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Patel U, Guruswamy T, Krzysko AJ, Charalambous H, Gades L, Wiaderek K, Quaranta O, Ren Y, Yakovenko A, Ruett U, Miceli A. High-resolution Compton spectroscopy using x-ray microcalorimeters. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113105. [PMID: 36461526 DOI: 10.1063/5.0092693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 10/23/2022] [Indexed: 06/17/2023]
Abstract
X-ray Compton spectroscopy is one of the few direct probes of the electron momentum distribution of bulk materials in ambient and operando environments. We report high-resolution inelastic x-ray scattering experiments with high momentum and energy transfer performed at a storage-ring-based high-energy x-ray light source facility using an x-ray transition-edge sensor (TES) microcalorimeter detector. The performance was compared with a silicon drift detector (SDD), an energy-resolving semiconductor detector, and Compton profiles were measured for lithium and cobalt oxide powders relevant to lithium-ion battery research. Spectroscopic analysis of the measured Compton profiles demonstrates the high-sensitivity to the low-Z elements and oxidation states. The line shape analysis of the measured Compton profiles in comparison with computed Hartree-Fock profiles is usually limited by the resolution of the semiconductor detector. We have characterized an x-ray TES microcalorimeter detector for high-resolution Compton scattering experiments using a bending magnet source at the Advanced Photon Source with a double crystal monochromator, providing monochromatic photon energies near 27.5 keV. The momentum resolution below 0.16 atomic units (a.u.) was measured, yielding an improvement of more than a factor of 7 over a state-of-the-art SDD for the same scattering geometry. Furthermore, the lineshapes of narrow valence and broad core electron profiles of sealed lithium metal were clearly resolved using an x-ray TES compared to smeared and broadened lineshapes observed when using the SDD. High-resolution Compton scattering using the energy-resolving area detector shown here presents new opportunities for spatial imaging of electron momentum distributions for a wide class of materials with applications ranging from electrochemistry to condensed matter physics.
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Affiliation(s)
- U Patel
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - T Guruswamy
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - A J Krzysko
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - H Charalambous
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - L Gades
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - K Wiaderek
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - O Quaranta
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Y Ren
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - A Yakovenko
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - U Ruett
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - A Miceli
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
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2
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Tomographic reconstruction of oxygen orbitals in lithium-rich battery materials. Nature 2021; 594:213-216. [PMID: 34108698 DOI: 10.1038/s41586-021-03509-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 03/31/2021] [Indexed: 02/05/2023]
Abstract
The electrification of heavy-duty transport and aviation will require new strategies to increase the energy density of electrode materials1,2. The use of anionic redox represents one possible approach to meeting this ambitious target. However, questions remain regarding the validity of the O2-/O- oxygen redox paradigm, and alternative explanations for the origin of the anionic capacity have been proposed3, because the electronic orbitals associated with redox reactions cannot be measured by standard experiments. Here, using high-energy X-ray Compton measurements together with first-principles modelling, we show how the electronic orbital that lies at the heart of the reversible and stable anionic redox activity can be imaged and visualized, and its character and symmetry determined. We find that differential changes in the Compton profile with lithium-ion concentration are sensitive to the phase of the electronic wave function, and carry signatures of electrostatic and covalent bonding effects4. Our study not only provides a picture of the workings of a lithium-rich battery at the atomic scale, but also suggests pathways to improving existing battery materials and designing new ones.
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3
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Brancewicz M, Andrejczuk A, Żukowski E, Dobrzyński L, Sakurai Y, Itou M, Pylak M. Electron momentum density of hexagonal Zn studied by high-resolution Compton scattering. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:188-195. [PMID: 33399568 DOI: 10.1107/s1600577520014721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
High-resolution (0.12 a.u.) electron momentum density projections (Compton profiles) of a hexagonal Zn single crystal have been measured along five high-symmetry directions in reciprocal space. The experiment was performed with the use of 115.6 keV synchrotron radiation on the BL08W station at SPring-8. The quality of the measured Compton profiles is significantly better than that of previous medium- and high-resolution data. The experimental data were compared with the corresponding theoretical Korringa-Kohn-Rostoker (KKR) and density functional theory (DFT) calculations. Some minor and major differences between the two theoretical band-structure calculations have been observed. However, the good quality experimental results indicate their better agreement with DFT.
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Affiliation(s)
- Marek Brancewicz
- Faculty of Physics, University of Białystok, ul. Ciołkowskiego 1L, Białystok 15-245, Poland
| | - Andrzej Andrejczuk
- Faculty of Physics, University of Białystok, ul. Ciołkowskiego 1L, Białystok 15-245, Poland
| | - Eugeniusz Żukowski
- Faculty of Physics, University of Białystok, ul. Ciołkowskiego 1L, Białystok 15-245, Poland
| | - Ludwik Dobrzyński
- National Centre for Nuclear Research, ul. Andrzeja Sołtana 7, Otwock, Świerk 05-400, Poland
| | - Yoshiharu Sakurai
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Masayoshi Itou
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Maciej Pylak
- National Centre for Nuclear Research, ul. Pasteura 7, Warsaw 02-093, Poland
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4
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Robarts HC, Millichamp TE, Lagos DA, Laverock J, Billington D, Duffy JA, O'Neill D, Giblin SR, Taylor JW, Kontrym-Sznajd G, Samsel-Czekała M, Bei H, Mu S, Samolyuk GD, Stocks GM, Dugdale SB. Extreme Fermi Surface Smearing in a Maximally Disordered Concentrated Solid Solution. PHYSICAL REVIEW LETTERS 2020; 124:046402. [PMID: 32058766 DOI: 10.1103/physrevlett.124.046402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/20/2019] [Indexed: 06/10/2023]
Abstract
We show that the Fermi surface can survive the presence of extreme compositional disorder in the equiatomic alloy Ni_{0.25}Fe_{0.25}Co_{0.25}Cr_{0.25}. Our high-resolution Compton scattering experiments reveal a Fermi surface which is smeared across a significant fraction of the Brillouin zone (up to 40% of 2π/a). The extent of this smearing and its variation on and between different sheets of the Fermi surface have been determined, and estimates of the electron mean free path and residual resistivity have been made by connecting this smearing with the coherence length of the quasiparticle states.
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Affiliation(s)
- Hannah C Robarts
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - Thomas E Millichamp
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - Daniel A Lagos
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - Jude Laverock
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - David Billington
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo 679-5198, Japan
- School of Physics and Astronomy, Cardiff University, Queen's Building, The Parade, Cardiff CF24 3AA, United Kingdom
| | - Jonathan A Duffy
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Daniel O'Neill
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Sean R Giblin
- School of Physics and Astronomy, Cardiff University, Queen's Building, The Parade, Cardiff CF24 3AA, United Kingdom
| | - Jonathan W Taylor
- DMSC-European Spallation Source, Universitetsparken 1, Copenhagen 2100, Denmark
| | - Grazyna Kontrym-Sznajd
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50-950 Wrocław 2, Poland
| | - Małgorzata Samsel-Czekała
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50-950 Wrocław 2, Poland
| | - Hongbin Bei
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Sai Mu
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - German D Samolyuk
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - G Malcolm Stocks
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Stephen B Dugdale
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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5
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Jagodziński P, Szlachetko J, Dousse JC, Hoszowska J, Szlachetko M, Vogelsang U, Banaś D, Pakendorf T, Meents A, van Bokhoven JA, Kubala-Kukuś A, Pajek M, Nachtegaal M. A DuMond-type crystal spectrometer for synchrotron-based X-ray emission studies in the energy range of 15-26 keV. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:063106. [PMID: 31255015 DOI: 10.1063/1.5087948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 05/18/2019] [Indexed: 06/09/2023]
Abstract
The design and performance of a high-resolution transmission-type X-ray spectrometer for use in the 15-26 keV energy range at synchrotron light sources is reported. Monte Carlo X-ray-tracing simulations were performed to optimize the performance of the transmission-type spectrometer, based on the DuMond geometry, for use at the Super X-ray absorption beamline of the Swiss Light Source at the Paul Scherrer Institute. This spectrometer provides an instrumental energy resolution of 3.5 eV for X-ray emission lines around 16 keV and 12.5 eV for emission lines at 26 keV, which is comparable to the natural linewidths of the K and L X-ray transitions in the covered energy range. First experimental data are presented and compared with results of the Monte Carlo X-ray simulations.
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Affiliation(s)
- P Jagodziński
- Swiss Light Source, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - J Szlachetko
- Institute of Nuclear Physics Polish Academy of Science, PL-31-342 Kraków, Poland
| | - J-Cl Dousse
- Department of Physics, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - J Hoszowska
- Department of Physics, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - M Szlachetko
- Swiss Light Source, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - U Vogelsang
- Swiss Light Source, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - D Banaś
- Institute of Physics, Jan Kochanowski University, PL-25-406 Kielce, Poland
| | - T Pakendorf
- PETRA, Deutsches Elektronen-Synchrotron (DESY), DE-22607 Hamburg, Germany
| | - A Meents
- PETRA, Deutsches Elektronen-Synchrotron (DESY), DE-22607 Hamburg, Germany
| | - J A van Bokhoven
- Swiss Light Source, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - A Kubala-Kukuś
- Institute of Physics, Jan Kochanowski University, PL-25-406 Kielce, Poland
| | - M Pajek
- Institute of Physics, Jan Kochanowski University, PL-25-406 Kielce, Poland
| | - M Nachtegaal
- Swiss Light Source, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
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6
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Vacancies, disorder-induced smearing of the electronic structure, and its implications for the superconductivity of anti-perovskite MgC 0.93Ni 2.85. Sci Rep 2017; 7:10148. [PMID: 28860522 PMCID: PMC5579060 DOI: 10.1038/s41598-017-09997-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/01/2017] [Indexed: 11/17/2022] Open
Abstract
The anti-perovskite superconductor MgC0.93Ni2.85 was studied using high-resolution x-ray Compton scattering combined with electronic structure calculations. Compton scattering measurements were used to determine experimentally a Fermi surface that showed good agreement with that of our supercell calculations, establishing the presence of the predicted hole and electron Fermi surface sheets. Our calculations indicate that the Fermi surface is smeared by the disorder due to the presence of vacancies on the C and Ni sites, but does not drastically change shape. The 20% reduction in the Fermi level density-of-states would lead to a significant (~70%) suppression of the superconducting Tc for pair-forming electron-phonon coupling. However, we ascribe the observed much smaller Tc reduction at our composition (compared to the stoichiometric compound) to the suppression of pair-breaking spin fluctuations.
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7
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Hafiz H, Suzuki K, Barbiellini B, Orikasa Y, Callewaert V, Kaprzyk S, Itou M, Yamamoto K, Yamada R, Uchimoto Y, Sakurai Y, Sakurai H, Bansil A. Visualizing redox orbitals and their potentials in advanced lithium-ion battery materials using high-resolution x-ray Compton scattering. SCIENCE ADVANCES 2017; 3:e1700971. [PMID: 28845452 PMCID: PMC5567762 DOI: 10.1126/sciadv.1700971] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/27/2017] [Indexed: 05/28/2023]
Abstract
Reduction-oxidation (redox) reactions are the key processes that underlie the batteries powering smartphones, laptops, and electric cars. A redox process involves transfer of electrons between two species. For example, in a lithium-ion battery, current is generated when conduction electrons from the lithium anode are transferred to the redox orbitals of the cathode material. The ability to visualize or image the redox orbitals and how these orbitals evolve under lithiation and delithiation processes is thus of great fundamental and practical interest for understanding the workings of battery materials. We show that inelastic scattering spectroscopy using high-energy x-ray photons (Compton scattering) can yield faithful momentum space images of the redox orbitals by considering lithium iron phosphate (LiFePO4 or LFP) as an exemplar cathode battery material. Our analysis reveals a new link between voltage and the localization of transition metal 3d orbitals and provides insight into the puzzling mechanism of potential shift and how it is connected to the modification of the bond between the transition metal and oxygen atoms. Our study thus opens a novel spectroscopic pathway for improving the performance of battery materials.
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Affiliation(s)
- Hasnain Hafiz
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Kosuke Suzuki
- Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | | | - Yuki Orikasa
- Department of Applied Chemistry, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | | | - Staszek Kaprzyk
- Department of Physics, Northeastern University, Boston, MA 02115, USA
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, aleja Mickiewicza 30, Krakow 30-059, Poland
| | - Masayoshi Itou
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan
| | - Kentaro Yamamoto
- Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Ryota Yamada
- Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Yoshiharu Uchimoto
- Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yoshiharu Sakurai
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan
| | - Hiroshi Sakurai
- Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA 02115, USA
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8
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Lehmkühler F, Forov Y, Elbers M, Steinke I, Sahle CJ, Weis C, Tsuji N, Itou M, Sakurai Y, Poulain A, Sternemann C. Temperature dependence of the hydrogen bond network in trimethylamine N-oxide and guanidine hydrochloride–water solutions. Phys Chem Chem Phys 2017; 19:28470-28475. [DOI: 10.1039/c7cp04958g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present an X-ray Compton scattering study on aqueous trimethylamine N-oxide (TMAO) and guanidine hydrochloride solutions (GdnHCl) as a function of temperature.
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Affiliation(s)
- Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESY
- 22607 Hamburg
- Germany
- The Hamburg Centre for Ultrafast Imaging
- 22761 Hamburg
| | - Yury Forov
- Fakultät Physik/DELTA
- Technische Universität Dortmund
- 44221 Dortmund
- Germany
| | - Mirko Elbers
- Fakultät Physik/DELTA
- Technische Universität Dortmund
- 44221 Dortmund
- Germany
| | - Ingo Steinke
- Deutsches Elektronen-Synchrotron DESY
- 22607 Hamburg
- Germany
- The Hamburg Centre for Ultrafast Imaging
- 22761 Hamburg
| | | | - Christopher Weis
- Fakultät Physik/DELTA
- Technische Universität Dortmund
- 44221 Dortmund
- Germany
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9
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Abstract
Frustrated interactions exist throughout nature, with examples ranging from protein folding through to frustrated magnetic interactions. Whilst magnetic frustration is observed in numerous electrically insulating systems, in metals it is a rare phenomenon. The interplay of itinerant conduction electrons mediating interactions between localised magnetic moments with strong spin-orbit coupling is likely fundamental to these systems. Therefore, knowledge of the precise shape and topology of the Fermi surface is important in any explanation of the magnetic behaviour. PdCrO2, a frustrated metallic magnet, offers the opportunity to examine the relationship between magnetic frustration, short-range magnetic order and Fermi surface topology. By mapping the short-range order in reciprocal space and experimentally determining the electronic structure, we have identified the dual role played by the Cr electrons in which the itinerant ones on the nested paramagnetic Fermi surface mediate the frustrated magnetic interactions between local moments.
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10
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Okada JT, Sit PHL, Watanabe Y, Barbiellini B, Ishikawa T, Wang YJ, Itou M, Sakurai Y, Bansil A, Ishikawa R, Hamaishi M, Paradis PF, Kimura K, Ishikawa T, Nanao S. Visualizing the mixed bonding properties of liquid boron with high-resolution x-ray Compton scattering. PHYSICAL REVIEW LETTERS 2015; 114:177401. [PMID: 25978262 DOI: 10.1103/physrevlett.114.177401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Indexed: 06/04/2023]
Abstract
Bonding characteristics of liquid boron at 2500 K are studied by using high-resolution Compton scattering. An excellent agreement is found between the measurements and the corresponding Car-Parrinello molecular dynamics simulations. Covalent bond pairs are clearly shown to dominate in liquid boron along with the coexistence of diffuse pairs. Our study reveals the complex bonding pattern of liquid boron and gives insight into the unusual properties of this high-temperature liquid.
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Affiliation(s)
- J T Okada
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki 305-8505, Japan
- PRESTO, JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- The Graduate University for Advanced Studies (SOKENDAI), 3-1-1, Yoshinodai, Chuo-ku, Sagamihara 252-5210, Japan
| | - P H-L Sit
- School of Energy and Environment, City University of Hong Kong Kowloon, Hong Kong S.A.R
| | - Y Watanabe
- Institute of Industrial Sciences, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
| | - B Barbiellini
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - T Ishikawa
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki 305-8505, Japan
- The Graduate University for Advanced Studies (SOKENDAI), 3-1-1, Yoshinodai, Chuo-ku, Sagamihara 252-5210, Japan
| | - Y J Wang
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - M Itou
- Japan Synchrotron Radiation Research Institute, SPring-8 Sayo-cho, Hyogo 679-5198, Japan
| | - Y Sakurai
- Japan Synchrotron Radiation Research Institute, SPring-8 Sayo-cho, Hyogo 679-5198, Japan
| | - A Bansil
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - R Ishikawa
- Institute of Industrial Sciences, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
| | - M Hamaishi
- Institute of Industrial Sciences, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
| | - P-F Paradis
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki 305-8505, Japan
| | - K Kimura
- Department of Advanced Materials Science, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - T Ishikawa
- RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - S Nanao
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki 305-8505, Japan
- Institute of Industrial Sciences, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
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11
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Okada JT, Sit PHL, Watanabe Y, Wang YJ, Barbiellini B, Ishikawa T, Itou M, Sakurai Y, Bansil A, Ishikawa R, Hamaishi M, Masaki T, Paradis PF, Kimura K, Ishikawa T, Nanao S. Persistence of covalent bonding in liquid silicon probed by inelastic x-ray scattering. PHYSICAL REVIEW LETTERS 2012; 108:067402. [PMID: 22401121 DOI: 10.1103/physrevlett.108.067402] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 06/28/2011] [Indexed: 05/31/2023]
Abstract
Metallic liquid silicon at 1787 K is investigated using x-ray Compton scattering. An excellent agreement is found between the measurements and the corresponding Car-Parrinello molecular dynamics simulations. Our results show persistence of covalent bonding in liquid silicon and provide support for the occurrence of theoretically predicted liquid-liquid phase transition in supercooled liquid states. The population of covalent bond pairs in liquid silicon is estimated to be 17% via a maximally localized Wannier function analysis. Compton scattering is shown to be a sensitive probe of bonding effects in the liquid state.
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Affiliation(s)
- J T Okada
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki, Japan
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12
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Barbiellini B, Koizumi A, Mijnarends PE, Al-Sawai W, Lin H, Nagao T, Hirota K, Itou M, Sakurai Y, Bansil A. Role of oxygen electrons in the metal-insulator transition in the magnetoresistive oxide La2-2xSr1+2xMn2O7 probed by compton scattering. PHYSICAL REVIEW LETTERS 2009; 102:206402. [PMID: 19519045 DOI: 10.1103/physrevlett.102.206402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Indexed: 05/27/2023]
Abstract
We have studied the [100]-[110] anisotropy of the Compton profile in the bilayer manganite. Quantitative agreement is found between theory and experiment with respect to the anisotropy in the two metallic phases (i.e., the low temperature ferromagnetic and the colossal magnetoresistant phase under a magnetic field of 7 T). Robust signatures of the metal-insulator transition are identified in the momentum density for the paramagnetic phase above the Curie temperature. We interpret our results as providing direct evidence for the transition from the metalliclike to the admixed ionic-covalent bonding accompanying the magnetic transition. The number of electrons involved in this phase transition is estimated. Our study demonstrates the sensitivity of the Compton scattering technique for identifying the number and type of electrons involved in the metal-insulator transition.
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Affiliation(s)
- B Barbiellini
- Physics Department, Northeastern University, Boston, Massachusetts 02115, USA
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13
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Dugdale SB, Watts RJ, Laverock J, Major Z, Alam MA, Samsel-Czekała M, Kontrym-Sznajd G, Sakurai Y, Itou M, Fort D. Observation of a strongly nested Fermi surface in the shape-memory alloy Ni0.62Al0.38. PHYSICAL REVIEW LETTERS 2006; 96:046406. [PMID: 16486859 DOI: 10.1103/physrevlett.96.046406] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Indexed: 05/06/2023]
Abstract
The Fermi surface topology of the shape-memory alloy Ni0.62Al0.38 has been determined using Compton scattering. A large area of this Fermi surface can be made to nest with other areas by translation through a vector of approximately 0.18[1,1,0](2pi/a), which corresponds to the wave vector associated with martensitic precursor phenomena such as phonon softening and diffuse streaking in electron diffraction patterns. This observation is compelling evidence that these phenomena are driven by the enhanced electron-lattice coupling due to the Fermi surface nesting.
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Affiliation(s)
- S B Dugdale
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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