1
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Harrison N, Chappell GL, Tobash PH. Indications of flat bands driving the δ to α volume collapse of plutonium. Proc Natl Acad Sci U S A 2024; 121:e2308729121. [PMID: 38354265 PMCID: PMC10895343 DOI: 10.1073/pnas.2308729121] [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: 06/14/2023] [Accepted: 01/05/2024] [Indexed: 02/16/2024] Open
Abstract
On cooling from the melt, plutonium (Pu) undergoes a series of structural transformations accompanied by a ≈ 28% reduction in volume from its δ phase to its α phase at low temperatures. While Pu's partially filled 5f-electron shells are known to be involved, their precise role in the transformations has remained unclear. By using calorimetry measurements on α-Pu and gallium-stabilized δ-Pu combined with resonant ultrasound and X-ray scattering data to account for the anomalously large softening of the lattice with temperature, we show here that the difference in electronic entropy between the α and δ phases dominates over the difference in phonon entropy. Rather than finding an electronic specific heat characteristic of broad f-electron bands in α-Pu, as might be expected to occur within a Kondo collapsed phase in analogy with cerium, we find it to be indicative of flatter subbands. An important role played by Pu's 5f electrons in the formation of its larger unit cell α phase comprising inequivalent lattice sites and varying bond lengths is therefore suggested.
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Affiliation(s)
- Neil Harrison
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM87545
| | - Greta L. Chappell
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM87545
- MST-16, Los Alamos National Laboratory, Los Alamos, NM87545
| | - Paul H. Tobash
- MST-16, Los Alamos National Laboratory, Los Alamos, NM87545
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2
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Li RS, Wang JT, Liu ZY, Zhou XH, Cao ZL, Xie Z. Electron correlation and relativistic effects on the electronic properties of a plutonium and americium mixed oxide (PuAmO 4): from single-particle approximation to dynamical mean-field theory. Phys Chem Chem Phys 2023; 25:30391-30404. [PMID: 37909910 DOI: 10.1039/d3cp02109b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
First-principles calculations were performed on a plutonium and americium mixed oxide (PuAmO4), aiming at revealing the effects of electron correlation, Pu/Am 5f-conduction electrons' hybridization, and relativity on its electronic properties. The many-body calculation suggests that the spin-orbit-coupling (SOC)-splitting of j = 5/2 and j = 7/2 manifolds are both in the weakly and moderately correlated states, respectively, implying that the jj coupling scheme is more appropriate for Pu/Am 5f electrons. The density of states, 5f occupation numbers, and Green's functions all suggest that both Pu and Am 5f electrons exhibit the coexistence of the localized and delocalized states. The admixture of 5fn atomic configurations, Pu/Am 5f-conduction electrons' hybridization, and dual characteristics of 5f electrons yield average occupation numbers of 5f electrons n5f = 4.78 and 5.86 for Pu and Am ions, respectively. Within the DFT+DMFT calculation, the weighted-summation-derived occupation numbers in terms of 5f4/5f5/5f6 and 5f5/5f6 configurations for Pu and Am 5f electrons, respectively, are in reasonable agreement with those of other DFT-based calculations.
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Affiliation(s)
- Ru-Song Li
- Shaanxi Engineering Research Center of Controllable Neutron Source, School of Electronic Information, Xijing University, Xi'an 710123, China.
| | - Jin-Tao Wang
- School of Nuclear Engineering, Xi'an Research Institute of High Technology, Xi'an 710025, China
| | - Zhi-Yong Liu
- Beijing Research Institute of High Technology, Beijing 100077, China
| | - Xiao-Hua Zhou
- Shaanxi Engineering Research Center of Controllable Neutron Source, School of Electronic Information, Xijing University, Xi'an 710123, China.
| | - Ze-Lin Cao
- Shaanxi Engineering Research Center of Controllable Neutron Source, School of Electronic Information, Xijing University, Xi'an 710123, China.
| | - Zheng Xie
- College of Rare Earth and Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, P. R. China.
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3
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Havela L, Legut D, Kolorenč J. Hydrogen in actinides: electronic and lattice properties. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 86:056501. [PMID: 36821855 DOI: 10.1088/1361-6633/acbe50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Hydrides of actinides, their magnetic, electronic, transport, and thermodynamic properties are discussed within a general framework of H impact on bonding, characterized by volume expansion, affecting mainly the 5fstates, and a charge transfer towards H, which influences mostly the 6dand 7sstates. These general mechanisms have diverse impact on individual actinides, depending on the degree of localization of their 5fstates. Hydrogenation of uranium yields UH2and UH3, binary hydrides that are strongly magnetic due to the 5fband narrowing and reduction of the 5f-6dhybridization. Pu hydrides become magnetic as well, mainly as a result of the stabilization of the magnetic 5f5state and elimination of the admixture of the non-magnetic 5f6component.Ab-initiocomputational analyses, which for example suggest that the ferromagnetism ofβ-UH3is rather intricate involving two non-collinear sublattices, are corroborated by spectroscopic studies of sputter-deposited thin films, yielding a clean surface and offering a variability of compositions. It is found that valence-band photoelectron spectra cannot be compared directly with the 5fnground-state density of states. Being affected by electron correlations in the excited final states, they rather reflect the atomic 5fn-1multiplets. Similar tendencies can be identified also in hydrides of binary and ternary intermetallic compounds. H absorption can be used as a tool for fine tuning of electronic structure around a quantum critical point. A new direction is represented by actinide polyhydrides with a potential for high-temperature superconductivity.
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Affiliation(s)
- Ladislav Havela
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Dominik Legut
- IT4Innovations, VŠB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava, Czech Republic
| | - Jindřich Kolorenč
- Institute of Physics (FZU), Czech Academy of Sciences, Na Slovance 2,182 00 Prague, Czech Republic
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4
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Surbella RG, Ducati LC, Schofield MH, McNamara BK, Pellegrini KL, Corbey JF, Schwantes JM, Autschbach J, Cahill CL. Plutonium Hybrid Materials: A Platform to Explore Assembly and Metal–Ligand Bonding. Inorg Chem 2022; 61:17963-17971. [DOI: 10.1021/acs.inorgchem.2c02084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert G. Surbella
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Lucas C. Ducati
- Department of Fundamental Chemistry Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil
| | - Mark H. Schofield
- Department of Chemistry, The George Washington University, 800 22nd Street NW, Washington, District of Columbia 20052, United States
| | - Bruce K. McNamara
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Kristi L. Pellegrini
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Jordan F. Corbey
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Jon M. Schwantes
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, 312 Natural Sciences Complex, Buffalo, New York 14260, United States
| | - Christopher L. Cahill
- Department of Chemistry, The George Washington University, 800 22nd Street NW, Washington, District of Columbia 20052, United States
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5
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Vallejo KD, Kabir F, Poudel N, Marianetti CA, Hurley DH, Simmonds PJ, Dennett CA, Gofryk K. Advances in actinide thin films: synthesis, properties, and future directions. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:123101. [PMID: 36179676 DOI: 10.1088/1361-6633/ac968e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Actinide-based compounds exhibit unique physics due to the presence of 5f electrons, and serve in many cases as important technological materials. Targeted thin film synthesis of actinide materials has been successful in generating high-purity specimens in which to study individual physical phenomena. These films have enabled the study of the unique electron configuration, strong mass renormalization, and nuclear decay in actinide metals and compounds. The growth of these films, as well as their thermophysical, magnetic, and topological properties, have been studied in a range of chemistries, albeit far fewer than most classes of thin film systems. This relative scarcity is the result of limited source material availability and safety constraints associated with the handling of radioactive materials. Here, we review recent work on the synthesis and characterization of actinide-based thin films in detail, describing both synthesis methods and modeling techniques for these materials. We review reports on pyrometallurgical, solution-based, and vapor deposition methods. We highlight the current state-of-the-art in order to construct a path forward to higher quality actinide thin films and heterostructure devices.
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Affiliation(s)
- Kevin D Vallejo
- Condensed Matter and Materials Physics, Idaho National Laboratory, Idaho Falls, ID 83415,United States of America
| | - Firoza Kabir
- Condensed Matter and Materials Physics, Idaho National Laboratory, Idaho Falls, ID 83415,United States of America
- Glenn T Seaborg Institute, Idaho National Laboratory, Idaho Falls, ID 83415, United States of America
| | - Narayan Poudel
- Condensed Matter and Materials Physics, Idaho National Laboratory, Idaho Falls, ID 83415,United States of America
| | - Chris A Marianetti
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, United States of America
| | - David H Hurley
- Condensed Matter and Materials Physics, Idaho National Laboratory, Idaho Falls, ID 83415,United States of America
| | - Paul J Simmonds
- Department of Physics, Boise State University, Boise, ID 83725, United States of America
- Micron School of Materials Science and Engineering, Boise State University, Boise, ID 83725,United States of America
| | - Cody A Dennett
- Condensed Matter and Materials Physics, Idaho National Laboratory, Idaho Falls, ID 83415,United States of America
| | - Krzysztof Gofryk
- Condensed Matter and Materials Physics, Idaho National Laboratory, Idaho Falls, ID 83415,United States of America
- Glenn T Seaborg Institute, Idaho National Laboratory, Idaho Falls, ID 83415, United States of America
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6
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Weber T, Fobes DM, Waizner J, Steffens P, Tucker GS, Böhm M, Beddrich L, Franz C, Gabold H, Bewley R, Voneshen D, Skoulatos M, Georgii R, Ehlers G, Bauer A, Pfleiderer C, Böni P, Janoschek M, Garst M. Topological magnon band structure of emergent Landau levels in a skyrmion lattice. Science 2022; 375:1025-1030. [PMID: 35239388 DOI: 10.1126/science.abe4441] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The motion of a spin excitation across topologically nontrivial magnetic order exhibits a deflection that is analogous to the effect of the Lorentz force on an electrically charged particle in an orbital magnetic field. We used polarized inelastic neutron scattering to investigate the propagation of magnons (i.e., bosonic collective spin excitations) in a lattice of skyrmion tubes in manganese silicide. For wave vectors perpendicular to the skyrmion tubes, the magnon spectra are consistent with the formation of finely spaced emergent Landau levels that are characteristic of the fictitious magnetic field used to account for the nontrivial topological winding of the skyrmion lattice. This provides evidence of a topological magnon band structure in reciprocal space, which is borne out of the nontrivial real-space topology of a magnetic order.
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Affiliation(s)
- T Weber
- Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France
| | - D M Fobes
- Los Alamos National Laboratory, Los Alamos, NM, USA
| | - J Waizner
- Institut für Theoretische Physik, Universität zu Köln, 50937 Köln, Germany
| | - P Steffens
- Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France
| | - G S Tucker
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.,Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M Böhm
- Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France
| | - L Beddrich
- Physik-Department, Technische Universität München, 85748 Garching, Germany.,MLZ, Technische Universität München, 85748 Garching, Germany
| | - C Franz
- Physik-Department, Technische Universität München, 85748 Garching, Germany.,MLZ, Technische Universität München, 85748 Garching, Germany
| | - H Gabold
- Physik-Department, Technische Universität München, 85748 Garching, Germany.,MLZ, Technische Universität München, 85748 Garching, Germany
| | - R Bewley
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK
| | - D Voneshen
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK.,Department of Physics, Royal Holloway University of London, Egham TW20 0EX, UK
| | - M Skoulatos
- Physik-Department, Technische Universität München, 85748 Garching, Germany.,MLZ, Technische Universität München, 85748 Garching, Germany
| | - R Georgii
- Physik-Department, Technische Universität München, 85748 Garching, Germany.,MLZ, Technische Universität München, 85748 Garching, Germany
| | - G Ehlers
- Neutron Technologies Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - A Bauer
- Physik-Department, Technische Universität München, 85748 Garching, Germany.,Centre for Quantum Engineering (ZQE), Technische Universität München, 85748 Garching, Germany
| | - C Pfleiderer
- Physik-Department, Technische Universität München, 85748 Garching, Germany.,Centre for Quantum Engineering (ZQE), Technische Universität München, 85748 Garching, Germany.,MCQST, Technische Universität München, 85748 Garching, Germany
| | - P Böni
- Physik-Department, Technische Universität München, 85748 Garching, Germany
| | - M Janoschek
- Los Alamos National Laboratory, Los Alamos, NM, USA.,Laboratory for Neutron and Muon Instrumentation (LIN), Paul Scherrer Institute, CH-5232 Villigen, Switzerland.,Physik-Institut, Universität Zürich, CH-8057 Zürich, Switzerland
| | - M Garst
- Institut für Theoretische Physik, Universität zu Köln, 50937 Köln, Germany.,Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany.,Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.,Institute for Quantum Materials and Technology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
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7
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Hurley DH, El-Azab A, Bryan MS, Cooper MWD, Dennett CA, Gofryk K, He L, Khafizov M, Lander GH, Manley ME, Mann JM, Marianetti CA, Rickert K, Selim FA, Tonks MR, Wharry JP. Thermal Energy Transport in Oxide Nuclear Fuel. Chem Rev 2021; 122:3711-3762. [PMID: 34919381 DOI: 10.1021/acs.chemrev.1c00262] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To efficiently capture the energy of the nuclear bond, advanced nuclear reactor concepts seek solid fuels that must withstand unprecedented temperature and radiation extremes. In these advanced fuels, thermal energy transport under irradiation is directly related to reactor performance as well as reactor safety. The science of thermal transport in nuclear fuel is a grand challenge as a result of both computational and experimental complexities. Here we provide a comprehensive review of thermal transport research on two actinide oxides: one currently in use in commercial nuclear reactors, uranium dioxide (UO2), and one advanced fuel candidate material, thorium dioxide (ThO2). In both materials, heat is carried by lattice waves or phonons. Crystalline defects caused by fission events effectively scatter phonons and lead to a degradation in fuel performance over time. Bolstered by new computational and experimental tools, researchers are now developing the foundational work necessary to accurately model and ultimately control thermal transport in advanced nuclear fuels. We begin by reviewing research aimed at understanding thermal transport in perfect single crystals. The absence of defects enables studies that focus on the fundamental aspects of phonon transport. Next, we review research that targets defect generation and evolution. Here the focus is on ion irradiation studies used as surrogates for damage caused by fission products. We end this review with a discussion of modeling and experimental efforts directed at predicting and validating mesoscale thermal transport in the presence of irradiation defects. While efforts in these research areas have been robust, challenging work remains in developing holistic tools to capture and predict thermal energy transport across widely varying environmental conditions.
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Affiliation(s)
- David H Hurley
- Idaho National Laboratory, 1955 North Fremont Avenue, Idaho Falls, Idaho 83415, United States
| | - Anter El-Azab
- School of Materials Engineering, Purdue University, 701 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Matthew S Bryan
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Michael W D Cooper
- Materials Science and Technology Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Cody A Dennett
- Idaho National Laboratory, 1955 North Fremont Avenue, Idaho Falls, Idaho 83415, United States
| | - Krzysztof Gofryk
- Idaho National Laboratory, 1955 North Fremont Avenue, Idaho Falls, Idaho 83415, United States
| | - Lingfeng He
- Idaho National Laboratory, 1955 North Fremont Avenue, Idaho Falls, Idaho 83415, United States
| | - Marat Khafizov
- Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 West 19th Ave, Columbus, Ohio 43210, United States
| | - Gerard H Lander
- European Commission, Joint Research Center, Postfach 2340, D-76125 Karlsruhe, Germany
| | - Michael E Manley
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - J Matthew Mann
- U.S. Air Force Research Laboratory, Sensors Directorate, 2241 Avionics Circle, Wright Patterson AFB, Ohio 45433, United States
| | - Chris A Marianetti
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Karl Rickert
- KBR, 2601 Mission Point Boulevard, Suite 300, Dayton, Ohio 45431, United States
| | - Farida A Selim
- Department of Physics and Astronomy, Bowling Green State University, 705 Ridge Street, Bowling Green, Ohio 43403, United States
| | - Michael R Tonks
- Department of Materials Science and Engineering, University of Florida, 158 Rhines Hall, Gainesville, Florida 32611, United States
| | - Janelle P Wharry
- School of Materials Engineering, Purdue University, 701 West Stadium Avenue, West Lafayette, Indiana 47907, United States
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8
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Abstract
In this tribute to K Alex Müller, I describe how his early insights have influenced future decades of research on perovskite ferroelectrics and more broadly transition metal oxides (TMOs) and related quantum materials. I use his influence on my own research journey to discuss impacts in three areas: structural phase transitions, precursor structure, and quantum paraelectricity. I emphasize materials functionality in ground, metastable, and excited states arising from competitions among lattice, charge, and spin degrees of freedom, which results in highly tunable landscapes and complex networks of multiscale configurations controlling macroscopic functions. I discuss competitions between short- and long-range forces as particularly important in TMOs (and related materials classes) because of their localized and directional metal orbitals and the polarizable oxygen ions. I emphasize crucial consequences of elasticity and metal–oxygen charge transfer.
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9
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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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10
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Abstract
A long-standing mystery in the material science of actinides concerns the question of why the bulk modulus of plutonium metal undergoes an anomalously large softening with increasing temperature compared to other metals. We show that a crucial step to understanding this phenomenon is taking into consideration the compressibility of thermally excited electronic configurations. We find this to lead to a previously unknown electronic softening contribution to the bulk modulus and a collapse of the bulk modulus when there exists a large partial pressure between different configurations. Plutonium metal exhibits an anomalously large softening of its bulk modulus at elevated temperatures that is made all the more extraordinary by the finding that it occurs irrespective of whether the thermal expansion coefficient is positive, negative, or zero—representing an extreme departure from conventional Grüneisen scaling. We show here that the cause of this softening is the compressibility of plutonium’s thermally excited electronic configurations, which has thus far not been considered in thermodynamic models. We show that when compressible electronic configurations are thermally activated, they invariably give rise to a softening of the bulk modulus regardless of the sign of their contribution to the thermal expansion. The electronically driven softening of the bulk modulus is shown to be in good agreement with elastic moduli measurements performed on the gallium-stabilized δ phase of plutonium over a range of temperatures and compositions and is shown to grow rapidly at small concentrations of gallium and at high temperatures, where it becomes extremely sensitive to hydrostatic pressure.
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11
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Valence fluctuation for f electrons in XGaO3 (X = Pu, Ce): a perspective from dynamic mean field theory. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06829-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Harrison N, Betts JB, Wartenbe MR, Balakirev FF, Richmond S, Jaime M, Tobash PH. Phase stabilization by electronic entropy in plutonium. Nat Commun 2019; 10:3159. [PMID: 31320635 PMCID: PMC6639308 DOI: 10.1038/s41467-019-11166-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/26/2019] [Indexed: 11/29/2022] Open
Abstract
Plutonium metal undergoes an anomalously large 25% collapse in volume from its largest volume δ phase (δ-Pu) to its low temperature α phase, yet the underlying thermodynamic mechanism has largely remained a mystery. Here we use magnetostriction measurements to isolate a previously hidden yet substantial electronic contribution to the entropy of δ-Pu, which we show to be crucial for the stabilization of this phase. The entropy originates from two competing instabilities of the 5f-electron shell, which we show to drive the volume of Pu in opposing directions, depending on the temperature and volume. Using calorimetry measurements, we establish a robust thermodynamic connection between the two excitation energies, the atomic volume, and the previously reported excess entropy of δ-Pu at elevated temperatures. Plutonium has strong electronic correlations, which makes it difficult to establish microscopic understanding of the complicated structural phase diagram. Here the authors identify an electronic contribution to the entropy that stabilises the δ-Pu phase.
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Affiliation(s)
- N Harrison
- Los Alamos National Laboratory, Los Alamos, Mail Stop E536, Los Alamos, NM, 87545, USA.
| | - J B Betts
- Los Alamos National Laboratory, Los Alamos, Mail Stop E536, Los Alamos, NM, 87545, USA
| | - M R Wartenbe
- Los Alamos National Laboratory, Los Alamos, Mail Stop E536, Los Alamos, NM, 87545, USA
| | - F F Balakirev
- Los Alamos National Laboratory, Los Alamos, Mail Stop E536, Los Alamos, NM, 87545, USA
| | - S Richmond
- Los Alamos National Laboratory, Los Alamos, Mail Stop E574, Los Alamos, NM, 87545, USA
| | - M Jaime
- Los Alamos National Laboratory, Los Alamos, Mail Stop E536, Los Alamos, NM, 87545, USA
| | - P H Tobash
- Los Alamos National Laboratory, Los Alamos, Mail Stop E574, Los Alamos, NM, 87545, USA
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13
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Walsh A, Sokol AA, Buckeridge J, Scanlon DO, Catlow CRA. Oxidation states and ionicity. NATURE MATERIALS 2018; 17:958-964. [PMID: 30275565 DOI: 10.1038/s41563-018-0165-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 08/09/2018] [Indexed: 05/28/2023]
Abstract
The concepts of oxidation state and atomic charge are entangled in modern materials science. We distinguish between these quantities and consider their fundamental limitations and utility for understanding material properties. We discuss the nature of bonding between atoms and the techniques that have been developed for partitioning electron density. While formal oxidation states help us count electrons (in ions, bonds, lone pairs), variously defined atomic charges are usefully employed in the description of physical processes including dielectric response and electronic spectroscopies. Such partial charges are introduced as quantitative measures in simple mechanistic models of a more complex reality, and therefore may not be comparable or transferable. In contrast, oxidation states are defined to be universal, with deviations constituting exciting challenges as evidenced in mixed-valence compounds, electrides and highly correlated systems. This Perspective covers how these concepts have evolved in recent years, our current understanding and their significance.
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Affiliation(s)
- Aron Walsh
- Department of Materials, Imperial College London, London, UK.
- Department of Materials Science and Engineering, Yonsei University, Seoul, Korea.
| | - Alexey A Sokol
- Department of Chemistry, University College London, London, UK
| | - John Buckeridge
- Department of Chemistry, University College London, London, UK
| | - David O Scanlon
- Department of Chemistry, University College London, London, UK
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, UK
| | - C Richard A Catlow
- Department of Chemistry, University College London, London, UK.
- School of Chemistry, Cardiff University, Cardiff, UK.
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14
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Amadon B, Dorado B. A unified and efficient theory for the structural properties of actinides and phases of plutonium. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:405603. [PMID: 30136656 DOI: 10.1088/1361-648x/aadc7a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We show that a calculation using density functional theory (DFT) in the generalized gradient approximation (GGA) supplemented by an explicit Coulomb interaction term between correlated electrons (GGA+U), can accurately describe structural properties of (1) the room temperature phases of U, Np, Pu, Am and Cm, and (2) the α, β, γ, δ and ϵ phases of plutonium, as does the combination of GGA with dynamical mean field theory (DMFT). It thus changes the view on the role of electronic interaction in these systems and opens the way to fast calculations of structural properties in actinides metallic system. We use ab initio values of effective Coulomb interactions and underline that Hund's exchange and spin-orbit coupling are of utmost importance in these calculations. Secondly, we show that phonons properties in δ plutonium are impacted by strong interactions. The GGA+DMFT results exhibits a lattice instability for the transverse (1 1 1) phonon mode. Moreover the amplitude of this lattice instability is consistent with the experimental temperature of stability of this phase. Our calculation thus shows that when the δ phase is thermodynamically unstable (at 0 K), it is also dynamically unstable.
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15
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Lu H, Huang L. Electronic correlations in cerium's high-pressure phases. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:395601. [PMID: 30136653 DOI: 10.1088/1361-648x/aadc7c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Under high pressure, cerium exhibits three distinct phases, namely [Formula: see text], [Formula: see text], and ϵ-cerium. It is unclear whether the 4f electronic correlations will play a vital role in these phases or not. By utilizing the combination of traditional density functional theory and single-site dynamical mean-field theory, we tried to calculate the electronic structures of cerium's high-pressure phases. Their momentum-resolved spectral functions, total and 4f partial density of states, local self-energy functions, and 4f electronic configurations were exhaustively studied. The calculated results show that the correlated 4f bands strongly hybridize with the conducting spd bands around the Fermi level. The Matsubara self-energy functions exhibit Fermi-liquid like characteristic in the low-frequency regime. In addition, the fluctuations among the 4f atomic eigenstates are somewhat prominent (especially for the ϵ phase), which lead to slight modification of the 4f occupancy. It is suggested that the 4f electrons in these phases tend to be itinerant.
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Affiliation(s)
- Haiyan Lu
- Science and Technology on Surface Physics and Chemistry Laboratory, PO Box 9-35, Jiangyou 621908, People's Republic of China
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16
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Abstract
Correlated electron materials display a rich variety of notable properties ranging from unconventional superconductivity to metal-insulator transitions. These properties are of interest from the point of view of applications but are hard to treat theoretically, as they result from multiple competing energy scales. Although possible in more weakly correlated materials, theoretical design and spectroscopy of strongly correlated electron materials have been a difficult challenge for many years. By treating all the relevant energy scales with sufficient accuracy, complementary advances in Green's functions and quantum Monte Carlo methods open a path to first-principles computational property predictions in this class of materials.
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Affiliation(s)
- Paul R C Kent
- Computational Sciences and Engineering Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Gabriel Kotliar
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA. .,Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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17
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Abstract
A model alloy, Mg69Zn27Yb4, concurrently forms bulk metallic glass, metastable quasicrystals (QCs), and crystalline approximant phases from the melt. We demonstrate that a transient QC phase nucleates first from the melt and subsequently transforms into an equilibrium approximant phase. This nucleation path is likely to be a general mechanism in metastable QC-forming systems. We observed a metastable-to-stable phase transformation when we deployed fast differential scanning calorimetry using the experimental strategy of interrupted cooling after the onset of crystallization followed by heating at ultrafast rates to “up-quench” the previously frozen structure. This strategy can yield the discovery of hidden transient phases that are key to understanding the crystallization behavior in metallic systems, polymers, biological solutions, and pharmaceutical substances. This study presents a unique Mg-based alloy composition in the Mg–Zn–Yb system which exhibits bulk metallic glass, metastable icosahedral quasicrystals (iQCs), and crystalline approximant phases in the as-cast condition. Microscopy revealed a smooth gradual transition from glass to QC. We also report the complete melting of a metastable eutectic phase mixture (including a QC phase), generated via suppression of the metastable-to-stable phase transition at high heating rates using fast differential scanning calorimetry (FDSC). The melting temperature and enthalpy of fusion of this phase mixture could be measured directly, which unambiguously proves its metastability in any temperature range. The kinetic pathway from liquid state to stable solid state (an approximant phase) minimizes the free-energy barrier for nucleation through an intermediate state (metastable QC phase) because of its low solid–liquid interfacial energy. At high undercooling of the liquid, where diffusion is limited, another approximant phase with near-liquid composition forms just above the glass-transition temperature. These experimental results shed light on the competition between metastable and stable crystals, and on glass formation via system frustration associated with the presence of several free-energy minima.
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Goldman N, Aradi B, Lindsey RK, Fried LE. Development of a Multicenter Density Functional Tight Binding Model for Plutonium Surface Hydriding. J Chem Theory Comput 2018; 14:2652-2660. [DOI: 10.1021/acs.jctc.8b00165] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nir Goldman
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
- Department of Chemical Engineering, University of California, Davis, California 95616, United States
| | - Bálint Aradi
- Bremen Center for Computational Materials Science, Universität Bremen, P.O.B. 330440, D-28334 Bremen, Germany
| | - Rebecca K. Lindsey
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Laurence E. Fried
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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Havela L, Mašková S, Kolorenč J, Colineau E, Griveau JC, Eloirdi R. Electronic properties of Pu 19Os simulating β-Pu: the strongly correlated Pu phase. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:085601. [PMID: 29388557 DOI: 10.1088/1361-648x/aaa520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We established the basic electronic properties of ζ-Pu19Os, which is a close analogue to β-Pu, and its low-temperature variety, η-Pu19Os. Their magnetic susceptibility is 15% higher than for δ-Pu. A specific heat study of ζ-Pu19Os shows a soft lattice similar to δ-Pu, leading to a low Debye temperature Θ D = 101 K. The linear electronic coefficient γ related to the quasiparticle density of states at the Fermi level points to a higher value, 55 ± 2 mJ (mol Pu K2)-1, compared to 40 mJ (mol K2)-1 for δ-Pu. The results confirm that β-Pu is probably the most strongly correlated Pu phase, as had been indicated by resistivity measurements. The volume and related Pu-Pu spacing is clearly not the primary tuning parameter for Pu metal, as the β-Pu density stands close to the ground-state α-phase and is much higher than that for δ-Pu. The η-Pu19Os phase has a record γ-value of 74 ± 2 mJ (mol Pu K2)-1. The enhancement is not reproduced by LDA+DMFT calculations in the fcc structure, which suggests that multiple diverse sites can be the key to the understanding of β-Pu.
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Affiliation(s)
- L Havela
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 12116 Prague 2, Czech Republic
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20
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Galley SS, Arico AA, Lee TH, Deng X, Yao YX, Sperling JM, Proust V, Storbeck JS, Dobrosavljevic V, Neu JN, Siegrist T, Baumbach RE, Albrecht-Schmitt TE, Kaltsoyannis N, Lanatà N. Uncovering the Origin of Divergence in the CsM(CrO4)2 (M = La, Pr, Nd, Sm, Eu; Am) Family through Examination of the Chemical Bonding in a Molecular Cluster and by Band Structure Analysis. J Am Chem Soc 2018; 140:1674-1685. [DOI: 10.1021/jacs.7b09474] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shane S. Galley
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Alexandra A. Arico
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Tsung-Han Lee
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08856-8019, United States
| | - Xiaoyu Deng
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08856-8019, United States
| | - Yong-Xin Yao
- Department of Physics and Astronomy, and Ames Laboratory, U.S. Department of Energy, Iowa State University, Ames, Iowa 50011, United States
| | - Joseph M. Sperling
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Vanessa Proust
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Julia S. Storbeck
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Vladimir Dobrosavljevic
- Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Jennifer N. Neu
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
- Department of Chemical Engineering, Florida State University, Tallahassee, Florida 32310, United States
| | - Theo Siegrist
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
- Department of Chemical Engineering, Florida State University, Tallahassee, Florida 32310, United States
| | - Ryan E. Baumbach
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Thomas E. Albrecht-Schmitt
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Nikolas Kaltsoyannis
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Nicola Lanatà
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
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21
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Li CM, Johansson B, Vitos L. Physical mechanism of δ-δ'-ε phase stability in plutonium. Sci Rep 2017; 7:5632. [PMID: 28717177 PMCID: PMC5514108 DOI: 10.1038/s41598-017-06009-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 06/06/2017] [Indexed: 11/09/2022] Open
Abstract
Based on first-principle calculations, we have systematically explored the nature of the elastic stability and the δ-δ′-ε phase transitions in pure Pu at high temperature. It is found that, both the electron-phonon coupling and the spin fluctuation effects tend to decrease the tetragonal elastic constant (C′) of δ-Pu, accounting for its anomalous softening at high temperature. The lattice thermal expansion together with the electron-phonon coupling can stiffen C′ of ε-Pu, promoting its mechanical stability at high temperature. The δ-ε transition is calculated to take place around 750–800 K, and is dominated by the phonon vibration. The δ′ intermediate phase is realized around 750 K mainly because of the thermal spin fluctuation.
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Affiliation(s)
- Chun-Mei Li
- College of Physical Science and Technology, Shenyang Normal University, 110034, Shenyang, China. .,Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, 110016, Shenyang, China.
| | - Börje Johansson
- Department of Materials Science and Engineering, KTH - Royal Institute of Technology, 10044, Stockholm, Sweden.,Department of Physics and Astronomy, Division of Materials Theory, Uppsala University, Box 516, 75120, Uppsala, Sweden.,School of Physics and Optoelectronic Technology & College of Advanced Science and Technology Dalian University of Technology, 116024, Dalian, China
| | - Levente Vitos
- Department of Materials Science and Engineering, KTH - Royal Institute of Technology, 10044, Stockholm, Sweden.,Department of Physics and Astronomy, Division of Materials Theory, Uppsala University, Box 516, 75120, Uppsala, Sweden.,Research Institute for Solid State Physics and Optics, Wigner Research Center for Physics, P.O. Box 49, HU-1525, Budapest, Hungary
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22
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Fobes DM, Bauer ED, Thompson JD, Sazonov A, Hutanu V, Zhang S, Ronning F, Janoschek M. Low temperature magnetic structure of CeRhIn 5 by neutron diffraction on absorption-optimized samples. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:17LT01. [PMID: 28349895 DOI: 10.1088/1361-648x/aa6696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Two aspects of the ambient pressure magnetic structure of heavy fermion material CeRhIn5 have remained under some debate since its discovery: whether the structure is indeed an incommensurate helix or a spin density wave, and what is the precise magnitude of the ordered magnetic moment. By using a single crystal sample optimized for hot neutrons to minimize neutron absorption by Rh and In, here we report an ordered moment of [Formula: see text]. In addition, by using spherical neutron polarimetry measurements on a similar single crystal sample, we have confirmed the helical nature of the magnetic structure, and identified a single chiral domain.
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Affiliation(s)
- D M Fobes
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States of America
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23
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Söderlind P. Lattice dynamics and elasticity for ε-plutonium. Sci Rep 2017; 7:1116. [PMID: 28442720 PMCID: PMC5430910 DOI: 10.1038/s41598-017-01034-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/23/2017] [Indexed: 11/09/2022] Open
Abstract
Lattice dynamics and elasticity for the high-temperature ε phase (body-centered cubic; bcc) of plutonium is predicted utilizing first-principles electronic structure coupled with a self-consistent phonon method that takes phonon-phonon interaction and strong anharmonicity into account. These predictions establish the first sensible lattice-dynamics and elasticity data on ε-Pu. The atomic forces required for the phonon scheme are highly accurate and derived from the total energies obtained from relativistic and parameter-free density-functional theory. The results appear reasonable but no data exist to compare with except those from dynamical mean-field theory that suggest ε-plutonium is mechanically unstable. Fundamental knowledge and understanding of the high-temperature bcc phase, that is generally present in all actinide metals before melting, is critically important for a proper interpretation of the phase diagram as well as practical modeling of high-temperature properties.
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Affiliation(s)
- Per Söderlind
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA.
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24
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Silver MA, Cary SK, Johnson JA, Baumbach RE, Arico AA, Luckey M, Urban M, Wang JC, Polinski MJ, Chemey A, Liu G, Chen KW, Van Cleve SM, Marsh ML, Eaton TM, van de Burgt LJ, Gray AL, Hobart DE, Hanson K, Maron L, Gendron F, Autschbach J, Speldrich M, Kögerler P, Yang P, Braley J, Albrecht-Schmitt TE. Characterization of berkelium(III) dipicolinate and borate compounds in solution and the solid state. Science 2017; 353:353/6302/aaf3762. [PMID: 27563098 DOI: 10.1126/science.aaf3762] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/29/2016] [Indexed: 11/02/2022]
Abstract
Berkelium is positioned at a crucial location in the actinide series between the inherently stable half-filled 5f(7) configuration of curium and the abrupt transition in chemical behavior created by the onset of a metastable divalent state that starts at californium. However, the mere 320-day half-life of berkelium's only available isotope, (249)Bk, has hindered in-depth studies of the element's coordination chemistry. Herein, we report the synthesis and detailed solid-state and solution-phase characterization of a berkelium coordination complex, Bk(III)tris(dipicolinate), as well as a chemically distinct Bk(III) borate material for comparison. We demonstrate that berkelium's complexation is analogous to that of californium. However, from a range of spectroscopic techniques and quantum mechanical calculations, it is clear that spin-orbit coupling contributes significantly to berkelium's multiconfigurational ground state.
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Affiliation(s)
- Mark A Silver
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Samantha K Cary
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Jason A Johnson
- Environmental Health and Safety, Florida State University, Tallahassee, FL 32306, USA
| | - Ryan E Baumbach
- National High Magnetic Field Laboratory, Tallahassee, FL 32310, USA
| | - Alexandra A Arico
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Morgan Luckey
- Department of Chemistry and Geochemistry and Department of Nuclear Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Matthew Urban
- Department of Chemistry and Geochemistry and Department of Nuclear Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Jamie C Wang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Matthew J Polinski
- Department of Chemistry and Biochemistry, Bloomsburg University of Pennsylvania, Bloomsburg, PA 17815, USA
| | - Alexander Chemey
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Guokui Liu
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Kuan-Wen Chen
- National High Magnetic Field Laboratory, Tallahassee, FL 32310, USA
| | - Shelley M Van Cleve
- Nuclear Materials Processing Group, Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37830, USA
| | - Matthew L Marsh
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Teresa M Eaton
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | | | - Ashley L Gray
- Environmental Health and Safety, Florida State University, Tallahassee, FL 32306, USA
| | - David E Hobart
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Kenneth Hanson
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Laurent Maron
- Laboratorie de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, 31077 Toulouse Cedex 4, France
| | - Frédéric Gendron
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Manfred Speldrich
- Institut für Anorganische Chemie, Rheinisch-Westfälische Technische Hochschule, Aachen University, D-52074 Aachen, Germany
| | - Paul Kögerler
- Institut für Anorganische Chemie, Rheinisch-Westfälische Technische Hochschule, Aachen University, D-52074 Aachen, Germany
| | - Ping Yang
- Theory Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Jenifer Braley
- Department of Chemistry and Geochemistry and Department of Nuclear Engineering, Colorado School of Mines, Golden, CO 80401, USA.
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25
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Relevance of Kondo physics for the temperature dependence of the bulk modulus in plutonium. Proc Natl Acad Sci U S A 2017; 114:E268. [PMID: 28074035 DOI: 10.1073/pnas.1618967114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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27
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Origin of the multiple configurations that drive the response of δ-plutonium's elastic moduli to temperature. Proc Natl Acad Sci U S A 2016; 113:11158-11161. [PMID: 27647904 DOI: 10.1073/pnas.1609215113] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The electronic and thermodynamic complexity of plutonium has resisted a fundamental understanding for this important elemental metal. A critical test of any theory is the unusual softening of the bulk modulus with increasing temperature, a result that is counterintuitive because no or very little change in the atomic volume is observed upon heating. This unexpected behavior has in the past been attributed to competing but never-observed electronic states with different bonding properties similar to the scenario with magnetic states in Invar alloys. Using the recent observation of plutonium dynamic magnetism, we construct a theory for plutonium that agrees with relevant measurements by using density-functional-theory (DFT) calculations with no free parameters to compute the effect of longitudinal spin fluctuations on the temperature dependence of the bulk moduli in δ-Pu. We show that the softening with temperature can be understood in terms of a continuous distribution of thermally activated spin fluctuations.
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28
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29
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Brito WH, Aguiar MCO, Haule K, Kotliar G. Metal-Insulator Transition in VO_{2}: A DFT+DMFT Perspective. PHYSICAL REVIEW LETTERS 2016; 117:056402. [PMID: 27517782 DOI: 10.1103/physrevlett.117.056402] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Indexed: 06/06/2023]
Abstract
We present a theoretical investigation of the electronic structure of rutile (metallic) and M_{1} and M_{2} monoclinic (insulating) phases of VO_{2} employing a fully self-consistent combination of density functional theory and embedded dynamical mean field theory calculations. We describe the electronic structure of the metallic and both insulating phases of VO_{2}, and propose a distinct mechanism for the gap opening. We show that Mott physics plays an essential role in all phases of VO_{2}: undimerized vanadium atoms undergo classical Mott transition through local moment formation (in the M_{2} phase), while strong superexchange within V dimers adds significant dynamic intersite correlations, which remove the singularity of self-energy for dimerized V atoms. The resulting transition from rutile to dimerized M_{1} phase is adiabatically connected to the Peierls-like transition, but is better characterized as the Mott transition in the presence of strong intersite exchange. As a consequence of Mott physics, the gap in the dimerized M_{1} phase is temperature dependent. The sole increase of electronic temperature collapses the gap, reminiscent of recent experiments.
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Affiliation(s)
- W H Brito
- Departamento de Física, Universidade Federal de Minas Gerais, C. P. 702, 30123-970 Belo Horizonte, Minas Gerais, Brazil
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - M C O Aguiar
- Departamento de Física, Universidade Federal de Minas Gerais, C. P. 702, 30123-970 Belo Horizonte, Minas Gerais, Brazil
| | - K Haule
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - G Kotliar
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
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30
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Söderlind P, Zhou F, Landa A, Klepeis JE. Phonon and magnetic structure in δ-plutonium from density-functional theory. Sci Rep 2015; 5:15958. [PMID: 26514238 PMCID: PMC4626764 DOI: 10.1038/srep15958] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 10/05/2015] [Indexed: 11/09/2022] Open
Abstract
We present phonon properties of plutonium metal obtained from a combination of density-functional-theory (DFT) electronic structure and the recently developed compressive sensing lattice dynamics (CSLD). The CSLD model is here trained on DFT total energies of several hundreds of quasi-random atomic configurations for best possible accuracy of the phonon properties. The calculated phonon dispersions compare better with experiment than earlier results obtained from dynamical mean-field theory. The density-functional model of the electronic structure consists of disordered magnetic moments with all relativistic effects and explicit orbital-orbital correlations. The magnetic disorder is approximated in two ways: (i) a special quasi-random structure and (ii) the disordered-local-moment method within the coherent potential approximation. Magnetism in plutonium has been debated intensely, but the present magnetic approach for plutonium is validated by the close agreement between the predicted magnetic form factor and that of recent neutron-scattering experiments.
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Affiliation(s)
- Per Söderlind
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - F Zhou
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - A Landa
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - J E Klepeis
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
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