1
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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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2
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Cai S, Zhao J, Ni N, Guo J, Yang R, Wang P, Han J, Long S, Zhou Y, Wu Q, Qiu X, Xiang T, Cava RJ, Sun L. The breakdown of both strange metal and superconducting states at a pressure-induced quantum critical point in iron-pnictide superconductors. Nat Commun 2023; 14:3116. [PMID: 37253725 DOI: 10.1038/s41467-023-38763-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/11/2023] [Indexed: 06/01/2023] Open
Abstract
Here we report the first observation of the concurrent breakdown of the strange metal (SM) normal state and superconductivity at a pressure-induced quantum critical point in Ca10(Pt4As8)((Fe0.97Pt0.03)2As2)5 superconductor. We find that, upon suppressing the superconducting state, the power exponent (α) changes from 1 to 2, and the slope of the temperature-linear resistivity per FeAs layer (A□) gradually diminishes. At a critical pressure, A□ and superconducting transition temperature (Tc) go to zero concurrently, where a quantum phase transition from a superconducting state with a SM normal state to a non-superconducting Fermi liquid state occurs. Scaling analysis reveals that the change of A□ with Tc obeys the relation of Tc ~ (A□)0.5, similar to what is seen in other chemically doped unconventional superconductors. These results suggest that there is a simple but powerful organizational principle of connecting the SM normal state with the high-Tc superconductivity.
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Affiliation(s)
- Shu Cai
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Jinyu Zhao
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Ni Ni
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
- Department of Physics and Astronomy, UCLA, Los Angeles, CA, 90095, USA
| | - Jing Guo
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- Songshan Lake Materials Laboratory, 523808, Dongguan, Guangdong, China
| | - Run Yang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Pengyu Wang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Jinyu Han
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Sijin Long
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Yazhou Zhou
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Qi Wu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Xianggang Qiu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
- Songshan Lake Materials Laboratory, 523808, Dongguan, Guangdong, China
| | - Tao Xiang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Robert J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
| | - Liling Sun
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.
- University of Chinese Academy of Sciences, 100190, Beijing, China.
- Songshan Lake Materials Laboratory, 523808, Dongguan, Guangdong, China.
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3
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Kang JH, Kim J, Park TB, Choi WS, Park S, Park T. Study on superconducting properties of CeIrIn 5thin films grown via pulsed laser deposition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:455602. [PMID: 36055248 DOI: 10.1088/1361-648x/ac8f09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
We report the growth of CeIrIn5thin films with different crystal orientations on a MgF2(001) substrate using pulsed laser deposition technique. X-ray diffraction analysis showed that the thin films were either mainlya-axis-oriented (TF1) or a combination ofa- andc-axis-oriented (TF2). The characteristic features of heavy-fermion superconductors, i.e. Kondo coherence and superconductivity, were clearly observed, where the superconducting transition temperature (Tc) and Kondo coherence temperature (Tcoh) are 0.58 K and 41 K for TF1 and 0.52 K and 37 K for TF2, respectively. The temperature dependencies of the upper critical field (Hc2) of both thin films and the CeIrIn5single crystal revealed a scaling behavior, indicating that the nature of unconventional superconductivity has not been changed in the thin film. The successful synthesis of CeIrIn5thin films is expected to open a new avenue for novel quantum phases that may have been difficult to explore in the bulk crystalline samples.
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Affiliation(s)
- Ji-Hoon Kang
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jihyun Kim
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Tae Beom Park
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Woo Seok Choi
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Sungmin Park
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Tuson Park
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
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4
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Are Heavy Fermion Strange Metals Planckian? CRYSTALS 2022; 12:251. [PMID: 35910592 PMCID: PMC8979306 DOI: 10.3390/cryst12020251] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/10/2022] [Indexed: 11/22/2022]
Abstract
Strange metal behavior refers to a linear temperature dependence of the electrical resistivity that is not due to electron–phonon scattering. It is seen in numerous strongly correlated electron systems, from the heavy fermion compounds, via transition metal oxides and iron pnictides, to magic angle twisted bi-layer graphene, frequently in connection with unconventional or “high temperature” superconductivity. To achieve a unified understanding of these phenomena across the different materials classes is a central open problem in condensed matter physics. Tests whether the linear-in-temperature law might be dictated by Planckian dissipation—scattering with the rate ∼kBT/ℏ—are receiving considerable attention. Here we assess the situation for strange metal heavy fermion compounds. They allow to probe the regime of extreme correlation strength, with effective mass or Fermi velocity renormalizations in excess of three orders of magnitude. Adopting the same procedure as done in previous studies, i.e., assuming a simple Drude conductivity with the above scattering rate, we find that for these strongly renormalized quasiparticles, scattering is much weaker than Planckian, implying that the linear temperature dependence should be due to other effects. We discuss implications of this finding and point to directions for further work.
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5
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Nguyen DH, Sidorenko A, Taupin M, Knebel G, Lapertot G, Schuberth E, Paschen S. Superconductivity in an extreme strange metal. Nat Commun 2021; 12:4341. [PMID: 34290244 PMCID: PMC8295387 DOI: 10.1038/s41467-021-24670-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 06/28/2021] [Indexed: 11/09/2022] Open
Abstract
Some of the highest-transition-temperature superconductors across various materials classes exhibit linear-in-temperature 'strange metal' or 'Planckian' electrical resistivities in their normal state. It is thus believed by many that this behavior holds the key to unlock the secrets of high-temperature superconductivity. However, these materials typically display complex phase diagrams governed by various competing energy scales, making an unambiguous identification of the physics at play difficult. Here we use electrical resistivity measurements into the micro-Kelvin regime to discover superconductivity condensing out of an extreme strange metal state-with linear resistivity over 3.5 orders of magnitude in temperature. We propose that the Cooper pairing is mediated by the modes associated with a recently evidenced dynamical charge localization-delocalization transition, a mechanism that may well be pertinent also in other strange metal superconductors.
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Affiliation(s)
- D H Nguyen
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, Vienna, Austria
| | - A Sidorenko
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, Vienna, Austria
| | - M Taupin
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, Vienna, Austria
| | - G Knebel
- Université Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, Grenoble, France
| | - G Lapertot
- Université Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, Grenoble, France
| | - E Schuberth
- Technische Universität München, Garching, Germany
| | - S Paschen
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, Vienna, Austria.
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6
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Yin L, Che L, Le T, Chen Y, Zhang Y, Lee H, Gnida D, Thompson JD, Kaczorowski D, Lu X. Point-contact spectroscopy of heavy fermion superconductors Ce 2PdIn 8and Ce 3PdIn 11in comparison with CeCoIn 5. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:205603. [PMID: 33690181 DOI: 10.1088/1361-648x/abed19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/09/2021] [Indexed: 06/12/2023]
Abstract
We report point-contact spectroscopy measurements on heavy fermion cousins CeCoIn5, Ce2PdIn8and Ce3PdIn11to systematically study the hybridization betweenfand conduction electrons. Below a temperatureT*, the spectrum of each compound exhibits an evolving Fano-like conductance shape, superimposed on a sloping background, that suggests the development of hybridization between localfand itinerant conduction electrons in the coherent heavy fermion state belowT*. We present a quantitative analysis of the conductance curves with a two-channel model to compare the tunneling process between normal metallic silver particles in our soft point-contact and heavy-fermion single crystals CeCoIn5, Ce2PdIn8and Ce3PdIn11.
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Affiliation(s)
- Lichang Yin
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Liqiang Che
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Tian Le
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Ye Chen
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Yongjun Zhang
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Hanoh Lee
- Department of Physics, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Daniel Gnida
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw, Poland
| | - Joe D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States of America
| | - Dariusz Kaczorowski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw, Poland
- Centre for Advanced Materials and Smart Structures, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw, Poland
| | - Xin Lu
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, People's Republic of China
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7
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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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8
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Martelli V, Cai A, Nica EM, Taupin M, Prokofiev A, Liu CC, Lai HH, Yu R, Ingersent K, Küchler R, Strydom AM, Geiger D, Haenel J, Larrea J, Si Q, Paschen S. Sequential localization of a complex electron fluid. Proc Natl Acad Sci U S A 2019; 116:17701-17706. [PMID: 31431528 PMCID: PMC6731632 DOI: 10.1073/pnas.1908101116] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Complex and correlated quantum systems with promise for new functionality often involve entwined electronic degrees of freedom. In such materials, highly unusual properties emerge and could be the result of electron localization. Here, a cubic heavy fermion metal governed by spins and orbitals is chosen as a model system for this physics. Its properties are found to originate from surprisingly simple low-energy behavior, with 2 distinct localization transitions driven by a single degree of freedom at a time. This result is unexpected, but we are able to understand it by advancing the notion of sequential destruction of an SU(4) spin-orbital-coupled Kondo entanglement. Our results implicate electron localization as a unified framework for strongly correlated materials and suggest ways to exploit multiple degrees of freedom for quantum engineering.
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Affiliation(s)
- Valentina Martelli
- Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria
| | - Ang Cai
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
- Rice Center for Quantum Materials, Rice University, Houston, TX 77005
| | - Emilian M Nica
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
- Rice Center for Quantum Materials, Rice University, Houston, TX 77005
| | - Mathieu Taupin
- Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria
| | - Andrey Prokofiev
- Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria
| | - Chia-Chuan Liu
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
- Rice Center for Quantum Materials, Rice University, Houston, TX 77005
| | - Hsin-Hua Lai
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
- Rice Center for Quantum Materials, Rice University, Houston, TX 77005
| | - Rong Yu
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
- Rice Center for Quantum Materials, Rice University, Houston, TX 77005
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Kevin Ingersent
- Department of Physics, University of Florida, Gainesville, FL 32611-8440
| | - Robert Küchler
- Physics of Quantum Materials, Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - André M Strydom
- Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, Auckland Park 2006, South Africa
| | - Diana Geiger
- Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria
| | - Jonathan Haenel
- Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria
| | - Julio Larrea
- Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria
| | - Qimiao Si
- Department of Physics and Astronomy, Rice University, Houston, TX 77005;
- Rice Center for Quantum Materials, Rice University, Houston, TX 77005
| | - Silke Paschen
- Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria;
- Department of Physics and Astronomy, Rice University, Houston, TX 77005
- Rice Center for Quantum Materials, Rice University, Houston, TX 77005
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9
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A peak in the critical current for quantum critical superconductors. Nat Commun 2018; 9:434. [PMID: 29382852 PMCID: PMC5789853 DOI: 10.1038/s41467-018-02899-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 01/08/2018] [Indexed: 11/09/2022] Open
Abstract
Generally, studies of the critical current Ic are necessary if superconductors are to be of practical use, because Ic sets the current limit below which there is a zero-resistance state. Here, we report a peak in the pressure dependence of the zero-field Ic, Ic(0), at a hidden quantum critical point (QCP), where a continuous antiferromagnetic transition temperature is suppressed by pressure toward 0 K in CeRhIn5 and 4.4% Sn-doped CeRhIn5. The Ic(0)s of these Ce-based compounds under pressure exhibit a universal temperature dependence, underlining that the peak in zero-field Ic(P) is determined predominantly by critical fluctuations associated with the hidden QCP. The dc conductivity σdc is a minimum at the QCP, showing anti-correlation with Ic(0). These discoveries demonstrate that a quantum critical point hidden inside the superconducting phase in strongly correlated materials can be exposed by the zero-field Ic, therefore providing a direct link between a QCP and unconventional superconductivity.
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10
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Shin D, Jung SG, Prathiba G, Seo S, Choi KY, Kim KH, Park T. Thermal annealing and pressure effects on BaFe 2-x Co x As 2 single crystals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:025501. [PMID: 29219115 DOI: 10.1088/1361-648x/aa9d1e] [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 investigate the pressure and thermal annealing effects on BaFe2-x Co x As2 (Co-Ba122) single crystals with x = 0.1 and 0.17 via electrical transport measurements. The thermal annealing treatment not only enhances the superconducting transition temperature (T c) from 9.6 to 12.7 K for x = 0.1 and from 18.1 to 21.0 K for x = 0.17, but also increases the antiferromagnetic transition temperature (T N). Simultaneous enhancement of T c and T N by the thermal annealing treatment indicates that thermal annealing could substantially improve the quality of the Co-doped Ba122 samples. Interestingly, T c of the Co-Ba122 compounds shows a scaling behavior with a linear dependence on the resistivity value at 290 K, irrespective of tuning parameters such as chemical doping, pressure, and thermal annealing. These results not only provide an effective way to access the intrinsic properties of the BaFe2As2 system, but may also shed a light on designing new materials with higher superconducting transition temperature.
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Affiliation(s)
- Dongwon Shin
- Center for Quantum Materials and Superconductivity (CQMS) and Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
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11
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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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12
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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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13
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Bang Y, Stewart GR. Superconducting properties of the s±-wave state: Fe-based superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:123003. [PMID: 28192286 DOI: 10.1088/1361-648x/aa564b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 12/20/2016] [Indexed: 06/06/2023]
Abstract
Although the pairing mechanism of Fe-based superconductors (FeSCs) has not yet been settled with consensus with regard to the pairing symmetry and the superconducting (SC) gap function, the vast majority of experiments support the existence of spin-singlet sign-changings-wave SC gaps on multi-bands (s±-wave state). This multi-bands±-wave state is a very unique gap stateper seand displays numerous unexpected novel SC properties, such as a strong reduction of the coherence peak, non-trivial impurity effects, nodal-gap-like nuclear magnetic resonance signals, various Volovik effects in the specific heat (SH) and thermal conductivity, and anomalous scaling behaviors with a SH jump and condensation energy versusTc, etc. In particular, many of these non-trivial SC properties can easily be mistaken as evidence for a nodal-gap state such as ad-wave gap. In this review, we provide detailed explanations of the theoretical principles for the various non-trivial SC properties of thes±-wave pairing state, and then critically compare the theoretical predictions with experiments on FeSCs. This will provide a pedagogical overview of to what extent we can coherently understand the wide range of different experiments on FeSCs within thes±-wave gap model.
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Affiliation(s)
- Yunkyu Bang
- Department of Physics, Chonnam National University, Kwangju 500-757, Republic of Korea
| | - G R Stewart
- Physics Department, University of Florida, Gainesville, FL 32611-8440, United States of America
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14
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Lonzarich G, Pines D, Yang YF. Toward a new microscopic framework for Kondo lattice materials. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:024501. [PMID: 27991444 DOI: 10.1088/1361-6633/80/2/024501] [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
Understanding the emergence and subsequent behavior of heavy electrons in Kondo lattice materials is one of the grand challenges in condensed matter physics. From this perspective we review the progress that has been made during the past decade and suggest some directions for future research. Our focus will be on developing a new microscopic framework that incorporates the basic concepts that emerge from a phenomenological description of the key experimental findings.
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Affiliation(s)
- Gilbert Lonzarich
- Cavendish Laboratory, Department of Physics, Cambridge University, Cambridge CB3 0HE, UK
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15
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Yang YF. Two-fluid model for heavy electron physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:074501. [PMID: 27214153 DOI: 10.1088/0034-4885/79/7/074501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The two-fluid model is a phenomenological description of the gradual change of the itinerant and local characters of f-electrons with temperature and other tuning parameters and has been quite successful in explaining many unusual and puzzling experimental observations in heavy electron materials. We review some of these results and discuss possible implications of the two-fluid model in understanding the microscopic origin of heavy electron physics.
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Affiliation(s)
- Yi-Feng Yang
- Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. Collaborative Innovation Center of Quantum Matter, Beijing 100190, People's Republic of China
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16
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Curro NJ. Nuclear magnetic resonance in Kondo lattice systems. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:064501. [PMID: 27182054 DOI: 10.1088/0034-4885/79/6/064501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nuclear magnetic resonance has emerged as a vital tool to explore the fundamental physics of Kondo lattice systems. Because nuclear spins experience two different hyperfine couplings to the itinerant conduction electrons and to the local f moments, the Knight shift can probe multiple types of spin correlations that are not accessible via other techniques. The Knight shift provides direct information about the onset of heavy electron coherence and the emergence of the heavy electron fluid.
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Affiliation(s)
- Nicholas J Curro
- Department of Physics, University of California, Davis, CA 95616, USA
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17
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Davidson R, Al-Owaedi OA, Milan DC, Zeng Q, Tory J, Hartl F, Higgins SJ, Nichols RJ, Lambert CJ, Low PJ. Effects of Electrode–Molecule Binding and Junction Geometry on the Single-Molecule Conductance of bis-2,2′:6′,2″-Terpyridine-based Complexes. Inorg Chem 2016; 55:2691-700. [DOI: 10.1021/acs.inorgchem.5b02094] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ross Davidson
- Department of Chemistry, Durham University, South
Rd, Durham, DH1 3LE, United Kingdom
| | - Oday A. Al-Owaedi
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
- Department of Laser Physics, Women Faculty of Science, Babylon University, Hillah, Iraq
| | - David C. Milan
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, United Kingdom
| | - Qiang Zeng
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, United Kingdom
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, Peoples’ Republic of China
| | - Joanne Tory
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, United Kingdom
| | - František Hartl
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, United Kingdom
| | - Simon J. Higgins
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, United Kingdom
| | - Richard J. Nichols
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, United Kingdom
| | - Colin J. Lambert
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Paul J. Low
- School
of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Crawley, Perth, Washington 6009, Australia
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18
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Baumbach RE, Hamlin JJ, Janoschek M, Singleton J, Maple MB. Frustrated magnetism in the spin-chain metal Yb2Fe12P7. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:046004. [PMID: 26742679 DOI: 10.1088/0953-8984/28/4/046004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Magnetization measurements for magnetic fields [Formula: see text] up to 60 T are reported for the noncentrosymmetric spin-chain metal Yb2Fe12P7. These measurements reveal behavior that is consistent with Ising-like spin chain magnetism that produces pronounced spin degeneracy. In particular, we find that although a Brillouin field dependence is observed in M(H) for [Formula: see text] with a saturation moment that is close to the expected value for free ions of Yb(3+) , non-Brillouin-like behavior is seen for [Formula: see text] with an initial saturation moment that is nearly half the free ion value. In addition, hysteretic behavior that extends above the ordering temperature [Formula: see text] is seen for [Formula: see text] but not for [Formula: see text], suggesting out-of-equilibrium physics. This point of view is strengthened by the observation of a spin reconfiguration in the ordered state for [Formula: see text] which is only seen for [Formula: see text] and after polarizing the spins. Together with the heat capacity data, these results suggest that the anomalous low temperature phenomena that were previously reported (Baumbach 2010 et al Phys. Rev. Lett. 105 106403) are driven by spin degeneracy that is related to the Ising-like one dimensional chain-like configuration of the Yb ions.
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Affiliation(s)
- R E Baumbach
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
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19
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Chen Y, Jiang WB, Guo CY, Ronning F, Bauer ED, Park T, Yuan HQ, Fisk Z, Thompson JD, Lu X. Reemergent superconductivity and avoided quantum criticality in Cd-doped CeIrIn(5) under pressure. PHYSICAL REVIEW LETTERS 2015; 114:146403. [PMID: 25910144 DOI: 10.1103/physrevlett.114.146403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Indexed: 06/04/2023]
Abstract
We investigated the electrical resistivity and heat capacity of 1% Cd-doped CeIrIn_{5} under hydrostatic pressure up to 2.7 GPa, near where long-range antiferromagnetic order is suppressed and bulk superconductivity suddenly reemerges. The pressure-induced T_{c} is close to that of pristine CeIrIn_{5} at 2.7 GPa, and no signatures of a quantum critical point under pressure support a local origin of the antiferromagnetic moments in Cd-CeIrIn_{5} at ambient pressure. Similarities between superconductors CeIrIn_{5} and CeCoIn_{5} in response to Cd substitutions suggest a common magnetic mechanism.
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Affiliation(s)
- Y Chen
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - W B Jiang
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - C Y Guo
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Tuson Park
- Department of Physics, Sungkyunkwan University, Suwon 440-746, South Korea
| | - H Q Yuan
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Z Fisk
- Department of Physics, University of California, Irvine, California 92697, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Xin Lu
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
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20
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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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21
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Controlling superconductivity by tunable quantum critical points. Nat Commun 2015; 6:6433. [PMID: 25737108 DOI: 10.1038/ncomms7433] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 01/28/2015] [Indexed: 11/08/2022] Open
Abstract
The heavy fermion compound CeRhIn5 is a rare example where a quantum critical point, hidden by a dome of superconductivity, has been explicitly revealed and found to have a local nature. The lack of additional examples of local types of quantum critical points associated with superconductivity, however, has made it difficult to unravel the role of quantum fluctuations in forming Cooper pairs. Here, we show the precise control of superconductivity by tunable quantum critical points in CeRhIn5. Slight tin-substitution for indium in CeRhIn5 shifts its antiferromagnetic quantum critical point from 2.3 GPa to 1.3 GPa and induces a residual impurity scattering 300 times larger than that of pure CeRhIn5, which should be sufficient to preclude superconductivity. Nevertheless, superconductivity occurs at the quantum critical point of the tin-doped metal. These results underline that fluctuations from the antiferromagnetic quantum criticality promote unconventional superconductivity in CeRhIn5.
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22
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Das P, Lin SZ, Ghimire NJ, Huang K, Ronning F, Bauer ED, Thompson JD, Batista CD, Ehlers G, Janoschek M. Magnitude of the magnetic exchange interaction in the heavy-fermion antiferromagnet CeRhIn₅. PHYSICAL REVIEW LETTERS 2014; 113:246403. [PMID: 25541784 DOI: 10.1103/physrevlett.113.246403] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Indexed: 06/04/2023]
Abstract
We have used high-resolution neutron spectroscopy experiments to determine the complete spin wave spectrum of the heavy-fermion antiferromagnet CeRhIn₅. The spin wave dispersion can be quantitatively reproduced with a simple frustrated J₁-J₂ model that also naturally explains the magnetic spin-spiral ground state of CeRhIn₅ and yields a dominant in-plane nearest-neighbor magnetic exchange constant J₀=0.74(3) meV. Our results pave the way to a quantitative understanding of the rich low-temperature phase diagram of the prominent CeTIn₅ (T=Co, Rh, Ir) class of heavy-fermion materials.
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Affiliation(s)
- Pinaki Das
- Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S-Z Lin
- T-4, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - N J Ghimire
- Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K Huang
- Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA and Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
| | - F Ronning
- Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - E D Bauer
- Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C D Batista
- T-4, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - G Ehlers
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6475, USA
| | - M Janoschek
- Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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23
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Arnold PL, Hollis E, Nichol GS, Love JB, Griveau JC, Caciuffo R, Magnani N, Maron L, Castro L, Yahia A, Odoh SO, Schreckenbach G. Oxo-functionalization and reduction of the uranyl ion through lanthanide-element bond homolysis: synthetic, structural, and bonding analysis of a series of singly reduced uranyl-rare earth 5f1-4f(n) complexes. J Am Chem Soc 2013; 135:3841-54. [PMID: 23451865 DOI: 10.1021/ja308993g] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The heterobimetallic complexes [{UO2Ln(py)2(L)}2], combining a singly reduced uranyl cation and a rare-earth trication in a binucleating polypyrrole Schiff-base macrocycle (Pacman) and bridged through a uranyl oxo-group, have been prepared for Ln = Sc, Y, Ce, Sm, Eu, Gd, Dy, Er, Yb, and Lu. These compounds are formed by the single-electron reduction of the Pacman uranyl complex [UO2(py)(H2L)] by the rare-earth complexes Ln(III)(A)3 (A = N(SiMe3)2, OC6H3Bu(t)2-2,6) via homolysis of a Ln-A bond. The complexes are dimeric through mutual uranyl exo-oxo coordination but can be cleaved to form the trimetallic, monouranyl "ate" complexes [(py)3LiOUO(μ-X)Ln(py)(L)] by the addition of lithium halides. X-ray crystallographic structural characterization of many examples reveals very similar features for monomeric and dimeric series, the dimers containing an asymmetric U2O2 diamond core with shorter uranyl U═O distances than in the monomeric complexes. The synthesis by Ln(III)-A homolysis allows [5f(1)-4f(n)]2 and Li[5f(1)-4f(n)] complexes with oxo-bridged metal cations to be made for all possible 4f(n) configurations. Variable-temperature SQUID magnetometry and IR, NIR, and EPR spectroscopies on the complexes are utilized to provide a basis for the better understanding of the electronic structure of f-block complexes and their f-electron exchange interactions. Furthermore, the structures, calculated by restricted-core or all-electron methods, are compared along with the proposed mechanism of formation of the complexes. A strong antiferromagnetic coupling between the metal centers, mediated by the oxo groups, exists in the U(V)Sm(III) monomer, whereas the dimeric U(V)Dy(III) complex was found to show magnetic bistability at 3 K, a property required for the development of single-molecule magnets.
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Affiliation(s)
- Polly L Arnold
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, Edinburgh, EH9 3JJ, UK.
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24
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Abstract
We obtain the conditions necessary for the emergence of various low-temperature ordered states (local-moment antiferromagnetism, unconventional superconductivity, quantum criticality, and Landau Fermi liquid behavior) in Kondo lattice materials by extending the two-fluid phenomenological theory of heavy-electron behavior to incorporate the concept of hybridization effectiveness. We use this expanded framework to present a new phase diagram and consistent physical explanation and quantitative description of measured emergent behaviors such as the pressure variation of the onset of local-moment antiferromagnetic ordering at T(N), the magnitude of the ordered moment, the growth of superconductivity within that ordered state, the location of a quantum critical point, and of a delocalization line in the pressure/temperature phase diagram at which local moments have disappeared and the heavy-electron Fermi surface has grown to its maximum size. We apply our model to CeRhIn(5) and a number of other heavy-electron materials and find good agreement with experiment.
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25
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Tobash PH, Ronning F, Thompson JD, Scott BL, Moll PJW, Batlogg B, Bauer ED. Single crystal study of the heavy-fermion antiferromagnet CePt₂In₇. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:015601. [PMID: 22133582 DOI: 10.1088/0953-8984/24/1/015601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report the synthesis, structure, and physical properties of single crystals of CePt(2)In(7). Single crystal x-ray diffraction analysis confirms the tetragonal I4/mmm structure of CePt(2)In(7) with unit cell parameters a = 4.5886(6) Å, c = 21.530(6) Å and V = 453.32(14) Å(3). The magnetic susceptibility, heat capacity, Hall effect and electrical resistivity measurements are all consistent with CePt(2)In(7) undergoing an antiferromagnetic order transition at T(N) = 5.5 K, which is field independent up to 9 T. Above T(N), the Sommerfeld coefficient of specific heat is γ ≈ 300 mJ mol(-1) K(-2), which is characteristic of an enhanced effective mass of itinerant charge carriers. The electrical resistivity is typical of heavy-fermion behavior and gives a residual resistivity ρ(0) ∼ 0.2 µΩ cm, indicating good crystal quality. CePt(2)In(7) also shows moderate anisotropy of the physical properties that is comparable to structurally related CeMIn(5) (M = Co, Rh, Ir) heavy-fermion superconductors.
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Affiliation(s)
- Paul H Tobash
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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26
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Park T, Sidorov VA, Lee H, Ronning F, Bauer ED, Sarrao JL, Thompson JD. Unconventional quantum criticality in the pressure-induced heavy-fermion superconductor CeRhIn₅. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:094218. [PMID: 21339571 DOI: 10.1088/0953-8984/23/9/094218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The lack of superconductivity in several candidate materials that exhibit a non-spin density wave quantum critical point has raised the question of whether the associated spectra of quantum fluctuations are beneficial to forming superconducting electron pairs. Here we discuss the possibility that the prototypical heavy-fermion antiferromagnet CeRhIn5 may be the first example of unconventional superconductors where superconductivity arises from Kondo-breakdown quantum criticality.
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Affiliation(s)
- Tuson Park
- Department of Physics, Sungkyunkwan University, Suwon 440-746, Korea. Los Alamos National Laboratory, Los Alamos, NM 87544, USA
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27
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Watanabe S, Miyake K. Roles of critical valence fluctuations in Ce- and Yb-based heavy fermion metals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:094217. [PMID: 21339570 DOI: 10.1088/0953-8984/23/9/094217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The roles of critical valence fluctuations of Ce and Yb are discussed as a key origin of several anomalies observed in Ce- and Yb-based heavy fermion systems. Recent development of the theory has revealed that a magnetic field is an efficient control parameter to induce the critical end point of the first-order valence transition. Metamagnetism and non-Fermi liquid behavior caused by this mechanism are discussed by comparing favorably with CeIrIn5, YbAgCu4 and YbIr2Zn20. The interplay of the magnetic order and valence fluctuations offers a key concept for understanding Ce- and Yb-based systems. It is shown that suppression of the magnetic order by enhanced valence fluctuations gives rise to the coincidence of the magnetic-transition point and valence crossover point at absolute zero as a function of pressure or magnetic field. The interplay is shown to resolve the outstanding puzzle in CeRhIn5 in a unified way. The broader applicability of this newly clarified mechanism is discussed by surveying promising materials such as YbAuCu4, β-YbAlB4 and YbRh2Si2.
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Affiliation(s)
- Shinji Watanabe
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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28
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Ramos SM, Fontes MB, Hering EN, Continentino MA, Baggio-Saitovich E, Neto FD, Bittar EM, Pagliuso PG, Bauer ED, Sarrao JL, Thompson JD. Superconducting quantum critical point in CeCoIn(5-x)Sn(x). PHYSICAL REVIEW LETTERS 2010; 105:126401. [PMID: 20867661 DOI: 10.1103/physrevlett.105.126401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Indexed: 05/29/2023]
Abstract
We report a combined pressure-doping study in the nearly two-dimensional heavy fermion superconductor CeCoIn5 as its superconducting phase is driven to the normal state by Sn doping and/or applied pressure. Temperature-pressure-dependent electrical resistivity measurements were performed at the vicinity of a superconducting quantum critical point where Tc→0. A universal plot of the concentration- and pressure-dependent phase diagram suggests that for the concentrations studied a single mechanism is responsible for reducing Tc and bringing the system to the superconducting quantum critical point. A two-band model with hybridization controlled by pressure and doping provides a consistent description of the phase diagram and the suppression of the d-wave superconductivity in this material.
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Affiliation(s)
- S M Ramos
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ, Brazil.
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29
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Abstract
Metallic magnetism is both ancient and modern, occurring in such familiar settings as the lodestone in compass needles and the hard drive in computers. Surprisingly, a rigorous theoretical basis for metallic ferromagnetism is still largely missing. The Stoner approach perturbatively treats Coulomb interactions when the latter need to be large, whereas the Nagaoka approach incorporates thermodynamically negligible holes into a half-filled band. Here, we show that the ferromagnetic order of the Kondo lattice is amenable to an asymptotically exact analysis over a range of interaction parameters. In this ferromagnetic phase, the conduction electrons and local moments are strongly coupled but the Fermi surface does not enclose the latter (i.e., it is "small"). Moreover, non-Fermi-liquid behavior appears over a range of frequencies and temperatures. Our results provide the basis to understand some long-standing puzzles in the ferromagnetic heavy fermion metals, and raise the prospect for a new class of ferromagnetic quantum phase transitions.
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