1
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Linker TM, Krishnamoorthy A, Daemen LL, Ramirez-Cuesta AJ, Nomura K, Nakano A, Cheng YQ, Hicks WR, Kolesnikov AI, Vashishta PD. Neutron scattering and neural-network quantum molecular dynamics investigation of the vibrations of ammonia along the solid-to-liquid transition. Nat Commun 2024; 15:3911. [PMID: 38724541 PMCID: PMC11082248 DOI: 10.1038/s41467-024-48246-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 04/25/2024] [Indexed: 05/12/2024] Open
Abstract
Vibrational spectroscopy allows us to understand complex physical and chemical interactions of molecular crystals and liquids such as ammonia, which has recently emerged as a strong hydrogen fuel candidate to support a sustainable society. We report inelastic neutron scattering measurement of vibrational properties of ammonia along the solid-to-liquid phase transition with high enough resolution for direct comparisons to ab-initio simulations. Theoretical analysis reveals the essential role of nuclear quantum effects (NQEs) for correctly describing the intermolecular spectrum as well as high energy intramolecular N-H stretching modes. This is achieved by training neural network models using ab-initio path-integral molecular dynamics (PIMD) simulations, thereby encompassing large spatiotemporal trajectories required to resolve low energy dynamics while retaining NQEs. Our results not only establish the role of NQEs in ammonia but also provide general computational frameworks to study complex molecular systems with NQEs.
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Affiliation(s)
- T M Linker
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089-0242, USA
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - A Krishnamoorthy
- Department of Mechanical Engineering Texas A&M, 400 Bizzell St, College Station, TX, 77843, USA
| | - L L Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - A J Ramirez-Cuesta
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - K Nomura
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089-0242, USA
| | - A Nakano
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089-0242, USA
| | - Y Q Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - W R Hicks
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - A I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - P D Vashishta
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089-0242, USA.
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2
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Drucker NC, Nguyen T, Han F, Siriviboon P, Luo X, Andrejevic N, Zhu Z, Bednik G, Nguyen QT, Chen Z, Nguyen LK, Liu T, Williams TJ, Stone MB, Kolesnikov AI, Chi S, Fernandez-Baca J, Nelson CS, Alatas A, Hogan T, Puretzky AA, Huang S, Yu Y, Li M. Topology stabilized fluctuations in a magnetic nodal semimetal. Nat Commun 2023; 14:5182. [PMID: 37626027 PMCID: PMC10457388 DOI: 10.1038/s41467-023-40765-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
The interplay between magnetism and electronic band topology enriches topological phases and has promising applications. However, the role of topology in magnetic fluctuations has been elusive. Here, we report evidence for topology stabilized magnetism above the magnetic transition temperature in magnetic Weyl semimetal candidate CeAlGe. Electrical transport, thermal transport, resonant elastic X-ray scattering, and dilatometry consistently indicate the presence of locally correlated magnetism within a narrow temperature window well above the thermodynamic magnetic transition temperature. The wavevector of this short-range order is consistent with the nesting condition of topological Weyl nodes, suggesting that it arises from the interaction between magnetic fluctuations and the emergent Weyl fermions. Effective field theory shows that this topology stabilized order is wavevector dependent and can be stabilized when the interband Weyl fermion scattering is dominant. Our work highlights the role of electronic band topology in stabilizing magnetic order even in the classically disordered regime.
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Affiliation(s)
- Nathan C Drucker
- Quantum Measurement Group, MIT, Cambridge, MA, USA.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
| | - Thanh Nguyen
- Quantum Measurement Group, MIT, Cambridge, MA, USA
- Department of Nuclear Science and Engineering, MIT, Cambridge, MA, USA
| | - Fei Han
- Quantum Measurement Group, MIT, Cambridge, MA, USA
- Department of Nuclear Science and Engineering, MIT, Cambridge, MA, USA
| | - Phum Siriviboon
- Quantum Measurement Group, MIT, Cambridge, MA, USA
- Department of Physics, MIT, Cambridge, MA, USA
| | - Xi Luo
- College of Science, University of Shanghai for Science and Technology, Shanghai, China
| | | | - Ziming Zhu
- School of Physics and Electronics, Hunan Normal University, Changsha, China
| | - Grigory Bednik
- Department of Nuclear Science and Engineering, MIT, Cambridge, MA, USA
| | | | - Zhantao Chen
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | | | | | - Travis J Williams
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Matthew B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | | | - Songxue Chi
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | | | - Christie S Nelson
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Ahmet Alatas
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Tom Hogan
- Quantum Design, Inc., San Diego, CA, USA
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Shengxi Huang
- Department of Electrical Engineering, Rice University, Houston, TX, USA
| | - Yue Yu
- Department of Physics and State Key Laboratory of Surface Physics, Fudan University, Shanghai, China.
| | - Mingda Li
- Quantum Measurement Group, MIT, Cambridge, MA, USA.
- Department of Nuclear Science and Engineering, MIT, Cambridge, MA, USA.
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3
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Gao B, Chen T, Wu XC, Flynn M, Duan C, Chen L, Huang CL, Liebman J, Li S, Ye F, Stone MB, Podlesnyak A, Abernathy DL, Adroja DT, Duc Le M, Huang Q, Nevidomskyy AH, Morosan E, Balents L, Dai P. Diffusive excitonic bands from frustrated triangular sublattice in a singlet-ground-state system. Nat Commun 2023; 14:2051. [PMID: 37045810 PMCID: PMC10097669 DOI: 10.1038/s41467-023-37669-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 03/26/2023] [Indexed: 04/14/2023] Open
Abstract
Magnetic order in most materials occurs when magnetic ions with finite moments arrange in a particular pattern below the ordering temperature. Intriguingly, if the crystal electric field (CEF) effect results in a spin-singlet ground state, a magnetic order can still occur due to the exchange interactions between neighboring ions admixing the excited CEF levels. The magnetic excitations in such a state are spin excitons generally dispersionless in reciprocal space. Here we use neutron scattering to study stoichiometric Ni2Mo3O8, where Ni2+ ions form a bipartite honeycomb lattice comprised of two triangular lattices, with ions subject to the tetrahedral and octahedral crystalline environment, respectively. We find that in both types of ions, the CEF excitations have nonmagnetic singlet ground states, yet the material has magnetic order. Furthermore, CEF spin excitons from the tetrahedral sites form a dispersive diffusive pattern around the Brillouin zone boundary, likely due to spin entanglement and geometric frustrations.
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Affiliation(s)
- Bin Gao
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Tong Chen
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Xiao-Chuan Wu
- Department of Physics, University of California, Santa Barbara, CA, 93106, USA
| | - Michael Flynn
- Department of Physics, University of California, Davis, CA, 95616, USA
- Department of Physics, Boston University, Boston, MA, 02215, USA
| | - Chunruo Duan
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Lebing Chen
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Chien-Lung Huang
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
- Department of Physics and Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, 701, Tainan, Taiwan
| | - Jesse Liebman
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Shuyi Li
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Feng Ye
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Matthew B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Andrey Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Douglas L Abernathy
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Devashibhai T Adroja
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - Manh Duc Le
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - Qingzhen Huang
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | | | - Emilia Morosan
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Leon Balents
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA, 93106, USA
- Canadian Institute for Advanced Research, Toronto, ON, Canada
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA.
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4
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A database of synthetic inelastic neutron scattering spectra from molecules and crystals. Sci Data 2023; 10:54. [PMID: 36693896 PMCID: PMC9873913 DOI: 10.1038/s41597-022-01926-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: 10/31/2022] [Accepted: 12/22/2022] [Indexed: 01/26/2023] Open
Abstract
Inelastic neutron scattering (INS) is a powerful tool to study the vibrational dynamics in a material. The analysis and interpretation of the INS spectra, however, are often nontrivial. Unlike diffraction, for which one can quickly calculate the scattering pattern from the structure, the calculation of INS spectra from the structure involves multiple steps requiring significant experience and computational resources. To overcome this barrier, a database of INS spectra consisting of commonly seen materials will be a valuable reference, and it will also lay the foundation of advanced data-driven analysis and interpretation of INS spectra. Here we report such a database compiled for over 20,000 organic molecules and over 10,000 inorganic crystals. The INS spectra are obtained from a streamlined workflow, and the synthetic INS spectra are also verified by available experimental data. The database is expected to greatly facilitate INS data analysis, and it can also enable the utilization of advanced analytics such as data mining and machine learning.Notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
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5
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Jin Z, Li Y, Hu Z, Hu B, Liu Y, Iida K, Kamazawa K, Stone MB, Kolesnikov AI, Abernathy DL, Zhang X, Chen H, Wang Y, Fang C, Wu B, Zaliznyak IA, Tranquada JM, Li Y. Magnetic molecular orbitals in MnSi. SCIENCE ADVANCES 2023; 9:eadd5239. [PMID: 36598989 PMCID: PMC9812394 DOI: 10.1126/sciadv.add5239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
A large body of knowledge about magnetism is attained from models of interacting spins, which usually reside on magnetic ions. Proposals beyond the ionic picture are uncommon and seldom verified by direct observations in conjunction with microscopic theory. Here, using inelastic neutron scattering to study the itinerant near-ferromagnet MnSi, we find that the system's fundamental magnetic units are interconnected, extended molecular orbitals consisting of three Mn atoms each rather than individual Mn atoms. This result is further corroborated by magnetic Wannier orbitals obtained by ab initio calculations. It contrasts the ionic picture with a concrete example and presents an unexplored regime of the spin waves where the wavelength is comparable to the spatial extent of the molecular orbitals. Our discovery brings important insights into not only the magnetism of MnSi but also a broad range of magnetic quantum materials where structural symmetry, electron itinerancy, and correlations act in concert.
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Affiliation(s)
- Zhendong Jin
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Yangmu Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY 11973, USA
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhigang Hu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Biaoyan Hu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Yiran Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Kazuki Iida
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai 319-1106, Ibaraki, Japan
| | - Kazuya Kamazawa
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai 319-1106, Ibaraki, Japan
| | - Matthew B. Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | | | - Douglas L. Abernathy
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Xiangyu Zhang
- State Key Laboratory for Advance Metals and Materials, University of Science and Technology Beijing, Beijing 10083, China
| | - Haiyang Chen
- State Key Laboratory for Advance Metals and Materials, University of Science and Technology Beijing, Beijing 10083, China
| | - Yandong Wang
- State Key Laboratory for Advance Metals and Materials, University of Science and Technology Beijing, Beijing 10083, China
| | - Chen Fang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Kavli Institute for Theoretical Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Biao Wu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Wilczek Quantum Center, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Igor A. Zaliznyak
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - John M. Tranquada
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Yuan Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
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6
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Scheie A, Ziebel M, Chica DG, Bae YJ, Wang X, Kolesnikov AI, Zhu X, Roy X. Spin Waves and Magnetic Exchange Hamiltonian in CrSBr. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202467. [PMID: 35798311 PMCID: PMC9443475 DOI: 10.1002/advs.202202467] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/03/2022] [Indexed: 05/14/2023]
Abstract
CrSBr is an air-stable two-dimensional (2D) van der Waals semiconducting magnet with great technological promise, but its atomic-scale magnetic interactions-crucial information for high-frequency switching-are poorly understood. An experimental study is presented to determine the CrSBr magnetic exchange Hamiltonian and bulk magnon spectrum. The A-type antiferromagnetic order using single crystal neutron diffraction is confirmed here. The magnon dispersions are also measured using inelastic neutron scattering and rigorously fit the excitation modes to a spin wave model. The magnon spectrum is well described by an intra-plane ferromagnetic Heisenberg exchange model with seven nearest in-plane exchanges. This fitted exchange Hamiltonian enables theoretical predictions of CrSBr behavior: as one example, the fitted Hamiltonian is used to predict the presence of chiral magnon edge modes with a spin-orbit enhanced CrSBr heterostructure.
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Affiliation(s)
- Allen Scheie
- Neutron Scattering DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Michael Ziebel
- Department of ChemistryColumbia UniversityNew YorkNY10027USA
| | - Daniel G. Chica
- Department of ChemistryColumbia UniversityNew YorkNY10027USA
| | - Youn June Bae
- Department of ChemistryColumbia UniversityNew YorkNY10027USA
| | - Xiaoping Wang
- Neutron Scattering DivisionOak Ridge National LaboratoryOak RidgeTN37831USA
| | | | - Xiaoyang Zhu
- Department of ChemistryColumbia UniversityNew YorkNY10027USA
| | - Xavier Roy
- Department of ChemistryColumbia UniversityNew YorkNY10027USA
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7
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Sala G, Mourigal M, Boone C, Butch NP, Christianson AD, Delaire O, DeSantis AJ, Hart CL, Hermann RP, Huegle T, Kent DN, Lin JYY, Lumsden MD, Manley ME, Quirinale DG, Stone MB, Z Y. CHESS: The future direct geometry spectrometer at the second target station. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:065109. [PMID: 35778024 DOI: 10.1063/5.0089740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
CHESS, chopper spectrometer examining small samples, is a planned direct geometry neutron chopper spectrometer designed to detect and analyze weak signals intrinsic to small cross sections (e.g., small mass, small magnetic moments, or neutron absorbing materials) in powders, liquids, and crystals. CHESS is optimized to enable transformative investigations of quantum materials, spin liquids, thermoelectrics, battery materials, and liquids. The broad dynamic range of the instrument is also well suited to study relaxation processes and excitations in soft and biological matter. The 15 Hz repetition rate of the Second Target Station at the Spallation Neutron Source enables the use of multiple incident energies within a single source pulse, greatly expanding the information gained in a single measurement. Furthermore, the high flux grants an enhanced capability for polarization analysis. This enables the separation of nuclear from magnetic scattering or coherent from incoherent scattering in hydrogenous materials over a large range of energy and momentum transfer. This paper presents optimizations and technical solutions to address the key requirements envisioned in the science case and the anticipated uses of this instrument.
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Affiliation(s)
- G Sala
- Spallation Neutron Source, Second Target Station, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M Mourigal
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - C Boone
- Spallation Neutron Source, Second Target Station, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - N P Butch
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - A D Christianson
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - O Delaire
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - A J DeSantis
- Spallation Neutron Source, Second Target Station, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - C L Hart
- Spallation Neutron Source, Second Target Station, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - R P Hermann
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Huegle
- Neutron Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - D N Kent
- Spallation Neutron Source, Second Target Station, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J Y Y Lin
- Spallation Neutron Source, Second Target Station, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M D Lumsden
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M E Manley
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - D G Quirinale
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Y Z
- Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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8
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Scheie A, Laurell P, McClarty PA, Granroth GE, Stone MB, Moessner R, Nagler SE. Dirac Magnons, Nodal Lines, and Nodal Plane in Elemental Gadolinium. PHYSICAL REVIEW LETTERS 2022; 128:097201. [PMID: 35302826 DOI: 10.1103/physrevlett.128.097201] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
We investigate the magnetic excitations of elemental gadolinium (Gd) using inelastic neutron scattering, showing that Gd is a Dirac magnon material with nodal lines at K and nodal planes at half integer ℓ. We find an anisotropic intensity winding around the K-point Dirac magnon cone, which is interpreted to indicate Berry phase physics. Using linear spin wave theory calculations, we show the nodal lines have nontrivial Berry phases, and topological surface modes. We also discuss the origin of the nodal plane in terms of a screw-axis symmetry, and introduce a topological invariant characterizing its presence and effect on the scattering intensity. Together, these results indicate a highly nontrivial topology, which is generic to hexagonal close packed ferromagnets. We discuss potential implications for other such systems.
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Affiliation(s)
- A Scheie
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Pontus Laurell
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - P A McClarty
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany
| | - G E Granroth
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - R Moessner
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany
| | - S E Nagler
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Quantum Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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9
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Lin JYY, Sala G, Stone MB. A super-resolution technique to analyze single-crystal inelastic neutron scattering measurements using direct-geometry chopper spectrometers. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:025101. [PMID: 35232127 DOI: 10.1063/5.0079031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
Direct-geometry time-of-flight chopper neutron spectroscopy is instrumental in studying dynamics in liquid, powder, and single crystal systems. We report here that real-space techniques in optical imagery can be adapted to obtain reciprocal-space super resolution dispersion for phonon or magnetic excitations from single-crystal neutron spectroscopy measurements. The procedure to reconstruct super-resolution energy dispersion of excitations relies on an accurate determination of the momentum and energy-dependent point spread function and a dispersion correction technique inspired by an image disparity calculation technique commonly used in stereo imaging. Applying these methods to spinwave dispersion data from a virtual neutron experiment demonstrates ∼5-fold improvement over nominal energy resolution.
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Affiliation(s)
- Jiao Y Y Lin
- Spallation Neutron Source Second Target Station, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Gabriele Sala
- Spallation Neutron Source Second Target Station, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Matthew B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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10
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Shrestha UR, Mamontov E, O'Neill HM, Zhang Q, Kolesnikov AI, Chu X. Experimental mapping of short-wavelength phonons in proteins. Innovation (N Y) 2022; 3:100199. [PMID: 35059681 PMCID: PMC8760453 DOI: 10.1016/j.xinn.2021.100199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 12/14/2021] [Indexed: 11/18/2022] Open
Abstract
Phonons are quasi-particles, observed as lattice vibrations in periodic materials, that often dampen in the presence of structural perturbations. Nevertheless, phonon-like collective excitations exist in highly complex systems, such as proteins, although the origin of such collective motions has remained elusive. Here we present a picture of temperature and hydration dependence of collective excitations in green fluorescent protein (GFP) obtained by inelastic neutron scattering. Our results provide evidence that such excitations can be used as a measure of flexibility/softness and are possibly associated with the protein’s activity. Moreover, we show that the hydration water in GFP interferes with the phonon propagation pathway, enhancing the structural rigidity and stability of GFP. Quantum phenomena in biology have long fascinated people around the world This work presents a direct experimental observation of phonons, the quantum vibrations in a protein The collective excitations or phonons in proteins were detected by utilizing inelastic neutron scattering technique at Oak Ridge National Laboratory Our results illustrate the flexibility-activity relationship in proteins by mapping the temperature and hydration dependence of these collective excitations
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Affiliation(s)
- Utsab R. Shrestha
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Eugene Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Hugh M. O'Neill
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Qiu Zhang
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | | | - Xiangqiang Chu
- Department of Nuclear Science and Technology, Graduate School of China Academy of Engineering Physics, Beijing 100193, China
- Corresponding author
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11
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Mamontov E, Cheng Y, Daemen LL, Kolesnikov AI, Ramirez-Cuesta AJ, Ryder MR, Stone MB. Low rotational barriers for the most dynamically active methyl groups in the proposed antiviral drugs for treatment of SARS-CoV-2, apilimod and tetrandrine. Chem Phys Lett 2021; 777:138727. [PMID: 33994552 PMCID: PMC8105138 DOI: 10.1016/j.cplett.2021.138727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/03/2021] [Accepted: 05/05/2021] [Indexed: 11/30/2022]
Abstract
A recent screening study highlighted a molecular compound, apilimod, for its efficacy against the SARS-CoV-2 virus, while another compound, tetrandrine, demonstrated a remarkable synergy with the benchmark antiviral drug, remdesivir. Here, we find that because of significantly reduced potential energy barriers, which also give rise to pronounced quantum effects, the rotational dynamics of the most dynamically active methyl groups in apilimod and tetrandrine are much faster than those in remdesivir. Because dynamics of methyl groups are essential for biochemical activity, screening studies based on the computed potential energy profiles may help identify promising candidates within a given class of drugs.
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Affiliation(s)
- Eugene Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yongqiang Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Luke L Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | | | | | - Matthew R Ryder
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Matthew B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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12
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Podlesnyak A, Nikitin SE, Ehlers G. Low-energy spin dynamics in rare-earth perovskite oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:403001. [PMID: 34252895 DOI: 10.1088/1361-648x/ac1367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
We review recent studies of spin dynamics in rare-earth orthorhombic perovskite oxides of the type RMO3, where R is a rare-earth ion and M is a transition-metal ion, using single-crystal inelastic neutron scattering (INS). After a short introduction to the magnetic INS technique in general, the results of INS experiments on both transition-metal and rare-earth subsystems for four selected compounds (YbFeO3, TmFeO3, YFeO3, YbAlO3) are presented. We show that the spectrum of magnetic excitations consists of two types of collective modes that are well separated in energy: gapped magnons with a typical bandwidth of <70 meV, associated with the antiferromagnetically (AFM) ordered transition-metal subsystem, and AFM fluctuations of <5 meV within the rare-earth subsystem, with no hybridization of those modes. We discuss the high-energy conventional magnon excitations of the 3dsubsystem only briefly, and focus in more detail on the spectacular dynamics of the rare-earth sublattice in these materials. We observe that the nature of the ground state and the low-energy excitation strongly depends on the identity of the rare-earth ion. In the case of non-Kramers ions, the low-symmetry crystal field completely eliminates the degeneracy of the multiplet state, creating a rich magnetic field-temperature phase diagram. In the case of Kramers ions, the resulting ground state is at least a doublet, which can be viewed as an effective quantum spin-1/2. Equally important is the fact that in Yb-based materials the nearest-neighbor exchange interaction dominates in one direction, despite the three-dimensional nature of the orthoperovskite crystal structure. The observation of a fractional spinon continuum and quantum criticality in YbAlO3demonstrates that Kramers rare-earth based magnets can provide realizations of various aspects of quantum low-dimensional physics.
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Affiliation(s)
- A Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - S E Nikitin
- Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - G Ehlers
- Neutron Technologies Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
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13
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Hu X, Pajerowski DM, Zhang D, Podlesnyak AA, Qiu Y, Huang Q, Zhou H, Klich I, Kolesnikov AI, Stone MB, Lee SH. Freezing of a Disorder Induced Spin Liquid with Strong Quantum Fluctuations. PHYSICAL REVIEW LETTERS 2021; 127:017201. [PMID: 34270292 PMCID: PMC10424116 DOI: 10.1103/physrevlett.127.017201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/26/2021] [Accepted: 06/03/2021] [Indexed: 06/13/2023]
Abstract
Sr_{2}CuTe_{0.5}W_{0.5}O_{6} is a square-lattice magnet with superexchange between S=1/2Cu^{2+} spins mediated by randomly distributed Te and W ions. Here, using sub-K temperature and 20 μeV energy resolution neutron scattering experiments we show that this system transits from a gapless disorder-induced spin liquid to a new quantum state below T_{f}=1.7(1) K, exhibiting a weak frozen moment of ⟨S⟩/S∼0.1 and low energy dynamic susceptibility, χ^{''}(ℏω), linear in energy which is surprising for such a weak freezing in this highly fluctuating quantum regime.
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Affiliation(s)
- Xiao Hu
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Daniel M. Pajerowski
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Depei Zhang
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Andrey A. Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Yiming Qiu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Qing Huang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Haidong Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Israel Klich
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | | | - Matthew B. Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Seung-Hun Lee
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
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14
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Metz PC, Huegle T, Olds D, Page K. Simulating and benchmarking neutron total scattering instrumentation from inception of events to reduced and fitted data. J Appl Crystallogr 2021. [DOI: 10.1107/s1600576721004787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
In the design and realization of modern neutron scattering instrumentation, particularly when designing beamline concepts from the ground up, it is desirable to fully benchmark against realistically simulated data. This is especially true for total scattering beamlines, where the future deliverable data is to be analysed in both reciprocal- and real-space representations, and needs must be carefully balanced to ensure sufficient range, resolution and flux of the instrument. An approach to optimize the design of neutron scattering instrumentation via a workflow including ray-tracing simulations, event-based data reduction, heuristic analysis and fitting against realistically simulated spectra is demonstrated here. The case of the DISCOVER beamline concept at the Spallation Neutron Source is used as an example. The results of the calculations are benchmarked through simulation of existing instrumentation and subsequent direct comparison with measured data. On the basis of the validated models, the ability to explore design characteristics for future beamline concepts or future instrument improvements is demonstrated through the examples of detector tube size and detector layout.
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15
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Computing inelastic neutron scattering spectra from molecular dynamics trajectories. Sci Rep 2021; 11:7938. [PMID: 33846390 PMCID: PMC8041884 DOI: 10.1038/s41598-021-86771-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/18/2021] [Indexed: 11/20/2022] Open
Abstract
Inelastic neutron scattering (INS) provides a weighted density of phonon modes. Currently, INS spectra can only be interpreted for perfectly crystalline materials because of high computational cost for electronic simulations. INS has the potential to provide detailed morphological information if sufficiently large volumes and appropriate structural variety are simulated. Here, we propose a method that allows direct comparison between INS data with molecular dynamics simulations, a simulation method that is frequently used to simulate semicrystalline/amorphous materials. We illustrate the technique by analyzing spectra of a well-studied conjugated polymer, poly(3-hexylthiophene-2,5-diyl) (P3HT) and conclude that our technique provides improved volume and structural variety, but that the classical force field requires improvement before the morphology can be accurately interpreted.
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16
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Cheng YQ, Kolesnikov AI, Ramirez-Cuesta AJ. Simulation of Inelastic Neutron Scattering Spectra Directly from Molecular Dynamics Trajectories. J Chem Theory Comput 2020; 16:7702-7708. [PMID: 33156633 DOI: 10.1021/acs.jctc.0c00937] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inelastic neutron scattering (INS) is a widely used technique to study atomic and molecular vibrations. With the increasing complexity of materials and thus the INS spectra, being able to simulate the spectra from various atomistic models becomes an essential step and also a major bottleneck for INS data analysis. The conventional approach using density functional theory and lattice dynamics often falls short when the materials of interest are complex (e.g., defective, disordered, heterogeneous, amorphous, large-scale), for which molecular dynamics driven by an interatomic force field is a more common approach. In this paper, we demonstrate a method to directly convert molecular dynamics trajectories into simulated INS spectra, including not only fundamental but also higher order excitations. The results are compared with data collected on various representative samples from different neutron spectrometers. This development will open great opportunities by providing the key tool to perform in-depth analysis of INS data and to validate and optimize computer models.
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Affiliation(s)
- Y Q Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - A I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - A J Ramirez-Cuesta
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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17
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Mamontov E, Cheng Y, Daemen LL, Kolesnikov AI, Ramirez-Cuesta AJ, Ryder MR, Stone MB. Hydration-Induced Disorder Lowers the Energy Barriers for Methyl Rotation in Drug Molecules. J Phys Chem Lett 2020; 11:10256-10261. [PMID: 33210927 DOI: 10.1021/acs.jpclett.0c02642] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The thermally activated dynamics of methyl groups are important for biochemical activity as they allow for a more efficient sampling of the energy landscape. Here, we compare methyl rotations in the dry and variously hydrated states of three primary drugs under consideration to treat the recent coronavirus disease (COVID-19), namely, hydroxychloroquine and its sulfate, dexamethasone and its sodium diphosphate, and remdesivir. We find that the main driving force behind the considerable reduction in the activation energy for methyl rotations in the hydrated state is the hydration-induced disorder in the methyl group local environments. Furthermore, the activation energy for methyl rotations in the hydration-induced disordered state is much lower than that in an isolated drug molecule, indicating that neither isolated molecules nor periodic crystalline structures can be used to analyze the potential landscape governing the side group dynamics in drug molecules. Instead, only the explicitly considered disordered structures can provide insight.
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Affiliation(s)
- Eugene Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yongqiang Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Luke L Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Anibal J Ramirez-Cuesta
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Matthew R Ryder
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Matthew B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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18
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Andreani C, Romanelli G, Parmentier A, Senesi R, Kolesnikov AI, Ko HY, Calegari Andrade MF, Car R. Hydrogen Dynamics in Supercritical Water Probed by Neutron Scattering and Computer Simulations. J Phys Chem Lett 2020; 11:9461-9467. [PMID: 33108193 DOI: 10.1021/acs.jpclett.0c02547] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, an investigation of supercritical water is presented combining inelastic and deep inelastic neutron scattering experiments and molecular dynamics simulations based on a machine-learned potential of ab initio quality. The local hydrogen dynamics is investigated at 250 bar and in the temperature range of 553-823 K, covering the evolution from subcritical liquid to supercritical gas-like water. The evolution of libration, bending, and stretching motions in the vibrational density of states is studied, analyzing the spectral features by a mode decomposition. Moreover, the hydrogen nuclear momentum distribution is measured, and its anisotropy is probed experimentally. It is shown that hydrogen bonds survive up to the higher temperatures investigated, and we discuss our results in the framework of the coupling between intramolecular modes and intermolecular librations. Results show that the local potential affecting hydrogen becomes less anisotropic within the molecular plane in the supercritical phase, and we attribute this result to the presence of more distorted hydrogen bonds.
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Affiliation(s)
- Carla Andreani
- Dipartimento di Fisica and NAST Centre, Università degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
- CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR di Messina, Viale F. Stagno dAlcontres 37, 98158 Messina, Italy
| | - Giovanni Romanelli
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | | | - Roberto Senesi
- Dipartimento di Fisica and NAST Centre, Università degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
- CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR di Messina, Viale F. Stagno dAlcontres 37, 98158 Messina, Italy
| | - Alexander I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Hsin-Yu Ko
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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19
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Ben Ishai P, Kidder MK, Kolesnikov AI, Anovitz LM. One-Dimensional Glassy Behavior of Ultraconfined Water Strings. J Phys Chem Lett 2020; 11:7798-7804. [PMID: 32845641 DOI: 10.1021/acs.jpclett.0c02026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Water is renowned for its anomalous behaviors, which can be linked to a distributed H-bond network in bulk water. Ultraconfinement of the water molecule can remove H-bonding, leaving only molecular water. In natural cordierite crystals, water is trapped in an orthorhombic channel with an average diameter of 5.7 Å, running through the center of the unit cell parallel to the c-axis. Calorimetric measurements reveal the existence of a one-dimensional (1D) glass linked to this water. In these channels, water molecules in truncated, sparse 1D strings interact only via dipole-dipole correlations. A physical 1D glass is formed from these strings. This unusual state can be explained by a modified Ising model. This model predicts a dependence of the glass transition temperature, Tg, on the size of these domains. This is confirmed experimentally.
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Affiliation(s)
- Paul Ben Ishai
- Department of Physics, Ariel University, 40700 Ariel, Israel
| | - Michelle K Kidder
- Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Lawrence M Anovitz
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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20
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Chapman CW, Arbanas G, Kolesnikov AI, Leal L, Danon Y, Wendorff C, Ramić K, Liu L, Rahnema F. Methodology for Generating Covariance Data of Thermal Neutron Scattering Cross Sections. NUCL SCI ENG 2020. [DOI: 10.1080/00295639.2020.1792716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Chris W. Chapman
- Oak Ridge National Laboratory, Nuclear Data and Criticality Safety, Reactor and Nuclear Systems Division, Oak Ridge, Tennessee 37831
| | - Goran Arbanas
- Oak Ridge National Laboratory, Nuclear Data and Criticality Safety, Reactor and Nuclear Systems Division, Oak Ridge, Tennessee 37831
| | | | - Luiz Leal
- Institut de Radioprotection et de Sûréte Nucléaire, 31, avenue de la division Leclerc, Fontenay-aux-Roses 92260, France
| | - Yaron Danon
- Rensselaer Polytechnic Institute, Gaerttner LINAC Center, 3021 Tibbits Avenue, Troy, New York 12180
| | - Carl Wendorff
- Rensselaer Polytechnic Institute, Gaerttner LINAC Center, 3021 Tibbits Avenue, Troy, New York 12180
| | - Kemal Ramić
- Rensselaer Polytechnic Institute, Gaerttner LINAC Center, 3021 Tibbits Avenue, Troy, New York 12180
| | - Li Liu
- Rensselaer Polytechnic Institute, Gaerttner LINAC Center, 3021 Tibbits Avenue, Troy, New York 12180
| | - Farzad Rahnema
- Georgia Institute of Technology, Nuclear and Radiological Engineering Department, 770 State Street, Atlanta, Georgia 30332
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21
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Mamontov E, Cheng Y, Daemen LL, Keum JK, Kolesnikov AI, Pajerowski D, Podlesnyak A, Ramirez-Cuesta AJ, Ryder MR, Stone MB. Effect of Hydration on the Molecular Dynamics of Hydroxychloroquine Sulfate. ACS OMEGA 2020; 5:21231-21240. [PMID: 32869009 PMCID: PMC7423024 DOI: 10.1021/acsomega.0c03091] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Chloroquine and its derivative hydroxychloroquine are primarily known as antimalaria drugs. Here, we investigate the influence of hydration water on the molecular dynamics in hydroxychloroquine sulfate, a commonly used solubilized drug form. When hydration, even at a low level, results in a disordered structure, as opposed to the highly ordered structure of dry hydroxychloroquine sulfate, the activation barriers for the rotation of methyl groups in the drug molecules become randomized and, on average, significantly reduced. The facilitated stochastic motions of the methyl groups may benefit the biomolecular activity due to the more efficient sampling of the energy landscape in the disordered hydration environment experienced by the drug molecules in vivo.
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22
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Dun Z, Bai X, Paddison JAM, Hollingworth E, Butch NP, Cruz CD, Stone MB, Hong T, Demmel F, Mourigal M, Zhou H. Quantum Versus Classical Spin Fragmentation in Dipolar Kagome Ice Ho 3Mg 2Sb 3O 14. PHYSICAL REVIEW. X 2020; 10:10.1103/PhysRevX.10.031069. [PMID: 37731951 PMCID: PMC10510738 DOI: 10.1103/physrevx.10.031069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
A promising route to realize entangled magnetic states combines geometrical frustration with quantum-tunneling effects. Spin-ice materials are canonical examples of frustration, and Ising spins in a transverse magnetic field are the simplest many-body model of quantum tunneling. Here, we show that the tripod-kagome lattice material Ho3Mg2Sb3O14 unites an icelike magnetic degeneracy with quantum-tunneling terms generated by an intrinsic splitting of the Ho3+ ground-state doublet, which is further coupled to a nuclear spin bath. Using neutron scattering and thermodynamic experiments, we observe a symmetry-breaking transition at T * ≈ 0.32 K to a remarkable state with three peculiarities: a concurrent recovery of magnetic entropy associated with the strongly coupled electronic and nuclear degrees of freedom; a fragmentation of the spin into periodic and icelike components; and persistent inelastic magnetic excitations down to T ≈ 0.12 K . These observations deviate from expectations of classical spin fragmentation on a kagome lattice, but can be understood within a model of dipolar kagome ice under a homogeneous transverse magnetic field, which we survey with exact diagonalization on small clusters and mean-field calculations. In Ho3Mg2Sb3O14, hyperfine interactions dramatically alter the single-ion and collective properties, and suppress possible quantum correlations, rendering the fragmentation with predominantly single-ion quantum fluctuations. Our results highlight the crucial role played by hyperfine interactions in frustrated quantum magnets and motivate further investigations of the role of quantum fluctuations on partially ordered magnetic states.
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Affiliation(s)
- Zhiling Dun
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Xiaojian Bai
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Joseph A. M. Paddison
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- Churchill College, University of Cambridge, Storey’s Way, Cambridge CB3 0DS, United Kingdom
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Emily Hollingworth
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | | | - Clarina D. Cruz
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Matthew B. Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Tao Hong
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Franz Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Martin Mourigal
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Haidong Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
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23
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Chen X, Krivenko I, Stone MB, Kolesnikov AI, Wolf T, Reznik D, Bedell KS, Lechermann F, Wilson SD. Unconventional Hund metal in a weak itinerant ferromagnet. Nat Commun 2020; 11:3076. [PMID: 32555246 PMCID: PMC7300033 DOI: 10.1038/s41467-020-16868-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/29/2020] [Indexed: 11/09/2022] Open
Abstract
The physics of weak itinerant ferromagnets is challenging due to their small magnetic moments and the ambiguous role of local interactions governing their electronic properties, many of which violate Fermi-liquid theory. While magnetic fluctuations play an important role in the materials' unusual electronic states, the nature of these fluctuations and the paradigms through which they arise remain debated. Here we use inelastic neutron scattering to study magnetic fluctuations in the canonical weak itinerant ferromagnet MnSi. Data reveal that short-wavelength magnons continue to propagate until a mode crossing predicted for strongly interacting quasiparticles is reached, and the local susceptibility peaks at a coherence energy predicted for a correlated Hund metal by first-principles many-body theory. Scattering between electrons and orbital and spin fluctuations in MnSi can be understood at the local level to generate its non-Fermi liquid character. These results provide crucial insight into the role of interorbital Hund's exchange within the broader class of enigmatic multiband itinerant, weak ferromagnets.
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Affiliation(s)
- Xiang Chen
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
| | - Igor Krivenko
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Matthew B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | | | - Thomas Wolf
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76131, Karlsruhe, Germany
| | - Dmitry Reznik
- Department of Physics, University of Colorado at Boulder, Boulder, CO, 80309, USA
| | - Kevin S Bedell
- Department of Physics, Boston College, Chestnut Hill, MA, 02467, USA
| | - Frank Lechermann
- I. Institut für Theoretische Physik, Universität Hamburg, 20355, Hamburg, Germany.
| | - Stephen D Wilson
- Materials Department, University of California, Santa Barbara, CA, 93106, USA.
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24
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Dally RL, Heng AJR, Keselman A, Bordelon MM, Stone MB, Balents L, Wilson SD. Three-Magnon Bound State in the Quasi-One-Dimensional Antiferromagnet α-NaMnO_{2}. PHYSICAL REVIEW LETTERS 2020; 124:197203. [PMID: 32469556 DOI: 10.1103/physrevlett.124.197203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
Here we report on the formation of a three-magnon bound state in the quasi-one-dimensional antiferromagnet α-NaMnO_{2}, where the single-ion, uniaxial anisotropy inherent to the Mn^{3+} ions in this material provides a binding mechanism capable of stabilizing higher order magnon bound states. While such states have long remained elusive in studies of antiferromagnetic chains, neutron scattering data presented here demonstrate that higher order n>2 composite magnons exist, and, specifically, that a weak three-magnon bound state is detected below the antiferromagnetic ordering transition of NaMnO_{2}. We corroborate our findings with exact numerical simulations of a one-dimensional Heisenberg chain with easy-axis anisotropy using matrix-product state techniques, finding a good quantitative agreement with the experiment. These results establish α-NaMnO_{2} as a unique platform for exploring the dynamics of composite magnon states inherent to a classical antiferromagnetic spin chain with Ising-like single ion anisotropy.
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Affiliation(s)
- Rebecca L Dally
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Alvin J R Heng
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Anna Keselman
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Mitchell M Bordelon
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Matthew B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Leon Balents
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Stephen D Wilson
- Materials Department, University of California, Santa Barbara, California 93106, USA
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25
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Pajerowski DM, Ng R, Peterson N, Zhang Y, Stone MB, Dos Santos AM, Bunn J, Fanelli V. 3D scanning and 3D printing AlSi10Mg single crystal mounts for neutron scattering. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:053902. [PMID: 32486750 DOI: 10.1063/5.0008599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
We present methods to quantify sample shapes and generate sample mounts as motivated by the needs of neutron scattering experiments. The 3D sample scanning was performed using photogrammetry and laser scanning, and a comparison is made between the two techniques. The aluminum alloy AlSi10Mg is shown to have favorable properties for many types of mounts used in neutron scattering. Parts were first prototyped with 3D plastic printers, and then, 3D AlSi10Mg prints were made. The final additively manufactured part holds the sample with more points of contact than is possible with traditional manufacturing. The goodness of fit between the mount and sample was measured by x-ray tomography.
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Affiliation(s)
- Daniel M Pajerowski
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Rachael Ng
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Nathan Peterson
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Yuxuan Zhang
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Matthew B Stone
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Antonio M Dos Santos
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Jeffrey Bunn
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Victor Fanelli
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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26
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Maharaj DD, Sala G, Stone MB, Kermarrec E, Ritter C, Fauth F, Marjerrison CA, Greedan JE, Paramekanti A, Gaulin BD. Octupolar versus Néel Order in Cubic 5d^{2} Double Perovskites. PHYSICAL REVIEW LETTERS 2020; 124:087206. [PMID: 32167347 DOI: 10.1103/physrevlett.124.087206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/30/2020] [Indexed: 05/13/2023]
Abstract
We report time-of-flight neutron spectroscopy and neutron and x-ray diffraction studies of the 5d^{2} double perovskite magnets, Ba_{2}MOsO_{6} (M=Zn,Mg,Ca). These materials host antiferromagnetically coupled 5d^{2} Os^{6+} ions decorating a face-centered cubic (fcc) lattice and are found to remain cubic down to the lowest temperatures. They all exhibit thermodynamic anomalies consistent with a single phase transition at a temperature T^{*}, and a gapped magnetic excitation spectrum with spectral weight concentrated at wave vectors typical of type-I antiferromagnetic orders. However, while muon spin resonance experiments show clear evidence for time-reversal symmetry breaking below T^{*}, we observe no corresponding magnetic Bragg scattering signal. These results are shown to be consistent with ferro-octupolar symmetry breaking below T^{*}, and are discussed in the context of other 5d double perovskite magnets and theories of exotic orders driven by multipolar interactions.
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Affiliation(s)
- D D Maharaj
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - G Sala
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - E Kermarrec
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - C Ritter
- Institut Laue-Langevin, Boîte Postale 156, 38042 Grenoble Cédex, France
| | - F Fauth
- CELLS-ALBA Synchrotron, Carrer de la Llum 2-26, 08290 Cerdanyola del Vallès, Barcelona, Spain
| | - C A Marjerrison
- Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - J E Greedan
- Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- Department of Chemistry and Chemical Biology, McMaster University, Ontario L8S 4M1, Canada
| | - A Paramekanti
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - B D Gaulin
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- Canadian Institute for Advanced Research, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
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Kolesnikov AI, Anovitz LM, Hawthorne FC, Podlesnyak A, Schenter GK. Effect of fine-tuning pore structures on the dynamics of confined water. J Chem Phys 2019; 150:204706. [DOI: 10.1063/1.5096771] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. I. Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - L. M. Anovitz
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - F. C. Hawthorne
- Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - A. Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - G. K. Schenter
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 93352, USA
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28
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Chen Q, Fan S, Taddei KM, Stone MB, Kolesnikov AI, Cheng J, Musfeldt JL, Zhou H, Aczel AA. Large Positive Zero-Field Splitting in the Cluster Magnet Ba3CeRu2O9. J Am Chem Soc 2019; 141:9928-9936. [DOI: 10.1021/jacs.9b03389] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Keith M. Taddei
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Matthew B. Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander I. Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jinguang Cheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | | | | | - Adam A. Aczel
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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29
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Wu S, Phelan WA, Liu L, Morey JR, Tutmaher JA, Neuefeind JC, Huq A, Stone MB, Feygenson M, Tam DW, Frandsen BA, Trump B, Wan C, Dunsiger SR, McQueen TM, Uemura YJ, Broholm CL. Incommensurate Magnetism Near Quantum Criticality in CeNiAsO. PHYSICAL REVIEW LETTERS 2019; 122:197203. [PMID: 31144966 PMCID: PMC11132998 DOI: 10.1103/physrevlett.122.197203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Indexed: 06/09/2023]
Abstract
We report the discovery of incommensurate magnetism near quantum criticality in CeNiAsO through neutron scattering and zero field muon spin rotation. For T
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Affiliation(s)
- Shan Wu
- Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
| | - W. A. Phelan
- Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - L. Liu
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - J. R. Morey
- Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - J. A. Tutmaher
- Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - J. C. Neuefeind
- Oak Ridge National Laboratory, Chemical and Engineering Materials Division, Oak Ridge, Tennessee 37831, USA
| | - Ashfia Huq
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee 37831, USA
| | - Matthew B. Stone
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee 37831, USA
| | - M. Feygenson
- Juelich Centre for Neutron Science, Forschungszentrum Juelich GmbH, 52425 Juelich, Germany
| | - David W. Tam
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Benjamin A. Frandsen
- Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA
| | - Benjamin Trump
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Cheng Wan
- Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - S. R. Dunsiger
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - T. M. McQueen
- Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Y. J. Uemura
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - C. L. Broholm
- Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee 37831, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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30
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Gaudet J, Smith EM, Dudemaine J, Beare J, Buhariwalla CRC, Butch NP, Stone MB, Kolesnikov AI, Xu G, Yahne DR, Ross KA, Marjerrison CA, Garrett JD, Luke GM, Bianchi AD, Gaulin BD. Quantum Spin Ice Dynamics in the Dipole-Octupole Pyrochlore Magnet Ce_{2}Zr_{2}O_{7}. PHYSICAL REVIEW LETTERS 2019; 122:187201. [PMID: 31144900 DOI: 10.1103/physrevlett.122.187201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/15/2019] [Indexed: 06/09/2023]
Abstract
Neutron scattering measurements on the pyrochlore magnet Ce_{2}Zr_{2}O_{7} reveal an unusual crystal field splitting of its lowest J=5/2 multiplet, such that its ground-state doublet is composed of m_{J}=±3/2, giving these doublets a dipole-octupole (DO) character with local Ising anisotropy. Its magnetic susceptibility shows weak antiferromagnetic correlations with θ_{CW}=-0.4(2) K, leading to a naive expectation of an all-in, all-out ordered state at low temperatures. Instead, our low-energy inelastic neutron scattering measurements show a dynamic quantum spin ice state, with suppressed scattering near |Q|=0, and no long-range order at low temperatures. This is consistent with recent theory predicting symmetry-enriched U(1) quantum spin liquids for such DO doublets decorating the pyrochlore lattice. Finally, we show that disorder, especially oxidation of powder samples, is important in Ce_{2}Zr_{2}O_{7} and could play an important role in the low-temperature behavior of this material.
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Affiliation(s)
- J Gaudet
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
- Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
- Center for Neutron Research, National Institute of Standards and Technology, MS 6100 Gaithersburg, Maryland 20899, USA
| | - E M Smith
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
| | - J Dudemaine
- Département de Physique, Université de Montréal, 2900 Boulevard Édouard-Montpetit, Montréal, Quebec, H3T 1J4, Canada
| | - J Beare
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
| | - C R C Buhariwalla
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
| | - N P Butch
- Center for Neutron Research, National Institute of Standards and Technology, MS 6100 Gaithersburg, Maryland 20899, USA
| | - M B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Guangyong Xu
- Center for Neutron Research, National Institute of Standards and Technology, MS 6100 Gaithersburg, Maryland 20899, USA
| | - D R Yahne
- Department of Physics, Colorado State University, 200 West Lake Street, Fort Collins, Colorado 80523-1875, USA
| | - K A Ross
- Department of Physics, Colorado State University, 200 West Lake Street, Fort Collins, Colorado 80523-1875, USA
- Canadian Institute for Advanced Research, 661 University Avenue, Toronto, Ontario, M5G 1M1, Canada
| | - C A Marjerrison
- Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
| | - J D Garrett
- Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
| | - G M Luke
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
- Canadian Institute for Advanced Research, 661 University Avenue, Toronto, Ontario, M5G 1M1, Canada
| | - A D Bianchi
- Département de Physique, Université de Montréal, 2900 Boulevard Édouard-Montpetit, Montréal, Quebec, H3T 1J4, Canada
- Regroupement Québécois sur les Matériaux de Pointe (RQMP), Quebec, H3T 3J7, Canada
| | - B D Gaulin
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
- Canadian Institute for Advanced Research, 661 University Avenue, Toronto, Ontario, M5G 1M1, Canada
- Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
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31
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Bai X, Paddison JAM, Kapit E, Koohpayeh SM, Wen JJ, Dutton SE, Savici AT, Kolesnikov AI, Granroth GE, Broholm CL, Chalker JT, Mourigal M. Magnetic Excitations of the Classical Spin Liquid MgCr_{2}O_{4}. PHYSICAL REVIEW LETTERS 2019; 122:097201. [PMID: 30932548 DOI: 10.1103/physrevlett.122.097201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Indexed: 06/09/2023]
Abstract
We report a comprehensive inelastic neutron-scattering study of the frustrated pyrochlore antiferromagnet MgCr_{2}O_{4} in its cooperative paramagnetic regime. Theoretical modeling yields a microscopic Heisenberg model with exchange interactions up to third-nearest neighbors, which quantitatively explains all of the details of the dynamic magnetic response. Our work demonstrates that the magnetic excitations in paramagnetic MgCr_{2}O_{4} are faithfully represented in the entire Brillouin zone by a theory of magnons propagating in a highly correlated paramagnetic background. Our results also suggest that MgCr_{2}O_{4} is proximate to a spiral spin-liquid phase distinct from the Coulomb phase, which has implications for the magnetostructural phase transition in MgCr_{2}O_{4}.
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Affiliation(s)
- X Bai
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - J A M Paddison
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- Churchill College, University of Cambridge, Storey's Way, Cambridge CB3 0DS, United Kingdom
| | - E Kapit
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Parks Road, Oxford OX1 3NP, United Kingdom
- Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA
| | - S M Koohpayeh
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - J-J Wen
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - S E Dutton
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - A T Savici
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - G E Granroth
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - C L Broholm
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J T Chalker
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Parks Road, Oxford OX1 3NP, United Kingdom
| | - M Mourigal
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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32
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Ewings RA, Stewart JR, Perring TG, Bewley RI, Le MD, Raspino D, Pooley DE, Škoro G, Waller SP, Zacek D, Smith CA, Riehl-Shaw RC. Upgrade to the MAPS neutron time-of-flight chopper spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:035110. [PMID: 30927771 DOI: 10.1063/1.5086255] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/01/2019] [Indexed: 05/23/2023]
Abstract
The MAPS direct geometry time-of-flight chopper spectrometer at the ISIS pulsed neutron and muon source has been in operation since 1999, and its novel use of a large array of position-sensitive neutron detectors paved the way for a later generations of chopper spectrometers around the world. Almost two decades of experience of user operations on MAPS, together with lessons learned from the operation of new generation instruments, led to a decision to perform three parallel upgrades to the instrument. These were to replace the primary beamline collimation with supermirror neutron guides, to install a disk chopper, and to modify the geometry of the poisoning in the water moderator viewed by MAPS. Together, these upgrades were expected to increase the neutron flux substantially, to allow more flexible use of repetition rate multiplication and to reduce some sources of background. Here, we report the details of these upgrades and compare the performance of the instrument before and after their installation as well as to Monte Carlo simulations. These illustrate that the instrument is performing in line with, and in some respects in excess of, expectations. It is anticipated that the improvement in performance will have a significant impact on the capabilities of the instrument. A few examples of scientific commissioning are presented to illustrate some of the possibilities.
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Affiliation(s)
- R A Ewings
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - J R Stewart
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - T G Perring
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - R I Bewley
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - M D Le
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - D Raspino
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - D E Pooley
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - G Škoro
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - S P Waller
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - D Zacek
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - C A Smith
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - R C Riehl-Shaw
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
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33
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Spencer EC, Kolesnikov AI, Woodfield BF, Ross NL. New Insights about CuO Nanoparticles from Inelastic Neutron Scattering. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:nano9030312. [PMID: 30813525 PMCID: PMC6473763 DOI: 10.3390/nano9030312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Inelastic Neutron Scattering (INS) spectroscopy has provided a unique insight into the magnetodymanics of nanoscale copper (II) oxide (CuO). We present evidence for the propagation of magnons in the directions of the ordering vectors of both the commensurate and helically modulated incommensurate antiferromagnetic phases of CuO. The temperature dependency of the magnon spin-wave intensity (in the accessible energy-range of the experiment) conforms to the Bose population of states at low temperatures (T ≤ 100 K), as expected for bosons, then intensity significantly increases, with maximum at about 225 K (close to TN), and decreases at higher temperatures. The obtained results can be related to gradual softening of the dispersion curves of magnon spin-waves and decreasing the spin gap with temperature approaching TN on heating, and slow dissipation of the short-range dynamic spin correlations at higher temperatures. However, the intensity of the magnon signal was found to be particle size dependent, and increases with decreasing particle size. This "reverse size effect" is believed to be related to either creation of single-domain particles at the nanoscale, or "superferromagnetism effect" and the formation of collective particle states.
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Affiliation(s)
- Elinor C Spencer
- Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
| | | | - Brian F Woodfield
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
| | - Nancy L Ross
- Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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34
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Cheng YQ, Daemen LL, Kolesnikov AI, Ramirez-Cuesta AJ. Simulation of Inelastic Neutron Scattering Spectra Using OCLIMAX. J Chem Theory Comput 2019; 15:1974-1982. [DOI: 10.1021/acs.jctc.8b01250] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Y. Q. Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge Tennessee 37831, United States
| | - L. L. Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge Tennessee 37831, United States
| | - A. I. Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge Tennessee 37831, United States
| | - A. J. Ramirez-Cuesta
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge Tennessee 37831, United States
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35
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Xue Z, Ramirez‐Cuesta AJ, Brown CM, Calder S, Cao H, Chakoumakos BC, Daemen LL, Huq A, Kolesnikov AI, Mamontov E, Podlesnyak AA, Wang X. Neutron Instruments for Research in Coordination Chemistry. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201801076] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Zi‐Ling Xue
- Department of Chemistry University of Tennessee 37996 Knoxville Tennessee United States
| | - Anibal J. Ramirez‐Cuesta
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Craig M. Brown
- Center for Neutron Research National Institute of Standards and Technology 20899 Gaithersburg Maryland United States
- Department of Chemical and Biomolecular Engineering University of Delaware 19716 Newark Delaware United States
| | - Stuart Calder
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Huibo Cao
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Bryan C. Chakoumakos
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Luke L. Daemen
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Ashfia Huq
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Alexander I. Kolesnikov
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Eugene Mamontov
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Andrey A. Podlesnyak
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
| | - Xiaoping Wang
- Neutron Scattering Division Oak Ridge National Laboratory 37831 Oak Ridge Tennessee United States
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36
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Gautam S, Kolesnikov AI, Rother G, Dai S, Qiao ZA, Cole D. Effects of Confinement and Pressure on the Vibrational Behavior of Nano-Confined Propane. J Phys Chem A 2018; 122:6736-6745. [PMID: 30040898 DOI: 10.1021/acs.jpca.8b05028] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fluids confined in nanopores exhibit significant deviations in their structure and dynamics from the bulk behavior. Although phase, structural, and diffusive behaviors of confined fluids have been investigated and reported extensively, confinement effects on the vibrational properties are less understood. We study the vibrational behavior of propane confined in 1.5 nm nanopores of MCM-41-S using inelastic neutron scattering (INS) and molecular dynamics (MD) simulations. Vibrational spectra have been obtained from INS data as functions of temperature and pressure. At ambient pressure, a strong quasielastic signal observed in the INS spectrum at 80 K suggests that confined propane remains liquid below the bulk phase melting point of 85 K. The quasielastic signal is heavily suppressed when either the pressure is increased to 1 kbar or the temperature is lowered to 30 K, indicating solidification of pore-confined propane. Confinement in MCM-41-S pores results in a glass-like state of propane that exhibits a relatively featureless low-energy vibrational spectrum compared to that of the bulk crystalline propane. Increasing the pressure to 3 kbar results in hardening of the intermolecular and methyl torsional modes. The INS data are used for estimating the isochoric specific heat of confined propane, which is compared with the specific heat of bulk propane reported in literature. Data from MD simulations are used to calculate the vibrational power spectra that agree qualitatively with the experimental data. Simulation data also suggest a reduction of the structural ordering (positional, orientational, and intramolecular) of propane under confinement.
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Affiliation(s)
- Siddharth Gautam
- School of Earth Sciences , The Ohio State University , Columbus , 43210 , Ohio United States
| | | | | | | | - Zhen-An Qiao
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry , Jilin University , Changchun 130012 , China
| | - David Cole
- School of Earth Sciences , The Ohio State University , Columbus , 43210 , Ohio United States
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Lee J, Matsuda M, Mydosh JA, Zaliznyak I, Kolesnikov AI, Süllow S, Ruff JPC, Granroth GE. Dual Nature of Magnetism in a Uranium Heavy-Fermion System. PHYSICAL REVIEW LETTERS 2018; 121:057201. [PMID: 30118279 DOI: 10.1103/physrevlett.121.057201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Indexed: 06/08/2023]
Abstract
The duality between the localized and itinerant nature of magnetism in 5f-electron systems has been a long-standing puzzle. Here, we report inelastic neutron scattering measurements, which reveal both local and itinerant aspects of magnetism in a single-crystalline system of UPt_{2}Si_{2}. In the antiferromagnetic state, we observe a broad continuum of diffuse magnetic scattering with a resonancelike gap of ≈7 meV and the surprising absence of coherent spin waves, suggestive of itinerant magnetism. While the gap closes above the Néel temperature, strong dynamic spin correlations persist to a high temperature. Nevertheless, the size and temperature dependence of the total magnetic spectral weight can be well described by a local moment with J=4. Furthermore, polarized neutron measurements reveal that the magnetic fluctuations are mostly transverse, with little or none of the longitudinal component expected for itinerant moments. These results suggest that a dual description of local and itinerant magnetism is required to understand UPt_{2}Si_{2} and, by extension, other 5f systems, in general.
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Affiliation(s)
- Jooseop Lee
- CHESS, Cornell University, Ithaca, New York 14853, USA
- CALDES, Institute for Basic Science, Pohang 37673, Korea
| | - Masaaki Matsuda
- Neutron Scattering Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, USA
| | - John A Mydosh
- Kamerlingh Onnes Laboratory and Lorentz Institute, Leiden University, 2300 RA Leiden, Netherlands
| | - Igor Zaliznyak
- CMPMSD, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Alexander I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, USA
| | - Stefan Süllow
- Technische Universität Braunschweig, Braunschweig, Germany
| | | | - Garrett E Granroth
- Neutron Scattering Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, USA
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Granroth GE, An K, Smith HL, Whitfield P, Neuefeind JC, Lee J, Zhou W, Sedov VN, Peterson PF, Parizzi A, Skorpenske H, Hartman SM, Huq A, Abernathy DL. Event-based processing of neutron scattering data at the Spallation Neutron Source. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576718004727] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The Spallation Neutron Source at Oak Ridge National Laboratory, USA, ushered in a new era of neutron scattering experiments through the use of event-based data. Tagging each neutron event allows pump–probe experiments, measurements with a parameter asynchronous to the source, measurements with continuously varying parameters and novel ways of testing instrument components. This contribution will focus on a few examples. A pulsed magnet has been used to study diffraction under extreme fields. Continuous ramping of temperature is becoming standard on the POWGEN diffractometer. Battery degradation and phase transformations under heat and stress are often studied on the VULCAN diffractometer. Supercooled Al2O3 was studied on NOMAD. A study of a metallic glass through its glass transition was performed on the ARCS spectrometer, and the effect of source variation on chopper stability was studied for the SEQUOIA spectrometer. Besides a summary of these examples, an overview is provided of the hardware and software advances to enable these and many other event-based measurements.
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Prisk TR, Hoffmann C, Kolesnikov AI, Mamontov E, Podlesnyak AA, Wang X, Kent PRC, Anovitz LM. Fast Rotational Diffusion of Water Molecules in a 2D Hydrogen Bond Network at Cryogenic Temperatures. PHYSICAL REVIEW LETTERS 2018; 120:196001. [PMID: 29799243 DOI: 10.1103/physrevlett.120.196001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Indexed: 05/15/2023]
Abstract
Individual water molecules or small clusters of water molecules contained within microporous minerals present an extreme case of confinement where the local structure of hydrogen bond networks are dramatically altered from bulk water. In the zinc silicate hemimorphite, the water molecules form a two-dimensional hydrogen bond network with hydroxyl groups in the crystal framework. Here, we present a combined experimental and theoretical study of the structure and dynamics of water molecules within this network. The water molecules undergo a continuous phase transition in their orientational configuration analogous to a two-dimensional Ising model. The incoherent dynamic structure factor reveals two thermally activated relaxation processes, one on a subpicosecond timescale and another on a 10-100 ps timescale, between 70 and 130 K. The slow process is an in-plane reorientation of the water molecule involving the breaking of hydrogen bonds with a framework that, despite the low temperatures involved, is analogous to rotational diffusion of water molecules in the bulk liquid. The fast process is a localized motion of the water molecule with no apparent analogs among known bulk or confined phases of water.
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Affiliation(s)
- T R Prisk
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 208996-6100, USA
| | - C Hoffmann
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - E Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A A Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - X Wang
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - P R C Kent
- Center for Nanophase Materials Sciences and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - L M Anovitz
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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40
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Savchenkov PS, Alekseev PA, Podlesnyak A, Kolesnikov AI, Nemkovski KS. Intermediate-valence state of the Sm and Eu in SmB 6 and EuCu 2Si 2: neutron spectroscopy data and analysis. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:055801. [PMID: 29324435 DOI: 10.1088/1361-648x/aaa1aa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Magnetic neutron scattering data for Sm (SmB6, Sm(Y)S) and Eu (EuCu2Si2-x Ge x ) intermediate-valence compounds have been analysed in terms of a generalized model of the intermediate-radius exciton. Special attention is paid to the correlation between the average ion's valence and parameters of the low-energy excitation in the neutron spectra, such as the resonance mode, including its magnetic form factor. Along with specific features of the formation of the intermediate-valence state for Sm and Eu ions, common physical mechanisms have been revealed for systems based on these elements from the middle of the rare-earth series. A consistent description of the existing experimental data has been obtained by using the concept of a loosely bound hole for the Eu f-electron shell in the intermediate-valence state, in analogy with the previously established loosely bound electron model for the Sm ion.
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Affiliation(s)
- P S Savchenkov
- National Research Nuclear University MEPhI, 115409, Moscow, Russia. National Research Centre Kurchatov Institute, 123182, Moscow, Russia
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41
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Marjerrison CA, Thompson CM, Sala G, Maharaj DD, Kermarrec E, Cai Y, Hallas AM, Wilson MN, Munsie TJS, Granroth GE, Flacau R, Greedan JE, Gaulin BD, Luke GM. Cubic Re 6+ (5d 1) Double Perovskites, Ba 2MgReO 6, Ba 2ZnReO 6, and Ba 2Y 2/3ReO 6: Magnetism, Heat Capacity, μSR, and Neutron Scattering Studies and Comparison with Theory. Inorg Chem 2016; 55:10701-10713. [PMID: 27700052 DOI: 10.1021/acs.inorgchem.6b01933] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Double perovskites (DP) of the general formula Ba2MReO6, where M = Mg, Zn, and Y2/3, all based on Re6+ (5d1, t2g1), were synthesized and studied using magnetization, heat capacity, muon spin relaxation, and neutron-scattering techniques. All are cubic, Fm3̅m, at ambient temperature to within the resolution of the X-ray and neutron diffraction data, although the muon data suggest the possibility of a local distortion for M = Mg. The M = Mg DP is a ferromagnet, Tc = 18 K, with a saturation moment ∼0.3 bohr magnetons at 3 K. There are two anomalies in the heat capacity: a sharp feature at 18 K and a broad maximum centered near 33 K. The total entropy loss below 45 K is 9.68 e.u., which approaches R ln 4 (11.52 e.u.) supporting a j = 3/2 ground state. The unit cell constants of Ba2MgReO6 and the isostructural, isoelectronic analogue, Ba2LiOsO6, differ by only 0.1%, yet the latter is an anti-ferromagnet. The M = Zn DP also appears to be a ferromagnet, Tc = 11 K, μsat(Re) = 0.1 μB. In this case the heat capacity shows a somewhat broad peak near 10 K and a broader maximum at ∼33 K, behavior that can be traced to a smaller particle size, ∼30 nm, for this sample. For both M = Mg and Zn, the low-temperature magnetic heat capacity follows a T3/2 behavior, consistent with a ferromagnetic spin wave. An attempt to attribute the broad 33 K heat capacity anomalies to a splitting of the j = 3/2 state by a crystal distortion is not supported by inelastic neutron scattering, which shows no transition at the expected energy of ∼7 meV nor any transition up to 100 meV. However, the results for the two ferromagnets are compared to the theory of Chen, Pereira, and Balents, and the computed heat capacity predicts the two maxima observed experimentally. The M = Y2/3 DP, with a significantly larger cell constant (3%) than the ferromagnets, shows predominantly anti-ferromagnetic correlations, and the ground state is complex with a spin frozen component Tg = 16 K from both direct current and alternating current susceptibility and μSR data but with a persistent dynamic component. The low-temperature heat capacity shows a T1 power law. The unit cell constant of B = Y2/3 is less than 1% larger than that of the ferromagnetic Os7+ (5d1) DP, Ba2NaOsO6.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Garrett E Granroth
- Quantum Condensed Matter Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Roxana Flacau
- Canadian Neutron Beam Centre, Canadian Nuclear Laboratories , Chalk River, Ontario K0J 1J0, Canada
| | - John E Greedan
- Brockhouse Institute for Materials Research , Hamilton, Ontario L8S 4M1, Canada
| | - Bruce D Gaulin
- Brockhouse Institute for Materials Research , Hamilton, Ontario L8S 4M1, Canada.,Canadian Institute for Advanced Research , 180 Dundas Street W, Toronto, Ontario M5G 1Z8, Canada
| | - Graeme M Luke
- Brockhouse Institute for Materials Research , Hamilton, Ontario L8S 4M1, Canada.,Canadian Institute for Advanced Research , 180 Dundas Street W, Toronto, Ontario M5G 1Z8, Canada
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Banerjee A, Bridges CA, Yan JQ, Aczel AA, Li L, Stone MB, Granroth GE, Lumsden MD, Yiu Y, Knolle J, Bhattacharjee S, Kovrizhin DL, Moessner R, Tennant DA, Mandrus DG, Nagler SE. Proximate Kitaev quantum spin liquid behaviour in a honeycomb magnet. NATURE MATERIALS 2016; 15:733-740. [PMID: 27043779 DOI: 10.1038/nmat4604] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 02/22/2016] [Indexed: 06/05/2023]
Abstract
Quantum spin liquids (QSLs) are topological states of matter exhibiting remarkable properties such as the capacity to protect quantum information from decoherence. Whereas their featureless ground states have precluded their straightforward experimental identification, excited states are more revealing and particularly interesting owing to the emergence of fundamentally new excitations such as Majorana fermions. Ideal probes of these excitations are inelastic neutron scattering experiments. These we report here for a ruthenium-based material, α-RuCl3, continuing a major search (so far concentrated on iridium materials) for realizations of the celebrated Kitaev honeycomb topological QSL. Our measurements confirm the requisite strong spin-orbit coupling and low-temperature magnetic order matching predictions proximate to the QSL. We find stacking faults, inherent to the highly two-dimensional nature of the material, resolve an outstanding puzzle. Crucially, dynamical response measurements above interlayer energy scales are naturally accounted for in terms of deconfinement physics expected for QSLs. Comparing these with recent dynamical calculations involving gauge flux excitations and Majorana fermions of the pure Kitaev model, we propose the excitation spectrum of α-RuCl3 as a prime candidate for fractionalized Kitaev physics.
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Affiliation(s)
- A Banerjee
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - C A Bridges
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - J-Q Yan
- Material Sciences and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - A A Aczel
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - L Li
- Department of Physics, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - M B Stone
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - G E Granroth
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Neutron Data Analysis &Visualization Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - M D Lumsden
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - Y Yiu
- Department of Physics, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - J Knolle
- Department of Physics, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
| | - S Bhattacharjee
- Max Planck Institute for the Physics of Complex Systems, D-01187 Dresden, Germany
- International Center for Theoretical Sciences, TIFR, Bangalore 560012, India
| | - D L Kovrizhin
- Department of Physics, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
| | - R Moessner
- Max Planck Institute for the Physics of Complex Systems, D-01187 Dresden, Germany
| | - D A Tennant
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - D G Mandrus
- Material Sciences and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - S E Nagler
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Bredesen Center, University of Tennessee, Knoxville, Tennessee 37966, USA
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43
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Kolesnikov AI, Reiter GF, Choudhury N, Prisk TR, Mamontov E, Podlesnyak A, Ehlers G, Seel AG, Wesolowski DJ, Anovitz LM. Quantum Tunneling of Water in Beryl: A New State of the Water Molecule. PHYSICAL REVIEW LETTERS 2016; 116:167802. [PMID: 27152824 DOI: 10.1103/physrevlett.116.167802] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 05/15/2023]
Abstract
Using neutron scattering and ab initio simulations, we document the discovery of a new "quantum tunneling state" of the water molecule confined in 5 Å channels in the mineral beryl, characterized by extended proton and electron delocalization. We observed a number of peaks in the inelastic neutron scattering spectra that were uniquely assigned to water quantum tunneling. In addition, the water proton momentum distribution was measured with deep inelastic neutron scattering, which directly revealed coherent delocalization of the protons in the ground state.
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Affiliation(s)
- Alexander I Kolesnikov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - George F Reiter
- Physics Department, University of Houston, Houston, Texas 77204, USA
| | - Narayani Choudhury
- Math and Science Division, Lake Washington Institute of Technology, Kirkland, Washington 98034, USA; School of Science, Technology, Engineering and Math, University of Washington, Bothell, Washington 98011, USA
| | - Timothy R Prisk
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Eugene Mamontov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Andrey Podlesnyak
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - George Ehlers
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Andrew G Seel
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - David J Wesolowski
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Lawrence M Anovitz
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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44
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Fuhrman WT, Leiner J, Nikolić P, Granroth GE, Stone MB, Lumsden MD, DeBeer-Schmitt L, Alekseev PA, Mignot JM, Koohpayeh SM, Cottingham P, Phelan WA, Schoop L, McQueen TM, Broholm C. Interaction driven subgap spin exciton in the Kondo insulator SmB6. PHYSICAL REVIEW LETTERS 2015; 114:036401. [PMID: 25659009 DOI: 10.1103/physrevlett.114.036401] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Indexed: 06/04/2023]
Abstract
Using inelastic neutron scattering, we map a 14 meV coherent resonant mode in the topological Kondo insulator SmB6 and describe its relation to the low energy insulating band structure. The resonant intensity is confined to the X and R high symmetry points, repeating outside the first Brillouin zone and dispersing less than 2 meV, with a 5d-like magnetic form factor. We present a slave-boson treatment of the Anderson Hamiltonian with a third neighbor dominated hybridized band structure. This approach produces a spin exciton below the charge gap with features that are consistent with the observed neutron scattering. We find that maxima in the wave vector dependence of the inelastic neutron scattering indicate band inversion.
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Affiliation(s)
- W T Fuhrman
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - J Leiner
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - P Nikolić
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA and School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, Virginia 22030, USA
| | - G E Granroth
- Neutron Data Analysis and Visualization Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M B Stone
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M D Lumsden
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - L DeBeer-Schmitt
- Instrument Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - P A Alekseev
- National Research Centre "Kurchatov Institute," 123182 Moscow, Russia and National Research Nuclear University "MEPhI," 115409 Moscow, Russia
| | - J-M Mignot
- Laboratoire Léon Brillouin, CEA-CNRS, CEA/Saclay, 91191 Gif sur Yvette, France
| | - S M Koohpayeh
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - P Cottingham
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA and Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - W Adam Phelan
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA and Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - L Schoop
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA and Department of Chemistry, Princeton University, Princeton, New Jersey 08540, USA
| | - T M McQueen
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA and Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA and Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - C Broholm
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA and Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA and Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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45
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Granroth G, Hahn S. Monte Carlo simulation of the resolution volume for the SEQUOIA spectrometer. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158303006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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46
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Xu Z, Stock C, Chi S, Kolesnikov AI, Xu G, Gu G, Tranquada JM. Neutron-scattering evidence for a periodically modulated superconducting phase in the underdoped cuprate La1.905Ba0.095CuO4. PHYSICAL REVIEW LETTERS 2014; 113:177002. [PMID: 25379931 DOI: 10.1103/physrevlett.113.177002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Indexed: 06/04/2023]
Abstract
The role of antiferromagnetic spin correlations in high-temperature superconductors remains a matter of debate. We present inelastic neutron-scattering evidence that gapless spin fluctuations coexist with superconductivity in La1.905Ba0.095CuO4. Furthermore, we observe that both the low-energy magnetic spectral weight and the spin incommensurability are enhanced with the onset of superconducting correlations. We propose that the coexistence occurs through intertwining of spatial modulations of the pair wave function and the antiferromagnetic correlations. This proposal is also directly relevant to sufficiently underdoped La(2-x)Sr(x)CuO(4) and YBa(2)Cu(3)O(6+x).
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Affiliation(s)
- Zhijun Xu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - C Stock
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Songxue Chi
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - A I Kolesnikov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Guangyong Xu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - Genda Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - J M Tranquada
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
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47
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Kolesnikov AI, Anovitz LM, Mamontov E, Podlesnyak A, Ehlers G. Strong Anisotropic Dynamics of Ultra-Confined Water. J Phys Chem B 2014; 118:13414-9. [DOI: 10.1021/jp505355b] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexander I. Kolesnikov
- Chemical and Engineering Materials
Division, ‡Chemical Sciences Division, and §Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Lawrence M. Anovitz
- Chemical and Engineering Materials
Division, ‡Chemical Sciences Division, and §Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Eugene Mamontov
- Chemical and Engineering Materials
Division, ‡Chemical Sciences Division, and §Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Andrey Podlesnyak
- Chemical and Engineering Materials
Division, ‡Chemical Sciences Division, and §Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Georg Ehlers
- Chemical and Engineering Materials
Division, ‡Chemical Sciences Division, and §Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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48
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Stone MB, Niedziela JL, Abernathy DL, DeBeer-Schmitt L, Ehlers G, Garlea O, Granroth GE, Graves-Brook M, Kolesnikov AI, Podlesnyak A, Winn B. A comparison of four direct geometry time-of-flight spectrometers at the Spallation Neutron Source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:045113. [PMID: 24784665 DOI: 10.1063/1.4870050] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The Spallation Neutron Source at Oak Ridge National Laboratory now hosts four direct geometry time-of-flight chopper spectrometers. These instruments cover a range of wave-vector and energy transfer space with varying degrees of neutron flux and resolution. The regions of reciprocal and energy space available to measure at these instruments are not exclusive and overlap significantly. We present a direct comparison of the capabilities of this instrumentation, conducted by data mining the instrument usage histories, and specific scanning regimes. In addition, one of the common science missions for these instruments is the study of magnetic excitations in condensed matter systems. We have measured the powder averaged spin wave spectra in one particular sample using each of these instruments, and use these data in our comparisons.
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Affiliation(s)
- M B Stone
- Quantum Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J L Niedziela
- Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - D L Abernathy
- Quantum Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - L DeBeer-Schmitt
- Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - G Ehlers
- Quantum Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - O Garlea
- Quantum Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - G E Granroth
- Neutron Data Analysis and Visualization Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M Graves-Brook
- Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A I Kolesnikov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A Podlesnyak
- Quantum Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - B Winn
- Quantum Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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49
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Spencer EC, Huang B, Parker SF, Kolesnikov AI, Ross NL, Woodfield BF. The thermodynamic properties of hydrated γ-Al2O3 nanoparticles. J Chem Phys 2013; 139:244705. [DOI: 10.1063/1.4850636] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Anovitz LM, Mamontov E, ben Ishai P, Kolesnikov AI. Anisotropic dynamics of water ultraconfined in macroscopically oriented channels of single-crystal beryl: a multifrequency analysis. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:052306. [PMID: 24329263 DOI: 10.1103/physreve.88.052306] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 08/09/2013] [Indexed: 06/03/2023]
Abstract
The properties of fluids can be significantly altered by the geometry of their confining environments. While there has been significant work on the properties of such confined fluids, the properties of fluids under ultraconfinement, environments where, at least in one plane, the dimensions of the confining environment are similar to that of the confined molecule, have not been investigated. This paper investigates the dynamic properties of water in beryl (Be(3)Al(2)Si(6)O(18)), the structure of which contains approximately 5-Å-diam channels parallel to the c axis. Three techniques, inelastic neutron scattering, quasielastic neutron scattering, and dielectric spectroscopy, have been used to quantify these properties over a dynamic range covering approximately 16 orders of magnitude. Because beryl can be obtained in large single crystals we were able to quantify directional variations, perpendicular and parallel to the channel directions, in the dynamics of the confined fluid. These are significantly anisotropic and, somewhat counterintuitively, show that vibrations parallel to the c-axis channels are significantly more hindered than those perpendicular to the channels. The effective potential for vibrations in the c direction is harder than the potential in directions perpendicular to it. There is evidence of single-file diffusion of water molecules along the channels at higher temperatures, but below 150 K this diffusion is strongly suppressed. No such suppression, however, has been observed in the channel-perpendicular direction. Inelastic neutron scattering spectra include an intramolecular stretching O-H peak at ~465 meV. As this is nearly coincident with that known for free water molecules and approximately 30 meV higher than that in liquid water or ice, this suggests that there is no hydrogen bonding constraining vibrations between the channel water and the beryl structure. However, dielectric spectroscopic measurements at higher temperatures and lower frequencies yield an activation energy for the dipole reorientation of 16.4 ± 0.14 kJ/mol, close to the energy required to break a hydrogen bond in bulk water. This may suggest the presence of some other form of bonding between the water molecules and the structure, but the resolution of the apparent contradiction between the inelastic neutron and dielectric spectroscopic results remains uncertain.
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Affiliation(s)
- Lawrence M Anovitz
- Chemical Sciences Division, MS 6110, P.O. Box 2008, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110, USA
| | - Eugene Mamontov
- Chemical and Engineering Materials Division, MS 6473, P.O. Box 2008, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6473, USA
| | - Paul ben Ishai
- Department of Applied Physics, The Hebrew University of Jerusalem, Givat Ram, 91904 Jerusalem, Israel
| | - Alexander I Kolesnikov
- Chemical and Engineering Materials Division, MS 6473, P.O. Box 2008, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6473, USA
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