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Ueland BG, Kreyssig A, Mun ED, Lynn JW, Harriger LW, Pratt DK, Prokeš K, Hüsges Z, Toft-Petersen R, Sauerbrei S, Saunders SM, Furukawa Y, Bud'ko SL, McQueeney RJ, Canfield PC, Goldman AI. Magnetic-field effects on the fragile antiferromagnetism in YbBiPt. PHYSICAL REVIEW. B 2019; 99:10.1103/physrevb.99.184431. [PMID: 38846064 PMCID: PMC11155531 DOI: 10.1103/physrevb.99.184431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2024]
Abstract
We present neutron-diffraction data for the cubic-heavy-fermion YbBiPt that show broad magnetic diffraction peaks due to the fragile short-range antiferromagnetic (AFM) order persist under an applied magnetic-field H . Our results for H ⊥ [ 1 ¯ 1 0 ] and a temperature of T = 0.14 1 K show that1 2 , 1 2 , 3 2 ) magnetic diffraction peak can be described by the same two-peak line shape found forμ 0 H = 0 T below the Néel temperature ofT N = 0.4 K . Both components of the peak exist forμ 0 H ≲ 1.4 T , which is well past the AFM phase boundary determined from our new resistivity data. Using neutron-diffraction data taken at T = 0.13 ( 2 ) K for H ∥ 0 0 1 taken at or1 1 0 , we show that domains of short-range AFM order change size throughout the previously determined AFM and non-Fermi liquid regions of the phase diagram, and that the appearance of a magnetic diffraction peak at1 2 , 1 2 , 1 2 atμ 0 H ≈ 0.4 T signals canting of the ordered magnetic moment away from1 1 1 . The continued broadness of the magnetic diffraction peaks under a magnetic field and their persistence across the AFM phase boundary established by detailed transport and thermodynamic experiments present an interesting quandary concerning the nature of YbBiPt's electronic ground state.
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Affiliation(s)
- B G Ueland
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A Kreyssig
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - E D Mun
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - J W Lynn
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - L W Harriger
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - D K Pratt
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - K Prokeš
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Z Hüsges
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - R Toft-Petersen
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - S Sauerbrei
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - S M Saunders
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Y Furukawa
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - S L Bud'ko
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - R J McQueeney
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - P C Canfield
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A I Goldman
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
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Weng ZF, Smidman M, Jiao L, Lu X, Yuan HQ. Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:094503. [PMID: 27533524 DOI: 10.1088/0034-4885/79/9/094503] [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
Heavy fermions have served as prototype examples of strongly-correlated electron systems. The occurrence of unconventional superconductivity in close proximity to the electronic instabilities associated with various degrees of freedom points to an intricate relationship between superconductivity and other electronic states, which is unique but also shares some common features with high temperature superconductivity. The magnetic order in heavy fermion compounds can be continuously suppressed by tuning external parameters to a quantum critical point, and the role of quantum criticality in determining the properties of heavy fermion systems is an important unresolved issue. Here we review the recent progress of studies on Ce based heavy fermion superconductors, with an emphasis on the superconductivity emerging on the edge of magnetic and charge instabilities as well as the quantum phase transitions which occur by tuning different parameters, such as pressure, magnetic field and doping. We discuss systems where multiple quantum critical points occur and whether they can be classified in a unified manner, in particular in terms of the evolution of the Fermi surface topology.
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Affiliation(s)
- Z F Weng
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
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Steglich F, Wirth S. Foundations of heavy-fermion superconductivity: lattice Kondo effect and Mott physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:084502. [PMID: 27376190 DOI: 10.1088/0034-4885/79/8/084502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This article overviews the development of heavy-fermion superconductivity, notably in such rare-earth-based intermetallic compounds which behave as Kondo-lattice systems. Heavy-fermion superconductivity is of unconventional nature in the sense that it is not mediated by electron-phonon coupling. Rather, in most cases the attractive interaction between charge carriers is apparently magnetic in origin. Fluctuations associated with an antiferromagnetic (AF) quantum critical point (QCP) play a major role. The first heavy-fermion superconductor CeCu2Si2 turned out to be the prototype of a larger group of materials for which the underlying, often pressure-induced, AF QCP is likely to be of a three-dimensional (3D) spin-density-wave (SDW) variety. For UBe13, the second heavy-fermion superconductor, a magnetic-field-induced 3D SDW QCP inside the superconducting phase can be conjectured. Such a 'conventional', itinerant QCP can be well understood within Landau's paradigm of order-parameter fluctuations. In contrast, the low-temperature normal-state properties of a few heavy-fermion superconductors are at odds with the Landau framework. They are characterized by an 'unconventional', local QCP which may be considered a zero-temperature 4 f-orbital selective Mott transition. Here, as concluded for YbRh2Si2, the breakdown of the Kondo effect concurring with the AF instability gives rise to an abrupt change of the Fermi surface. Very recently, superconductivity was discovered for this compound at ultra-low temperatures. Therefore, YbRh2Si2 along with CeRhIn5 under pressure provide a natural link between the large group of about fifty low-temperature heavy-fermion superconductors and other families of unconventional superconductors with substantially higher T c, e.g. the doped Mott insulators of the perovskite-type cuprates and the organic charge-transfer salts.
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Affiliation(s)
- Frank Steglich
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany. Center for Correlated Matter, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Fermi surface reconstruction and multiple quantum phase transitions in the antiferromagnet CeRhIn5. Proc Natl Acad Sci U S A 2015; 112:673-8. [PMID: 25561536 DOI: 10.1073/pnas.1413932112] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Conventional, thermally driven continuous phase transitions are described by universal critical behavior that is independent of the specific microscopic details of a material. However, many current studies focus on materials that exhibit quantum-driven continuous phase transitions (quantum critical points, or QCPs) at absolute zero temperature. The classification of such QCPs and the question of whether they show universal behavior remain open issues. Here we report measurements of heat capacity and de Haas-van Alphen (dHvA) oscillations at low temperatures across a field-induced antiferromagnetic QCP (Bc0 ≈ 50 T) in the heavy-fermion metal CeRhIn5. A sharp, magnetic-field-induced change in Fermi surface is detected both in the dHvA effect and Hall resistivity at B0* ≈ 30 T, well inside the antiferromagnetic phase. Comparisons with band-structure calculations and properties of isostructural CeCoIn5 suggest that the Fermi-surface change at B0* is associated with a localized-to-itinerant transition of the Ce-4f electrons in CeRhIn5. Taken in conjunction with pressure experiments, our results demonstrate that at least two distinct classes of QCP are observable in CeRhIn5, a significant step toward the derivation of a universal phase diagram for QCPs.
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Hamann A, Stockert O, Fritsch V, Grube K, Schneidewind A, Löhneysen HV. Evolution of the magnetic structure in CeCu(5.5)Au(0.5) under pressure towards quantum criticality. PHYSICAL REVIEW LETTERS 2013; 110:096404. [PMID: 23496732 DOI: 10.1103/physrevlett.110.096404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Indexed: 06/01/2023]
Abstract
In the prototypical heavy-fermion system CeCu(6-x)Au(x), a magnetic quantum critical point can be tuned by Au concentration x, hydrostatic pressure p, or magnetic field B. A striking equivalence of the tuning behavior with x or p had been found with respect to thermodynamic and transport properties. By means of elastic neutron scattering on single crystalline CeCu(5.5)Au(0.5), we demonstrate this x-p equivalence on a microscopic level by showing that the magnetic ordering wave vector q(m) can be tuned accordingly. At ambient pressure,CeCu(5.5)Au(0.5) orders at q(m)≈(0.59 0 0). Upon applying p=4.1 kbar, q(m)≈(0.61 0 0.21) is found corresponding to CeCu(5.6)Au(0.4) at ambient pressure. The transition seems to occur in a first-order fashion and to be governed by slight changes in the nesting properties of the Fermi surface.
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Affiliation(s)
- A Hamann
- Institut für Festkörperphysik, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany
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Stock C, Broholm C, Demmel F, Van Duijn J, Taylor JW, Kang HJ, Hu R, Petrovic C. From incommensurate correlations to mesoscopic spin resonance in YbRh2Si2. PHYSICAL REVIEW LETTERS 2012; 109:127201. [PMID: 23005978 DOI: 10.1103/physrevlett.109.127201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Indexed: 06/01/2023]
Abstract
Spin fluctuations are reported near the magnetic field-driven quantum critical point in YbRh(2)Si(2). On cooling, ferromagnetic fluctuations evolve into incommensurate correlations located at q(0) = ±(δ,δ), with δ = 0.14 ± 0.04 r.l.u. At low temperatures, an in-plane magnetic field induces a sharp intradoublet resonant excitation at an energy E(0) = gμ(B)μ(0)H with g = 3.8 ± 0.2. The intensity is localized at the zone center, indicating precession of spin density extending ξ = 6 ± 2 Å beyond the 4f site.
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Affiliation(s)
- C Stock
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
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Arndt J, Stockert O, Schmalzl K, Faulhaber E, Jeevan HS, Geibel C, Schmidt W, Loewenhaupt M, Steglich F. Spin fluctuations in normal state CeCu2Si2 on approaching the quantum critical point. PHYSICAL REVIEW LETTERS 2011; 106:246401. [PMID: 21770582 DOI: 10.1103/physrevlett.106.246401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Indexed: 05/31/2023]
Abstract
We report on the magnetic excitation spectrum in the normal state of the heavy-fermion superconductor CeCu92)Si(2) on approaching the quantum critical point (QCP). The magnetic response in the superconducting state is characterized by a transfer of spectral weight to energies above a spin excitation gap. In the normal state, a slowing-down of the quasielastic magnetic response is observed, which conforms to the scaling expected for a QCP of spin-density-wave type. This interpretation is substantiated by an analysis of specific heat data and the momentum dependence of the magnetic excitation spectrum. Our study represents the first direct observation of an almost critical slowing-down of the normal state magnetic response at a QCP when suppressing superconductivity. The results strongly imply that the coupling of Cooper pairs in CeCu(2)Si(2) is mediated by overdamped spin fluctuations.
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Affiliation(s)
- Julia Arndt
- Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany.
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Fermi-surface collapse and dynamical scaling near a quantum-critical point. Proc Natl Acad Sci U S A 2010; 107:14547-51. [PMID: 20668246 DOI: 10.1073/pnas.1009202107] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Quantum criticality arises when a macroscopic phase of matter undergoes a continuous transformation at zero temperature. While the collective fluctuations at quantum-critical points are being increasingly recognized as playing an important role in a wide range of quantum materials, the nature of the underlying quantum-critical excitations remains poorly understood. Here we report in-depth measurements of the Hall effect in the heavy-fermion metal YbRh(2)Si(2), a prototypical system for quantum criticality. We isolate a rapid crossover of the isothermal Hall coefficient clearly connected to the quantum-critical point from a smooth background contribution; the latter exists away from the quantum-critical point and is detectable through our studies only over a wide range of magnetic field. Importantly, the width of the critical crossover is proportional to temperature, which violates the predictions of conventional theory and is instead consistent with an energy over temperature, E/T, scaling of the quantum-critical single-electron fluctuation spectrum. Our results provide evidence that the quantum-dynamical scaling and a critical Kondo breakdown simultaneously operate in the same material. Correspondingly, we infer that macroscopic scale-invariant fluctuations emerge from the microscopic many-body excitations associated with a collapsing Fermi-surface. This insight is expected to be relevant to the unconventional finite-temperature behavior in a broad range of strongly correlated quantum systems.
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Kroha J, Klein M, Nuber A, Reinert F, Stockert O, v Löhneysen H. High-temperature signatures of quantum criticality in heavy-fermion systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:164203. [PMID: 21386409 DOI: 10.1088/0953-8984/22/16/164203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We propose a new criterion for distinguishing the Hertz-Millis (HM) and the local quantum critical (LQC) mechanism in heavy-fermion systems with a magnetic quantum phase transition (QPT). The criterion is based on our finding that the complete spin screening of Kondo ions can be suppressed by the Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling to the surrounding magnetic ions even without magnetic ordering and that, consequently, the signature of this suppression can be observed in spectroscopic measurements above the magnetic ordering temperature. We apply the criterion to high-resolution photoemission measurements on CeCu(6 - x)Au(x) and conclude that the QPT in this system is dominated by the LQC scenario.
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Affiliation(s)
- J Kroha
- Physikalisches Institut and Bethe Center for Theoretical Physics, Universität Bonn, Nussallee 12, 53115 Bonn, Germany.
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