1
|
Naritsuka M, Terashima T, Matsuda Y. Controlling unconventional superconductivity in artificially engineered f-electron Kondo superlattices. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:273001. [PMID: 33946054 DOI: 10.1088/1361-648x/abfdf2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials, including high-Tccuprates, iron pnictides, and heavy-fermion compounds. Interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures provide a new approach to this most fundamental and hotly debated subject. We have been able to use a recent state-of-the-art molecular-beam-epitaxy technique to fabricate superlattices consisting of different heavy-fermion compounds with atomic thickness. These Kondo superlattices provide a unique opportunity to study the mutual interaction between unconventional superconductivity and magnetic order through the atomic interface. Here, we design and fabricate hybrid Kondo superlattices consisting of alternating layers of superconducting CeCoIn5withd-wave pairing symmetry and nonmagnetic metal YbCoIn5or antiferromagnetic heavy fermion metals such as CeRhIn5and CeIn3. In these Kondo superlattices, superconducting heavy electrons are confined within the two-dimensional CeCoIn5block layers and interact with neighboring nonmagnetic or magnetic layers through the interface. Superconductivity is strongly influenced by local inversion symmetry breaking at the interface in CeCoIn5/YbCoIn5superlattices. The superconducting and antiferromagnetic states coexist in spatially separated layers in CeCoIn5/CeRhIn5and CeCoIn5/CeIn3superlattices, but their mutual coupling via the interface significantly modifies the superconducting and magnetic properties. The fabrication of a wide variety of hybrid superlattices paves a new way to study the relationship between unconventional superconductivity and magnetism in strongly correlated materials.
Collapse
Affiliation(s)
- M Naritsuka
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Terashima
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| |
Collapse
|
2
|
Lin SZ, Kim DY, Bauer ED, Ronning F, Thompson JD, Movshovich R. Interplay of the Spin Density Wave and a Possible Fulde-Ferrell-Larkin-Ovchinnikov State in CeCoIn_{5} in Rotating Magnetic Field. PHYSICAL REVIEW LETTERS 2020; 124:217001. [PMID: 32530696 DOI: 10.1103/physrevlett.124.217001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
The d-wave superconductor CeCoIn_{5} has been proposed as a strong candidate for supporting the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state near the low-temperature boundary of its upper critical field. Neutron diffraction, however, finds spin-density-wave (SDW) order in this part of the phase diagram for field in the a-b plane, and evidence for the SDW disappears as the applied field is rotated toward the tetragonal c axis. It is important to understand the interplay between the SDW and a possible FFLO state in CeCoIn_{5}, as the mere existence of an SDW does not necessarily exclude an FFLO state. Here, based on a model constructed on the basis of available experiments, we show that an FFLO state competes with an SDW phase. The SDW state in CeCoIn_{5} is stabilized when the field is directed close to the a-b plane. When the field is rotated toward the c axis, the FFLO state emerges, and the SDW phase disappears. In the FFLO state, the nodal planes with extra quasiparticles (where the superconducting order parameter is zero) are perpendicular to the field, and in the SDW phase, the quasiparticle density of states is reduced. We test this model prediction by measuring heat transported by normal quasiparticles in the superconducting state. As a function of field, we observe a reduction of thermal conductivity for field close to the a-b plane and an enhancement of thermal conductivity when field is close to the c axis, consistent with theoretical expectations. Our modeling and experiments, therefore, indicate the existence of the FFLO state when field is parallel to the c axis.
Collapse
Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Duk Y Kim
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
| | - Eric D Bauer
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Filip Ronning
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Roman Movshovich
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| |
Collapse
|
3
|
Liu YP, Zhang YJ, Dong JJ, Lee H, Wei ZX, Zhang WL, Chen CY, Yuan HQ, Yang YF, Qi J. Hybridization Dynamics in CeCoIn_{5} Revealed by Ultrafast Optical Spectroscopy. PHYSICAL REVIEW LETTERS 2020; 124:057404. [PMID: 32083911 DOI: 10.1103/physrevlett.124.057404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 06/10/2023]
Abstract
We investigate the quasiparticle dynamics in the prototypical heavy fermion CeCoIn_{5} using ultrafast optical pump-probe spectroscopy. Our results indicate that this material system undergoes hybridization fluctuations before the establishment of heavy electron coherence, as the temperature decreases from ∼120 K (T^{†}) to ∼55 K (T^{*}). We reveal that the anomalous coherent phonon softening and damping reduction below T^{*} are directly associated with the emergence of collective hybridization. We also discover a distinct collective mode with an energy of ∼8 meV, which may be experimental evidence of the predicted unconventional density wave. Our findings provide important information for understanding the hybridization dynamics in heavy fermion systems.
Collapse
Affiliation(s)
- Y P Liu
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
- Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - Y J Zhang
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - J J Dong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - H Lee
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - Z X Wei
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
- Institute of Electronic and Information Engineering, University of Electronic Science and Technology of China, Dongguan 523808, China
| | - W L Zhang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - C Y Chen
- Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - H Q Yuan
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - Yi-Feng Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - J Qi
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Naritsuka M, Rosa PFS, Luo Y, Kasahara Y, Tokiwa Y, Ishii T, Miyake S, Terashima T, Shibauchi T, Ronning F, Thompson JD, Matsuda Y. Tuning the Pairing Interaction in a d-Wave Superconductor by Paramagnons Injected through Interfaces. PHYSICAL REVIEW LETTERS 2018; 120:187002. [PMID: 29775349 DOI: 10.1103/physrevlett.120.187002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Indexed: 06/08/2023]
Abstract
Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials. A new approach to this most fundamental and hotly debated issue focuses on the role of interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures. Here we fabricate hybrid superlattices consisting of alternating atomic layers of the heavy-fermion superconductor CeCoIn_{5} and antiferromagnetic (AFM) metal CeRhIn_{5}, in which the AFM order can be suppressed by applying pressure. We find that the superconducting and AFM states coexist in spatially separated layers, but their mutual coupling via the interface significantly modifies the superconducting properties. An analysis of upper critical fields reveals that, upon suppressing the AFM order by applied pressure, the force binding superconducting electron pairs acquires an extreme strong-coupling nature. This demonstrates that superconducting pairing can be tuned nontrivially by magnetic fluctuations (paramagnons) injected through the interface.
Collapse
Affiliation(s)
- M Naritsuka
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - P F S Rosa
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - Yongkang Luo
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - Y Kasahara
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Tokiwa
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
- Center for Electronic Correlations and Magnetism, Institute of Physics, Augsburg University, 86159 Augsburg, Germany
| | - T Ishii
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - S Miyake
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Terashima
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Shibauchi
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| |
Collapse
|
7
|
Shishido H, Yamada S, Sugii K, Shimozawa M, Yanase Y, Yamashita M. Anomalous Change in the de Haas-van Alphen Oscillations of CeCoIn_{5} at Ultralow Temperatures. PHYSICAL REVIEW LETTERS 2018; 120:177201. [PMID: 29756834 DOI: 10.1103/physrevlett.120.177201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 03/07/2018] [Indexed: 06/08/2023]
Abstract
We perform de Haas-van Alphen (dHvA) measurements of the heavy-fermion superconductor CeCoIn_{5} down to 2 mK above the upper critical field. We find that the dHvA amplitudes show an anomalous suppression, concomitantly with a shift of the dHvA frequency, below the transition temperature T_{n}=20 mK. We suggest that the change is owing to magnetic breakdown caused by a field-induced antiferromagnetic (AFM) state emerging below T_{n}, revealing the origin of the field-induced quantum critical point (QCP) in CeCoIn_{5}. The field dependence of T_{n} is found to be very weak for 7-10 T, implying that an enhancement of AFM order by suppressing the critical spin fluctuations near the AFM QCP competes with the field suppression effect on the AFM phase. We suggest that the appearance of a field-induced AFM phase is a generic feature of unconventional superconductors, which emerge near an AFM QCP, including CeCoIn_{5}, CeRhIn_{5}, and high-T_{c} cuprates.
Collapse
Affiliation(s)
- Hiroaki Shishido
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
- Institute for Nanofabrication Research, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
| | - Shogo Yamada
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Kaori Sugii
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Masaaki Shimozawa
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Youichi Yanase
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Minoru Yamashita
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| |
Collapse
|
8
|
Spatially Nonuniform Superconductivity in Quasi-Two-Dimensional Organic Charge-Transfer Salts. CRYSTALS 2018. [DOI: 10.3390/cryst8050183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
9
|
Distinct domain switching in Nd 0.05Ce 0.95CoIn 5 at low and high fields. Sci Rep 2018; 8:1295. [PMID: 29358702 PMCID: PMC5778004 DOI: 10.1038/s41598-018-19555-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 01/03/2018] [Indexed: 11/08/2022] Open
Abstract
Nd0.05Ce0.95CoIn5 features a magnetic field-driven quantum phase transition that separates two antiferromagnetic phases with an identical magnetic structure inside the superconducting condensate. Using neutron diffraction we demonstrate that the population of the two magnetic domains in the two phases is affected differently by the rotation of the magnetic field in the tetragonal basal plane. In the low-field SDW-phase the domain population is only weakly affected while in the high-field Q-phase they undergo a sharp switch for fields around the a-axis. Our results provide evidence that the anisotropic spin susceptibility in both phases arises ultimately from spin-orbit interactions but are qualitatively different in the two phases. This provides evidence that the electronic structure is changed at the quantum phase transition, which yields a modified coupling between magnetism and superconductivity in the Q-phase.
Collapse
|
10
|
Mazzone DG, Raymond S, Gavilano JL, Steffens P, Schneidewind A, Lapertot G, Kenzelmann M. Spin Resonance and Magnetic Order in an Unconventional Superconductor. PHYSICAL REVIEW LETTERS 2017; 119:187002. [PMID: 29219605 DOI: 10.1103/physrevlett.119.187002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Indexed: 06/07/2023]
Abstract
Unconventional superconductivity in many materials is believed to be mediated by magnetic fluctuations. It is an open question how magnetic order can emerge from a superconducting condensate and how it competes with the magnetic spin resonance in unconventional superconductors. Here we study a model d-wave superconductor that develops spin-density wave order, and find that the spin resonance is unaffected by the onset of static magnetic order. This result suggests a scenario, in which the resonance in Nd_{0.05}Ce_{0.95}CoIn_{5} is a longitudinal mode with fluctuating moments along the ordered magnetic moments.
Collapse
Affiliation(s)
- D G Mazzone
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - S Raymond
- Univ. Grenoble Alpes and CEA, INAC, MEM, F-38000 Grenoble, France
| | - J L Gavilano
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - P Steffens
- Institut Laue-Langevin, 38042 Grenoble, France
| | - A Schneidewind
- Jülich Center for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany
| | - G Lapertot
- Univ. Grenoble Alpes and CEA, INAC, PHELIQS, F-38000 Grenoble, France
| | - M Kenzelmann
- Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| |
Collapse
|
11
|
Waßer F, Lee CH, Kihou K, Steffens P, Schmalzl K, Qureshi N, Braden M. Anisotropic resonance modes emerging in an antiferromagnetic superconducting state. Sci Rep 2017; 7:10307. [PMID: 28871098 PMCID: PMC5583249 DOI: 10.1038/s41598-017-10208-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 08/04/2017] [Indexed: 11/09/2022] Open
Abstract
Two strong arguments in favor of magnetically driven unconventional superconductivity arise from the coexistence and closeness of superconducting and magnetically ordered phases on the one hand, and from the emergence of magnetic spin-resonance modes at the superconducting transition on the other hand. Combining these two arguments one may ask about the nature of superconducting spin-resonance modes occurring in an antiferromagnetic state. This problem can be studied in underdoped BaFe2 As2, for which the local coexistence of large moment antiferromagnetism and superconductivity is well established by local probes. However, polarized neutron scattering experiments are required to identify the nature of the resonance modes. In the normal state of Co underdoped BaFe2 As2 the antiferromagnetic order results in broad magnetic gaps opening in all three spin directions that are reminiscent of the magnetic response in the parent compound. In the superconducting state two distinct anisotropic resonance excitations emerge, but in contrast to numerous studies on optimum and over-doped BaFe2 As2 there is no isotropic resonance excitation. The two anisotropic resonance modes appearing within the antiferromagnetic phase are attributed to a band selective superconducting state, in which longitudinal magnetic excitations are gapped by antiferromagnetic order with sizable moment.
Collapse
Affiliation(s)
- F Waßer
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937, Köln, Germany.
| | - C H Lee
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan
| | - K Kihou
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan
| | - P Steffens
- Institut Laue Langevin, 71 avenue des Martyrs, 38000, Grenoble, France
| | - K Schmalzl
- Jülich Centre for Neutron Science, Forschungszentrum Jülich GmbH, Outstation at Institut Laue-Langevin, 71 avenue des Martyrs, 38000, Grenoble, France
| | - N Qureshi
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937, Köln, Germany.,Institut Laue Langevin, 71 avenue des Martyrs, 38000, Grenoble, France
| | - M Braden
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937, Köln, Germany.
| |
Collapse
|
12
|
Zaliznyak IA, Savici AT, Ovidiu Garlea V, Winn B, Filges U, Schneeloch J, Tranquada JM, Gu G, Wang A, Petrovic C. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS. ACTA ACUST UNITED AC 2017. [DOI: 10.1088/1742-6596/862/1/012030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
13
|
Competing magnetic orders in the superconducting state of heavy-fermion CeRhIn 5. Proc Natl Acad Sci U S A 2017; 114:5384-5388. [PMID: 28487488 DOI: 10.1073/pnas.1703016114] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Applied pressure drives the heavy-fermion antiferromagnet CeRhIn5 toward a quantum critical point that becomes hidden by a dome of unconventional superconductivity. Magnetic fields suppress this superconducting dome, unveiling the quantum phase transition of local character. Here, we show that [Formula: see text] magnetic substitution at the Ce site in CeRhIn5, either by Nd or Gd, induces a zero-field magnetic instability inside the superconducting state. This magnetic state not only should have a different ordering vector than the high-field local-moment magnetic state, but it also competes with the latter, suggesting that a spin-density-wave phase is stabilized in zero field by Nd and Gd impurities, similarly to the case of Ce0.95Nd0.05CoIn5 Supported by model calculations, we attribute this spin-density wave instability to a magnetic-impurity-driven condensation of the spin excitons that form inside the unconventional superconducting state.
Collapse
|
14
|
Kim DY, Lin SZ, Weickert F, Bauer ED, Ronning F, Thompson JD, Movshovich R. Resonances in the Field-Angle-Resolved Thermal Conductivity of CeCoIn_{5}. PHYSICAL REVIEW LETTERS 2017; 118:197001. [PMID: 28548529 DOI: 10.1103/physrevlett.118.197001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Indexed: 06/07/2023]
Abstract
The thermal conductivity measurement in a rotating magnetic field is a powerful probe of the structure of the superconducting energy gap. We present high-precision measurements of the low-temperature thermal conductivity in the unconventional heavy-fermion superconductor CeCoIn_{5}, with the heat current J along the nodal [110] direction of its d_{x^{2}-y^{2}} order parameter and the magnetic field up to 7 T rotating in the ab plane. In contrast to the smooth oscillations found previously for J∥[100], we observe a sharp resonancelike peak in the thermal conductivity when the magnetic field is also in the [110] direction, parallel to the heat current. We explain this peak qualitatively via a model of the heat transport in a d-wave superconductor. In addition, we observe two smaller but also very sharp peaks in the thermal conductivity for the field directions at angles Θ≈±33° with respect to J. The origin of the observed resonances at Θ≈±33° at present defies theoretical explanation. The challenge of uncovering their source will dictate exploring theoretically more complex models, which might include, e.g., fine details of the Fermi surface, Andreev bound vortex core states, a secondary superconducting order parameter, and the existence of gaps in spin and charge excitations.
Collapse
Affiliation(s)
- Duk Y Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Shi-Zeng Lin
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | - Eric D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Filip Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Roman Movshovich
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| |
Collapse
|
15
|
Mazzone DG, Raymond S, Gavilano JL, Ressouche E, Niedermayer C, Birk JO, Ouladdiaf B, Bastien G, Knebel G, Aoki D, Lapertot G, Kenzelmann M. Field-induced magnetic instability within a superconducting condensate. SCIENCE ADVANCES 2017; 3:e1602055. [PMID: 28560326 PMCID: PMC5438216 DOI: 10.1126/sciadv.1602055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 03/20/2017] [Indexed: 06/07/2023]
Abstract
The application of magnetic fields, chemical substitution, or hydrostatic pressure to strongly correlated electron materials can stabilize electronic phases with different organizational principles. We present evidence for a field-induced quantum phase transition, in superconducting Nd0.05Ce0.95CoIn5, that separates two antiferromagnetic phases with identical magnetic symmetry. At zero field, we find a spin-density wave that is suppressed at the critical field μ0H* = 8 T. For H > H*, a spin-density phase emerges and shares many properties with the Q phase in CeCoIn5. These results suggest that the magnetic instability is not magnetically driven, and we propose that it is driven by a modification of superconducting condensate at H*.
Collapse
Affiliation(s)
- Daniel Gabriel Mazzone
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Stéphane Raymond
- Institute for Nanosciences and Cryogenics, Commissariat à l’Energie Atomique et aux Energies Alternatives, Université Grenoble Alpes, 38054 Grenoble, France
| | - Jorge Luis Gavilano
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Eric Ressouche
- Institute for Nanosciences and Cryogenics, Commissariat à l’Energie Atomique et aux Energies Alternatives, Université Grenoble Alpes, 38054 Grenoble, France
| | - Christof Niedermayer
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Jonas Okkels Birk
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Department of Physics, Technical University of Denmark (DTU), DK-2800 Kongens Lyngby, Denmark
| | | | - Gaël Bastien
- Institute for Nanosciences and Cryogenics, Commissariat à l’Energie Atomique et aux Energies Alternatives, Université Grenoble Alpes, 38054 Grenoble, France
| | - Georg Knebel
- Institute for Nanosciences and Cryogenics, Commissariat à l’Energie Atomique et aux Energies Alternatives, Université Grenoble Alpes, 38054 Grenoble, France
| | - Dai Aoki
- Institute for Nanosciences and Cryogenics, Commissariat à l’Energie Atomique et aux Energies Alternatives, Université Grenoble Alpes, 38054 Grenoble, France
| | - Gérard Lapertot
- Institute for Nanosciences and Cryogenics, Commissariat à l’Energie Atomique et aux Energies Alternatives, Université Grenoble Alpes, 38054 Grenoble, France
| | - Michel Kenzelmann
- Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| |
Collapse
|
16
|
Kenzelmann M. Exotic magnetic states in Pauli-limited superconductors. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:034501. [PMID: 28112100 DOI: 10.1088/1361-6633/80/3/034501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Magnetism and superconductivity compete or interact in complex and intricate ways. Here we review the special case where novel magnetic phenomena appear due to superconductivity, but do not exist without it. Such states have recently been identified in unconventional superconductors. They are different from the mere coexistence of magnetic order and superconductivity in conventional superconductors, or from competing magnetic and superconducting phases in many materials. We describe the recent progress in the study of such exotic magnetic phases, and articulate the many open questions in this field.
Collapse
Affiliation(s)
- M Kenzelmann
- Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Paglione J, Tanatar MA, Reid JP, Shakeripour H, Petrovic C, Taillefer L. Quantum Critical Quasiparticle Scattering within the Superconducting State of CeCoIn_{5}. PHYSICAL REVIEW LETTERS 2016; 117:016601. [PMID: 27419578 DOI: 10.1103/physrevlett.117.016601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Indexed: 06/06/2023]
Abstract
The thermal conductivity κ of the heavy-fermion metal CeCoIn_{5} was measured in the normal and superconducting states as a function of temperature T and magnetic field H, for a current and field parallel to the [100] direction. Inside the superconducting state, when the field is lower than the upper critical field H_{c2}, κ/T is found to increase as T→0, just as in a metal and in contrast to the behavior of all known superconductors. This is due to unpaired electrons on part of the Fermi surface, which dominate the transport above a certain field. The evolution of κ/T with field reveals that the electron-electron scattering (or transport mass m^{⋆}) of those unpaired electrons diverges as H→H_{c2} from below, in the same way that it does in the normal state as H→H_{c2} from above. This shows that the unpaired electrons sense the proximity of the field-tuned quantum critical point of CeCoIn_{5} at H^{⋆}=H_{c2} even from inside the superconducting state. The fact that the quantum critical scattering of the unpaired electrons is much weaker than the average scattering of all electrons in the normal state reveals a k-space correlation between the strength of pairing and the strength of scattering, pointing to a common mechanism, presumably antiferromagnetic fluctuations.
Collapse
Affiliation(s)
- Johnpierre Paglione
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
| | - M A Tanatar
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
- Ames Laboratory USDOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - J-Ph Reid
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
| | - H Shakeripour
- Department of Physics, Isfahan University of Technology, Isfahan 84156-83111, Iran
| | - C Petrovic
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
- Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Louis Taillefer
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
| |
Collapse
|