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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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Unconventional short-range structural fluctuations in cuprate superconductors. Sci Rep 2022; 12:20483. [DOI: 10.1038/s41598-022-22150-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/10/2022] [Indexed: 11/29/2022] Open
Abstract
AbstractThe interplay between structural and electronic degrees of freedom in complex materials is the subject of extensive debate in physics and materials science. Particularly interesting questions pertain to the nature and extent of pre-transitional short-range order in diverse systems ranging from shape-memory alloys to unconventional superconductors, and how this microstructure affects macroscopic properties. Here we use neutron and X-ray diffuse scattering to uncover universal structural fluctuations in La2-xSrxCuO4 and Tl2Ba2CuO6+δ, two cuprate superconductors with distinct point disorder effects and with optimal superconducting transition temperatures that differ by more than a factor of two. The fluctuations are present in wide doping and temperature ranges, including compositions that maintain high average structural symmetry, and they exhibit unusual, yet simple scaling behaviour. The scaling regime is robust and universal, similar to the well-known critical fluctuations close to second-order phase transitions, but with a distinctly different physical origin. We relate this behaviour to pre-transitional phenomena in a broad class of systems with structural and magnetic transitions, and propose an explanation based on rare structural fluctuations caused by intrinsic nanoscale inhomogeneity. We also uncover parallels with superconducting fluctuations, which indicates that the underlying inhomogeneity plays an important role in cuprate physics.
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Zheng C, Hoffmann R, Perkins TS, Calvagna F, Fotovat R, Ferels C, Mohr A, Kremer RK, Köhler J, Simon A, Bu K, Huang F. Synthesis, structure, and magnetic properties of the quaternary oxysulfides Ln
5V3O7S6 (Ln = La, Ce). ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2021. [DOI: 10.1515/znb-2021-0107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Two rare earth oxysulfides Ln
5V3O7S6 (Ln = La, Ce) have been synthesized and their structures determined. The two isostructural compounds crystallize in the orthorhombic space group Pmmn (no. 59). The structure features one-dimensional edge-sharing VS4O2 octahedron chains parallel to the b axis. The bonding between V and S/O is covalent, and between Ln
3+ and the rest of the matrix ionic. Magnetic susceptibility measurement revealed that V is in a mixed valence state of V3+ and V4+. Its magnetic behavior follows the Curie-Weiss law.
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Affiliation(s)
- Chong Zheng
- Department of Chemistry and Biochemistry , Northern Illinois University , DeKalb , IL , 60115 , USA
| | - Roald Hoffmann
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , USA ,
| | - Timothy S. Perkins
- Department of Chemistry , Coker University , Hartsville , SC , 29550 , USA
| | - Frank Calvagna
- Department of Chemistry , Rock Valley College , Rockford , IL , 61114 , USA
| | - Roxanna Fotovat
- Department of Chemistry and Biochemistry , Northern Illinois University , DeKalb , IL , 60115 , USA
| | - Crystal Ferels
- Department of Chemistry and Biochemistry , Northern Illinois University , DeKalb , IL , 60115 , USA
| | - Alyssa Mohr
- Department of Chemistry and Biochemistry , Northern Illinois University , DeKalb , IL , 60115 , USA
| | - Reinhard K. Kremer
- Max-Planck-Institut für Festkörperforschung , Heisenbergstrasse 1 , D-70569 Stuttgart , Germany
| | - Jürgen Köhler
- Max-Planck-Institut für Festkörperforschung , Heisenbergstrasse 1 , D-70569 Stuttgart , Germany
| | - Arndt Simon
- Max-Planck-Institut für Festkörperforschung , Heisenbergstrasse 1 , D-70569 Stuttgart , Germany
| | - Kejun Bu
- Shanghai Institute of Ceramics , Chinese Academy of Sciences , Shanghai , 200050 , P. R. China
| | - Fuqiang Huang
- Shanghai Institute of Ceramics , Chinese Academy of Sciences , Shanghai , 200050 , P. R. China
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Li Y, Zaki N, Garlea VO, Savici AT, Fobes D, Xu Z, Camino F, Petrovic C, Gu G, Johnson PD, Tranquada JM, Zaliznyak IA. Electronic properties of the bulk and surface states of Fe 1+yTe 1-xSe x. NATURE MATERIALS 2021; 20:1221-1227. [PMID: 33888904 DOI: 10.1038/s41563-021-00984-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
The idea of employing non-Abelian statistics for error-free quantum computing ignited interest in reports of topological surface superconductivity and Majorana zero modes (MZMs) in FeTe0.55Se0.45. However, the topological features and superconducting properties are not observed uniformly across the sample surface. The understanding and practical control of these electronic inhomogeneities present a prominent challenge for potential applications. Here, we combine neutron scattering, scanning angle-resolved photoemission spectroscopy, and microprobe composition and resistivity measurements to characterize the electronic state of Fe1+yTe1-xSex. We establish a phase diagram in which the superconductivity is observed only at sufficiently low Fe concentration, in association with distinct antiferromagnetic correlations, whereas the coexisting topological surface state occurs only at sufficiently high Te concentration. We find that FeTe0.55Se0.45 is located very close to both phase boundaries, which explains the inhomogeneity of superconducting and topological states. Our results demonstrate the compositional control required for use of topological MZMs in practical applications.
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Affiliation(s)
- Yangmu Li
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Nader Zaki
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Vasile O Garlea
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Andrei T Savici
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - David Fobes
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Zhijun Xu
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, MD, USA
| | - Fernando Camino
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA
| | - Cedomir Petrovic
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Genda Gu
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Peter D Johnson
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - John M Tranquada
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Igor A Zaliznyak
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA.
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Abstract
Emergent electronic phenomena in iron-based superconductors have been at the forefront of condensed matter physics for more than a decade. Much has been learned about the origins and intertwined roles of ordered phases, including nematicity, magnetism, and superconductivity, in this fascinating class of materials. In recent years, focus has been centered on the peculiar and highly unusual properties of FeSe and its close cousins. This family of materials has attracted considerable attention due to the discovery of unexpected superconducting gap structures, a wide range of superconducting critical temperatures, and evidence for nontrivial band topology, including associated spin-helical surface states and vortex-induced Majorana bound states. Here, we review superconductivity in iron chalcogenide superconductors, including bulk FeSe, doped bulk FeSe, FeTe1−xSex, intercalated FeSe materials, and monolayer FeSe and FeTe1−xSex on SrTiO3. We focus on the superconducting properties, including a survey of the relevant experimental studies, and a discussion of the different proposed theoretical pairing scenarios. In the last part of the paper, we review the growing recent evidence for nontrivial topological effects in FeSe-related materials, focusing again on interesting implications for superconductivity.
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