1
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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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Urbieta M, Barbry M, Koval P, Rivacoba A, Sánchez-Portal D, Aizpurua J, Zabala N. Footprints of atomic-scale features in plasmonic nanoparticles as revealed by electron energy loss spectroscopy. Phys Chem Chem Phys 2024; 26:14991-15004. [PMID: 38741574 DOI: 10.1039/d4cp01034e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
We present a first-principles theoretical study of the atomistic footprints in the valence electron energy loss spectroscopy (EELS) of nanometer-size metallic particles. Charge density maps of excited plasmons and EEL spectra for specific electron paths through a nanoparticle (Na380 atom cluster) are modeled using ab initio calculations within time-dependent density functional theory. Our findings unveil the atomic-scale sensitivity of EELS within this low-energy spectral range. Whereas localized surface plasmons (LSPs) are particularly sensitive to the atomistic structure of the surface probed by the electron beam, confined bulk plasmons (CBPs) reveal quantum size effects within the nanoparticle's volume. Moreover, we prove that classical local dielectric theories mimicking the atomistic structure of the nanoparticles reproduce the LSP trends observed in quantum calculations, but fall short in describing the CBP behavior observed under different electron trajectories.
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Affiliation(s)
- Mattin Urbieta
- Matematika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola (Eibarko Atala), University of the Basque Country UPV/EHU, 20018 Eibar, Spain.
- Centro de Física de Materiales CSIC - UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
| | - Marc Barbry
- Centro de Física de Materiales CSIC - UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
| | - Peter Koval
- Simune Atomistics S.L., Avenida de Tolosa 76, Donostia-San Sebastian 20018, Spain
| | - Alberto Rivacoba
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
| | - Daniel Sánchez-Portal
- Centro de Física de Materiales CSIC - UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
| | - Javier Aizpurua
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Department of Electricity and Electronics, FCT-ZTF, University of the Basque Country (UPV/EHU), Barrio Sarriena z/g, Leioa, Bizkaia 48940, Spain.
- Ikerbasque, Basque Foundation for Science, Bilbao, Bizkaia 48011, Spain
| | - Nerea Zabala
- Centro de Física de Materiales CSIC - UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Department of Electricity and Electronics, FCT-ZTF, University of the Basque Country (UPV/EHU), Barrio Sarriena z/g, Leioa, Bizkaia 48940, Spain.
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3
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Auad Y, Dias EJC, Tencé M, Blazit JD, Li X, Zagonel LF, Stéphan O, Tizei LHG, García de Abajo FJ, Kociak M. μeV electron spectromicroscopy using free-space light. Nat Commun 2023; 14:4442. [PMID: 37488103 PMCID: PMC10366080 DOI: 10.1038/s41467-023-39979-0] [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: 01/10/2023] [Accepted: 07/03/2023] [Indexed: 07/26/2023] Open
Abstract
The synergy between free electrons and light has recently been leveraged to reach an impressive degree of simultaneous spatial and spectral resolution, enabling applications in microscopy and quantum optics. However, the required combination of electron optics and light injection into the spectrally narrow modes of arbitrary specimens remains a challenge. Here, we demonstrate microelectronvolt spectral resolution with a sub-nanometer probe of photonic modes with quality factors as high as 104. We rely on mode matching of a tightly focused laser beam to whispering gallery modes to achieve a 108-fold increase in light-electron coupling efficiency. By adapting the shape and size of free-space optical beams to address specific physical questions, our approach allows us to interrogate any type of photonic structure with unprecedented spectral and spatial detail.
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Affiliation(s)
- Yves Auad
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Eduardo J C Dias
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Castelldefels, Barcelona, Spain
| | - Marcel Tencé
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Jean-Denis Blazit
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Xiaoyan Li
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Luiz Fernando Zagonel
- Gleb Wataghin Institute of Physics, University of Campinas - UNICAMP, 13083-859, Campinas, SP, Brazil
| | - Odile Stéphan
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Luiz H G Tizei
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - 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.
| | - Mathieu Kociak
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France.
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4
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Egerton R, Wang Y, Crozier PA. Spatial Resolution in Aloof EELS. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:362-364. [PMID: 37613395 DOI: 10.1093/micmic/ozad067.169] [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)
- Ray Egerton
- Physics Department, University of Alberta, Edmonton, Canada
| | - Yifan Wang
- School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, AZ, USA
| | - Peter A Crozier
- School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, AZ, USA
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5
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Flannigan DJ, VandenBussche EJ. Pulsed-beam transmission electron microscopy and radiation damage. Micron 2023; 172:103501. [PMID: 37390662 DOI: 10.1016/j.micron.2023.103501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/02/2023]
Abstract
We review the use of pulsed electron-beams in transmission electron microscopes (TEMs) for the purpose of mitigating specimen damage. We begin by placing the importance of TEMs with respect to materials characterization into proper context, and we provide a brief overview of established methods for reducing or eliminating the deleterious effects of beam-induced damage. We then introduce the concept of pulsed-beam TEM, and we briefly describe the basic methods and instrument configurations used to create so-called temporally structured electron beams. Following a brief overview of the use of high-dose-rate pulsed-electron beams in cancer radiation therapy, we review historical speculations and more recent compelling but mostly anecdotal findings of a pulsed-beam TEM damage effect. This is followed by an in-depth technical review of recent works seeking to establish cause-and-effect relationships, to conclusively uncover the presence of an effect, and to explore the practicality of the approach. These studies, in particular, provide the most compelling evidence to date that using a pulsed electron beam in the TEM is indeed a viable way to mitigate damage. Throughout, we point out current gaps in understanding, and we conclude with a brief perspective of current needs and future directions.
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Affiliation(s)
- David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN 55455, USA; Minnesota Institute for Ultrafast Science, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Elisah J VandenBussche
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN 55455, USA; Minnesota Institute for Ultrafast Science, University of Minnesota, Minneapolis, MN 55455, USA
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6
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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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7
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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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8
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Chaupard M, Degrouard J, Li X, Stéphan O, Kociak M, Gref R, de Frutos M. Nanoscale Multimodal Analysis of Sensitive Nanomaterials by Monochromated STEM-EELS in Low-Dose and Cryogenic Conditions. ACS NANO 2023; 17:3452-3464. [PMID: 36745677 DOI: 10.1021/acsnano.2c09571] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Scanning transmission electron microscopy coupled with electron energy loss spectroscopy (STEM-EELS) provides spatially resolved chemical information down to the atomic scale. However, studying radiation-sensitive specimens such as organic-inorganic composites remains extremely challenging. Here, we analyzed metal-organic framework nanoparticles (nanoMOFs) at low-dose (10 e-/Å2) and liquid nitrogen temperatures, similar to cryo-TEM conditions usually employed for high-resolution imaging of biological specimens. Our results demonstrate that monochromated STEM-EELS enables damage-free analysis of nanoMOFs, providing in a single experiment, signatures of intact functional groups comparable with infrared, ultraviolet, and X-ray data, with an energy resolution down to 7 meV. The signals have been mapped at the nanoscale (<10 nm) for each of these energy spectral ranges, including the chemical features observed for high energy losses (X-ray range). By controlling beam irradiation and monitoring spectral changes, our work provides insights into the possible pathways of chemical reactions occurring under electron exposure. These results demonstrate the possibilities for characterizing at the nanoscale the chemistry of sensitive systems such as organic and biological materials.
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Affiliation(s)
- Maeva Chaupard
- Laboratoire de Physique des Solides, CNRS, UMR 8502, Université Paris-Saclay, F-91405 Orsay, France
- Institut des Sciences Moléculaires d'Orsay, CNRS, UMR 8214, Université Paris-Saclay, F-91405 Orsay, France
| | - Jéril Degrouard
- Laboratoire de Physique des Solides, CNRS, UMR 8502, Université Paris-Saclay, F-91405 Orsay, France
| | - Xiaoyan Li
- Laboratoire de Physique des Solides, CNRS, UMR 8502, Université Paris-Saclay, F-91405 Orsay, France
| | - Odile Stéphan
- Laboratoire de Physique des Solides, CNRS, UMR 8502, Université Paris-Saclay, F-91405 Orsay, France
| | - Mathieu Kociak
- Laboratoire de Physique des Solides, CNRS, UMR 8502, Université Paris-Saclay, F-91405 Orsay, France
| | - Ruxandra Gref
- Institut des Sciences Moléculaires d'Orsay, CNRS, UMR 8214, Université Paris-Saclay, F-91405 Orsay, France
| | - Marta de Frutos
- Laboratoire de Physique des Solides, CNRS, UMR 8502, Université Paris-Saclay, F-91405 Orsay, France
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9
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Sub-resolution contrast in neutral helium microscopy through facet scattering for quantitative imaging of nanoscale topographies on macroscopic surfaces. Nat Commun 2023; 14:904. [PMID: 36801860 PMCID: PMC9938237 DOI: 10.1038/s41467-023-36578-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/07/2023] [Indexed: 02/19/2023] Open
Abstract
Nanoscale thin film coatings and surface treatments are ubiquitous across industry, science, and engineering; imbuing specific functional or mechanical properties (such as corrosion resistance, lubricity, catalytic activity and electronic behaviour). Non-destructive nanoscale imaging of thin film coatings across large (ca. centimetre) lateral length scales, crucial to a wide range of modern industry, remains a significant technical challenge. By harnessing the unique nature of the helium atom-surface interaction, neutral helium microscopy images these surfaces without altering the sample under investigation. Since the helium atom scatters exclusively from the outermost electronic corrugation of the sample, the technique is completely surface sensitive. Furthermore, with a cross-section that is orders of magnitude larger than that of electrons, neutrons and photons, the probe particle routinely interacts with features down to the scale of surface defects and small adsorbates (including hydrogen). Here, we highlight the capacity of neutral helium microscopy for sub-resolution contrast using an advanced facet scattering model based on nanoscale features. By replicating the observed scattered helium intensities, we demonstrate that sub-resolution contrast arises from the unique surface scattering of the incident probe. Consequently, it is now possible to extract quantitative information from the helium atom image, including localised ångström-scale variations in topography.
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10
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Konečná A, Iyikanat F, García de Abajo FJ. Entangling free electrons and optical excitations. SCIENCE ADVANCES 2022; 8:eabo7853. [PMID: 36427323 PMCID: PMC9699672 DOI: 10.1126/sciadv.abo7853] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 10/07/2022] [Indexed: 05/30/2023]
Abstract
The inelastic interaction between flying particles and optical nanocavities gives rise to entangled states in which some excitations of the latter are paired with momentum changes in the former. Specifically, free-electron entanglement with nanocavity modes opens appealing opportunities associated with the strong interaction capabilities of the electrons. However, the achievable degree of entanglement is currently limited by the lack of control over the resulting state mixtures. Here, we propose a scheme to generate pure entanglement between designated optical-cavity excitations and separable free-electron states. We shape the electron wave function profile to select the accessible cavity modes and simultaneously associate them with targeted electron scattering directions. This concept is exemplified through theoretical calculations of free-electron entanglement with degenerate and nondegenerate plasmon modes in silver nanoparticles and atomic vibrations in an inorganic molecule. The generated entanglement can be further propagated through its electron component to extend quantum interactions beyond existing protocols.
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Affiliation(s)
- Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- Central European Institute of Technology, Brno University of Technology, Brno 61200, Czech Republic
| | - Fadil Iyikanat
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - F. Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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11
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García de Abajo FJ, Dias EJC, Di Giulio V. Complete Excitation of Discrete Quantum Systems by Single Free Electrons. PHYSICAL REVIEW LETTERS 2022; 129:093401. [PMID: 36083663 DOI: 10.1103/physrevlett.129.093401] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
We reveal a wealth of nonlinear and recoil effects in the interaction between individual low-energy electrons (≲100 eV) and samples comprising a discrete number of states. Adopting a quantum theoretical description of combined free-electron and two-level systems, we find a maximum achievable excitation probability of 100%, which requires specific conditions relating to the coupling strength and the transition symmetry, as we illustrate through calculations for dipolar and quadrupolar modes. Strong recoil effects are observed when the kinetic energy of the probe lies close to the transition threshold, although the associated probability remains independent of the electron wave function even when fully accounting for nonlinear interactions with arbitrarily complex multilevel samples. Our work reveals the potential of free electrons to control localized excitations and delineates the boundaries of such control.
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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
| | - Eduardo J C Dias
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Valerio Di Giulio
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
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12
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Egerton R, Watanabe M. Spatial Resolution in Transmission Electron Microscopy. Micron 2022; 160:103304. [DOI: 10.1016/j.micron.2022.103304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/05/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
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13
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Lin CC, Wang SM, Chen BY, Chi CH, Chang IL, Chang CW. Scanning Electron Thermal Absorbance Microscopy for Light Element Detection and Atomic Number Analysis. NANO LETTERS 2022; 22:2667-2673. [PMID: 35266397 DOI: 10.1021/acs.nanolett.1c04502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Recent developments in nanoscale thermal metrology using electron microscopy have made impressive advancements in measuring either phononic or thermal transport properties of nanoscale samples. However, its potential in material analysis has never been considered. Here we introduce a direct thermal absorbance measurement platform in scanning electron microscope (SEM) and demonstrate that its signal can be utilized for atomic number (Z) analysis at nanoscales. We prove that the measured absorbance of materials is complementary to signals of backscattering electrons but exhibits a much higher collection efficiency and signal-to-noise ratio. Thus, it not only enables successful detections of light elements/compounds under low acceleration voltages of SEM but also allows quantitative Z analyses in agreement with simulations. The direct thermal absorbance measurement platform would become an ideal tool for SEM, especially for thin films, light elements/compounds, or biological samples at nanoscales.
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Affiliation(s)
- Ching-Che Lin
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Shih-Ming Wang
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
- Department of Mechanical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Bo-Yi Chen
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Cheng-Hung Chi
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - I-Ling Chang
- Department of Mechanical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Chih-Wei Chang
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
- Center of Atomic Initiative for New Materials (AI-MAT), National Taiwan University, Taipei, 10617, Taiwan
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14
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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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15
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Ogawa T, Yamazawa Y, Kawai S, Mouri A, Katane J, Park IY, Takai Y, Agemura T. A Novel Monochromator with Offset Cylindrical Lenses and Its Application to a Low-Voltage Scanning Electron Microscope. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-13. [PMID: 35164889 DOI: 10.1017/s1431927622000150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Low-voltage scanning electron microscopes (LV-SEMs) are widely used in nanoscience. However, image resolution for SEMs is restricted by chromatic aberration due to energy spread of the electron beam at low acceleration voltage. This study introduces a new monochromator (MC) with offset cylindrical lenses (CLs) as one solution for LV-SEMs. The MC optics, with highly excited CLs in offset layouts, has advantageous high performance and simple experimental setup, making it suitable for field emission LV-SEMs. In a preliminary evaluation, our MC reduced the energy spread from 770 to 67 meV. The MC was integrated into a commercial SEM equipped with an out-lens (a conventional objective lens without immersion magnetic or retarding electric fields) and an Everhart–Thornley detector. Comparing SEM images under two conditions with the MC turned on or off, the spatial resolution was improved by 58% at 0.5 and 1 keV. The filtering effect of the MC decreased the probe current with a ratio (i.e., transmittance) of 5.7%, which was consistent with estimations based on measured energy spreads. To the best of our knowledge, this is the first report on an effective MC with higher-energy resolution than 100 meV and the results offer encouraging prospects for LV-SEM technology.
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Affiliation(s)
- Takashi Ogawa
- Advanced Instrumentation Institute, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong, Daejeon34113, Republic of Korea
- Major in Nano Science, University of Science and Technology, 217 Gajeong-ro, Yuseong, Daejeon34113, Republic of Korea
| | - Yu Yamazawa
- Hitachi High-Tech Corporation, 882 Ichige, Hitachinaka, Ibaraki312-8504, Japan
| | - Satoshi Kawai
- Hitachi High-Tech Corporation, 882 Ichige, Hitachinaka, Ibaraki312-8504, Japan
| | - Atsushi Mouri
- Hitachi High-Tech Corporation, 882 Ichige, Hitachinaka, Ibaraki312-8504, Japan
| | - Junichi Katane
- Hitachi High-Tech Corporation, 882 Ichige, Hitachinaka, Ibaraki312-8504, Japan
| | - In-Yong Park
- Advanced Instrumentation Institute, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong, Daejeon34113, Republic of Korea
- Major in Nano Science, University of Science and Technology, 217 Gajeong-ro, Yuseong, Daejeon34113, Republic of Korea
| | - Yoshizo Takai
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, Japan
| | - Toshihide Agemura
- Hitachi High-Tech Corporation, 882 Ichige, Hitachinaka, Ibaraki312-8504, Japan
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16
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17
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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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18
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19
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Xue R, Liang C, Li Y, Chen X, Li F, Ren S, Chen F. Solid-state separation of hypoxanthine tautomers through a doping strategy. CrystEngComm 2022. [DOI: 10.1039/d2ce00146b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solid-state separation of hypoxanthine tautomers was realized by a doping strategy. The doping forms of hypoxanthine in HAmG, AG β and AG α are N7-hypoxanthine, and in GM and dehydrated-GM are N9-hypoxanthine.
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Affiliation(s)
- Rongrong Xue
- School of Resources and Chemical Engineering, Sanming University, Sanming 365004, Fujian, China
| | - Chengfeng Liang
- School of Resources and Chemical Engineering, Sanming University, Sanming 365004, Fujian, China
| | - Yanping Li
- School of Resources and Chemical Engineering, Sanming University, Sanming 365004, Fujian, China
| | - Xiuzhi Chen
- School of Resources and Chemical Engineering, Sanming University, Sanming 365004, Fujian, China
| | - Fuying Li
- School of Resources and Chemical Engineering, Sanming University, Sanming 365004, Fujian, China
| | - Shizhao Ren
- School of Resources and Chemical Engineering, Sanming University, Sanming 365004, Fujian, China
| | - Fenghua Chen
- School of Resources and Chemical Engineering, Sanming University, Sanming 365004, Fujian, China
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20
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Elbaum M, Seifer S, Houben L, Wolf SG, Rez P. Toward Compositional Contrast by Cryo-STEM. Acc Chem Res 2021; 54:3621-3631. [PMID: 34491730 DOI: 10.1021/acs.accounts.1c00279] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Electron microscopy (EM) is the most versatile tool for the study of matter at scales ranging from subatomic to visible. The high vacuum environment and the charged irradiation require careful stabilization of many specimens of interest. Biological samples are particularly sensitive due to their composition of light elements suspended in an aqueous medium. Early investigators developed techniques of embedding and staining with heavy metal salts for contrast enhancement. Indeed, the Nobel Prize in 1974 recognized Claude, de Duve, and Palade for establishment of the field of cell biology, largely due to their developments in separation and preservation of cellular components for electron microscopy. A decade later, cryogenic fixation was introduced. Vitrification of the water avoids the need for dehydration and provides an ideal matrix in which the organic macromolecules are suspended; the specimen represents a native state, suddenly frozen in time at temperatures below -150 °C. The low temperature maintains a low vapor pressure for the electron microscope, and the amorphous nature of the medium avoids diffraction contrast from crystalline ice. Such samples are extremely delicate, however, and cryo-EM imaging is a race for information in the face of ongoing damage by electron irradiation. Through this journey, cryo-EM enhanced the resolution scale from membranes to molecules and most recently to atoms. Cryo-EM pioneers, Dubochet, Frank, and Henderson, were awarded the Nobel Prize in 2017 for high resolution structure determination of biological macromolecules.A relatively untapped feature of cryo-EM is its preservation of composition. Nothing is added and nothing removed. Analytical spectroscopies based on electron energy loss or X-ray emission can be applied, but the very small interaction cross sections conflict with the weak exposures required to preserve sample integrity. To what extent can we interpret quantitatively the pixel intensities in images themselves? Conventional cryo-transmission electron microscopy (TEM) is limited in this respect, due to the strong dependence of the contrast transfer on defocus and the absence of contrast at low spatial frequencies.Inspiration comes largely from a different modality for cryo-tomography, using soft X-rays. Contrast depends on the difference in atomic absorption between carbon and oxygen in a region of the spectrum between their core level ionization energies, the so-called water window. Three dimensional (3D) reconstruction provides a map of the local X-ray absorption coefficient. The quantitative contrast enables the visualization of organic materials without stain and measurement of their concentration quantitatively. We asked, what aspects of the quantitative contrast might be transferred to cryo-electron microscopy?Compositional contrast is accessible in scanning transmission EM (STEM) via incoherent elastic scattering, which is sensitive to the atomic number Z. STEM can be regarded as a high energy, low angle diffraction measurement performed pixel by pixel with a weakly convergent beam. When coherent diffraction effects are absent, that is, in amorphous materials, a dark field signal measures quantitatively the flux scattered from the specimen integrated over the detector area. Learning to interpret these signals will open a new dimension in cryo-EM. This Account describes our efforts so far to introduce STEM for cryo-EM and tomography of biological specimens. We conclude with some thoughts on further developments.
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Affiliation(s)
| | | | | | | | - Peter Rez
- Department of Physics, Arizona State University, 550 E Tyler Drive, Tempe, Arizona 85287, United States
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21
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Konečná A, Li J, Edgar JH, García de Abajo FJ, Hachtel JA. Revealing Nanoscale Confinement Effects on Hyperbolic Phonon Polaritons with an Electron Beam. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2103404. [PMID: 34453472 DOI: 10.1002/smll.202103404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/29/2021] [Indexed: 06/13/2023]
Abstract
Hyperbolic phonon polaritons (HPhPs) in hexagonal boron nitride (hBN) enable the direct manipulation of mid-infrared light at nanometer scales, many orders of magnitude below the free-space light wavelength. High-resolution monochromated electron energy-loss spectroscopy (EELS) facilitates measurement of excitations with energies extending into the mid-infrared while maintaining nanoscale spatial resolution, making it ideal for detecting HPhPs. The electron beam is a precise source and probe of HPhPs, which allows the observation of nanoscale confinement in HPhP structures and directly extract hBN polariton dispersions for both modes in the bulk of the flake and modes along the edge. The measurements reveal technologically important nontrivial phenomena, such as localized polaritons induced by environmental heterogeneity, enhanced and suppressed excitation due to 2D interference, and strong modification of high-momenta excitations such as edge-confined polaritons by nanoscale heterogeneity on edge boundaries. The work opens exciting prospects for the design of real-world optical mid-infrared devices based on hyperbolic polaritons.
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Affiliation(s)
- Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
- Central European Institute of Technology, Brno University of Technology, Brno, 612 00, Czech Republic
| | - Jiahan Li
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - James H Edgar
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Campanys 23, Barcelona, 08010, Spain
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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22
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Chen S, Wu C, Han B, Liu Z, Mi Z, Hao W, Zhao J, Wang X, Zhang Q, Liu K, Qi J, Cao J, Feng J, Yu D, Li J, Gao P. Atomic-scale imaging of CH 3NH 3PbI 3 structure and its decomposition pathway. Nat Commun 2021; 12:5516. [PMID: 34535678 PMCID: PMC8448763 DOI: 10.1038/s41467-021-25832-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/03/2021] [Indexed: 11/13/2022] Open
Abstract
Understanding the atomic structure and structural instability of organic-inorganic hybrid perovskites is the key to appreciate their remarkable photoelectric properties and understand failure mechanism. Here, using low-dose imaging technique by direct-detection electron-counting camera in a transmission electron microscope, we investigate the atomic structure and decomposition pathway of CH3NH3PbI3 (MAPbI3) at the atomic scale. We successfully image the atomic structure of perovskite in real space under ultra-low electron dose condition, and observe a two-step decomposition process, i.e., initial loss of MA+ followed by the collapse of perovskite structure into 6H-PbI2 with their critical threshold doses also determined. Interestingly, an intermediate phase (MA0.5PbI3) with locally ordered vacancies can robustly exist before perovskite collapses, enlightening strategies for prevention and recovery of perovskite structure during the degradation. Associated with the structure evolution, the bandgap gradually increases from ~1.6 eV to ~2.1 eV. In addition, it is found that C-N bonds can be readily destroyed under irradiation, releasing NH3 and HI and leaving hydrocarbons. These findings enhance our understanding of the photoelectric properties and failure mechanism of MAPbI3, providing potential strategies into material optimization.
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Affiliation(s)
- Shulin Chen
- Electron Microscopy Laboratory, International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, China
| | - Changwei Wu
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Bo Han
- Electron Microscopy Laboratory, International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Zhetong Liu
- Electron Microscopy Laboratory, International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Zhou Mi
- School of Materials Science and Engineering, School of Mechanical Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China
| | - Weizhong Hao
- School of Materials Science and Engineering, School of Mechanical Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China
| | - Jinjin Zhao
- School of Materials Science and Engineering, School of Mechanical Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China.
| | - Xiao Wang
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
| | - Qing Zhang
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, China
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
| | - Junlei Qi
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, China
| | - Jian Cao
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, China
| | - Jicai Feng
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, China
| | - Dapeng Yu
- Department of Physics, South University of Science and Technology, Shenzhen, China
| | - Jiangyu Li
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
- Guangdong Provisional Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen, China.
| | - Peng Gao
- Electron Microscopy Laboratory, International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China.
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23
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Zhang Y, Lu PH, Rotunno E, Troiani F, van Schayck JP, Tavabi AH, Dunin-Borkowski RE, Grillo V, Peters PJ, Ravelli RBG. Single-particle cryo-EM: alternative schemes to improve dose efficiency. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1343-1356. [PMID: 34475283 PMCID: PMC8415325 DOI: 10.1107/s1600577521007931] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
Imaging of biomolecules by ionizing radiation, such as electrons, causes radiation damage which introduces structural and compositional changes of the specimen. The total number of high-energy electrons per surface area that can be used for imaging in cryogenic electron microscopy (cryo-EM) is severely restricted due to radiation damage, resulting in low signal-to-noise ratios (SNR). High resolution details are dampened by the transfer function of the microscope and detector, and are the first to be lost as radiation damage alters the individual molecules which are presumed to be identical during averaging. As a consequence, radiation damage puts a limit on the particle size and sample heterogeneity with which electron microscopy (EM) can deal. Since a transmission EM (TEM) image is formed from the scattering process of the electron by the specimen interaction potential, radiation damage is inevitable. However, we can aim to maximize the information transfer for a given dose and increase the SNR by finding alternatives to the conventional phase-contrast cryo-EM techniques. Here some alternative transmission electron microscopy techniques are reviewed, including phase plate, multi-pass transmission electron microscopy, off-axis holography, ptychography and a quantum sorter. Their prospects for providing more or complementary structural information within the limited lifetime of the sample are discussed.
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Affiliation(s)
- Yue Zhang
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, Maastricht 6229 ER, The Netherlands
| | - Peng-Han Lu
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Enzo Rotunno
- CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/A, I-41125 Modena, Italy
| | - Filippo Troiani
- CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/A, I-41125 Modena, Italy
| | - J. Paul van Schayck
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, Maastricht 6229 ER, The Netherlands
| | - Amir H. Tavabi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Rafal E. Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Vincenzo Grillo
- CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/A, I-41125 Modena, Italy
| | - Peter J. Peters
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, Maastricht 6229 ER, The Netherlands
| | - Raimond B. G. Ravelli
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, Maastricht 6229 ER, The Netherlands
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24
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Kalinin SV, Ziatdinov M, Hinkle J, Jesse S, Ghosh A, Kelley KP, Lupini AR, Sumpter BG, Vasudevan RK. Automated and Autonomous Experiments in Electron and Scanning Probe Microscopy. ACS NANO 2021; 15:12604-12627. [PMID: 34269558 DOI: 10.1021/acsnano.1c02104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Machine learning and artificial intelligence (ML/AI) are rapidly becoming an indispensable part of physics research, with domain applications ranging from theory and materials prediction to high-throughput data analysis. In parallel, the recent successes in applying ML/AI methods for autonomous systems from robotics to self-driving cars to organic and inorganic synthesis are generating enthusiasm for the potential of these techniques to enable automated and autonomous experiments (AE) in imaging. Here, we aim to analyze the major pathways toward AE in imaging methods with sequential image formation mechanisms, focusing on scanning probe microscopy (SPM) and (scanning) transmission electron microscopy ((S)TEM). We argue that automated experiments should necessarily be discussed in a broader context of the general domain knowledge that both informs the experiment and is increased as the result of the experiment. As such, this analysis should explore the human and ML/AI roles prior to and during the experiment and consider the latencies, biases, and prior knowledge of the decision-making process. Similarly, such discussion should include the limitations of the existing imaging systems, including intrinsic latencies, non-idealities, and drifts comprising both correctable and stochastic components. We further pose that the role of the AE in microscopy is not the exclusion of human operators (as is the case for autonomous driving), but rather automation of routine operations such as microscope tuning, etc., prior to the experiment, and conversion of low latency decision making processes on the time scale spanning from image acquisition to human-level high-order experiment planning. Overall, we argue that ML/AI can dramatically alter the (S)TEM and SPM fields; however, this process is likely to be highly nontrivial and initiated by combined human-ML workflows and will bring challenges both from the microscope and ML/AI sides. At the same time, these methods will enable opportunities and paradigms for scientific discovery and nanostructure fabrication.
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25
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Rizvi A, Mulvey JT, Carpenter BP, Talosig R, Patterson JP. A Close Look at Molecular Self-Assembly with the Transmission Electron Microscope. Chem Rev 2021; 121:14232-14280. [PMID: 34329552 DOI: 10.1021/acs.chemrev.1c00189] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Molecular self-assembly is pervasive in the formation of living and synthetic materials. Knowledge gained from research into the principles of molecular self-assembly drives innovation in the biological, chemical, and materials sciences. Self-assembly processes span a wide range of temporal and spatial domains and are often unintuitive and complex. Studying such complex processes requires an arsenal of analytical and computational tools. Within this arsenal, the transmission electron microscope stands out for its unique ability to visualize and quantify self-assembly structures and processes. This review describes the contribution that the transmission electron microscope has made to the field of molecular self-assembly. An emphasis is placed on which TEM methods are applicable to different structures and processes and how TEM can be used in combination with other experimental or computational methods. Finally, we provide an outlook on the current challenges to, and opportunities for, increasing the impact that the transmission electron microscope can have on molecular self-assembly.
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Affiliation(s)
- Aoon Rizvi
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Justin T Mulvey
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Brooke P Carpenter
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Rain Talosig
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Joseph P Patterson
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
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26
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Verification of water presence in graphene liquid cells. Micron 2021; 149:103109. [PMID: 34332298 DOI: 10.1016/j.micron.2021.103109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 12/24/2022]
Abstract
Graphene liquid cells (GLCs) present the thinnest possible sample enclosures for liquid phase electron microscopy. However, the actual presence of liquid within a GLC is not always guaranteed. Of key importance is to reliably test the presence of the liquid, which is most frequently water or saline. Here, the commonly used methods for verifying the presence of water were evaluated. It is shown that depending on the type of sample, applying a single criterion does not always conclusively verify the presence of water. Testing liquid filling for a specific GLC sample preparation protocol should thus be considered critically. The most reliable method is direct observation of the water exciton peak using electron energy loss spectroscopy (EELS). But if this method cannot be carried out, water filling of the GLC can be verified from a combination of higher contrast in the image, the presence of bubbles, and an oxygen signal in the EEL spectrum, which can be accomplished at a high electron dose in spot mode. Nanoparticle movement does not always occur in a GLC.
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27
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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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28
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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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29
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Rozenberg M, Fausto R, Reva I. Variable temperature FTIR spectra of polycrystalline purine nucleobases and estimating strengths of individual hydrogen bonds. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 251:119323. [PMID: 33508682 DOI: 10.1016/j.saa.2020.119323] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/19/2020] [Accepted: 12/05/2020] [Indexed: 06/12/2023]
Abstract
In the first part of this work, we report the FTIR spectra of pure NH and isotopically substituted ND (10-15% D and 80-90% D) polycrystalline hypoxanthine, xanthine, adenine and guanine recorded in the 400-4000 cm-1 range, as a function of temperature (10-300 K). We provide assignments of the stretching and out-of-plane bending amine (NH2) and imine (NH) bands to the distinct H-bonds present in the crystal, based on the temperature sensitivity and isotopic exchange behavior. Empirical correlations between spectral and thermodynamic or structural parameters enabled us to estimate the energies and lengths of H-bonds in the studied nucleobase crystals and to correlate them with literature data. The empirical H-bonding energies are compared with H-bonding and stacking energies computed for hypoxanthine. In the second part, strategies for using the empirical correlations together with information extracted from quantum mechanical data (in particular from the Bader's quantum theory of atoms in molecules, QTAIM) for the evaluation of hydrogen bonding properties are discussed, and their advantages and drawbacks pointed out. The justification for a cooperative use of quantum-mechanical calculations with empirical spectra-energy correlations is discussed.
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Affiliation(s)
- M Rozenberg
- The Hebrew University of Jerusalem, Department of Inorganic and Analytical Chemistry, Jerusalem, Givat Ram 91904, Israel.
| | - R Fausto
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal.
| | - I Reva
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal; University of Coimbra, CIEPQPF, Department of Chemical Engineering, 3030-790 Coimbra, Portugal.
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30
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Guido CA, Rotunno E, Zanfrognini M, Corni S, Grillo V. Exploring the Spatial Features of Electronic Transitions in Molecular and Biomolecular Systems by Swift Electrons. J Chem Theory Comput 2021; 17:2364-2373. [PMID: 33646769 PMCID: PMC8047794 DOI: 10.1021/acs.jctc.1c00045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
![]()
We
devise a new kind of experiment that extends the technology
of electron energy loss spectroscopy to probe (supra-)molecular systems: by using
an electron beam in a configuration that avoids
molecular damage and a very recently introduced electron optics setup
for the analysis of the outcoming electrons, one can obtain information
on the spatial features of the investigated excitations. Physical
insight into the proposed experiment is provided by means of a simple
but rigorous model to obtain the transition rate and selection rule.
Numerical simulations of DNA G-quadruplexes and other biomolecular
systems, based on time dependent density functional theory calculations,
point out that the conceived new technique can probe the multipolar
components and even the chirality of molecular transitions, superseding
the usual optical spectroscopies for those cases that are problematic,
such as dipole-forbidden transitions, at a very high spatial resolution.
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Affiliation(s)
- Ciro A Guido
- Dipartimento di Scienze Chimiche, Università di Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Enzo Rotunno
- CNR-NANO, Institute of Nanoscience, via Campi 213/A, Modena, Italy
| | | | - Stefano Corni
- Dipartimento di Scienze Chimiche, Università di Padova, via F. Marzolo 1, 35131 Padova, Italy.,CNR-NANO, Institute of Nanoscience, via Campi 213/A, Modena, Italy
| | - Vincenzo Grillo
- CNR-NANO, Institute of Nanoscience, via Campi 213/A, Modena, Italy
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31
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March K, Venkatraman K, Truong CD, Williams D, Chiu PL, Rez P. Protein secondary structure signatures from energy loss spectra recorded in the electron microscope. J Microsc 2020; 282:215-223. [PMID: 33305823 DOI: 10.1111/jmi.12995] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 01/13/2023]
Abstract
Infrared spectroscopy is a powerful technique for characterising protein structure. It is now possible to record energy losses corresponding to the infrared region in the electron microscope and to avoid damage by positioning the probe in the region adjacent to the structure being studied. Spectra from bacteriorhodopsin, a protein that is predominately a α helix, and OmpF porin, a protein that is mainly β sheet show significant differences over a spectral range from ∼0.1 to 0.25 eV (∼1000 to 1800 cm-1 ). Although the energy resolution equivalent to 60 cm-1 is inferior to Fourier Transform InfraRed Spectroscopy (FTIR) the spectra are very sensitive to molecular orientation. Polar bonds aligned parallel to the specimen grid make particularly strong contributions to the energy loss spectra. Ultra-high-resolution energy loss spectroscopy in the electron microscope can potentially add useful information to imaging and diffraction for determining the secondary structure misfolding believed to be responsible for dementia diseases such as Alzheimer's.
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Affiliation(s)
- Katia March
- Eyring Materials Center, Arizona State University, Tempe, Arizona.,Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Paris, France
| | - Kartik Venkatraman
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona
| | - Chloe Du Truong
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona.,School of Molecular Sciences, Arizona State University, Tempe, Arizona
| | - Dewight Williams
- Eyring Materials Center, Arizona State University, Tempe, Arizona
| | - Po-Lin Chiu
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona.,School of Molecular Sciences, Arizona State University, Tempe, Arizona
| | - Peter Rez
- Department of Physics, Arizona State University, Tempe, Arizona
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32
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Ilett M, S'ari M, Freeman H, Aslam Z, Koniuch N, Afzali M, Cattle J, Hooley R, Roncal-Herrero T, Collins SM, Hondow N, Brown A, Brydson R. Analysis of complex, beam-sensitive materials by transmission electron microscopy and associated techniques. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190601. [PMID: 33100161 PMCID: PMC7661278 DOI: 10.1098/rsta.2019.0601] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
We review the use of transmission electron microscopy (TEM) and associated techniques for the analysis of beam-sensitive materials and complex, multiphase systems in-situ or close to their native state. We focus on materials prone to damage by radiolysis and explain that this process cannot be eliminated or switched off, requiring TEM analysis to be done within a dose budget to achieve an optimum dose-limited resolution. We highlight the importance of determining the damage sensitivity of a particular system in terms of characteristic changes that occur on irradiation under both an electron fluence and flux by presenting results from a series of molecular crystals. We discuss the choice of electron beam accelerating voltage and detectors for optimizing resolution and outline the different strategies employed for low-dose microscopy in relation to the damage processes in operation. In particular, we discuss the use of scanning TEM (STEM) techniques for maximizing information content from high-resolution imaging and spectroscopy of minerals and molecular crystals. We suggest how this understanding can then be carried forward for in-situ analysis of samples interacting with liquids and gases, provided any electron beam-induced alteration of a specimen is controlled or used to drive a chosen reaction. Finally, we demonstrate that cryo-TEM of nanoparticle samples snap-frozen in vitreous ice can play a significant role in benchmarking dynamic processes at higher resolution. This article is part of a discussion meeting issue 'Dynamic in situ microscopy relating structure and function'.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Rik Brydson
- Leeds Electron Microscopy and Spectroscopy (LEMAS) Centre, School of Chemical and Process Engineering, Bragg Centre for Materials Research, University of Leeds, Leeds LS2 9JT, UK
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33
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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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34
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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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35
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Yu R, García de Abajo FJ. Chemical identification through two-dimensional electron energy-loss spectroscopy. SCIENCE ADVANCES 2020; 6:eabb4713. [PMID: 32923595 PMCID: PMC7455491 DOI: 10.1126/sciadv.abb4713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/26/2020] [Indexed: 05/29/2023]
Abstract
We explore a disruptive approach to nanoscale sensing by performing electron energy loss spectroscopy through the use of low-energy ballistic electrons that propagate on a two-dimensional semiconductor. In analogy to free-space electron microscopy, we show that the presence of analyte molecules in the vicinity of the semiconductor produces substantial energy losses in the electrons, which can be resolved by energy-selective electron injection and detection through actively controlled potential gates. The infrared excitation spectra of the molecules are thereby gathered in this electronic device, enabling the identification of chemical species with high sensitivity. Our realistic theoretical calculations demonstrate the superiority of this technique for molecular sensing, capable of performing spectral identification at the zeptomol level within a microscopic all-electrical device.
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Affiliation(s)
- Renwen Yu
- ICFO-Institut de Ciències Fòtoniques, Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - F. Javier García de Abajo
- ICFO-Institut de Ciències Fòtoniques, 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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36
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Tizei LHG, Mkhitaryan V, Lourenço-Martins H, Scarabelli L, Watanabe K, Taniguchi T, Tencé M, Blazit JD, Li X, Gloter A, Zobelli A, Schmidt FP, Liz-Marzán LM, García de Abajo FJ, Stéphan O, Kociak M. Tailored Nanoscale Plasmon-Enhanced Vibrational Electron Spectroscopy. NANO LETTERS 2020; 20:2973-2979. [PMID: 31967839 PMCID: PMC7227010 DOI: 10.1021/acs.nanolett.9b04659] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/08/2020] [Indexed: 05/24/2023]
Abstract
Atomic vibrations and phonons are an excellent source of information on nanomaterials that we can access through a variety of methods including Raman scattering, infrared spectroscopy, and electron energy-loss spectroscopy (EELS). In the presence of a plasmon local field, vibrations are strongly modified and, in particular, their dipolar strengths are highly enhanced, thus rendering Raman scattering and infrared spectroscopy extremely sensitive techniques. Here, we experimentally demonstrate that the interaction between a relativistic electron and vibrational modes in nanostructures is fundamentally modified in the presence of plasmons. We finely tune the energy of surface plasmons in metallic nanowires in the vicinity of hexagonal boron nitride, making it possible to monitor and disentangle both strong phonon-plasmon coupling and plasmon-driven phonon enhancement at the nanometer scale. Because of the near-field character of the electron beam-phonon interaction, optically inactive phonon modes are also observed. Besides increasing our understanding of phonon physics, our results hold great potential for investigating sensing mechanisms and chemistry in complex nanomaterials down to the molecular level.
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Affiliation(s)
- Luiz H. G. Tizei
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
| | - Vahagn Mkhitaryan
- The
Barcelona Institute of Science and Technology, ICFO-Institut de Ciencies Fotoniques, 08860 Castelldefels (Barcelona), Spain
| | - Hugo Lourenço-Martins
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
| | - Leonardo Scarabelli
- CIC
biomaGUNE and Ciber-BBN, Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los
Angeles, California 90095, United States
| | - Kenji Watanabe
- National
Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- National
Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - Marcel Tencé
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
| | - Jean-Denis Blazit
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
| | - Xiaoyan Li
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
| | - Alexandre Gloter
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
| | - Alberto Zobelli
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
| | | | - Luis M. Liz-Marzán
- CIC
biomaGUNE and Ciber-BBN, Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain
- Ikerbasque,
Basque Foundation for Science, 48013 Bilbao, Spain
| | - F. Javier García de Abajo
- The
Barcelona Institute of Science and Technology, ICFO-Institut de Ciencies Fotoniques, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avanats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Odile Stéphan
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
| | - Mathieu Kociak
- Laboratoire
de Physique des Solides, Université
Paris-Saclay, CNRS, 91405, Orsay, France
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37
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Chen Q, Dwyer C, Sheng G, Zhu C, Li X, Zheng C, Zhu Y. Imaging Beam-Sensitive Materials by Electron Microscopy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907619. [PMID: 32108394 DOI: 10.1002/adma.201907619] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/20/2019] [Indexed: 05/15/2023]
Abstract
Electron microscopy allows the extraction of multidimensional spatiotemporally correlated structural information of diverse materials down to atomic resolution, which is essential for figuring out their structure-property relationships. Unfortunately, the high-energy electrons that carry this important information can cause damage by modulating the structures of the materials. This has become a significant problem concerning the recent boost in materials science applications of a wide range of beam-sensitive materials, including metal-organic frameworks, covalent-organic frameworks, organic-inorganic hybrid materials, 2D materials, and zeolites. To this end, developing electron microscopy techniques that minimize the electron beam damage for the extraction of intrinsic structural information turns out to be a compelling but challenging need. This article provides a comprehensive review on the revolutionary strategies toward the electron microscopic imaging of beam-sensitive materials and associated materials science discoveries, based on the principles of electron-matter interaction and mechanisms of electron beam damage. Finally, perspectives and future trends in this field are put forward.
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Affiliation(s)
- Qiaoli Chen
- Center for Electron Microscopy, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Christian Dwyer
- Department of Physics, Arizona State University, Tempe, AZ, 85287-1504, USA
| | - Guan Sheng
- Advanced Membranes and Porous Materials Center, Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Chongzhi Zhu
- Center for Electron Microscopy, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Xiaonian Li
- Center for Electron Microscopy, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Changlin Zheng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, 200438, China
| | - Yihan Zhu
- Center for Electron Microscopy, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China
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38
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Collins SM, Kepaptsoglou DM, Hou J, Ashling CW, Radtke G, Bennett TD, Midgley PA, Ramasse QM. Functional Group Mapping by Electron Beam Vibrational Spectroscopy from Nanoscale Volumes. NANO LETTERS 2020; 20:1272-1279. [PMID: 31944111 DOI: 10.1021/acs.nanolett.9b04732] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Vibrational spectroscopies directly record details of bonding in materials, but spatially resolved methods have been limited to surface techniques for mapping functional groups at the nanoscale. Electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope presents a route to functional group analysis from nanoscale volumes using transmitted subnanometer electron probes. Here, we now use vibrational EELS to map distinct carboxylate and imidazolate linkers in a metal-organic framework (MOF) crystal-glass composite material. Domains <100 nm in size are observed using vibrational EELS, with recorded spatial resolution <15 nm at interfaces in the composite. This nanoscale functional group mapping is confirmed by correlated EELS at core ionization edges as well as X-ray energy dispersive spectroscopy for elemental mapping of the metal centers of the two constituent MOFs. These results present a complete nanoscale analysis of the building blocks of the MOF composite and establish spatially resolved functional group analysis using electron beam spectroscopy for crystalline and amorphous organic and metal-organic solids.
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Affiliation(s)
- Sean M Collins
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FS , United Kingdom
| | - Demie M Kepaptsoglou
- SuperSTEM Laboratory , SciTech Daresbury Campus , Daresbury WA4 4AD , United Kingdom
- Department of Physics , University of York , Heslington, York YO10 5DD , United Kingdom
| | - Jingwei Hou
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FS , United Kingdom
| | - Christopher W Ashling
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FS , United Kingdom
| | - Guillaume Radtke
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC , 75005 Paris , France
| | - Thomas D Bennett
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FS , United Kingdom
| | - Paul A Midgley
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FS , United Kingdom
| | - Quentin M Ramasse
- SuperSTEM Laboratory , SciTech Daresbury Campus , Daresbury WA4 4AD , United Kingdom
- School of Chemical and Process Engineering and School of Physics , University of Leeds , Leeds LS2 9JT , United Kingdom
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39
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Zeiger PM, Rusz J. Efficient and Versatile Model for Vibrational STEM-EELS. PHYSICAL REVIEW LETTERS 2020; 124:025501. [PMID: 32004041 DOI: 10.1103/physrevlett.124.025501] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/18/2019] [Indexed: 06/10/2023]
Abstract
We introduce a novel method for the simulation of the impact scattering in vibrational scanning transmission electron microscopy electron energy loss spectroscopy simulations. The phonon-loss process is modeled by a combination of molecular dynamics and elastic multislice calculations within a modified frozen phonon approximation. The key idea is thereby to use a so-called δ thermostat in the classical molecular dynamics simulation to generate frequency dependent configurations of the vibrating specimen's atomic structure. The method includes correlated motion of atoms and provides vibrational spectrum images at a cost comparable to standard frozen phonon calculations. We demonstrate good agreement of our method with simulations and experiments for a 15 nm flake of hexagonal boron nitride.
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Affiliation(s)
- Paul M Zeiger
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, Uppsala 75120, Sweden
| | - Ján Rusz
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, Uppsala 75120, Sweden
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40
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Lingerfelt DB, Ganesh P, Jakowski J, Sumpter BG. Understanding Beam-Induced Electronic Excitations in Materials. J Chem Theory Comput 2020; 16:1200-1214. [DOI: 10.1021/acs.jctc.9b00792] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David B. Lingerfelt
- Nanomaterials Theory Institute, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Panchapakesan Ganesh
- Nanomaterials Theory Institute, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jacek Jakowski
- Nanomaterials Theory Institute, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Bobby G. Sumpter
- Nanomaterials Theory Institute, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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41
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Radtke G, Taverna D, Menguy N, Pandolfi S, Courac A, Le Godec Y, Krivanek OL, Lovejoy TC. Polarization Selectivity in Vibrational Electron-Energy-Loss Spectroscopy. PHYSICAL REVIEW LETTERS 2019; 123:256001. [PMID: 31922788 DOI: 10.1103/physrevlett.123.256001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Indexed: 06/10/2023]
Abstract
Orientation-dependent aloof-beam vibrational electron-energy-loss spectroscopy is carried out on uniaxial icosahedral B_{12}P_{2} submicron crystals. We demonstrate that the high sensitivity of the signal to the crystal orientation allows for an unambiguous determination of the symmetry of normal modes occurring at the Brillouin zone center of this anisotropic compound. The experimental results are assessed using first-principles quantum mechanical calculations (density functional theory) of the dielectric response of the specimen. The high spatial resolution inherent to this technique when implemented in the transmission electron microscope thus opens the door to nanoscale orientation-dependent vibrational spectroscopy.
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Affiliation(s)
- G Radtke
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - D Taverna
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - N Menguy
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - S Pandolfi
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - A Courac
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - Y Le Godec
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - O L Krivanek
- Nion Co., 11511 NE 118th Street, Kirkland, Washington 98034, USA
| | - T C Lovejoy
- Nion Co., 11511 NE 118th Street, Kirkland, Washington 98034, USA
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Zachman MJ, Hachtel JA, Idrobo JC, Chi M. Emerging Electron Microscopy Techniques for Probing Functional Interfaces in Energy Materials. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902993] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Michael J. Zachman
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Jordan A. Hachtel
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Miaofang Chi
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
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Zachman MJ, Hachtel JA, Idrobo JC, Chi M. Emerging Electron Microscopy Techniques for Probing Functional Interfaces in Energy Materials. Angew Chem Int Ed Engl 2019; 59:1384-1396. [PMID: 31081976 DOI: 10.1002/anie.201902993] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/01/2019] [Indexed: 11/10/2022]
Abstract
Interfaces play a fundamental role in many areas of chemistry. However, their localized nature requires characterization techniques with high spatial resolution in order to fully understand their structure and properties. State-of-the-art atomic resolution or in situ scanning transmission electron microscopy and electron energy-loss spectroscopy are indispensable tools for characterizing the local structure and chemistry of materials with single-atom resolution, but they are not able to measure many properties that dictate function, such as vibrational modes or charge transfer, and are limited to room-temperature samples containing no liquids. Here, we outline emerging electron microscopy techniques that are allowing these limitations to be overcome and highlight several recent studies that were enabled by these techniques. We then provide a vision for how these techniques can be paired with each other and with in situ methods to deliver new insights into the static and dynamic behavior of functional interfaces.
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Affiliation(s)
- Michael J Zachman
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Miaofang Chi
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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Yan X, Liu C, Gadre CA, Dai S, Gu L, Yu K, Aoki T, Wu R, Pan X. Unexpected Strong Thermally Induced Phonon Energy Shift for Mapping Local Temperature. NANO LETTERS 2019; 19:7494-7502. [PMID: 31517496 DOI: 10.1021/acs.nanolett.9b03307] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Measuring temperature in nanoscale is crucial for the research and development of microelectronic devices. Plasmon resonance has been utilized to map local temperature gradient in metallic materials (Al) due to their large coefficients of thermal expansion. However, most semiconductors (including Si and SiC) possess much smaller coefficients of thermal expansion due to their strong covalent bonding in crystal structure, for which the plasmon-based temperature measurement becomes unreliable. Here, we report an unexpected strong, thermally induced phonon energy shift in SiC by spatially resolved vibrational spectroscopy in transmission electron microscopy with in situ heating, demonstrating that this shift can be applied as a useful tool for measuring nanoscale temperature. When a bulk phonon spectrum is used, the spatial resolution of vibrational spectroscopy can be as high as one nanometer. Molecular dynamics simulations reveal that lattice expansion only contributes a small fraction of phonon energy shift and that vibrant motions away from the bonds are predominate factors. This study gains deeper insight into the understanding of dynamic behaviors of the phonon and provides a new avenue to measure local temperature in nanodevices.
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Krivanek O, Dellby N, Hachtel J, Idrobo JC, Hotz M, Plotkin-Swing B, Bacon N, Bleloch A, Corbin G, Hoffman M, Meyer C, Lovejoy T. Progress in ultrahigh energy resolution EELS. Ultramicroscopy 2019; 203:60-67. [DOI: 10.1016/j.ultramic.2018.12.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 12/08/2018] [Accepted: 12/09/2018] [Indexed: 11/28/2022]
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46
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Hachtel JA, Huang J, Popovs I, Jansone-Popova S, Keum JK, Jakowski J, Lovejoy TC, Dellby N, Krivanek OL, Idrobo JC. Identification of site-specific isotopic labels by vibrational spectroscopy in the electron microscope. Science 2019; 363:525-528. [DOI: 10.1126/science.aav5845] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/28/2018] [Indexed: 01/25/2023]
Abstract
The identification of isotopic labels by conventional macroscopic techniques lacks spatial resolution and requires relatively large quantities of material for measurements. We recorded the vibrational spectra of an α amino acid, l-alanine, with damage-free “aloof” electron energy-loss spectroscopy in a scanning transmission electron microscope to directly resolve carbon-site–specific isotopic labels in real space with nanoscale spatial resolution. An isotopic red shift of 4.8 ± 0.4 milli–electron volts in C–O asymmetric stretching modes was observed for 13C-labeled l-alanine at the carboxylate carbon site, which was confirmed by macroscopic infrared spectroscopy and theoretical calculations. The accurate measurement of this shift opens the door to nondestructive, site-specific, spatially resolved identification of isotopically labeled molecules with the electron microscope.
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Jokisaari JR, Hachtel JA, Hu X, Mukherjee A, Wang C, Konecna A, Lovejoy TC, Dellby N, Aizpurua J, Krivanek OL, Idrobo JC, Klie RF. Vibrational Spectroscopy of Water with High Spatial Resolution. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802702. [PMID: 30062804 DOI: 10.1002/adma.201802702] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/02/2018] [Indexed: 05/15/2023]
Abstract
The ability to examine the vibrational spectra of liquids with nanometer spatial resolution will greatly expand the potential to study liquids and liquid interfaces. In fact, the fundamental properties of water, including complexities in its phase diagram, electrochemistry, and bonding due to nanoscale confinement are current research topics. For any liquid, direct investigation of ordered liquid structures, interfacial double layers, and adsorbed species at liquid-solid interfaces are of interest. Here, a novel way of characterizing the vibrational properties of liquid water with high spatial resolution using transmission electron microscopy is reported. By encapsulating water between two sheets of boron nitride, the ability to capture vibrational spectra to quantify the structure of the liquid, its interaction with the liquid-cell surfaces, and the ability to identify isotopes including H2 O and D2 O using electron energy-loss spectroscopy is demonstrated. The electron microscope used here, equipped with a high-energy-resolution monochromator, is able to record vibrational spectra of liquids and molecules and is sensitive to surface and bulk morphological properties both at the nano- and micrometer scales. These results represent an important milestone for liquid and isotope-labeled materials characterization with high spatial resolution, combining nanoscale imaging with vibrational spectroscopy.
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Affiliation(s)
- Jacob R Jokisaari
- Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Xuan Hu
- Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Arijita Mukherjee
- Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Canhui Wang
- Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Andrea Konecna
- Center for Material Physics (CSIC-UPV/EHU) and DIPC, Donostia - San Sebastián Gipuzkoa, 20018, Spain
| | | | - Niklas Dellby
- Nion Company, 11511 NE 118th St., Kirkland, WA, 98034, USA
| | - Javier Aizpurua
- Center for Material Physics (CSIC-UPV/EHU) and DIPC, Donostia - San Sebastián Gipuzkoa, 20018, Spain
| | | | - Juan-Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Robert F Klie
- Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA
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Haiber DM, Crozier PA. Nanoscale Probing of Local Hydrogen Heterogeneity in Disordered Carbon Nitrides with Vibrational Electron Energy-Loss Spectroscopy. ACS NANO 2018; 12:5463-5472. [PMID: 29767996 DOI: 10.1021/acsnano.8b00884] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In graphitic carbon nitrides, (photo)catalytic functionality is underpinned by the effect that residual hydrogen content, manifesting in amine (N-H x) defects, has on its optoelectronic properties. Therefore, a detailed understanding of the variation in the local structure of graphitic carbon nitrides is key for understanding structure-activity relationships. Here, we apply aloof-beam vibrational electron energy-loss spectroscopy in the scanning transmission electron microscope (STEM) to locally detect variations in hydrogen content in two different layered carbon nitrides with nanometer resolution. Through low dose rate TEM, we obtain atomically resolved images from crystalline and disordered carbon nitrides. By employing an aloof-beam configuration in a monochromated STEM, radiation damage can be dramatically reduced, yielding vibrational spectra from carbon nitrides to be assessed on 10's of nanometer length scales. We find that in disordered graphitic carbon nitrides the relative amine content can vary locally up to 27%. Cyano (C≡N) defects originating from uncondensed precursor are also revealed by probing small volumes, which cannot be detected by infrared absorption or Raman scattering spectroscopies. The utility of this technique is realized for heterogeneous soft materials, such as disordered graphitic carbon nitrides, in which methods to probe catalytically active sites remain elusive.
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Affiliation(s)
- Diane M Haiber
- School for the Engineering of Matter, Transport and Energy , Arizona State University , 501 E. Tyler Mall , Tempe , Arizona 85287-6106 , United States
| | - Peter A Crozier
- School for the Engineering of Matter, Transport and Energy , Arizona State University , 501 E. Tyler Mall , Tempe , Arizona 85287-6106 , United States
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Konečná A, Neuman T, Aizpurua J, Hillenbrand R. Surface-Enhanced Molecular Electron Energy Loss Spectroscopy. ACS NANO 2018; 12:4775-4786. [PMID: 29641179 DOI: 10.1021/acsnano.8b01481] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) is becoming an important technique in spatially resolved spectral characterization of optical and vibrational properties of matter at the nanoscale. EELS has played a significant role in understanding localized polaritonic excitations in nanoantennas and also allows for studying molecular excitations in nanoconfined samples. Here we theoretically describe the interaction of a localized electron beam with molecule-covered polaritonic nanoantennas, and propose the concept of surface-enhanced molecular EELS exploiting the electromagnetic coupling between the nanoantenna and the molecular sample. Particularly, we study plasmonic and infrared phononic antennas covered by molecular layers, exhibiting either an excitonic or vibrational response. We demonstrate that EEL spectra of these molecule-antenna coupled systems exhibit Fano-like or strong coupling features, similar to the ones observed in far-field optical and infrared spectroscopy. EELS offers the advantage to acquire spectral information with nanoscale spatial resolution, and importantly, to control the antenna-molecule coupling on demand. Considering ongoing instrumental developments, EELS in STEM shows the potential to become a powerful tool for fundamental studies of molecules that are naturally or intentionally located on nanostructures supporting localized plasmon or phonon polaritons. Surface-enhanced EELS might also enable STEM-EELS applications such as remote- and thus damage-free-sensing of the excitonic and vibrational response of molecules, quantum dots, or 2D materials.
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Affiliation(s)
- Andrea Konečná
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
| | - Tomáš Neuman
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
| | - Javier Aizpurua
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
- Donostia International Physics Center DIPC , Donostia-San Sebastián , 20018 , Spain
| | - Rainer Hillenbrand
- IKERBASQUE, Basque Foundation for Science , Bilbao , 48013 , Spain
- CIC NanoGUNE and UPV/EHU , Donostia-San Sebastián , 20018 , Spain
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50
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Exploring the capabilities of monochromated electron energy loss spectroscopy in the infrared regime. Sci Rep 2018; 8:5637. [PMID: 29618757 PMCID: PMC5884780 DOI: 10.1038/s41598-018-23805-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/19/2018] [Indexed: 11/09/2022] Open
Abstract
Monochromated electron energy loss spectroscopy (EELS) is one of the leading techniques to study materials properties that correspond to low (<5 eV) energy losses (i.e. band-gaps, plasmons, and excitons) with nanoscale spatial resolution. Recently a new generation of monochromators have become available, opening regimes and unlocking excitations that were previously unobservable in the electron microscope. The capabilities of these new instruments are still being explored, and here we study the effect of monochromation on various aspects of EELS analysis in the infrared (<1 eV) regime. We investigate the effect of varying levels of monochromation on energy resolution, zero-loss peak (ZLP) tail reduction, ZLP tail shape, signal-to-noise-ratio, and spatial resolution. From these experiments, the new capabilities of monochromated EELS are shown to be highly promising for the future of localized spectroscopic analysis.
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