School of Physics, Engineering and Technology, University of York, York, UK
| | - Q M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, UK
- School of Chemical and Process Engineering, University of Leeds, Leeds, UK
- School of Physics and Astronomy, University of Leeds, Leeds, UK
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5
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Shi R, Li Q, Xu X, Han B, Zhu R, Liu F, Qi R, Zhang X, Du J, Chen J, Yu D, Zhu X, Guo J, Gao P. Atomic-scale observation of localized phonons at FeSe/SrTiO 3 interface. Nat Commun 2024; 15:3418. [PMID: 38653990 DOI: 10.1038/s41467-024-47688-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 04/03/2024] [Indexed: 04/25/2024] Open
Abstract
In single unit-cell FeSe grown on SrTiO3, the superconductivity transition temperature features a significant enhancement. Local phonon modes at the interface associated with electron-phonon coupling may play an important role in the interface-induced enhancement. However, such phonon modes have eluded direct experimental observations. The complicated atomic structure of the interface brings challenges to obtain the accurate structure-phonon relation knowledge. Here, we achieve direct characterizations of atomic structure and phonon modes at the FeSe/SrTiO3 interface with atomically resolved imaging and electron energy loss spectroscopy in an electron microscope. We find several phonon modes highly localized (~1.3 nm) at the unique double layer Ti-O terminated interface, one of which (~ 83 meV) engages in strong interactions with the electrons in FeSe based on ab initio calculations. This finding of the localized interfacial phonon associated with strong electron-phonon coupling provides new insights into understanding the origin of superconductivity enhancement at the FeSe/SrTiO3 interface.
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Affiliation(s)
- Ruochen Shi
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
| | - Qize Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA
| | - Xiaofeng Xu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bo Han
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
| | - Ruixue Zhu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
| | - Fachen Liu
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Ruishi Qi
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA
| | - Xiaowen Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
| | - Jinlong Du
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
| | - Ji Chen
- Institute of Condensed Matter and Material Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, 100871, China
| | - Dapeng Yu
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China
- Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen, 518055, China
- Hefei National Laboratory, 230088, Hefei, China
| | - Xuetao Zhu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Jiandong Guo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Peng Gao
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China.
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 100871, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, 100871, China.
- Hefei National Laboratory, 230088, Hefei, China.
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Yan J, Shi R, Wei J, Li Y, Qi R, Wu M, Li X, Feng B, Gao P, Shibata N, Ikuhara Y. Nanoscale Localized Phonons at Al 2O 3 Grain Boundaries. NANO LETTERS 2024; 24:3323-3330. [PMID: 38466652 DOI: 10.1021/acs.nanolett.3c04149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Nanoscale defects like grain boundaries (GBs) would introduce local phonon modes and affect the bulk materials' thermal, electrical, optical, and mechanical properties. It is highly desirable to correlate the phonon modes and atomic arrangements for individual defects to precisely understand the structure-property relation. Here we investigated the localized phonon modes of Al2O3 GBs by combination of the vibrational electron energy loss spectroscopy (EELS) in scanning transmission electron microscope and density functional perturbation theory (DFPT). The differences between GB and bulk obtained from the vibrational EELS show that the GB exhibited more active vibration at the energy range of <50 meV and >80 meV, and further DFPT results proved the wide distribution of bond lengths at GB are the main factor for the emergence of local phonon modes. This research provides insights into the phonon-defect relation and would be of importance in the design and application of polycrystalline materials.
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Affiliation(s)
- Jingyuan Yan
- Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
| | - Ruochen Shi
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
- International Center for Quantum Materials, Peking University, Beijing 100871, China
| | - Jiake Wei
- Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yuehui Li
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
- International Center for Quantum Materials, Peking University, Beijing 100871, China
| | - Ruishi Qi
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
- International Center for Quantum Materials, Peking University, Beijing 100871, China
- Department of Physics, University of California at Berkeley, Berkeley 94720, California, United States
| | - Mei Wu
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
- International Center for Quantum Materials, Peking University, Beijing 100871, China
| | - Xiaomei Li
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
- School of Integrated Circuits, East China Normal University, Shanghai 200241, China
| | - Bin Feng
- Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
| | - Peng Gao
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
- International Center for Quantum Materials, Peking University, Beijing 100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, China
| | - Naoya Shibata
- Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
| | - Yuichi Ikuhara
- Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
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7
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Moradifar P, Liu Y, Shi J, Siukola Thurston ML, Utzat H, van Driel TB, Lindenberg AM, Dionne JA. Accelerating Quantum Materials Development with Advances in Transmission Electron Microscopy. Chem Rev 2023. [PMID: 37979189 DOI: 10.1021/acs.chemrev.2c00917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2023]
Abstract
Quantum materials are driving a technology revolution in sensing, communication, and computing, while simultaneously testing many core theories of the past century. Materials such as topological insulators, complex oxides, superconductors, quantum dots, color center-hosting semiconductors, and other types of strongly correlated materials can exhibit exotic properties such as edge conductivity, multiferroicity, magnetoresistance, superconductivity, single photon emission, and optical-spin locking. These emergent properties arise and depend strongly on the material's detailed atomic-scale structure, including atomic defects, dopants, and lattice stacking. In this review, we describe how progress in the field of electron microscopy (EM), including in situ and in operando EM, can accelerate advances in quantum materials and quantum excitations. We begin by describing fundamental EM principles and operation modes. We then discuss various EM methods such as (i) EM spectroscopies, including electron energy loss spectroscopy (EELS), cathodoluminescence (CL), and electron energy gain spectroscopy (EEGS); (ii) four-dimensional scanning transmission electron microscopy (4D-STEM); (iii) dynamic and ultrafast EM (UEM); (iv) complementary ultrafast spectroscopies (UED, XFEL); and (v) atomic electron tomography (AET). We describe how these methods could inform structure-function relations in quantum materials down to the picometer scale and femtosecond time resolution, and how they enable precision positioning of atomic defects and high-resolution manipulation of quantum materials. For each method, we also describe existing limitations to solve open quantum mechanical questions, and how they might be addressed to accelerate progress. Among numerous notable results, our review highlights how EM is enabling identification of the 3D structure of quantum defects; measuring reversible and metastable dynamics of quantum excitations; mapping exciton states and single photon emission; measuring nanoscale thermal transport and coupled excitation dynamics; and measuring the internal electric field and charge density distribution of quantum heterointerfaces- all at the quantum materials' intrinsic atomic and near atomic-length scale. We conclude by describing open challenges for the future, including achieving stable sample holders for ultralow temperature (below 10K) atomic-scale spatial resolution, stable spectrometers that enable meV energy resolution, and high-resolution, dynamic mapping of magnetic and spin fields. With atomic manipulation and ultrafast characterization enabled by EM, quantum materials will be poised to integrate into many of the sustainable and energy-efficient technologies needed for the 21st century.
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Affiliation(s)
- Parivash Moradifar
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Yin Liu
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jiaojian Shi
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road MS69, Menlo Park, California 94025, United States
| | | | - Hendrik Utzat
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Tim B van Driel
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Aaron M Lindenberg
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road MS69, Menlo Park, California 94025, United States
| | - Jennifer A Dionne
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Radiology, Stanford University, Stanford, California 94305, United States
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8
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Yannai M, Adiv Y, Dahan R, Wang K, Gorlach A, Rivera N, Fishman T, Krüger M, Kaminer I. Lossless Monochromator in an Ultrafast Electron Microscope Using Near-Field THz Radiation. PHYSICAL REVIEW LETTERS 2023; 131:145002. [PMID: 37862634 DOI: 10.1103/physrevlett.131.145002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 07/03/2023] [Accepted: 08/21/2023] [Indexed: 10/22/2023]
Abstract
The ability to form monoenergetic electron beams is vital for high-resolution electron spectroscopy and imaging. Such capabilities are commonly achieved using an electron monochromator, which energy filters a dispersed electron beam, thus reducing the electron flux to yield down to meV energy resolution. This reduction in flux hinders the use of monochromators in many applications, such as ultrafast transmission electron microscopes (UTEMs). Here, we develop and demonstrate a mechanism for electron energy monochromation that does not reduce the flux-a lossless monochromator. The mechanism is based on the interaction of free-electron pulses with single-cycle THz near fields, created by nonlinear conversion of an optical laser pulse near the electron beam path inside a UTEM. Our experiment reduces the electron energy spread by a factor of up to 2.9 without compromising the beam flux. Moreover, as the electron-THz interaction takes place over an extended region of many tens of microns in free space, the realized technique is highly robust-granting uniform monochromation over a wide area, larger than the electron beam diameter. We further demonstrate the wide tunability of our method by monochromating the electron beam at multiple primary electron energies from 60 to 200 keV, studying the effect of various electron and THz parameters on its performance. Our findings have direct applications in the fast-growing field of ultrafast electron microscopy, allowing time- and energy-resolved studies of exciton physics, phononic vibrational resonances, charge transport effects, and optical excitations in the mid IR to the far IR.
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Affiliation(s)
- Michael Yannai
- Faculty of Electrical & Computer Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Yuval Adiv
- Faculty of Electrical & Computer Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Raphael Dahan
- Faculty of Electrical & Computer Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Kangpeng Wang
- Faculty of Electrical & Computer Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201815, China
| | - Alexey Gorlach
- Faculty of Electrical & Computer Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Nicholas Rivera
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Tal Fishman
- Faculty of Electrical & Computer Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Michael Krüger
- Solid State Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Department of Physics, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Ido Kaminer
- Faculty of Electrical & Computer Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel
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9
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Wang Y, Yang S, Crozier PA. Spectroscopic Observation and Modeling of Photonic Modes in CeO2 Nanostructures. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1307-1314. [PMID: 37488821 DOI: 10.1093/micmic/ozad059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 04/24/2023] [Accepted: 05/02/2023] [Indexed: 07/26/2023]
Abstract
Photonic modes in dielectric nanostructures, e.g., wide gap semiconductor like CeO2 (ceria), have the potential for various applications such as information transmission and sensing technology. To fully understand the properties of such phenomenon at the nanoscale, electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope was employed to detect and explore photonic modes in well-defined ceria nanocubes. To facilitate the interpretation of the observations, EELS simulations were performed with finite-element methods. The simulations allow the electric and magnetic field distributions associated with different modes to be determined. A simple analytical eigenfunction model was also used to estimate the energy of the photonic modes. In addition, by comparing various spectra taken at different location relative to the cube, the effect of the surrounding environment on the modes could be sensed. This work gives a high-resolution description of the photonic modes' properties in nanostructures, while demonstrating the advantage of EELS in characterizing optical phenomena locally.
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Affiliation(s)
- Yifan Wang
- School for Engineering of Matter, Transport & Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287, USA
| | - Shize Yang
- Eyring Materials Center, Arizona State University, 1001 S McAllister Ave, Tempe, AZ 85287-8301, USA
| | - Peter A Crozier
- School for Engineering of Matter, Transport & Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287, USA
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10
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Xu M, Bao DL, Li A, Gao M, Meng D, Li A, Du S, Su G, Pennycook SJ, Pantelides ST, Zhou W. Single-atom Vibrational Spectroscopy with Chemical Bonding Sensitivity. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:616-617. [PMID: 37613043 DOI: 10.1093/micmic/ozad067.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Mingquan Xu
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - De-Liang Bao
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Aowen Li
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Meng Gao
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Dongqian Meng
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Ang Li
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Shixuan Du
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Gang Su
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Stephen J Pennycook
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Sokrates T Pantelides
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN, USA
| | - Wu Zhou
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
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11
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Wang X, Gadre C, Yan X, Pan X. Optimal Sample Thickness for Dark-field Vibrational Electron Energy Loss Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1788-1789. [PMID: 37613900 DOI: 10.1093/micmic/ozad067.925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Xiaowang Wang
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Chaitanya Gadre
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Xingxu Yan
- Department of Materials Science and Engineering, University of California, Irvine, CA, United States
- Irvine Materials Research Institute, University of California-Irvine, Irvine, CA, United States
| | - Xiaoqing Pan
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
- Department of Materials Science and Engineering, University of California, Irvine, CA, United States
- Irvine Materials Research Institute, University of California-Irvine, Irvine, CA, United States
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12
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Lee T, Qi J, Gadre CA, Huyan H, Ko ST, Zuo Y, Du C, Li J, Aoki T, Wu R, Luo J, Ong SP, Pan X. Atomic-scale Origin of the Low Grain-boundary Resistance in Perovskite Solid Electrolyte Li0.375Sr0.4375Ta0.75Zr0.25O3. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1267-1269. [PMID: 37613147 DOI: 10.1093/micmic/ozad067.649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Tom Lee
- Department of Materials Science and Engineering, University of California at Irvine, Irvine, CA, United States
| | - Ji Qi
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, United States
| | - Chaitanya A Gadre
- Department of Physics and Astronomy, University of California at Irvine, Irvine, CA, United States
| | - Huaixun Huyan
- Department of Materials Science and Engineering, University of California at Irvine, Irvine, CA, United States
| | - Shu-Ting Ko
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, United States
| | - Yunxing Zuo
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, United States
| | - Chaojie Du
- Department of Materials Science and Engineering, University of California at Irvine, Irvine, CA, United States
| | - Jie Li
- Department of Physics and Astronomy, University of California at Irvine, Irvine, CA, United States
| | - Toshihiro Aoki
- Irvine Materials Research Institute, University of California at Irvine, Irvine, CA, United States
| | - Ruqian Wu
- Department of Physics and Astronomy, University of California at Irvine, Irvine, CA, United States
| | - Jian Luo
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, United States
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, United States
| | - Shyue Ping Ong
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, United States
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of California at Irvine, Irvine, CA, United States
- Department of Physics and Astronomy, University of California at Irvine, Irvine, CA, United States
- Irvine Materials Research Institute, University of California at Irvine, Irvine, CA, United States
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13
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Chao HY, Venkatraman K, Moniri S, Jiang Y, Tang X, Dai S, Gao W, Miao J, Chi M. In Situ and Emerging Transmission Electron Microscopy for Catalysis Research. Chem Rev 2023. [PMID: 37327473 DOI: 10.1021/acs.chemrev.2c00880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Catalysts are the primary facilitator in many dynamic processes. Therefore, a thorough understanding of these processes has vast implications for a myriad of energy systems. The scanning/transmission electron microscope (S/TEM) is a powerful tool not only for atomic-scale characterization but also in situ catalytic experimentation. Techniques such as liquid and gas phase electron microscopy allow the observation of catalysts in an environment conducive to catalytic reactions. Correlated algorithms can greatly improve microscopy data processing and expand multidimensional data handling. Furthermore, new techniques including 4D-STEM, atomic electron tomography, cryogenic electron microscopy, and monochromated electron energy loss spectroscopy (EELS) push the boundaries of our comprehension of catalyst behavior. In this review, we discuss the existing and emergent techniques for observing catalysts using S/TEM. Challenges and opportunities highlighted aim to inspire and accelerate the use of electron microscopy to further investigate the complex interplay of catalytic systems.
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Affiliation(s)
- Hsin-Yun Chao
- Center for Nanophase Materials Sciences, One Bethel Valley Road, Building 4515, Oak Ridge, Tennessee 37831-6064, United States
| | - Kartik Venkatraman
- Center for Nanophase Materials Sciences, One Bethel Valley Road, Building 4515, Oak Ridge, Tennessee 37831-6064, United States
| | - Saman Moniri
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
| | - Yongjun Jiang
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237, China
| | - Xuan Tang
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237, China
| | - Sheng Dai
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237, China
| | - Wenpei Gao
- School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jianwei Miao
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
| | - Miaofang Chi
- Center for Nanophase Materials Sciences, One Bethel Valley Road, Building 4515, Oak Ridge, Tennessee 37831-6064, United States
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14
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Xu M, Bao DL, Li A, Gao M, Meng D, Li A, Du S, Su G, Pennycook SJ, Pantelides ST, Zhou W. Single-atom vibrational spectroscopy with chemical-bonding sensitivity. NATURE MATERIALS 2023; 22:612-618. [PMID: 36928385 DOI: 10.1038/s41563-023-01500-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 02/06/2023] [Indexed: 05/05/2023]
Abstract
Correlation of lattice vibrational properties with local atomic configurations in materials is essential for elucidating functionalities that involve phonon transport in solids. Recent developments in vibrational spectroscopy in a scanning transmission electron microscope have enabled direct measurements of local phonon modes at defects and interfaces by combining high spatial and energy resolution. However, pushing the ultimate limit of vibrational spectroscopy in a scanning transmission electron microscope to reveal the impact of chemical bonding on local phonon modes requires extreme sensitivity of the experiment at the chemical-bond level. Here we demonstrate that, with improved instrument stability and sensitivity, the specific vibrational signals of the same substitutional impurity and the neighbouring carbon atoms in monolayer graphene with different chemical-bonding configurations are clearly resolved, complementary with density functional theory calculations. The present work opens the door to the direct observation of local phonon modes with chemical-bonding sensitivity, and provides more insights into the defect-induced physics in graphene.
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Affiliation(s)
- Mingquan Xu
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - De-Liang Bao
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
| | - Aowen Li
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Meng Gao
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Dongqian Meng
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Ang Li
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Shixuan Du
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China
- Institute of Physics, Chinese Academy of Sciences, Beijing, P. R. China
| | - Gang Su
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Stephen J Pennycook
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Sokrates T Pantelides
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China.
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA.
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN, USA.
| | - Wu Zhou
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, P. R. China.
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15
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Li N, Shi R, Li Y, Qi R, Liu F, Zhang X, Liu Z, Li Y, Guo X, Liu K, Jiang Y, Li XZ, Chen J, Liu L, Wang EG, Gao P. Phonon transition across an isotopic interface. Nat Commun 2023; 14:2382. [PMID: 37185918 PMCID: PMC10130007 DOI: 10.1038/s41467-023-38053-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 04/13/2023] [Indexed: 05/17/2023] Open
Abstract
Isotopic mixtures result in distinct properties of materials such as thermal conductivity and nuclear process. However, the knowledge of isotopic interface remains largely unexplored mainly due to the challenges in atomic-scale isotopic identification. Here, using electron energy-loss spectroscopy in a scanning transmission electron microscope, we reveal momentum-transfer-dependent phonon behavior at the h-10BN/h-11BN isotope heterostructure with sub-unit-cell resolution. We find the phonons' energy changes gradually across the interface, featuring a wide transition regime. Phonons near the Brillouin zone center have a transition regime of ~3.34 nm, whereas phonons at the Brillouin zone boundary have a transition regime of ~1.66 nm. We propose that the isotope-induced charge effect at the interface accounts for the distinct delocalization behavior. Moreover, the variation of phonon energy between atom layers near the interface depends on both of momentum transfer and mass change. This study provides new insights into the isotopic effects in natural materials.
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Affiliation(s)
- Ning Li
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Ruochen Shi
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
| | - Yifei Li
- School of Materials Science and Engineering, Peking University, 100871, Beijing, China
| | - Ruishi Qi
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA
| | - Fachen Liu
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Xiaowen Zhang
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
| | - Zhetong Liu
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Yuehui Li
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
| | - Xiangdong Guo
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, 100190, Beijing, China
| | - Kaihui Liu
- Institute of Condensed Matter and Material Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Quantum Matter, 100871, Beijing, China
| | - Ying Jiang
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Quantum Matter, 100871, Beijing, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China
| | - Xin-Zheng Li
- Institute of Condensed Matter and Material Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Peking University, 100871, Beijing, China
| | - Ji Chen
- Institute of Condensed Matter and Material Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, 100871, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China.
| | - Lei Liu
- School of Materials Science and Engineering, Peking University, 100871, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China.
| | - En-Ge Wang
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China.
- Songshan Lake Materials Laboratory, 523808, Dongguan, China.
- School of Physics, Shanghai University, 200444, Shanghai, China.
| | - Peng Gao
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China.
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, 100871, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China.
- Hefei National Laboratory, 230088, Hefei, China.
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16
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Rodríguez-Álvarez J, Labarta A, Idrobo JC, Dell'Anna R, Cian A, Giubertoni D, Borrisé X, Guerrero A, Perez-Murano F, Fraile Rodríguez A, Batlle X. Imaging of Antiferroelectric Dark Modes in an Inverted Plasmonic Lattice. ACS NANO 2023; 17:8123-8132. [PMID: 37089111 PMCID: PMC10173685 DOI: 10.1021/acsnano.2c11016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Plasmonic lattice nanostructures are of technological interest because of their capacity to manipulate light below the diffraction limit. Here, we present a detailed study of dark and bright modes in the visible and near-infrared energy regime of an inverted plasmonic honeycomb lattice by a combination of Au+ focused ion beam lithography with nanometric resolution, optical and electron spectroscopy, and finite-difference time-domain simulations. The lattice consists of slits carved in a gold thin film, exhibiting hotspots and a set of bright and dark modes. We proposed that some of the dark modes detected by electron energy-loss spectroscopy are caused by antiferroelectric arrangements of the slit polarizations with two times the size of the hexagonal unit cell. The plasmonic resonances take place within the 0.5-2 eV energy range, indicating that they could be suitable for a synergistic coupling with excitons in two-dimensional transition metal dichalcogenides materials or for designing nanoscale sensing platforms based on near-field enhancement over a metallic surface.
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Affiliation(s)
- Javier Rodríguez-Álvarez
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Amílcar Labarta
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Juan Carlos Idrobo
- Materials Science and Engineering Department, University of Washington, Seattle, Washington 98195, United States
| | - Rossana Dell'Anna
- Sensors & Devices Center, FBK - Bruno Kessler Foundation, via Sommarive, 18, Povo, TN 38123, Italy
| | - Alessandro Cian
- Sensors & Devices Center, FBK - Bruno Kessler Foundation, via Sommarive, 18, Povo, TN 38123, Italy
| | - Damiano Giubertoni
- Sensors & Devices Center, FBK - Bruno Kessler Foundation, via Sommarive, 18, Povo, TN 38123, Italy
| | - Xavier Borrisé
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - Albert Guerrero
- Institut de Microelectrònica de Barcelona (IMB-CNM, CSIC), Bellaterra 08193, Spain
| | | | - Arantxa Fraile Rodríguez
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Xavier Batlle
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
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17
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Lee T, Qi J, Gadre CA, Huyan H, Ko ST, Zuo Y, Du C, Li J, Aoki T, Wu R, Luo J, Ong SP, Pan X. Atomic-scale origin of the low grain-boundary resistance in perovskite solid electrolyte Li 0.375Sr 0.4375Ta 0.75Zr 0.25O 3. Nat Commun 2023; 14:1940. [PMID: 37024455 PMCID: PMC10079928 DOI: 10.1038/s41467-023-37115-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 03/02/2023] [Indexed: 04/08/2023] Open
Abstract
Oxide solid electrolytes (OSEs) have the potential to achieve improved safety and energy density for lithium-ion batteries, but their high grain-boundary (GB) resistance generally is a bottleneck. In the well-studied perovskite oxide solid electrolyte, Li3xLa2/3-xTiO3 (LLTO), the ionic conductivity of grain boundaries is about three orders of magnitude lower than that of the bulk. In contrast, the related Li0.375Sr0.4375Ta0.75Zr0.25O3 (LSTZ0.75) perovskite exhibits low grain boundary resistance for reasons yet unknown. Here, we use aberration-corrected scanning transmission electron microscopy and spectroscopy, along with an active learning moment tensor potential, to reveal the atomic scale structure and composition of LSTZ0.75 grain boundaries. Vibrational electron energy loss spectroscopy is applied for the first time to reveal atomically resolved vibrations at grain boundaries of LSTZ0.75 and to characterize the otherwise unmeasurable Li distribution therein. We find that Li depletion, which is a major reason for the low grain boundary ionic conductivity of LLTO, is absent for the grain boundaries of LSTZ0.75. Instead, the low grain boundary resistivity of LSTZ0.75 is attributed to the formation of a nanoscale defective cubic perovskite interfacial structure that contained abundant vacancies. Our study provides new insights into the atomic scale mechanisms of low grain boundary resistivity.
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Affiliation(s)
- Tom Lee
- Department of Materials Science and Engineering, University of California at Irvine, Irvine, CA, USA
| | - Ji Qi
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Chaitanya A Gadre
- Department of Physics and Astronomy, University of California at Irvine, Irvine, CA, USA
| | - Huaixun Huyan
- Department of Materials Science and Engineering, University of California at Irvine, Irvine, CA, USA
| | - Shu-Ting Ko
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Yunxing Zuo
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Chaojie Du
- Department of Materials Science and Engineering, University of California at Irvine, Irvine, CA, USA
| | - Jie Li
- Department of Physics and Astronomy, University of California at Irvine, Irvine, CA, USA
| | - Toshihiro Aoki
- Irvine Materials Research Institute, University of California at Irvine, Irvine, CA, USA
| | - Ruqian Wu
- Department of Physics and Astronomy, University of California at Irvine, Irvine, CA, USA.
| | - Jian Luo
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA.
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA.
| | - Shyue Ping Ong
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA.
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of California at Irvine, Irvine, CA, USA.
- Department of Physics and Astronomy, University of California at Irvine, Irvine, CA, USA.
- Irvine Materials Research Institute, University of California at Irvine, Irvine, CA, USA.
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18
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Kisielowski C, Specht P, Helveg S, Chen FR, Freitag B, Jinschek J, Van Dyck D. Probing the Boundary between Classical and Quantum Mechanics by Analyzing the Energy Dependence of Single-Electron Scattering Events at the Nanoscale. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:971. [PMID: 36985865 PMCID: PMC10051121 DOI: 10.3390/nano13060971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
The relation between the energy-dependent particle and wave descriptions of electron-matter interactions on the nanoscale was analyzed by measuring the delocalization of an evanescent field from energy-filtered amplitude images of sample/vacuum interfaces with a special aberration-corrected electron microscope. The spatial field extension coincided with the energy-dependent self-coherence length of propagating wave packets that obeyed the time-dependent Schrödinger equation, and underwent a Goos-Hänchen shift. The findings support the view that wave packets are created by self-interferences during coherent-inelastic Coulomb interactions with a decoherence phase close to Δφ = 0.5 rad. Due to a strictly reciprocal dependence on energy, the wave packets shrink below atomic dimensions for electron energy losses beyond 1000 eV, and thus appear particle-like. Consequently, our observations inevitably include pulse-like wave propagations that stimulate structural dynamics in nanomaterials at any electron energy loss, which can be exploited to unravel time-dependent structure-function relationships on the nanoscale.
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Affiliation(s)
- Christian Kisielowski
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Rd., Berkeley, CA 94720, USA
| | - Petra Specht
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720, USA
| | - Stig Helveg
- Center for Visualizing Catalytic Processes (VISION), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Fu-Rong Chen
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Bert Freitag
- Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands
| | - Joerg Jinschek
- National Centre for Nano Fabrication and Characterization (DTU Nanolab), Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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19
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Du J, Chen JH, Li Y, Shi R, Wu M, Xiao YF, Gao P. Electron Microscopy Probing Electron-Photon Interactions in SiC Nanowires with Ultrawide Energy and Momentum Match. NANO LETTERS 2022; 22:6207-6214. [PMID: 35905393 DOI: 10.1021/acs.nanolett.2c01672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Light-matter interactions are commonly probed by optical spectroscopy, which, however, has some fundamental limitations such as diffraction-limited spatial resolution, tiny momentum transfer, and noncontinuous excitation/detection. In this work, through the use of scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) with ultrawide energy and momentum match and subnanometer spatial resolution, the longitudinal Fabry-Perot (FP) resonating modes and the transverse whispering-gallery modes (WGMs) in individual SiC nanowires are simultaneously excited and detected, which span from near-infrared (∼1.2 μm) to ultraviolet (∼0.2 μm) spectral regime, and the momentum transfer can range up to 108 cm-1. The size effects on the resonant spectra of nanowires are also revealed. This work provides an alternative technique to optical resonating spectroscopy and light-matter interactions in dielectric nanostructures, which is promising for modulating free electrons via photonic structures.
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Affiliation(s)
- Jinlong Du
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing100871, China
| | - Jin-Hui Chen
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing100871, China
- Institute of Electromagnetics and Acoustics, Xiamen University, Xiamen361005, China
| | - Yuehui Li
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing100871, China
- International Center for Quantum Materials, Peking University, Beijing100871, China
| | - Ruochen Shi
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing100871, China
- International Center for Quantum Materials, Peking University, Beijing100871, China
| | - Mei Wu
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing100871, China
- International Center for Quantum Materials, Peking University, Beijing100871, China
| | - Yun-Feng Xiao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing100871, China
| | - Peng Gao
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing100871, China
- International Center for Quantum Materials, Peking University, Beijing100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing100871, China
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20
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Sub-nanometer mapping of strain-induced band structure variations in planar nanowire core-shell heterostructures. Nat Commun 2022; 13:4089. [PMID: 35835772 PMCID: PMC9283334 DOI: 10.1038/s41467-022-31778-3] [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: 01/12/2022] [Accepted: 07/01/2022] [Indexed: 11/22/2022] Open
Abstract
Strain relaxation mechanisms during epitaxial growth of core-shell nanostructures play a key role in determining their morphologies, crystal structure and properties. To unveil those mechanisms, we perform atomic-scale aberration-corrected scanning transmission electron microscopy studies on planar core-shell ZnSe@ZnTe nanowires on α-Al2O3 substrates. The core morphology affects the shell structure involving plane bending and the formation of low-angle polar boundaries. The origin of this phenomenon and its consequences on the electronic band structure are discussed. We further use monochromated valence electron energy-loss spectroscopy to obtain spatially resolved band-gap maps of the heterostructure with sub-nanometer spatial resolution. A decrease in band-gap energy at highly strained core-shell interfacial regions is found, along with a switch from direct to indirect band-gap. These findings represent an advance in the sub-nanometer-scale understanding of the interplay between structure and electronic properties associated with highly mismatched semiconductor heterostructures, especially with those related to the planar growth of heterostructured nanowire networks. Planar growth of nanowire arrays involves interactions between materials that affect the electronic behavior of the effective heterojunction. Here, authors show how core curvature and cross-section morphology affect shell growth, demonstrating how strain at the core-shell interface induces electronic band modulations in ZnSe@ZnTe nanowires.
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Gadre CA, Yan X, Song Q, Li J, Gu L, Huyan H, Aoki T, Lee SW, Chen G, Wu R, Pan X. Nanoscale imaging of phonon dynamics by electron microscopy. Nature 2022; 606:292-297. [PMID: 35676428 PMCID: PMC9177420 DOI: 10.1038/s41586-022-04736-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 04/07/2022] [Indexed: 11/08/2022]
Abstract
Spatially resolved vibrational mapping of nanostructures is indispensable to the development and understanding of thermal nanodevices1, modulation of thermal transport2 and novel nanostructured thermoelectric materials3-5. Through the engineering of complex structures, such as alloys, nanostructures and superlattice interfaces, one can significantly alter the propagation of phonons and suppress material thermal conductivity while maintaining electrical conductivity2. There have been no correlative experiments that spatially track the modulation of phonon properties in and around nanostructures due to spatial resolution limitations of conventional optical phonon detection techniques. Here we demonstrate two-dimensional spatial mapping of phonons in a single silicon-germanium (SiGe) quantum dot (QD) using monochromated electron energy loss spectroscopy in the transmission electron microscope. Tracking the variation of the Si optical mode in and around the QD, we observe the nanoscale modification of the composition-induced red shift. We observe non-equilibrium phonons that only exist near the interface and, furthermore, develop a novel technique to differentially map phonon momenta, providing direct evidence that the interplay between diffuse and specular reflection largely depends on the detailed atomistic structure: a major advancement in the field. Our work unveils the non-equilibrium phonon dynamics at nanoscale interfaces and can be used to study actual nanodevices and aid in the understanding of heat dissipation near nanoscale hotspots, which is crucial for future high-performance nanoelectronics.
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Affiliation(s)
- Chaitanya A Gadre
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
| | - Xingxu Yan
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, USA
- Irvine Materials Research Institute, University of California Irvine, Irvine, CA, USA
| | - Qichen Song
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jie Li
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
| | - Lei Gu
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
| | - Huaixun Huyan
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, USA
| | - Toshihiro Aoki
- Irvine Materials Research Institute, University of California Irvine, Irvine, CA, USA
| | - Sheng-Wei Lee
- Institute of Materials Science and Engineering, National Central University, Taoyuan, Taiwan
| | - Gang Chen
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ruqian Wu
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
| | - Xiaoqing Pan
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA.
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, USA.
- Irvine Materials Research Institute, University of California Irvine, Irvine, CA, USA.
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22
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Mendis BG. Quantum theory of magnon excitation by high energy electron beams. Ultramicroscopy 2022; 239:113548. [DOI: 10.1016/j.ultramic.2022.113548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/25/2022] [Accepted: 05/04/2022] [Indexed: 10/18/2022]
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Rez P, Boland T, Elsässer C, Singh A. Localized Phonon Densities of States at Grain Boundaries in Silicon. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-8. [PMID: 35293309 DOI: 10.1017/s143192762200040x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Since it is now possible to record vibrational spectra at nanometer scales in the electron microscope, it is of interest to explore whether extended defects in crystals such as dislocations or grain boundaries will result in measurable changes of the phonon densities of states (dos) that are reflected in the spectra. Phonon densities of states were calculated for a set of high angle grain boundaries in silicon. The boundaries are modeled by supercells with up to 160 atoms, and the vibrational densities of states were calculated by taking the Fourier transform of the velocity–velocity autocorrelation function from molecular dynamics simulations with larger supercells doubled in all three directions. In selected cases, the results were checked on the original supercells by comparison with the densities of states obtained by diagonalizing the dynamical matrix calculated using density functional theory. Near the core of the grain boundary, the height of the optic phonon peak in the dos at 60 meV was suppressed relative to features due to acoustic phonons that are largely unchanged relative to their bulk values. This can be attributed to the variation in the strength of bonds in grain boundary core regions where there is a range of bond lengths.
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Affiliation(s)
- Peter Rez
- Department of Physics, Arizona State University, Tempe, AZ85287-1504, USA
| | - Tara Boland
- School For Engineering of Matter Transport and Energy, Arizona State University, Tempe, AZ85287-6106, USA
| | - Christian Elsässer
- Fraunhofer Institute for Mechanics of Materials IWM, Wöhlerstraße 11, 79108Freiburg, Germany
| | - Arunima Singh
- Department of Physics, Arizona State University, Tempe, AZ85287-1504, USA
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Atomic-scale probing of heterointerface phonon bridges in nitride semiconductor. Proc Natl Acad Sci U S A 2022; 119:2117027119. [PMID: 35181607 PMCID: PMC8872775 DOI: 10.1073/pnas.2117027119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2022] [Indexed: 11/18/2022] Open
Abstract
Interface phonon modes that are generated by several atomic layers at the heterointerface play a major role in the interface thermal conductance for nanoscale high-power devices such as nitride-based high-electron-mobility transistors and light-emitting diodes. Here we measure the local phonon spectra across AlN/Si and AlN/Al interfaces using atomically resolved vibrational electron energy-loss spectroscopy in a scanning transmission electron microscope. At the AlN/Si interface, we observe various interface phonon modes, of which the extended and localized modes act as bridges to connect the bulk AlN modes and bulk Si modes and are expected to boost the phonon transport, thus substantially contributing to interface thermal conductance. In comparison, no such phonon bridge is observed at the AlN/Al interface, for which partially extended modes dominate the interface thermal conductivity. This work provides valuable insights into understanding the interfacial thermal transport in nitride semiconductors and useful guidance for thermal management via interface engineering.
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Ko W, Gai Z, Puretzky AA, Liang L, Berlijn T, Hachtel JA, Xiao K, Ganesh P, Yoon M, Li AP. Understanding Heterogeneities in Quantum Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2106909. [PMID: 35170112 DOI: 10.1002/adma.202106909] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Quantum materials are usually heterogeneous, with structural defects, impurities, surfaces, edges, interfaces, and disorder. These heterogeneities are sometimes viewed as liabilities within conventional systems; however, their electronic and magnetic structures often define and affect the quantum phenomena such as coherence, interaction, entanglement, and topological effects in the host system. Therefore, a critical need is to understand the roles of heterogeneities in order to endow materials with new quantum functions for energy and quantum information science applications. In this article, several representative examples are reviewed on the recent progress in connecting the heterogeneities to the quantum behaviors of real materials. Specifically, three intertwined topic areas are assessed: i) Reveal the structural, electronic, magnetic, vibrational, and optical degrees of freedom of heterogeneities. ii) Understand the effect of heterogeneities on the behaviors of quantum states in host material systems. iii) Control heterogeneities for new quantum functions. This progress is achieved by establishing the atomistic-level structure-property relationships associated with heterogeneities in quantum materials. The understanding of the interactions between electronic, magnetic, photonic, and vibrational states of heterogeneities enables the design of new quantum materials, including topological matter and quantum light emitters based on heterogenous 2D materials.
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Affiliation(s)
- Wonhee Ko
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Zheng Gai
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Tom Berlijn
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Mina Yoon
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - An-Ping Li
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
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26
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Hoglund ER, Bao DL, O'Hara A, Makarem S, Piontkowski ZT, Matson JR, Yadav AK, Haislmaier RC, Engel-Herbert R, Ihlefeld JF, Ravichandran J, Ramesh R, Caldwell JD, Beechem TE, Tomko JA, Hachtel JA, Pantelides ST, Hopkins PE, Howe JM. Emergent interface vibrational structure of oxide superlattices. Nature 2022; 601:556-561. [PMID: 35082421 PMCID: PMC8791828 DOI: 10.1038/s41586-021-04238-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 11/09/2021] [Indexed: 02/05/2023]
Abstract
As the length scales of materials decrease, the heterogeneities associated with interfaces become almost as important as the surrounding materials. This has led to extensive studies of emergent electronic and magnetic interface properties in superlattices1–9. However, the interfacial vibrations that affect the phonon-mediated properties, such as thermal conductivity10,11, are measured using macroscopic techniques that lack spatial resolution. Although it is accepted that intrinsic phonons change near boundaries12,13, the physical mechanisms and length scales through which interfacial effects influence materials remain unclear. Here we demonstrate the localized vibrational response of interfaces in strontium titanate–calcium titanate superlattices by combining advanced scanning transmission electron microscopy imaging and spectroscopy, density functional theory calculations and ultrafast optical spectroscopy. Structurally diffuse interfaces that bridge the bounding materials are observed and this local structure creates phonon modes that determine the global response of the superlattice once the spacing of the interfaces approaches the phonon spatial extent. Our results provide direct visualization of the progression of the local atomic structure and interface vibrations as they come to determine the vibrational response of an entire superlattice. Direct observation of such local atomic and vibrational phenomena demonstrates that their spatial extent needs to be quantified to understand macroscopic behaviour. Tailoring interfaces, and knowing their local vibrational response, provides a means of pursuing designer solids with emergent infrared and thermal responses. The vibrational states emerging at the interface in oxide superlattices are characterized theoretically and at atomic resolution, showing the impact of material length scales on structure and vibrational response.
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Affiliation(s)
- Eric R Hoglund
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA.
| | - De-Liang Bao
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
| | - Andrew O'Hara
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
| | - Sara Makarem
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA
| | | | - Joseph R Matson
- Department of Mechanical Engineering and Electrical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Ajay K Yadav
- Department of Materials Science and Engineering, University of California Berkley, Berkley, CA, USA
| | - Ryan C Haislmaier
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, USA
| | - Roman Engel-Herbert
- Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany.,Institut für Physik, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jon F Ihlefeld
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA
| | - Jayakanth Ravichandran
- Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California Berkley, Berkley, CA, USA
| | - Joshua D Caldwell
- Department of Mechanical Engineering and Electrical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Thomas E Beechem
- Sandia National Laboratories, Albuquerque, NM, USA.,Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA.,School of Mechanical Engineering and the Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - John A Tomko
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| | - Sokrates T Pantelides
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA. .,Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN, USA.
| | - Patrick E Hopkins
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA. .,Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA. .,Department of Physics, University of Virginia, Charlottesville, VA, USA.
| | - James M Howe
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA.
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27
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OUP accepted manuscript. Microscopy (Oxf) 2022; 71:i174-i199. [DOI: 10.1093/jmicro/dfab050] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/20/2021] [Accepted: 01/28/2022] [Indexed: 11/14/2022] Open
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29
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Abstract
The breakdown of translational symmetry at heterointerfaces leads to the emergence of new phonon modes localized at the interface1. These modes have an essential role in thermal and electrical transport properties in devices, especially in miniature ones wherein the interface may dominate the entire response of the device2. Although related theoretical work began decades ago1,3-5, experimental research is totally absent owing to challenges in achieving the combined spatial, momentum and spectral resolutions required to probe localized modes. Here, using the four-dimensional electron energy-loss spectroscopy technique, we directly measure both the local vibrational spectra and the interface phonon dispersion relation for an epitaxial cubic boron nitride/diamond heterointerface. In addition to bulk phonon modes, we observe modes localized at the interface and modes isolated from the interface. These features appear only within approximately one nanometre around the interface. The localized modes observed here are predicted to substantially affect the interface thermal conductance and electron mobility. Our findings provide insights into lattice dynamics at heterointerfaces, and the demonstrated experimental technique should be useful in thermal management, electrical engineering and topological phononics.
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30
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Tsurusawa H, Nakanishi N, Kawano K, Chen Y, Dutka M, Van Leer B, Mizoguchi T. Robotic fabrication of high-quality lamellae for aberration-corrected transmission electron microscopy. Sci Rep 2021; 11:21599. [PMID: 34732755 PMCID: PMC8566590 DOI: 10.1038/s41598-021-00595-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 10/14/2021] [Indexed: 11/09/2022] Open
Abstract
Aberration-corrected scanning transmission electron microscopy (STEM) is widely used for atomic-level imaging of materials but severely requires damage-free and thin samples (lamellae). So far, the preparation of the high-quality lamella from a bulk largely depends on manual processes by a skilled operator. This limits the throughput and repeatability of aberration-corrected STEM experiments. Here, inspired by the recent successes of "robot scientists", we demonstrate robotic fabrication of high-quality lamellae by focused-ion-beam (FIB) with automation software. First, we show that the robotic FIB can prepare lamellae with a high success rate, where the FIB system automatically controls rough-milling, lift-out, and final-thinning processes. Then, we systematically optimized the FIB parameters of the final-thinning process for single crystal Si. The optimized Si lamellae were evaluated by aberration-corrected STEM, showing atomic-level images with 55 pm resolution and quantitative repeatability of the spatial resolution and lamella thickness. We also demonstrate robotic fabrication of high-quality lamellae of SrTiO3 and sapphire, suggesting that the robotic FIB system may be applicable for a wide range of materials. The throughput of the robotic fabrication was typically an hour per lamella. Our robotic FIB will pave the way for the operator-free, high-throughput, and repeatable fabrication of the high-quality lamellae for aberration-corrected STEM.
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Affiliation(s)
- Hideyo Tsurusawa
- Thermo Fisher Scientific, FEI Japan Ltd., 4-12-2, Higashi-Shinagawa, Shinagawa-ku, Tokyo, 140-0002, Japan.
| | - Nobuto Nakanishi
- Thermo Fisher Scientific, FEI Japan Ltd., 4-12-2, Higashi-Shinagawa, Shinagawa-ku, Tokyo, 140-0002, Japan
| | - Kayoko Kawano
- Thermo Fisher Scientific, FEI Japan Ltd., 4-12-2, Higashi-Shinagawa, Shinagawa-ku, Tokyo, 140-0002, Japan
| | - Yiqiang Chen
- Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG, Eindhoven, The Netherlands
| | - Mikhail Dutka
- Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG, Eindhoven, The Netherlands
| | - Brandon Van Leer
- Thermo Fisher Scientific, 5350 NE Dawson Creek Drive, Hillsboro, OR, 97124, USA
| | - Teruyasu Mizoguchi
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
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31
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Ribet SM, Murthy AA, Roth EW, Dos Reis R, Dravid VP. Making the Most of your Electrons: Challenges and Opportunities in Characterizing Hybrid Interfaces with STEM. MATERIALS TODAY (KIDLINGTON, ENGLAND) 2021; 50:100-115. [PMID: 35241968 PMCID: PMC8887695 DOI: 10.1016/j.mattod.2021.05.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Inspired by the unique architectures composed of hard and soft materials in natural and biological systems, synthetic hybrid structures and associated soft-hard interfaces have recently evoked significant interest. Soft matter is typically dominated by fluctuations even at room temperature, while hard matter (which often serves as the substrate or anchor for the soft component) is governed by rigid mechanical behavior. This dichotomy offers considerable opportunities to leverage the disparate properties offered by these components across a wide spectrum spanning from basic science to engineering insights with significant technological overtones. Such hybrid structures, which include polymer nanocomposites, DNA functionalized nanoparticle superlattices and metal organic frameworks to name a few, have delivered promising insights into the areas of catalysis, environmental remediation, optoelectronics, medicine, and beyond. The interfacial structure between these hard and soft phases exists across a variety of length scales and often strongly influence the functionality of hybrid systems. While scanning/transmission electron microscopy (S/TEM) has proven to be a valuable tool for acquiring intricate molecular and nanoscale details of these interfaces, the unusual nature of hybrid composites presents a suite of challenges that make assessing or establishing the classical structure-property relationships especially difficult. These include challenges associated with preparing electron-transparent samples and obtaining sufficient contrast to resolve the interface between dissimilar materials given the dose sensitivity of soft materials. We discuss each of these challenges and supplement a review of recent developments in the field with additional experimental investigations and simulations to present solutions for attaining a nano or atomic-level understanding of these interfaces. These solutions present a host of opportunities for investigating and understanding the role interfaces play in this unique class of functional materials.
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Affiliation(s)
- Stephanie M Ribet
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL
| | - Akshay A Murthy
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL
- International Institute of Nanotechnology, Northwestern University, Evanston, IL
| | - Eric W Roth
- The NUANCE Center, Northwestern University, Evanston, IL
| | - Roberto Dos Reis
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL
- The NUANCE Center, Northwestern University, Evanston, IL
| | - Vinayak P Dravid
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL
- International Institute of Nanotechnology, Northwestern University, Evanston, IL
- The NUANCE Center, Northwestern University, Evanston, IL
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Yu R, Konečná A, de Abajo FJG. Inelastic Scattering of Electron Beams by Nonreciprocal Nanotructures. PHYSICAL REVIEW LETTERS 2021; 127:157404. [PMID: 34678034 DOI: 10.1103/physrevlett.127.157404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Probing optical excitations with high resolution is important for understanding their dynamics and controlling their interaction with other photonic elements. This can be done using state-of-the-art electron microscopes, which provide the means to sample optical excitations with combined meV-sub-nm energy-space resolution. For reciprocal photonic systems, electrons traveling in opposite directions produce identical signals, while this symmetry is broken in nonreciprocal structures. Here, we theoretically investigate this phenomenon by analyzing electron energy-loss spectroscopy (EELS) and cathodoluminescence (CL) for structures consisting of magnetically biased InAs as an instance of gyrotropic nonreciprocal material. We find that the spectral features associated with excitations of InAs films depend on the electron propagation direction in both EELS and CL, and can be tuned by varying the applied magnetic field within a relatively modest subtesla regime. The magnetic field modifies the optical field distribution of the sampled resonances, and this in turn produces a direction-dependent coupling to the electron. The present results pave the way to the use of electron microscope spectroscopies to explore the near-field characteristics of nonreciprocal systems with high spatial resolution.
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Affiliation(s)
- Renwen Yu
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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33
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Mendis BG. A semi-classical theory of magnetic inelastic scattering in transmission electron energy loss spectroscopy. Ultramicroscopy 2021; 230:113390. [PMID: 34555803 DOI: 10.1016/j.ultramic.2021.113390] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 11/30/2022]
Abstract
The feasibility of detecting magnetic excitations using monochromated electron energy loss spectroscopy in the transmission electron microscope is examined. Inelastic scattering cross-sections are derived using a semi-classical electrodynamic model, and applied to AC magnetic susceptibility measurements and magnon characterization. Consideration is given to electron probes with a magnetic moment, such as vortex beams, where additional inelastic scattering can take place due to the change in magnetic potential energy of the incident electron in a non-uniform magnetic field. This so-called 'Stern-Gerlach' energy loss can be used to enhance the strength of the scattering by increasing the orbital angular momentum of the vortex beam, and enables separation of magnetic from non-magnetic (i.e. dielectric) energy losses, thus providing a promising experimental route for detecting magnons. AC magnetic susceptibility measurements are however not feasible using Stern-Gerlach energy losses for a vortex beam.
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Affiliation(s)
- B G Mendis
- Department of Physics, Durham University, South Road, Durham DH1 3LE, UK.
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34
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Liu JJ. Advances and Applications of Atomic-Resolution Scanning Transmission Electron Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-53. [PMID: 34414878 DOI: 10.1017/s1431927621012125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Although scanning transmission electron microscopy (STEM) images of individual heavy atoms were reported 50 years ago, the applications of atomic-resolution STEM imaging became wide spread only after the practical realization of aberration correctors on field-emission STEM/TEM instruments to form sub-Ångstrom electron probes. The innovative designs and advances of electron optical systems, the fundamental understanding of electron–specimen interaction processes, and the advances in detector technology all played a major role in achieving the goal of atomic-resolution STEM imaging of practical materials. It is clear that tremendous advances in computer technology and electronics, image acquisition and processing algorithms, image simulations, and precision machining synergistically made atomic-resolution STEM imaging routinely accessible. It is anticipated that further hardware/software development is needed to achieve three-dimensional atomic-resolution STEM imaging with single-atom chemical sensitivity, even for electron-beam-sensitive materials. Artificial intelligence, machine learning, and big-data science are expected to significantly enhance the impact of STEM and associated techniques on many research fields such as materials science and engineering, quantum and nanoscale science, physics and chemistry, and biology and medicine. This review focuses on advances of STEM imaging from the invention of the field-emission electron gun to the realization of aberration-corrected and monochromated atomic-resolution STEM and its broad applications.
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Affiliation(s)
- Jingyue Jimmy Liu
- Department of Physics, Arizona State University, Tempe, AZ85287, USA
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35
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Venkatraman K, Crozier PA. Role of Convergence and Collection Angles in the Excitation of Long- and Short-Wavelength Phonons with Vibrational Electron Energy-Loss Spectroscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-9. [PMID: 34172104 DOI: 10.1017/s1431927621012034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Current generation electron monochromators employed as attachments to scanning transmission electron microscopes (STEM) offer the ability to obtain vibrational information from materials using electron energy-loss spectroscopy (EELS). We show here that in crystals, long- and short-wavelength phonon modes can be probed simultaneously with on-axis vibrational STEM EELS. The long-wavelength phonons are probed via dipole scattering, while the short-wavelength modes are probed via impact scattering of the incident electrons. The localized character of the short-wavelength modes is demonstrated by scanning the electron beam across the edge of a hexagonal boron nitride nanoparticle. It is found that employing convergence angles that encompass multiple Brillouin zone boundaries enhances the short-wavelength phonon contribution to the vibrational energy-loss spectrum much more than that achieved by employing collection angles that encompass multiple Brillouin zone boundaries. Probing short-wavelength phonons at high spatial resolution with on-axis vibrational STEM EELS will help develop a fundamental connection between vibrational excitations and bonding arrangements at atomic-scale heterogeneities in materials.
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Affiliation(s)
- Kartik Venkatraman
- School for the Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ85287, USA
| | - Peter A Crozier
- School for the Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ85287, USA
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36
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Konečná A, Iyikanat F, García de Abajo FJ. Theory of Atomic-Scale Vibrational Mapping and Isotope Identification with Electron Beams. ACS NANO 2021; 15:9890-9899. [PMID: 34006088 DOI: 10.1021/acsnano.1c01071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Transmission electron microscopy and spectroscopy currently enable the acquisition of spatially resolved spectral information from a specimen by focusing electron beams down to a sub-angstrom spot and then analyzing the energy of the inelastically scattered electrons with few-meV energy resolution. This technique has recently been used to experimentally resolve vibrational modes in 2D materials emerging at mid-infrared frequencies. Here, on the basis of first-principles theory, we demonstrate the possibility of identifying single isotope atom impurities in a nanostructure through the trace that they leave in the spectral and spatial characteristics of the vibrational modes. Specifically, we examine a hexagonal boron nitride molecule as an example of application, in which the presence of a single isotope impurity is revealed through changes in the electron spectra, as well as in the space-, energy-, and momentum-resolved inelastic electron signal. We compare these results with conventional far-field spectroscopy, showing that electron beams offer superior spatial resolution combined with the ability to probe the complete set of vibrational modes, including those that are optically dark. Our study is relevant for the atomic-scale characterization of vibrational modes in materials of interest, including a detailed mapping of isotope distributions.
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Affiliation(s)
- Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Fadil Iyikanat
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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37
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Madsen J, Susi T. The abTEM code: transmission electron microscopy from first principles. OPEN RESEARCH EUROPE 2021; 1:24. [PMID: 37645137 PMCID: PMC10446032 DOI: 10.12688/openreseurope.13015.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/18/2021] [Indexed: 09/27/2023]
Abstract
Simulation of transmission electron microscopy (TEM) images or diffraction patterns is often required to interpret experimental data. Since nuclear cores dominate electron scattering, the scattering potential is typically described using the independent atom model, which completely neglects valence bonding and its effect on the transmitting electrons. As instrumentation has advanced, new measurements have revealed subtle details of the scattering potential that were previously not accessible to experiment. We have created an open-source simulation code designed to meet these demands by integrating the ability to calculate the potential via density functional theory (DFT) with a flexible modular software design. abTEM can simulate most standard imaging modes and incorporates the latest algorithmic developments. The development of new techniques requires a program that is accessible to domain experts without extensive programming experience. abTEM is written purely in Python and designed for easy modification and extension. The effective use of modern open-source libraries makes the performance of abTEM highly competitive with existing optimized codes on both CPUs and GPUs and allows us to leverage an extensive ecosystem of libraries, such as the Atomic Simulation Environment and the DFT code GPAW. abTEM is designed to work in an interactive Python notebook, creating a seamless and reproducible workflow from defining an atomic structure, calculating molecular dynamics (MD) and electrostatic potentials, to the analysis of results, all in a single, easy-to-read document. This article provides ongoing documentation of abTEM development. In this first version, we show use cases for hexagonal boron nitride, where valence bonding can be detected, a 4D-STEM simulation of molybdenum disulfide including ptychographic phase reconstruction, a comparison of MD and frozen phonon modeling for convergent-beam electron diffraction of a 2.6-million-atom silicon system, and a performance comparison of our fast implementation of the PRISM algorithm for a decahedral 20000-atom gold nanoparticle.
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Affiliation(s)
- Jacob Madsen
- Faculty of Physics, University of Vienna, Vienna, 1090, Austria
| | - Toma Susi
- Faculty of Physics, University of Vienna, Vienna, 1090, Austria
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38
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Madsen J, Susi T. The abTEM code: transmission electron microscopy from first principles. OPEN RESEARCH EUROPE 2021; 1:24. [PMID: 37645137 PMCID: PMC10446032 DOI: 10.12688/openreseurope.13015.2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/18/2021] [Indexed: 08/31/2023]
Abstract
Simulation of transmission electron microscopy (TEM) images or diffraction patterns is often required to interpret experimental data. Since nuclear cores dominate electron scattering, the scattering potential is typically described using the independent atom model, which completely neglects valence bonding and its effect on the transmitting electrons. As instrumentation has advanced, new measurements have revealed subtle details of the scattering potential that were previously not accessible to experiment. We have created an open-source simulation code designed to meet these demands by integrating the ability to calculate the potential via density functional theory (DFT) with a flexible modular software design. abTEM can simulate most standard imaging modes and incorporates the latest algorithmic developments. The development of new techniques requires a program that is accessible to domain experts without extensive programming experience. abTEM is written purely in Python and designed for easy modification and extension. The effective use of modern open-source libraries makes the performance of abTEM highly competitive with existing optimized codes on both CPUs and GPUs and allows us to leverage an extensive ecosystem of libraries, such as the Atomic Simulation Environment and the DFT code GPAW. abTEM is designed to work in an interactive Python notebook, creating a seamless and reproducible workflow from defining an atomic structure, calculating molecular dynamics (MD) and electrostatic potentials, to the analysis of results, all in a single, easy-to-read document. This article provides ongoing documentation of abTEM development. In this first version, we show use cases for hexagonal boron nitride, where valence bonding can be detected, a 4D-STEM simulation of molybdenum disulfide including ptychographic phase reconstruction, a comparison of MD and frozen phonon modeling for convergent-beam electron diffraction of a 2.6-million-atom silicon system, and a performance comparison of our fast implementation of the PRISM algorithm for a decahedral 20000-atom gold nanoparticle.
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Affiliation(s)
- Jacob Madsen
- Faculty of Physics, University of Vienna, Vienna, 1090, Austria
| | - Toma Susi
- Faculty of Physics, University of Vienna, Vienna, 1090, Austria
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39
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García
de Abajo FJ, Di Giulio V. Optical Excitations with Electron Beams: Challenges and Opportunities. ACS PHOTONICS 2021; 8:945-974. [PMID: 35356759 PMCID: PMC8939335 DOI: 10.1021/acsphotonics.0c01950] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 05/20/2023]
Abstract
Free electron beams such as those employed in electron microscopes have evolved into powerful tools to investigate photonic nanostructures with an unrivaled combination of spatial and spectral precision through the analysis of electron energy losses and cathodoluminescence light emission. In combination with ultrafast optics, the emerging field of ultrafast electron microscopy utilizes synchronized femtosecond electron and light pulses that are aimed at the sampled structures, holding the promise to bring simultaneous sub-Å-sub-fs-sub-meV space-time-energy resolution to the study of material and optical-field dynamics. In addition, these advances enable the manipulation of the wave function of individual free electrons in unprecedented ways, opening sound prospects to probe and control quantum excitations at the nanoscale. Here, we provide an overview of photonics research based on free electrons, supplemented by original theoretical insights and discussion of several stimulating challenges and opportunities. In particular, we show that the excitation probability by a single electron is independent of its wave function, apart from a classical average over the transverse beam density profile, whereas the probability for two or more modulated electrons depends on their relative spatial arrangement, thus reflecting the quantum nature of their interactions. We derive first-principles analytical expressions that embody these results and have general validity for arbitrarily shaped electrons and any type of electron-sample interaction. We conclude with some perspectives on various exciting directions that include disruptive approaches to noninvasive spectroscopy and microscopy, the possibility of sampling the nonlinear optical response at the nanoscale, the manipulation of the density matrices associated with free electrons and optical sample modes, and appealing applications in optical modulation of electron beams, all of which could potentially revolutionize the use of free electrons in photonics.
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Affiliation(s)
- F. Javier García
de Abajo
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
- E-mail:
| | - Valerio Di Giulio
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels, Barcelona, Spain
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40
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Dyck O, Swett JL, Lupini AR, Mol JA, Jesse S. Imaging Secondary Electron Emission from a Single Atomic Layer. SMALL METHODS 2021; 5:e2000950. [PMID: 34927845 DOI: 10.1002/smtd.202000950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/17/2020] [Indexed: 06/14/2023]
Abstract
Graphene-based devices hold promise for a wide range of technological applications. Yet characterizing the structure and the electrical properties of a material that is only one atomic layer thick still poses technical challenges. Recent investigations indicate that secondary-electron electron-beam-induced current (SE-EBIC) imaging can reveal subtle details regarding electrical conductivity and electron transport with high spatial resolution. Here, it is shown that the SEEBIC imaging mode can be used to detect suspended single layers of graphene and distinguish between different numbers of layers. Pristine and contaminated areas of graphene are also compared to show that pristine graphene exhibits a substantially lower SE yield than contaminated regions. This SEEBIC imaging mode may provide valuable information for the engineering of surface coatings where SE yield is a priority.
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Affiliation(s)
- Ondrej Dyck
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Jacob L Swett
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
| | - Andrew R Lupini
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Jan A Mol
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
- School of Physics and Astronomy, Queen Mary University of London, London, E1 4NS, UK
| | - Stephen Jesse
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
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41
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ab initio description of bonding for transmission electron microscopy. Ultramicroscopy 2021; 231:113253. [PMID: 33773844 DOI: 10.1016/j.ultramic.2021.113253] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 02/12/2021] [Accepted: 02/20/2021] [Indexed: 01/10/2023]
Abstract
The simulation of transmission electron microscopy (TEM) images or diffraction patterns is often required to interpret their contrast and extract specimen features. This is especially true for high-resolution phase-contrast imaging of materials, but electron scattering simulations based on atomistic models are widely used in materials science and structural biology. Since electron scattering is dominated by the nuclear cores, the scattering potential is typically described by the widely applied independent atom model. This approximation is fast and fairly accurate, especially for scanning TEM (STEM) annular dark-field contrast, but it completely neglects valence bonding and its effect on the transmitting electrons. However, an emerging trend in electron microscopy is to use new instrumentation and methods to extract the maximum amount of information from each electron. This is evident in the increasing popularity of techniques such as 4D-STEM combined with ptychography in materials science, and cryogenic microcrystal electron diffraction in structural biology, where subtle differences in the scattering potential may be both measurable and contain additional insights. Thus, there is increasing interest in electron scattering simulations based on electrostatic potentials obtained from first principles, mainly via density functional theory, which was previously mainly required for holography. In this Review, we discuss the motivation and basis for these developments, survey the pioneering work that has been published thus far, and give our outlook for the future. We argue that a physically better justified ab initio description of the scattering potential is both useful and viable for an increasing number of systems, and we expect such simulations to steadily gain in popularity and importance.
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42
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García de Abajo FJ, Konečná A. Optical Modulation of Electron Beams in Free Space. PHYSICAL REVIEW LETTERS 2021; 126:123901. [PMID: 33834791 DOI: 10.1103/physrevlett.126.123901] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 02/16/2021] [Indexed: 05/21/2023]
Abstract
We exploit free-space interactions between electron beams and tailored light fields to imprint on-demand phase profiles on the electron wave functions. Through rigorous semiclassical theory involving a quantum description of the electrons, we show that monochromatic optical fields focused in vacuum can be used to correct electron beam aberrations and produce selected focal shapes. Stimulated elastic Compton scattering is exploited to imprint the required electron phase, which is proportional to the integral of the optical field intensity along the electron path and depends on the transverse beam position. The required light intensities are attainable in currently available ultrafast electron microscope setups, thus opening the field of free-space optical manipulation of electron beams.
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Affiliation(s)
- F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
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43
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Mkhitaryan V, March K, Tseng EN, Li X, Scarabelli L, Liz-Marzán LM, Chen SY, Tizei LHG, Stéphan O, Song JM, Kociak M, García de Abajo FJ, Gloter A. Can Copper Nanostructures Sustain High-Quality Plasmons? NANO LETTERS 2021; 21:2444-2452. [PMID: 33651617 DOI: 10.1021/acs.nanolett.0c04667] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Silver, king among plasmonic materials, features low inelastic absorption in the visible-infrared (vis-IR) spectral region compared to other metals. In contrast, copper is commonly regarded as too lossy for actual applications. Here, we demonstrate vis-IR plasmons with quality factors >60 in long copper nanowires (NWs), as determined by electron energy-loss spectroscopy. We explain this result by noticing that most of the electromagnetic energy in these plasmons lies outside the metal, thus becoming less sensitive to inelastic absorption. Measurements for silver and copper NWs of different diameters allow us to elucidate the relative importance of radiative and nonradiative losses in plasmons spanning a wide spectral range down to <20 meV. Thermal population of such low-energy modes becomes significant and generates electron energy gains associated with plasmon absorption, rendering an experimental determination of the NW temperature. Copper is therefore emerging as an attractive, cheap, abundant material platform for high-quality plasmonics in elongated nanostructures.
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Affiliation(s)
- Vahagn Mkhitaryan
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Spain
| | - Katia March
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Eric Nestor Tseng
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Xiaoyan Li
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Leonardo Scarabelli
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain
| | - Luis M Liz-Marzán
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 38013 Bilbao, Spain
- Centro de Investigación Biomédica en Red, Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Paseo de Miramón 182, 28014 Donostia-San Sebastián, Spain
| | - Shih-Yun Chen
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Luiz H G Tizei
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Odile Stéphan
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Jenn-Ming Song
- Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan
| | - Mathieu Kociak
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Alexandre Gloter
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
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Computation and data driven discovery of topological phononic materials. Nat Commun 2021; 12:1204. [PMID: 33619273 PMCID: PMC7900202 DOI: 10.1038/s41467-021-21293-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 01/21/2021] [Indexed: 11/20/2022] Open
Abstract
The discovery of topological quantum states marks a new chapter in both condensed matter physics and materials sciences. By analogy to spin electronic system, topological concepts have been extended into phonons, boosting the birth of topological phononics (TPs). Here, we present a high-throughput screening and data-driven approach to compute and evaluate TPs among over 10,000 real materials. We have discovered 5014 TP materials and grouped them into two main classes of Weyl and nodal-line (ring) TPs. We have clarified the physical mechanism for the occurrence of single Weyl, high degenerate Weyl, individual nodal-line (ring), nodal-link, nodal-chain, and nodal-net TPs in various materials and their mutual correlations. Among the phononic systems, we have predicted the hourglass nodal net TPs in TeO3, as well as the clean and single type-I Weyl TPs between the acoustic and optical branches in half-Heusler LiCaAs. In addition, we found that different types of TPs can coexist in many materials (such as ScZn). Their potential applications and experimental detections have been discussed. This work substantially increases the amount of TP materials, which enables an in-depth investigation of their structure-property relations and opens new avenues for future device design related to TPs. Topological phononic (TP) materials are attracting wide attentions and it is more difficult to seek TP materials compared to electronic materials. Here, the authors present a high-throughput screening and data-driven approach to discover 5014 TP materials and further clarify the mechanism for the occurrence of various TPs.
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45
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Qi R, Li N, Du J, Shi R, Huang Y, Yang X, Liu L, Xu Z, Dai Q, Yu D, Gao P. Four-dimensional vibrational spectroscopy for nanoscale mapping of phonon dispersion in BN nanotubes. Nat Commun 2021; 12:1179. [PMID: 33608559 PMCID: PMC7896073 DOI: 10.1038/s41467-021-21452-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/26/2021] [Indexed: 11/17/2022] Open
Abstract
Directly mapping local phonon dispersion in individual nanostructures can advance our understanding of their thermal, optical, and mechanical properties. However, this requires high detection sensitivity and combined spatial, energy and momentum resolutions, thus has been elusive. Here, we demonstrate a four-dimensional electron energy loss spectroscopy technique, and present position-dependent phonon dispersion measurements in individual boron nitride nanotubes. By scanning the electron beam in real space while monitoring both the energy loss and the momentum transfer, we are able to reveal position- and momentum-dependent lattice vibrations at nanometer scale. Our measurements show that the phonon dispersion of multi-walled nanotubes is locally close to hexagonal-boron nitride crystals. Interestingly, acoustic phonons are sensitive to defect scattering, while optical modes are insensitive to small voids. This work not only provides insights into vibrational properties of boron nitride nanotubes, but also demonstrates potential of the developed technique in nanoscale phonon dispersion measurements.
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Affiliation(s)
- Ruishi Qi
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
- International Center for Quantum Materials, Peking University, Beijing, China
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Ning Li
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
- International Center for Quantum Materials, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Jinlong Du
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Ruochen Shi
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
- International Center for Quantum Materials, Peking University, Beijing, China
| | - Yang Huang
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin, China
- Hebei Key Laboratory of Boron Nitride Micro and Nano Materials, Hebei University of Technology, Tianjin, China
| | - Xiaoxia Yang
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China
| | - Lei Liu
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Zhi Xu
- Songshan Lake Materials Lab, Institute of Physics, Chinese Academy of Sciences, Guangdong, China
| | - Qing Dai
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China
| | - Dapeng Yu
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen, China
| | - Peng Gao
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China.
- International Center for Quantum Materials, Peking University, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, and Beijing Key Laboratory of Quantum Devices, Beijing, China.
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46
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Yan X, Liu C, Gadre CA, Gu L, Aoki T, Lovejoy TC, Dellby N, Krivanek OL, Schlom DG, Wu R, Pan X. Single-defect phonons imaged by electron microscopy. Nature 2021; 589:65-69. [DOI: 10.1038/s41586-020-03049-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 10/07/2020] [Indexed: 11/09/2022]
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47
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DiStefano JG, Murthy AA, Hao S, Dos Reis R, Wolverton C, Dravid VP. Topology of transition metal dichalcogenides: the case of the core-shell architecture. NANOSCALE 2020; 12:23897-23919. [PMID: 33295919 DOI: 10.1039/d0nr06660e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Non-planar architectures of the traditionally flat 2D materials are emerging as an intriguing paradigm to realize nascent properties within the family of transition metal dichalcogenides (TMDs). These non-planar forms encompass a diversity of curvatures, morphologies, and overall 3D architectures that exhibit unusual characteristics across the hierarchy of length-scales. Topology offers an integrated and unified approach to describe, harness, and eventually tailor non-planar architectures through both local and higher order geometry. Topological design of layered materials intrinsically invokes elements highly relevant to property manipulation in TMDs, such as the origin of strain and its accommodation by defects and interfaces, which have broad implications for improved material design. In this review, we discuss the importance and impact of geometry on the structure and properties of TMDs. We present a generalized geometric framework to classify and relate the diversity of possible non-planar TMD forms. We then examine the nature of curvature in the emerging core-shell architecture, which has attracted high interest due to its versatility and design potential. We consider the local structure of curved TMDs, including defect formation, strain, and crystal growth dynamics, and factors affecting the morphology of core-shell structures, such as synthesis conditions and substrate morphology. We conclude by discussing unique aspects of TMD architectures that can be leveraged to engineer targeted, exotic properties and detail how advanced characterization tools enable detection of these features. Varying the topology of nanomaterials has long served as a potent methodology to engineer unusual and exotic properties, and the time is ripe to apply topological design principles to TMDs to drive future nanotechnology innovation.
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Affiliation(s)
- Jennifer G DiStefano
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
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48
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Egerton RF, Venkatraman K, March K, Crozier PA. Properties of Dipole-Mode Vibrational Energy Losses Recorded From a TEM Specimen. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:1117-1123. [PMID: 32867870 DOI: 10.1017/s1431927620024423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The authors discuss the dipole vibrational modes that predominate in the energy-loss spectra of ionic materials below 1 eV, concentrating on thin-film specimens of typical transmission electron microscopy (TEM) thickness. The thickness dependence of the intensity is shown to be a useful guide to the bulk or surface character of vibrational peaks. The lateral and depth resolution of the energy-loss signal is investigated with the aid of finite-element calculations.
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Affiliation(s)
- Ray F Egerton
- Physics Department, University of Alberta, Edmonton, Alberta, CanadaT6G 2E1
| | - Kartik Venkatraman
- School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, AZ85281, USA
| | - Katia March
- Eyring Materials Center, Arizona State University, Tempe, AZ85281, USA
| | - Peter A Crozier
- School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, AZ85281, USA
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Rez P, Singh A. Lattice resolution of vibrational modes in the electron microscope. Ultramicroscopy 2020; 220:113162. [PMID: 33189051 DOI: 10.1016/j.ultramic.2020.113162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 10/28/2020] [Accepted: 11/01/2020] [Indexed: 10/23/2022]
Abstract
The combination of aberration correction and ultra high energy resolution with monochromators has made it possible to record images showing lattice resolution in phonon modes, both with a displaced collection aperture and more recently with an on -axis collection aperture. In practice the objective aperture has to include Bragg reflections that correspond to the observed lattice image spacings, and the specimen has to be sufficiently thick for adequate phonon scattered intensity. There has been controversy as to whether the images with the on axis detector are really a consequence of lattice resolution in a phonon mode or just a transfer of information from an image that was formed by elastically scattered electrons. We present results of calculations based on a theory that includes the possibility of dynamical electron diffraction for both incident and scattered electrons and the full phonon dispersion relation. We show that Umklapp scattering from the second Brillouin Zone back to the first Brillouin Zone is necessary for lattice resolution with the on axis detector and that it is therefore reasonable to attribute the lattice resolution to the phonon scattering.
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Affiliation(s)
- Peter Rez
- Department of Physics, Arizona State University, Tempe, AZ 85287-1504, USA.
| | - Arunima Singh
- Department of Physics, Arizona State University, Tempe, AZ 85287-1504, USA
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Li Y, Qi R, Shi R, Li N, Gao P. Manipulation of surface phonon polaritons in SiC nanorods. Sci Bull (Beijing) 2020; 65:820-826. [PMID: 36659200 DOI: 10.1016/j.scib.2020.02.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/10/2020] [Accepted: 02/11/2020] [Indexed: 01/21/2023]
Abstract
Surface phonon polaritons (SPhPs) are potentially very attractive for subwavelength control and manipulation of light at the infrared to terahertz wavelengths. Probing their propagation behavior in nanostructures is crucial to guide rational device design. Here, aided by monochromatic scanning transmission electron microscopy-electron energy loss spectroscopy technique, we measure the dispersion relation of SPhPs in individual SiC nanorods and reveal the effects of size and shape. We find that the SPhPs can be modulated by the geometric shape and size of SiC nanorods. The energy of SPhPs shows red-shift with decreasing radius and the surface optical phonon is mainly concentrated on the surface with large radius. Therefore, the fields can be precisely confined in specific positions by varying the size of the nanorod, allowing effective tuning at nanometer scale. The findings of this work are in agreement with dielectric response theory and numerical simulation, and provide novel strategies for manipulating light in polar dielectrics through shape and size control, enabling the design of novel nanoscale phonon-photonic devices.
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Affiliation(s)
- Yuehui Li
- International Center for Quantum Materials, Peking University, Beijing 100871, China; Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
| | - Ruishi Qi
- International Center for Quantum Materials, Peking University, Beijing 100871, China; Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
| | - Ruochen Shi
- International Center for Quantum Materials, Peking University, Beijing 100871, China; Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
| | - Ning Li
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
| | - Peng Gao
- International Center for Quantum Materials, Peking University, Beijing 100871, China; Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
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