1
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Posey VA, Turkel S, Rezaee M, Devarakonda A, Kundu AK, Ong CS, Thinel M, Chica DG, Vitalone RA, Jing R, Xu S, Needell DR, Meirzadeh E, Feuer ML, Jindal A, Cui X, Valla T, Thunström P, Yilmaz T, Vescovo E, Graf D, Zhu X, Scheie A, May AF, Eriksson O, Basov DN, Dean CR, Rubio A, Kim P, Ziebel ME, Millis AJ, Pasupathy AN, Roy X. Two-dimensional heavy fermions in the van der Waals metal CeSiI. Nature 2024; 625:483-488. [PMID: 38233620 DOI: 10.1038/s41586-023-06868-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 11/14/2023] [Indexed: 01/19/2024]
Abstract
Heavy-fermion metals are prototype systems for observing emergent quantum phases driven by electronic interactions1-6. A long-standing aspiration is the dimensional reduction of these materials to exert control over their quantum phases7-11, which remains a significant challenge because traditional intermetallic heavy-fermion compounds have three-dimensional atomic and electronic structures. Here we report comprehensive thermodynamic and spectroscopic evidence of an antiferromagnetically ordered heavy-fermion ground state in CeSiI, an intermetallic comprising two-dimensional (2D) metallic sheets held together by weak interlayer van der Waals (vdW) interactions. Owing to its vdW nature, CeSiI has a quasi-2D electronic structure, and we can control its physical dimension through exfoliation. The emergence of coherent hybridization of f and conduction electrons at low temperature is supported by the temperature evolution of angle-resolved photoemission and scanning tunnelling spectra near the Fermi level and by heat capacity measurements. Electrical transport measurements on few-layer flakes reveal heavy-fermion behaviour and magnetic order down to the ultra-thin regime. Our work establishes CeSiI and related materials as a unique platform for studying dimensionally confined heavy fermions in bulk crystals and employing 2D device fabrication techniques and vdW heterostructures12 to manipulate the interplay between Kondo screening, magnetic order and proximity effects.
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Affiliation(s)
| | - Simon Turkel
- Physics Department, Columbia University, New York, NY, USA
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Mehdi Rezaee
- Physics Department, Harvard University, Cambridge, MA, USA
| | | | - Asish K Kundu
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Chin Shen Ong
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Morgan Thinel
- Chemistry Department, Columbia University, New York, NY, USA
- Physics Department, Columbia University, New York, NY, USA
| | - Daniel G Chica
- Chemistry Department, Columbia University, New York, NY, USA
| | | | - Ran Jing
- Physics Department, Columbia University, New York, NY, USA
| | - Suheng Xu
- Physics Department, Columbia University, New York, NY, USA
| | - David R Needell
- Chemistry Department, Columbia University, New York, NY, USA
| | - Elena Meirzadeh
- Chemistry Department, Columbia University, New York, NY, USA
| | | | - Apoorv Jindal
- Physics Department, Columbia University, New York, NY, USA
| | - Xiaomeng Cui
- Physics Department, Harvard University, Cambridge, MA, USA
| | - Tonica Valla
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
- Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain
| | - Patrik Thunström
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Turgut Yilmaz
- National Synchrotron Light Source II, Brookhaven National Lab, Upton, NY, USA
| | - Elio Vescovo
- National Synchrotron Light Source II, Brookhaven National Lab, Upton, NY, USA
| | - David Graf
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - Xiaoyang Zhu
- Chemistry Department, Columbia University, New York, NY, USA
| | - Allen Scheie
- Neutron Scattering Division, Oak Ridge National Lab, Oak Ridge, TN, USA
- MPA-Q, Los Alamos National Lab, Los Alamos, NM, USA
| | - Andrew F May
- Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN, USA
| | - Olle Eriksson
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
- Wallenberg Initiative Materials Science for Sustainability, Uppsala University, Uppsala, Sweden
| | - D N Basov
- Physics Department, Columbia University, New York, NY, USA
| | - Cory R Dean
- Physics Department, Columbia University, New York, NY, USA
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science and Department of Physics, Hamburg, Germany.
- Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (ETSF), Departmento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Universidad del País Vasco (UPV/EHU), San Sebastián, Spain.
- Center for Computational Quantum Physics, Flatiron Institute, New York, NY, USA.
| | - Philip Kim
- Physics Department, Harvard University, Cambridge, MA, USA
| | | | - Andrew J Millis
- Physics Department, Columbia University, New York, NY, USA.
- Center for Computational Quantum Physics, Flatiron Institute, New York, NY, USA.
| | - Abhay N Pasupathy
- Physics Department, Columbia University, New York, NY, USA.
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA.
| | - Xavier Roy
- Chemistry Department, Columbia University, New York, NY, USA.
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2
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Wang H, Park TB, Kim J, Jang H, Bauer ED, Thompson JD, Park T. Evidence for charge delocalization crossover in the quantum critical superconductor CeRhIn 5. Nat Commun 2023; 14:7341. [PMID: 37957188 PMCID: PMC10643617 DOI: 10.1038/s41467-023-42965-1] [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: 01/16/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
The nature of charge degrees-of-freedom distinguishes scenarios for interpreting the character of a second order magnetic transition at zero temperature, that is, a magnetic quantum critical point (QCP). Heavy-fermion systems are prototypes of this paradigm, and in those, the relevant question is where, relative to a magnetic QCP, does the Kondo effect delocalize their f-electron degrees-of-freedom. Herein, we use pressure-dependent Hall measurements to identify a finite-temperature scale Eloc that signals a crossover from f-localized to f-delocalized character. As a function of pressure, Eloc(P) extrapolates smoothly to zero temperature at the antiferromagnetic QCP of CeRhIn5 where its Fermi surface reconstructs, hallmarks of Kondo-breakdown criticality that generates critical magnetic and charge fluctuations. In 4.4% Sn-doped CeRhIn5, however, Eloc(P) extrapolates into its magnetically ordered phase and is decoupled from the pressure-induced magnetic QCP, which implies a spin-density-wave (SDW) type of criticality that produces only critical fluctuations of the SDW order parameter. Our results demonstrate the importance of experimentally determining Eloc to characterize quantum criticality and the associated consequences for understanding the pairing mechanism of superconductivity that reaches a maximum Tc in both materials at their respective magnetic QCP.
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Affiliation(s)
- Honghong Wang
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea
- Department of Physics, Sungkyunkwan University, Suwon, South Korea
| | - Tae Beom Park
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea
- Department of Physics, Sungkyunkwan University, Suwon, South Korea
- Institute of Basic Science, Sungkyunkwan University, Suwon, South Korea
| | - Jihyun Kim
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea
- Department of Physics, Sungkyunkwan University, Suwon, South Korea
| | - Harim Jang
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea
- Department of Physics, Sungkyunkwan University, Suwon, South Korea
| | - Eric D Bauer
- Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | - Tuson Park
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea.
- Department of Physics, Sungkyunkwan University, Suwon, South Korea.
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3
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Ahmed N, Sharma T, Spillecke L, Koo C, Ansari KU, Tripathi S, Caneschi A, Klingeler R, Rajaraman G, Shanmugam M. Probing the Origin of Ferro-/Antiferromagnetic Exchange Interactions in Cu(II)–4f Complexes. Inorg Chem 2022; 61:5572-5587. [DOI: 10.1021/acs.inorgchem.2c00065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Naushad Ahmed
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai 400076, Maharashtra, India
| | - Tanu Sharma
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai 400076, Maharashtra, India
| | - Lena Spillecke
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany
| | - Changhyun Koo
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany
| | - Kamal Uddin Ansari
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai 400076, Maharashtra, India
| | - Shalini Tripathi
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai 400076, Maharashtra, India
| | - Andrea Caneschi
- Department of Industrial Engineering, “DIEF” and INSTM RU, University of Florence, Via di S. Marta 3, 50131 Florence, Italy
| | - Rüdiger Klingeler
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai 400076, Maharashtra, India
| | - Maheswaran Shanmugam
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai 400076, Maharashtra, India
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4
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Non-monotonic pressure dependence of high-field nematicity and magnetism in CeRhIn 5. Nat Commun 2020; 11:3482. [PMID: 32661299 PMCID: PMC7359027 DOI: 10.1038/s41467-020-17274-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 06/22/2020] [Indexed: 11/28/2022] Open
Abstract
CeRhIn5 provides a textbook example of quantum criticality in a heavy fermion system: Pressure suppresses local-moment antiferromagnetic (AFM) order and induces superconductivity in a dome around the associated quantum critical point (QCP) near pc ≈ 23 kbar. Strong magnetic fields also suppress the AFM order at a field-induced QCP at Bc ≈ 50 T. In its vicinity, a nematic phase at B* ≈ 28 T characterized by a large in-plane resistivity anisotropy emerges. Here, we directly investigate the interrelation between these phenomena via magnetoresistivity measurements under high pressure. As pressure increases, the nematic transition shifts to higher fields, until it vanishes just below pc. While pressure suppresses magnetic order in zero field as pc is approached, we find magnetism to strengthen under strong magnetic fields due to suppression of the Kondo effect. We reveal a strongly non-mean-field-like phase diagram, much richer than the common local-moment description of CeRhIn5 would suggest. Multiple quantum critical behaviors exist in the heavy fermion material CeRhIn5, but their interrelation is less studied. Here, Helm et al. investigate the interrelation of two quantum critical points and other relevant orders, revealing a strongly non-mean-field-like phase diagram.
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5
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Song Y, Wang W, Van Dyke JS, Pouse N, Ran S, Yazici D, Schneidewind A, Čermák P, Qiu Y, Maple MB, Morr DK, Dai P. Nature of the spin resonance mode in CeCoIn 5. COMMUNICATIONS PHYSICS 2020; 3:10.1038/s42005-020-0365-8. [PMID: 33655080 PMCID: PMC7919742 DOI: 10.1038/s42005-020-0365-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
Spin-fluctuation-mediated unconventional superconductivity can emerge at the border of magnetism, featuring a superconducting order parameter that changes sign in momentum space. Detection of such a sign-change is experimentally challenging, since most probes are not phase-sensitive. The observation of a spin resonance mode (SRM) from inelastic neutron scattering is often seen as strong phase-sensitive evidence for a sign-changing superconducting order parameter, by assuming the SRM is a spin-excitonic bound state. Here we show that for the heavy fermion superconductor CeCoIn5, its SRM defies expectations for a spin-excitonic bound state, and is not a manifestation of sign-changing superconductivity. Instead, the SRM in CeCoIn5 likely arises from a reduction of damping to a magnon-like mode in the superconducting state, due to its proximity to magnetic quantum criticality. Our findings emphasize the need for more stringent tests of whether SRMs are spin-excitonic, when using their presence to evidence sign-changing superconductivity.
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Affiliation(s)
- Yu Song
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
| | - Weiyi Wang
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
| | - John S. Van Dyke
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Naveen Pouse
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sheng Ran
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Duygu Yazici
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - A. Schneidewind
- Jülich Center for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany
| | - Petr Čermák
- Jülich Center for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany
- Present address: Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Praha, Czech Republic
| | - Y. Qiu
- NIST center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - M. B. Maple
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Dirk K. Morr
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
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6
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Rosa PFS, Thomas SM, Balakirev FF, Bauer ED, Fernandes RM, Thompson JD, Ronning F, Jaime M. Enhanced Hybridization Sets the Stage for Electronic Nematicity in CeRhIn_{5}. PHYSICAL REVIEW LETTERS 2019; 122:016402. [PMID: 31012717 DOI: 10.1103/physrevlett.122.016402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 09/26/2018] [Indexed: 06/09/2023]
Abstract
High magnetic fields induce a pronounced in-plane electronic anisotropy in the tetragonal antiferromagnetic metal CeRhIn_{5} at H^{*}≳30 T for fields ≃20° off the c axis. Here we investigate the response of the underlying crystal lattice in magnetic fields to 45 T via high-resolution dilatometry. At low fields, a finite magnetic field component in the tetragonal ab plane explicitly breaks the tetragonal (C_{4}) symmetry of the lattice revealing a finite nematic susceptibility. A modest a-axis expansion at H^{*} hence marks the crossover to a fluctuating nematic phase with large nematic susceptibility. Magnetostriction quantum oscillations confirm a Fermi surface change at H^{*} with the emergence of new orbits. By analyzing the field-induced change in the crystal-field ground state, we conclude that the in-plane Ce 4f hybridization is enhanced at H^{*}, in agreement with the in-plane lattice expansion. We argue that the nematic behavior observed in this prototypical heavy-fermion material is of electronic origin, and is driven by the hybridization between 4f and conduction electrons which carries the f-electron anisotropy to the Fermi surface.
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Affiliation(s)
- P F S Rosa
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S M Thomas
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F F Balakirev
- National High Magnetic Field Laboratory, Los Alamos, New Mexico 87545, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M Jaime
- National High Magnetic Field Laboratory, Los Alamos, New Mexico 87545, USA
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7
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Stock C, Rodriguez-Rivera JA, Schmalzl K, Demmel F, Singh DK, Ronning F, Thompson JD, Bauer ED. From Ising Resonant Fluctuations to Static Uniaxial Order in Antiferromagnetic and Weakly Superconducting CeCo(In_{1-x}Hg_{x})_{5}(x=0.01). PHYSICAL REVIEW LETTERS 2018; 121:037003. [PMID: 30085774 DOI: 10.1103/physrevlett.121.037003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Indexed: 06/08/2023]
Abstract
CeCo(In_{0.990}Hg_{0.010})_{5} is a charge doped variant of the d-wave CoCoIn_{5} superconductor with coexistent antiferromagnetic and superconducting transitions occurring at T_{N}=3.4 and T_{c}=1.4 K, respectively. We use neutron diffraction and spectroscopy to show that the magnetic resonant fluctuations present in the parent superconducting phase are replaced by collinear c-axis magnetic order with three-dimensional Ising critical fluctuations. No low-energy transverse spin fluctuations are observable in this doping-induced antiferromagnetic phase and the dynamic resonant spectral weight predominately shifts to the elastic channel. Static (τ>0.2 ns) collinear Ising order is proximate to superconductivity in CeCoIn_{5} and is stabilized through hole doping with Hg.
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Affiliation(s)
- C Stock
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - J A Rodriguez-Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
- Department of Materials Science, University of Maryland, College Park, Maryland 20742, USA
| | - K Schmalzl
- Forschungszentrum Juelich GmbH, Juelich Centre for Neutron Science at ILL, 71 avenue des Martyrs, 38000 Grenoble, France
| | - F Demmel
- ISIS Facility, Rutherford Appleton Labs, Chilton, Didcot OX11 0QX, United Kingdom
| | - D K Singh
- Department of Physics and Astronomy, University of Missouri, Missouri 65211, USA
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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8
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Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn 5. Nature 2017; 548:313-317. [PMID: 28783723 DOI: 10.1038/nature23315] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 06/14/2017] [Indexed: 11/08/2022]
Abstract
Electronic nematic materials are characterized by a lowered symmetry of the electronic system compared to the underlying lattice, in analogy to the directional alignment without translational order in nematic liquid crystals. Such nematic phases appear in the copper- and iron-based high-temperature superconductors, and their role in establishing superconductivity remains an open question. Nematicity may take an active part, cooperating or competing with superconductivity, or may appear accidentally in such systems. Here we present experimental evidence for a phase of fluctuating nematic character in a heavy-fermion superconductor, CeRhIn5 (ref. 5). We observe a magnetic-field-induced state in the vicinity of a field-tuned antiferromagnetic quantum critical point at Hc ≈ 50 tesla. This phase appears above an out-of-plane critical field H* ≈ 28 tesla and is characterized by a substantial in-plane resistivity anisotropy in the presence of a small in-plane field component. The in-plane symmetry breaking has little apparent connection to the underlying lattice, as evidenced by the small magnitude of the magnetostriction anomaly at H*. Furthermore, no anomalies appear in the magnetic torque, suggesting the absence of metamagnetism in this field range. The appearance of nematic behaviour in a prototypical heavy-fermion superconductor highlights the interrelation of nematicity and unconventional superconductivity, suggesting nematicity to be common among correlated materials.
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9
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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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10
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Song Y, Van Dyke J, Lum IK, White BD, Jang S, Yazici D, Shu L, Schneidewind A, Čermák P, Qiu Y, Maple MB, Morr DK, Dai P. Robust upward dispersion of the neutron spin resonance in the heavy fermion superconductor Ce 1-xYb xCoIn 5. Nat Commun 2016; 7:12774. [PMID: 27677397 PMCID: PMC5052703 DOI: 10.1038/ncomms12774] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 07/27/2016] [Indexed: 11/17/2022] Open
Abstract
The neutron spin resonance is a collective magnetic excitation that appears in the unconventional copper oxide, iron pnictide and heavy fermion superconductors. Although the resonance is commonly associated with a spin-exciton due to the d(s±)-wave symmetry of the superconducting order parameter, it has also been proposed to be a magnon-like excitation appearing in the superconducting state. Here we use inelastic neutron scattering to demonstrate that the resonance in the heavy fermion superconductor Ce1-xYbxCoIn5 with x=0, 0.05 and 0.3 has a ring-like upward dispersion that is robust against Yb-doping. By comparing our experimental data with a random phase approximation calculation using the electronic structure and the momentum dependence of the -wave superconducting gap determined from scanning tunnelling microscopy (STM) for CeCoIn5, we conclude that the robust upward-dispersing resonance mode in Ce1-xYbxCoIn5 is inconsistent with the downward dispersion predicted within the spin-exciton scenario.
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Affiliation(s)
- Yu Song
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - John Van Dyke
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - I. K. Lum
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA
| | - B. D. White
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA
| | - Sooyoung Jang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA
| | - Duygu Yazici
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA
| | - L. Shu
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - A. Schneidewind
- Jülich Center for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany
| | - Petr Čermák
- Jülich Center for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany
| | - Y. Qiu
- NIST Center for Neutron Research, National Institute of Standard and Technology, Gaithersburg, Maryland 20899, USA
| | - M. B. Maple
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
- Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA
| | - Dirk K. Morr
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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11
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Raymond S, Lapertot G. Ising Incommensurate Spin Resonance of CeCoIn5: A Dynamical Precursor of the Q Phase. PHYSICAL REVIEW LETTERS 2015; 115:037001. [PMID: 26230821 DOI: 10.1103/physrevlett.115.037001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Indexed: 06/04/2023]
Abstract
It is shown through detailed inelastic neutron scattering experiments that the gapped collective magnetic excitation of the unconventional superconductor CeCoIn5, the spin resonance mode, is incommensurate and that the corresponding fluctuations are of an Ising nature. The incommensurate peak position of these fluctuations corresponds to the propagation vector of the adjacent field induced static magnetic ordered phase, the so-called Q phase. Furthermore, the direction of the magnetic moment fluctuations is also the direction of the ordered magnetic moments of the Q phase. Hence, the resonance mode and the Q phase share the same symmetry and this strongly supports a scenario where the static order is realized by a condensation of the magnetic excitation.
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Affiliation(s)
- S Raymond
- Université Grenoble Alpes, INAC-SPSMS, F-38000 Grenoble, France and CEA, INAC-SPSMS, F-38000 Grenoble, France
| | - G Lapertot
- Université Grenoble Alpes, INAC-SPSMS, F-38000 Grenoble, France and CEA, INAC-SPSMS, F-38000 Grenoble, France
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Kratochvilova M, Uhlirova K, Prchal J, Prokleska J, Misek M, Sechovsky V. Tuning the pressure-induced superconductivity in Pd-substituted CeRhIn5. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:095602. [PMID: 25679366 DOI: 10.1088/0953-8984/27/9/095602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The effect of substituting Rh in CeRh(1-x)Pd(x)In5 with Pd up to x = 0.25 has been studied on single crystals. The crystals have been grown by means of the In self-flux method and characterized by x-ray diffraction and microprobe. The tetragonal HoCoGa5-type of structure and the c/a ratio of the parent compound remains intact by the Pd substitution; the unit cell volume increases by 0.6% with x = 0.25 of Pd. The low-temperature behavior of resistivity was studied also under hydrostatic pressure up to 2.25 GPa. The Pd substitution for Rh affects the magnetic behavior and the maximum value of the superconducting transition temperature measured at pressures above 2 GPa only negligibly. On the other hand, the results provide evidence that superconductivity in CeRh(0.75)Pd(0.25)In5 is induced at significantly lower pressures, i.e. the Pd substitution for Rh shifts the CeRh(1-x)Pd(x)In5 system closer to coexistence of magnetism and superconductivity at ambient pressure.
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