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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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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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Kent PRC, Annaberdiyev A, Benali A, Bennett MC, Landinez Borda EJ, Doak P, Hao H, Jordan KD, Krogel JT, Kylänpää I, Lee J, Luo Y, Malone FD, Melton CA, Mitas L, Morales MA, Neuscamman E, Reboredo FA, Rubenstein B, Saritas K, Upadhyay S, Wang G, Zhang S, Zhao L. QMCPACK: Advances in the development, efficiency, and application of auxiliary field and real-space variational and diffusion quantum Monte Carlo. J Chem Phys 2020; 152:174105. [DOI: 10.1063/5.0004860] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- P. R. C. Kent
- Center for Nanophase Materials Sciences Division and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Abdulgani Annaberdiyev
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202, USA
| | - Anouar Benali
- Computational Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, USA
| | - M. Chandler Bennett
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Edgar Josué Landinez Borda
- Quantum Simulations Group, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551, USA
| | - Peter Doak
- Center for Nanophase Materials Sciences Division and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Hongxia Hao
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Kenneth D. Jordan
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Jaron T. Krogel
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Ilkka Kylänpää
- Computational Physics Laboratory, Tampere University, P.O. Box 692, 33014 Tampere, Finland
| | - Joonho Lee
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Ye Luo
- Computational Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, USA
| | - Fionn D. Malone
- Quantum Simulations Group, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551, USA
| | - Cody A. Melton
- Sandia National Laboratories, Albuquerque, New Mexico 87123, USA
| | - Lubos Mitas
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202, USA
| | - Miguel A. Morales
- Quantum Simulations Group, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551, USA
| | - Eric Neuscamman
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Fernando A. Reboredo
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Brenda Rubenstein
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Kayahan Saritas
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Shiv Upadhyay
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Guangming Wang
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202, USA
| | - Shuai Zhang
- Laboratory for Laser Energetics, University of Rochester, 250 E River Rd., Rochester, New York 14623, USA
| | - Luning Zhao
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
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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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Suzuki K, Barbiellini B, Orikasa Y, Go N, Sakurai H, Kaprzyk S, Itou M, Yamamoto K, Uchimoto Y, Wang YJ, Hafiz H, Bansil A, Sakurai Y. Extracting the redox orbitals in Li battery materials with high-resolution x-ray compton scattering spectroscopy. PHYSICAL REVIEW LETTERS 2015; 114:087401. [PMID: 25768779 DOI: 10.1103/physrevlett.114.087401] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Indexed: 06/04/2023]
Abstract
We present an incisive spectroscopic technique for directly probing redox orbitals based on bulk electron momentum density measurements via high-resolution x-ray Compton scattering. Application of our method to spinel Li_{x}Mn_{2}O_{4}, a lithium ion battery cathode material, is discussed. The orbital involved in the lithium insertion and extraction process is shown to mainly be the oxygen 2p orbital. Moreover, the manganese 3d states are shown to experience spatial delocalization involving 0.16±0.05 electrons per Mn site during the battery operation. Our analysis provides a clear understanding of the fundamental redox process involved in the working of a lithium ion battery.
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Affiliation(s)
- K Suzuki
- Faculty of Science and Technology, Gunma University, Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - B Barbiellini
- Physics Department, Northeastern University, Boston, Massachusetts 02115, USA
| | - Y Orikasa
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - N Go
- Faculty of Science and Technology, Gunma University, Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - H Sakurai
- Faculty of Science and Technology, Gunma University, Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - S Kaprzyk
- Physics Department, Northeastern University, Boston, Massachusetts 02115, USA
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, aleja Mickiewicza 30, 30-059 Krakow, Poland
| | - M Itou
- Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Sayo, Hyogo 679-5198, Japan
| | - K Yamamoto
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Y Uchimoto
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yung Jui Wang
- Physics Department, Northeastern University, Boston, Massachusetts 02115, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - H Hafiz
- Physics Department, Northeastern University, Boston, Massachusetts 02115, USA
| | - A Bansil
- Physics Department, Northeastern University, Boston, Massachusetts 02115, USA
| | - Y Sakurai
- Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Sayo, Hyogo 679-5198, Japan
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Ernsting D, Billington D, Haynes TD, Millichamp TE, Taylor JW, Duffy JA, Giblin SR, Dewhurst JK, Dugdale SB. Calculating electron momentum densities and Compton profiles using the linear tetrahedron method. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:495501. [PMID: 25390292 DOI: 10.1088/0953-8984/26/49/495501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A method for computing electron momentum densities and Compton profiles from ab initio calculations is presented. Reciprocal space is divided into optimally-shaped tetrahedra for interpolation, and the linear tetrahedron method is used to obtain the momentum density and its projections such as Compton profiles. Results are presented and evaluated against experimental data for Be, Cu, Ni, Fe3Pt, and YBa2Cu4O8, demonstrating the accuracy of our method in a wide variety of crystal structures.
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Affiliation(s)
- D Ernsting
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK
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7
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Kontrym-Sznajd G, Samsel-Czekała M. Special directions in momentum space. II. Hexagonal, tetragonal and trigonal symmetries. J Appl Crystallogr 2012. [DOI: 10.1107/s0021889812041283] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
This paper is a continuation of a previous one,Special directions in momentum space. I. Cubic symmetries[Kontrym-Sznajd & Samsel-Czekała (2011).J. Appl. Cryst.44, 1246–1254], where new sets of special directions (SDs), having the full symmetry of the Brillouin zone, were proposed for cubic lattices. In the present paper, such directions are derived for structures with unique six-, four- and threefold axes,i.e.hexagonal, tetragonal and trigonal lattices, for both two- and three-dimensional space. The SDs presented here allow for construction, in the whole space, of anisotropic quantities from the knowledge of such quantities along a limited number of SDs. The task at hand is to determine as many anisotropic components as the number of available sampling directions. Also discussed is a way of dealing with data when the number of anisotropic components is restricted by a non-optimal set of SDs.
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8
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Li H, Tokii M, Matsumoto M. Compton profiles and nesting of Fermi surfaces for B2-TiNi and B2-TiPd. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:015501. [PMID: 22155847 DOI: 10.1088/0953-8984/24/1/015501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The band structures of the shape memory alloys B2-TiNi and B2-TiPd are calculated by the full potential linearized augmented plane wave method with the local density approximation. The theoretical Compton profiles for B2-TiNi and B2-TiPd are calculated. In addition, the three-dimensional (3D) occupation number densities obtained by Lock-Crisp-West (LCW) analysis are presented for the first time. These 3D occupation number densities are in good agreement with the Compton scattering experiment for TiNi. Both shape memory alloys are based on martensitic transformation, which is caused by soft phonons. The charge-density wave is created by nesting of Fermi surfaces, which leads to phonon softening. To examine the nesting vectors quantitatively, we calculate the generalized susceptibility χ(q). χ(q) shows peaks at 0.315[110]2π/a and 0.4[111]2π/a for TiNi and at 0.275[110]2π/a and 0.395[111]2π/a for TiPd. Although the nesting vector in the [110] direction agrees with that from the phonon experiment, the nesting vector in the [111] direction differs from that in the experimental results.
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Affiliation(s)
- Hua Li
- Graduate School of Library, Information and Media Studies, University of Tsukuba, 1-2 Kasuga, Tsukuba, Ibaraki, 305-8550, Japan
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9
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Kontrym-Sznajd G, Samsel-Czekała M. Special directions in momentum space. I. Cubic symmetries. J Appl Crystallogr 2011. [DOI: 10.1107/s0021889811037411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Some new sets of special directions (SDs) in the Brillouin zone for cubic structures are presented. They allow for construction in the reciprocal space of anisotropic quantities, having Γ1symmetry, from knowledge of such quantities along a limited number of SDs. These SDs also define which spectra, measured, for example, in Compton scattering experiments, are the most efficient for reconstructing three-dimensional densities from their one-dimensional projections. The new SDs are compared with results obtained by other authors.
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Sahariya J, Tiwari S, Mund HS, Sarma S, Srinivasan A, Itou M, Sakurai Y, Ahuja BL. A magnetic Compton scattering study of Ga rich Co-Ni-Ga ferromagnetic shape memory alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:386002. [PMID: 21900735 DOI: 10.1088/0953-8984/23/38/386002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The temperature dependent spin momentum densities of Co(1.8)NiGa(1.2) and Co(2)Ni(0.76)Ga(1.24) alloys have been measured using the magnetic Compton scattering technique. The individual contributions of constituents in the formation of the total spin moment are also calculated using Compton line shape analysis. The magnetic Compton data when compared with the magnetization data obtained using a vibrating sample magnetometer show a negligible orbital contribution. The spin moments deduced from the experimental Compton data are compared with the theoretical results obtained from the full potential linearized augmented plane wave method and are found to be in good agreement. The origin of the magnetism in both alloys is also described in terms of the e(g) and t(2g) contributions of Ni and Co.
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Affiliation(s)
- Jagrati Sahariya
- Department of Physics, University College of Science, M L Sukhadia University, Udaipur 313001, India
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11
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Sakurai Y, Itou M, Barbiellini B, Mijnarends PE, Markiewicz RS, Kaprzyk S, Gillet JM, Wakimoto S, Fujita M, Basak S, Wang YJ, Al-Sawai W, Lin H, Bansil A, Yamada K. Imaging Doped Holes in a Cuprate Superconductor with High-Resolution Compton Scattering. Science 2011; 332:698-702. [DOI: 10.1126/science.1199391] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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12
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Bosak A, Hoesch M, Krisch M, Chernyshov D, Pattison P, Schulze-Briese C, Winkler B, Milman V, Refson K, Antonangeli D, Farber D. 3D imaging of the Fermi surface by thermal diffuse scattering. PHYSICAL REVIEW LETTERS 2009; 103:076403. [PMID: 19792668 DOI: 10.1103/physrevlett.103.076403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Indexed: 05/28/2023]
Abstract
We use thermal diffuse scattering of x rays to visualize the lens-shaped portions of the Fermi surface in metallic zinc. Our interpretation of the nature of the observed scattered intensity anomalies is supported by the incorporation of inelastic x-ray scattering measurements as well as ab initio calculations of the electronic structure and lattice dynamics. Our work demonstrates that thermal diffuse scattering complements well-established techniques and is a powerful tool in its own right for studying the shape of the Fermi surface through the associated electron-phonon coupling.
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Affiliation(s)
- A Bosak
- European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex, France
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Opeil CP, Mihaila B, Schulze RK, Mañosa L, Planes A, Hults WL, Fisher RA, Riseborough PS, Littlewood PB, Smith JL, Lashley JC. Combined experimental and theoretical investigation of the premartensitic transition in Ni2MnGa. PHYSICAL REVIEW LETTERS 2008; 100:165703. [PMID: 18518220 DOI: 10.1103/physrevlett.100.165703] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Indexed: 05/26/2023]
Abstract
Ultraviolet-photoemission (UPS) measurements and supporting specific-heat, thermal-expansion, resistivity, and magnetic-moment measurements are reported for the magnetic shape-memory alloy Ni2MnGa over the temperature range 100<T<250 K. All measurements detect clear signatures of the premartensitic transition (T(PM) approximately 247 K) and the martensitic transition (T(M) approximately 196 K). Temperature-dependent UPS shows a dramatic depletion of states (pseudogap) at T(PM) located 0.3 eV below the Fermi energy. First-principles electronic structure calculations show that the peak observed at 0.3 eV in the UPS spectra for T>T(PM) is due to the Ni d minority-spin electrons. Below T(M) this peak disappears, resulting in an enhanced density of states at energies around 0.8 eV. This enhancement reflects Ni d and Mn d electronic contributions to the majority-spin density of states.
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Affiliation(s)
- C P Opeil
- Physics Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, Massachusetts 02467, USA
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Nygård K, Hakala M, Manninen S, Itou M, Sakurai Y, Hämäläinen K. Configurational energetics in ice ih probed by compton scattering. PHYSICAL REVIEW LETTERS 2007; 99:197401. [PMID: 18233110 DOI: 10.1103/physrevlett.99.197401] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Indexed: 05/25/2023]
Abstract
Temperature-induced changes in the ground-state electron momentum density of polycrystalline ice Ih are studied with high accuracy by Compton scattering utilizing synchrotron radiation. A unique feasibility of the technique to provide direct experimental information on configurational enthalpies and heat capacities is demonstrated. The configurational enthalpy, obtained with an accuracy of 1.5 meV, evolves linearly with temperature above T=100 K. Consequently the configurational heat capacity is found to be constant, c{p}{config}=(0.44+/-0.11) J g{-1} K-1, in this temperature regime. Obtaining these quantities experimentally is fundamentally important for evaluating the accuracy of molecular-dynamics simulations schemes.
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Affiliation(s)
- K Nygård
- Division of X-Ray Physics, Department of Physical Sciences, FI-00014, University of Helsinki, Finland.
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