1
|
Krenkel EH, Tanatar MA, Ghimire S, Joshi KR, Chen S, Petrovic C, Prozorov R. Robust superconductivity and the suppression of charge-density wave in the quasi-skutteruditesCa3(Ir1-xRhx)4Sn13single crystals at ambient pressure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:385702. [PMID: 38838680 DOI: 10.1088/1361-648x/ad5485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 06/05/2024] [Indexed: 06/07/2024]
Abstract
Single crystals of the quasi-skutterudite compounds Ca3(Ir1-xRhx)4Sn13(3-4-13) were synthesized by flux growth and characterized by x-ray diffraction, energy dispersive x-ray spectroscopy, magnetization, resistivity, and radio frequency magnetic susceptibility techniques. The coexistence and competition between the charge density wave (CDW) and superconductivity was studied by varying the Rh/Ir ratio. The superconducting transition temperature,Tc, varies from 7 K in pure Ir (x = 0) to 8.3 K in pure Rh (x = 1). Temperature-dependent electrical resistivity reveals monotonic suppression of the CDW transition temperature,TCDW(x). The CDW starts in pure Ir,x = 0, atTCDW≈ 40 K and extrapolates roughly linearly to zero atxc≈0.53-0.58 under the superconducting dome. Magnetization and transport measurements show a significant influence of CDW on superconducting and normal states. Meissner expulsion is substantially reduced in the CDW region, indicating competition between the CDW and superconductivity. The low-temperature resistivity is higher in the CDW part of the phase diagram, consistent with the reduced density of states due to CDW gapping. Its temperature dependence just aboveTcshows signs of non-Fermi liquid behavior in a cone-like composition pattern. We conclude that the Ca3(Ir1-xRhx)4Sn13alloy is a good candidate for a composition-driven quantum critical point at ambient pressure.
Collapse
Affiliation(s)
- Elizabeth H Krenkel
- Ames National Laboratory, Ames, IA 50011, United States of America
- Department of Physics & Astronomy, Iowa State University, Ames, IA 50011, United States of America
| | - Makariy A Tanatar
- Ames National Laboratory, Ames, IA 50011, United States of America
- Department of Physics & Astronomy, Iowa State University, Ames, IA 50011, United States of America
| | - Sunil Ghimire
- Ames National Laboratory, Ames, IA 50011, United States of America
- Department of Physics & Astronomy, Iowa State University, Ames, IA 50011, United States of America
| | - Kamal R Joshi
- Ames National Laboratory, Ames, IA 50011, United States of America
| | - Shuzhang Chen
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, United States of America
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800, United States of America
| | - Cedomir Petrovic
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, United States of America
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800, United States of America
| | - Ruslan Prozorov
- Ames National Laboratory, Ames, IA 50011, United States of America
- Department of Physics & Astronomy, Iowa State University, Ames, IA 50011, United States of America
| |
Collapse
|
2
|
Xu HS, Wu S, Zheng H, Yin R, Li Y, Wang X, Tang K. Research Progress of FeSe-based Superconductors Containing Ammonia/Organic Molecules Intercalation. Top Curr Chem (Cham) 2022; 380:11. [PMID: 35122164 DOI: 10.1007/s41061-022-00368-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 01/17/2022] [Indexed: 10/19/2022]
Abstract
As an important part of Fe-based superconductors, FeSe-based superconductors have become a hot field in condensed matter physics. The exploration and preparation of such superconducting materials form the basis of studying their physical properties. With the help of various alkali/alkaline-earth/rare-earth metals, different kinds of ammonia/organic molecules have been intercalated into the FeSe layer to form a large number of FeSe-based superconductors with diverse structures and different layer spacing. Metal cations can effectively provide carriers to the superconducting FeSe layer, thus significantly increasing the superconducting transition temperature. The orientation of organic molecules often plays an important role in structural modification and can be used to fine-tune superconductivity. This review introduces the crystal structures and superconducting properties of several typical FeSe-based superconductors containing ammonia/organic molecules intercalation discovered in recent years, and the effects of FeSe layer spacing and superconducting transition temperature are briefly summarized.
Collapse
Affiliation(s)
- Han-Shu Xu
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230026, People's Republic of China.
| | - Shusheng Wu
- Department of Chemistry, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Hui Zheng
- Department of Chemistry, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Ruotong Yin
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Yuanji Li
- Department of Physics, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Xiaoxiong Wang
- College of Physics Science, Qingdao University, Qingdao, 266071, People's Republic of China.
| | - Kaibin Tang
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230026, People's Republic of China. .,Department of Chemistry, University of Science and Technology of China, Hefei, 230026, People's Republic of China.
| |
Collapse
|
3
|
Makarov D, Volkov OM, Kákay A, Pylypovskyi OV, Budinská B, Dobrovolskiy OV. New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2101758. [PMID: 34705309 DOI: 10.1002/adma.202101758] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/16/2021] [Indexed: 06/13/2023]
Abstract
Traditionally, the primary field, where curvature has been at the heart of research, is the theory of general relativity. In recent studies, however, the impact of curvilinear geometry enters various disciplines, ranging from solid-state physics over soft-matter physics, chemistry, and biology to mathematics, giving rise to a plethora of emerging domains such as curvilinear nematics, curvilinear studies of cell biology, curvilinear semiconductors, superfluidity, optics, 2D van der Waals materials, plasmonics, magnetism, and superconductivity. Here, the state of the art is summarized and prospects for future research in curvilinear solid-state systems exhibiting such fundamental cooperative phenomena as ferromagnetism, antiferromagnetism, and superconductivity are outlined. Highlighting the recent developments and current challenges in theory, fabrication, and characterization of curvilinear micro- and nanostructures, special attention is paid to perspective research directions entailing new physics and to their strong application potential. Overall, the perspective is aimed at crossing the boundaries between the magnetism and superconductivity communities and drawing attention to the conceptual aspects of how extension of structures into the third dimension and curvilinear geometry can modify existing and aid launching novel functionalities. In addition, the perspective should stimulate the development and dissemination of research and development oriented techniques to facilitate rapid transitions from laboratory demonstrations to industry-ready prototypes and eventual products.
Collapse
Affiliation(s)
- Denys Makarov
- Helmholtz-Zentrum Dresden - Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, 01328, Dresden, Germany
| | - Oleksii M Volkov
- Helmholtz-Zentrum Dresden - Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, 01328, Dresden, Germany
| | - Attila Kákay
- Helmholtz-Zentrum Dresden - Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, 01328, Dresden, Germany
| | - Oleksandr V Pylypovskyi
- Helmholtz-Zentrum Dresden - Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, 01328, Dresden, Germany
- Kyiv Academic University, Kyiv, 03142, Ukraine
| | - Barbora Budinská
- Superconductivity and Spintronics Laboratory, Nanomagnetism and Magnonics, Faculty of Physics, University of Vienna, Vienna, 1090, Austria
| | - Oleksandr V Dobrovolskiy
- Superconductivity and Spintronics Laboratory, Nanomagnetism and Magnonics, Faculty of Physics, University of Vienna, Vienna, 1090, Austria
| |
Collapse
|
4
|
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
|
5
|
Zhang J, Ding F, Lee JJ, Shan G, Bobev S. One Structure, Two Elements-LuGe 2 Superconductor vs Ordinary Metallic Conductor LuSn 2. A Case Study on How Site-Selective Germanium for Tin Atom Substitution Leads to Modulating of the Charge Distribution. Inorg Chem 2020; 59:16853-16864. [PMID: 32970413 DOI: 10.1021/acs.inorgchem.0c01062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The substitution of chemically similar elements in a given crystal structure is an effective way to enhance physical properties, but the understanding on such improvements is usually impeded because the substitutions are random, and the roles of the different atoms cannot be distinguished by crystallographic symmetry. Herein, we provide a detailed crystallographic analysis and property measurements for the continuous solid solutions LuGexSn2-x (0 < x < 2). The results show that there is no apparent change of the global symmetry, with the end-members LuGe2 and LuSn2, as well as the intermediate LuGexSn2-x compositions adopting the ZrSi2 type structure (space group Cmcm, Pearson index oC12). Yet, the refinements of the crystal structures from single-crystal X-ray diffraction data show that Ge-Sn atom substitutions are not random, but occur preferentially at the zigzag chain. The patterned distribution of two group 14 elements leads to a significant variation in chemical bonding and charge ordering within the other structural fragment, the 2D square nets, thereby resulting in tuned electron transport. The enhancement is greater than that for the typical Bloch-Gruneisen model and more akin to that for the parallel-resistor model. Magnetization measurements on single crystals show bulk superconductivity in all LuGexSn2-x samples with shielding fractions as high as 90%. Specific heat data confirm the effect to originate from residual metallic tin in the material, indicating that Sn atom substitutions in the 2D square nets cause disruptions of the hypervalent bonding and local anisotropy, which ultimately leads to vanishing of the superconducting state in the end-member LuGe2. This work sheds light on how the complexity in chemical interactions by two different carbon congeners leads to changes in the physical properties and how they can be correlated with the induced charge distribution. These studies also provide a general approach to modulation of charge density and. thus, of emerging physical properties in other classes of intermetallic systems based on the main-group elements of groups 13 to 15.
Collapse
Affiliation(s)
- Jiliang Zhang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.,Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Fazhu Ding
- Key Laboratory of Applied Superconductivity and Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jey-Jau Lee
- National Synchrotron Radiation Research Center, Hsinchu 30076 Taiwan, Republic of China
| | - Guangcun Shan
- School of Instrument Science and Optoelectronics Engineering & Institute of Precision Mechanics and Quantum Sensing, Beihang University, Beijing 100083, People's Republic of China.,Institute of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany
| | - Svilen Bobev
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| |
Collapse
|
6
|
Yu J, Wang M, Frandsen BA, Sun H, Yin J, Liu Z, Wu S, Yi M, Xu Z, Acharya A, Huang Q, Bourret-Courchesne E, Lynn JW, Birgeneau RJ. Structural, magnetic, and electronic evolution of the spin-ladder system BaFe 2S 3-x Se x with isoelectronic substitution. PHYSICAL REVIEW. B 2020; 101:10.1103/PhysRevB.101.235134. [PMID: 34136736 PMCID: PMC8204408 DOI: 10.1103/physrevb.101.235134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report experimental studies of a series of BaFe2S3-x Se x (0 ⩽ x ⩽ 3) single crystals and powder specimens using x-ray diffraction, neutron-diffraction, muon-spin-relaxation, and electrical transport measurements. A structural transformation from Cmcm (BaFe2S3) to Pnma (BaFe2Se3) was identified around x = 0.7 - 1. Neutron-diffraction measurements on the samples with x = 0.2, 0.4, and 0.7 reveal that the Néel temperature of the stripe antiferromagnetic order is gradually suppressed from ~120 to 85 K, while the magnitude of the ordered Fe2+ moments shows very little variation. Similarly, the block antiferromagnetic order in BaFe2Se3 remains robust for 1.5 ⩽ x ⩽ 3 with negligible variation in the ordered moment and a slight decrease of the Néel temperature from 250 K (x = 3) to 225 K (x = 1.5). The sample with x = 1 near the Cmcm and Pnma border shows coexisting, two-dimensional, short-range stripe- and block-type antiferromagnetic correlations. The system remains insulating for all x, but the thermal activation gap shows an abrupt increase when traversing the boundary from the Cmcm stripe phase to the Pnma block phase. The results demonstrate that the crystal structure, magnetic order, and electronic properties are strongly coupled in the BaFe2S3-x Se x system.
Collapse
Affiliation(s)
- Jia Yu
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
| | - Meng Wang
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
| | - Benjamin A. Frandsen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA
| | - Hualei Sun
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
| | - Junjie Yin
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
| | - Zengjia Liu
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
| | - Shan Wu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Ming Yi
- Department of Physics, University of California, Berkeley, California 94720, USA
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Zhijun Xu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Arani Acharya
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Qingzhen Huang
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Edith Bourret-Courchesne
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jeffrey W. Lynn
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Robert J. Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| |
Collapse
|
7
|
Electrical resistivity across a nematic quantum critical point. Nature 2019; 567:213-217. [PMID: 30760921 DOI: 10.1038/s41586-019-0923-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 11/29/2018] [Indexed: 11/08/2022]
Abstract
Correlated electron systems are highly susceptible to various forms of electronic order. By tuning the transition temperature towards absolute zero, striking deviations from conventional metallic (Fermi-liquid) behaviour can be realized. Evidence for electronic nematicity, a correlated electronic state with broken rotational symmetry, has been reported in a host of metallic systems1-5 that exhibit this so-called quantum critical behaviour. In all cases, however, the nematicity is found to be intertwined with other forms of order, such as antiferromagnetism5-7 or charge-density-wave order8, that might themselves be responsible for the observed behaviour. The iron chalcogenide FeSe1-xSx is unique in this respect because its nematic order appears to exist in isolation9-11, although until now, the impact of nematicity on the electronic ground state has been obscured by superconductivity. Here we use high magnetic fields to destroy the superconducting state in FeSe1-xSx and follow the evolution of the electrical resistivity across the nematic quantum critical point. Classic signatures of quantum criticality are revealed: an enhancement in the coefficient of the T2 resistivity (due to electron-electron scattering) on approaching the critical point and, at the critical point itself, a strictly T-linear resistivity that extends over a decade in temperature T. In addition to revealing the phenomenon of nematic quantum criticality, the observation of T-linear resistivity at a nematic critical point also raises the question of whether strong nematic fluctuations play a part in the transport properties of other 'strange metals', in which T-linear resistivity is observed over an extended regime in their respective phase diagrams.
Collapse
|
8
|
Sun JP, Wang ZC, Liu ZY, Xu SX, Eto T, Sui Y, Wang BS, Uwatoko Y, Cao GH, Cheng JG. Effect of pressure on the self-hole-doped superconductor RbGd 2Fe 4As 4O 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:044001. [PMID: 30543523 DOI: 10.1088/1361-648x/aaf0b9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
RbGd2Fe4As4O2 is a newly discovered self-hole-doped stoichiometric superconductor, which has a hybrid structure with separated double FeAs layers and exhibits a high superconducting transition temperature T c = 35 K. Here, we report the effect of pressure (P) on its T c and normal-state transport properties by measuring the temperature dependence of resistivity ρ(T) under various pressures up to 14 GPa with a cubic anvil cell apparatus. We found that the T c is suppressed monotonically to ca. 12.5 K upon increasing pressure to 14 GPa with a slope change of T c(P) at around 4 GPa. In addition, the low-temperature normal-state ρ(T), which is proportional to T n , also evolves gradually from a non-Fermi-liquid with n = 1 at ambient pressure to a Fermi liquid with n = 2 at P ⩾ 4 GPa. Accompanying with the non-Fermi-liquid to Fermi-liquid crossover, the quadratic temperature coefficient of resistivity, which reflects the effective mass of charge carriers, also experiences a significant reduction as commonly observed in the vicinity of a magnetic quantum critical point (QCP). Our results indicate that the stoichiometric RbGd2Fe4As4O2 at ambient pressure might be located near a QCP such that the enhanced critical spin fluctuations lead to high-T c superconductivity. The application of pressure should broaden the electronic bandwidth and weaken the spin fluctuations, and then restore a Fermi-liquid ground state with lower T c.
Collapse
Affiliation(s)
- J P Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Zhang W, Wei Y, Xie T, Liu Z, Gong D, Ma X, Hu D, Čermák P, Schneidewind A, Tucker G, Meng S, Huesges Z, Lu Z, Song J, Luo W, Xu L, Zhu Z, Yin X, Li HF, Yang YF, Luo H, Li S. Unconventional Antiferromagnetic Quantum Critical Point in Ba(Fe_{0.97}Cr_{0.03})_{2}(As_{1-x}P_{x})_{2}. PHYSICAL REVIEW LETTERS 2019; 122:037001. [PMID: 30735415 DOI: 10.1103/physrevlett.122.037001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 10/04/2018] [Indexed: 06/09/2023]
Abstract
We have systematically studied physical properties of Ba(Fe_{0.97}Cr_{0.03})_{2}(As_{1-x}P_{x})_{2}, where superconductivity in BaFe_{2}(As_{1-x}P_{x})_{2} is fully suppressed by just 3% of Cr substitution of Fe. A quantum critical point is revealed at x∼0.42, where non-Fermi-liquid behaviors similar to those in BaFe_{2}(As_{1-x}P_{x})_{2} are observed. Neutron diffraction and inelastic neutron scattering measurements suggest that the quantum critical point is associated with the antiferromagnetic order, which is not of conventional spin-density-wave type as evidenced by the ω/T scaling of spin excitations. On the other hand, no divergence of low-temperature nematic susceptibility is observed when x is decreased to 0.42 from higher doping level, demonstrating that there are no nematic quantum critical fluctuations. Our results suggest that non-Fermi-liquid behaviors in iron-based superconductors can be solely resulted from the antiferromagnetic quantum critical fluctuations, which cast doubts on the role of nematic fluctuations played in the normal-state properties in iron-based superconductors.
Collapse
Affiliation(s)
- Wenliang Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Yuan Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Tao Xie
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Zhaoyu Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Dongliang Gong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaoyan Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Ding Hu
- Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, China
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Petr Čermák
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstrasse 1, 85748 Garching, Germany
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16, Praha, Czech Republic
| | - Astrid Schneidewind
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstrasse 1, 85748 Garching, Germany
| | - Gregory Tucker
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Siqin Meng
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-14109 Berlin, Germany
- China Institute of Atomic Energy, Beijing 102413, China
| | - Zita Huesges
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-14109 Berlin, Germany
| | - Zhilun Lu
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-14109 Berlin, Germany
| | - Jianming Song
- Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999, China
| | - Wei Luo
- Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999, China
| | - Liangcai Xu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zengwei Zhu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xunqing Yin
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, 999078 Macau, China
| | - Hai-Feng Li
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, 999078 Macau, China
| | - Yi-Feng Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Huiqian Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Shiliang Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| |
Collapse
|
10
|
Chen RY, Wang NL. Progress in Cr- and Mn-based superconductors: a key issues review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:012503. [PMID: 30523906 DOI: 10.1088/1361-6633/aaed0d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The presence of magnetic ions was first believed to be detrimental to superconductivity. However, unconventional superconductivity has been widely induced by doping or applying external pressure in magnetic systems such as heavy fermion, cuprate and iron-based superconductors in which magnetic fluctuations are suggested to serve as the pairing glue for Cooper pairs. The discovery of superconductivity in the magnetic compounds CrAs and MnP under high pressures has further expanded this family of superconductors and provided new platforms for investigating the interplay between magnetism and superconductivity. CrAs and MnP represent the first superconductors among the transition metal Cr- and Mn-based compounds in which the electronic states near the Fermi level are dominated by Cr/Mn 3d electrons. Shortly after their discovery, new types of Cr-based quasi-one-dimensional superconductors A2Cr3As3 and ACr3As3 (A [Formula: see text] K, Rb, Cs or Na) were discovered at ambient pressure. The close proximity of superconductivity to magnetic instability in these systems suggests that spin fluctuations may play crucial roles in mediating the Cooper pairing. In this article we review the basic physical properties of these novel superconductors and the progress achieved in recent studies.
Collapse
Affiliation(s)
- R Y Chen
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | | |
Collapse
|
11
|
Ding QP, Meier WR, Cui J, Xu M, Böhmer AE, Bud'ko SL, Canfield PC, Furukawa Y. Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe_{1-x}Ni_{x})_{4}As_{4} Revealed by NMR. PHYSICAL REVIEW LETTERS 2018; 121:137204. [PMID: 30312082 DOI: 10.1103/physrevlett.121.137204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Indexed: 06/08/2023]
Abstract
Two ordering states, antiferromagnetism and nematicity, have been observed in most iron-based superconductors (SCs). In contrast to those SCs, the newly discovered SC CaK(Fe_{1-x}Ni_{x})_{4}As_{4} exhibits an antiferromagnetic (AFM) state, called hedgehog spin-vortex crystal (SVC) structure, without nematic order, providing the opportunity for the investigation into the relationship between spin fluctuations and SC without any effects of nematic fluctuations. Our ^{75}As nuclear magnetic resonance studies on CaK(Fe_{1-x}Ni_{x})_{4}As_{4} (0≤x≤0.049) revealed that CaKFe_{4}As_{4} is located close to a hidden hedgehog SVC AFM quantum-critical point (QCP). The magnetic QCP without nematicity in CaK(Fe_{1-x}Ni_{x})_{4}As_{4} highlights the close connection of spin fluctuations and superconductivity in iron-based SCs. The advantage of stoichiometric composition also makes CaKFe_{4}As_{4} an ideal platform for further detailed investigation of the relationship between magnetic QCP and superconductivity in iron-based SCs without disorder effects.
Collapse
Affiliation(s)
- Q-P Ding
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - W R Meier
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - J Cui
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| | - M Xu
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A E Böhmer
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - S L Bud'ko
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - P C Canfield
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Y Furukawa
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| |
Collapse
|
12
|
Thewalt E, Hayes IM, Hinton JP, Little A, Patankar S, Wu L, Helm T, Stan CV, Tamura N, Analytis JG, Orenstein J. Imaging Anomalous Nematic Order and Strain in Optimally Doped BaFe_{2}(As,P)_{2}. PHYSICAL REVIEW LETTERS 2018; 121:027001. [PMID: 30085755 DOI: 10.1103/physrevlett.121.027001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 06/08/2023]
Abstract
We present the strain and temperature dependence of an anomalous nematic phase in optimally doped BaFe_{2}(As,P)_{2}. Polarized ultrafast optical measurements reveal broken fourfold rotational symmetry in a temperature range above T_{c} in which bulk probes do not detect a phase transition. Using ultrafast microscopy, we find that the magnitude and sign of this nematicity vary on a 50-100 μm length scale, and the temperature at which it onsets ranges from 40 K near a domain boundary to 60 K deep within a domain. Scanning Laue microdiffraction maps of local strain at room temperature indicate that the nematic order appears most strongly in regions of weak, isotropic strain. These results indicate that nematic order arises in a genuine phase transition rather than by enhancement of local anisotropy by a strong nematic susceptibility. We interpret our results in the context of a proposed surface nematic phase.
Collapse
Affiliation(s)
- Eric Thewalt
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ian M Hayes
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James P Hinton
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Arielle Little
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Shreyas Patankar
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Liang Wu
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Toni Helm
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Camelia V Stan
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Nobumichi Tamura
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Joseph Orenstein
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| |
Collapse
|
13
|
Stolyarov VS, Veshchunov IS, Grebenchuk SY, Baranov DS, Golovchanskiy IA, Shishkin AG, Zhou N, Shi Z, Xu X, Pyon S, Sun Y, Jiao W, Cao GH, Vinnikov LY, Golubov AA, Tamegai T, Buzdin AI, Roditchev D. Domain Meissner state and spontaneous vortex-antivortex generation in the ferromagnetic superconductor EuFe 2(As 0.79P 0.21) 2. SCIENCE ADVANCES 2018; 4:eaat1061. [PMID: 30027117 PMCID: PMC6044740 DOI: 10.1126/sciadv.aat1061] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 06/01/2018] [Indexed: 06/02/2023]
Abstract
The interplay between superconductivity and magnetism is one of the oldest enigmas in physics. Usually, the strong exchange field of ferromagnet suppresses singlet superconductivity via the paramagnetic effect. In EuFe2(As0.79P0.21)2, a material that becomes not only superconducting at 24.2 K but also ferromagnetic below 19 K, the coexistence of the two antagonistic phenomena becomes possible because of the unusually weak exchange field produced by the Eu subsystem. We demonstrate experimentally and theoretically that when the ferromagnetism adds to superconductivity, the Meissner state becomes spontaneously inhomogeneous, characterized by a nanometer-scale striped domain structure. At yet lower temperature and without any externally applied magnetic field, the system locally generates quantum vortex-antivortex pairs and undergoes a phase transition into a domain vortex-antivortex state characterized by much larger domains and peculiar Turing-like patterns. We develop a quantitative theory of this phenomenon and put forth a new way to realize superconducting superlattices and control the vortex motion in ferromagnetic superconductors by tuning magnetic domains-unprecedented opportunity to consider for advanced superconducting hybrids.
Collapse
Affiliation(s)
- Vasily S. Stolyarov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow 141700, Russia
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow 142432, Russia
- National University of Science and Technology MISiS, Moscow 119049, Russia
- Fundamental Physical and Chemical Engineering Department, Moscow State University, Moscow 119991, Russia
- Solid State Physics Department, Kazan Federal University, Kazan 420008, Russia
| | - Ivan S. Veshchunov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow 141700, Russia
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Sergey Yu. Grebenchuk
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow 141700, Russia
| | - Denis S. Baranov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow 141700, Russia
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow 142432, Russia
- Laboratoire de Physique et d’Etude des Materiaux, UMR8213, École supérieure de physique et de chimie industrielles de la Ville de Paris, Paris Sciences et Lettres Research University, Institut des NanoSciences de Paris–Sorbonne Universite, 10 rue Vauquelin, 75005 Paris, France
| | - Igor A. Golovchanskiy
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow 141700, Russia
- National University of Science and Technology MISiS, Moscow 119049, Russia
| | - Andrey G. Shishkin
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow 141700, Russia
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow 142432, Russia
| | - Nan Zhou
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China
| | - Zhixiang Shi
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China
| | - Xiaofeng Xu
- Department of Physics, Changshu Institute of Technology, Changshu 215500, China
| | - Sunseng Pyon
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yue Sun
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Wenhe Jiao
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Guang-Han Cao
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Lev Ya. Vinnikov
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow 142432, Russia
| | - Alexander A. Golubov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow 141700, Russia
- Faculty of Science and Technology and MESA+ Institute of Nanotechnology, University of Twente, 7500 AE Enschede, Netherlands
| | - Tsuyoshi Tamegai
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Alexander I. Buzdin
- University Bordeaux, Laboratoire Ondes et Matière d’Aquitaine, F-33405 Talence, France
- Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS Cambridge, UK
| | - Dimitri Roditchev
- Laboratoire de Physique et d’Etude des Materiaux, UMR8213, École supérieure de physique et de chimie industrielles de la Ville de Paris, Paris Sciences et Lettres Research University, Institut des NanoSciences de Paris–Sorbonne Universite, 10 rue Vauquelin, 75005 Paris, France
| |
Collapse
|
14
|
Hussey NE, Buhot J, Licciardello S. A tale of two metals: contrasting criticalities in the pnictides and hole-doped cuprates. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:052501. [PMID: 29353812 DOI: 10.1088/1361-6633/aaa97c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The iron-based high temperature superconductors share a number of similarities with their copper-based counterparts, such as reduced dimensionality, proximity to states of competing order, and a critical role for 3d electron orbitals. Their respective temperature-doping phase diagrams also contain certain commonalities that have led to claims that the metallic and superconducting (SC) properties of both families are governed by their proximity to a quantum critical point (QCP) located inside the SC dome. In this review, we critically examine these claims and highlight significant differences in the bulk physical properties of both systems. While there is now a large body of evidence supporting the presence of a (magnetic) QCP in the iron pnictides, the situation in the cuprates is much less apparent, at least for the end point of the pseudogap phase. We argue that the opening of the normal state pseudogap in cuprates, so often tied to a putative QCP, arises from a momentum-dependent breakdown of quasiparticle coherence that sets in at much higher doping levels but which is driven by the proximity to the Mott insulating state at half filling. Finally, we present a new scenario for the cuprates in which this loss of quasiparticle integrity and its evolution with momentum, temperature and doping plays a key role in shaping the resultant phase diagram.
Collapse
Affiliation(s)
- N E Hussey
- High Field Magnet Laboratory (HFML-EMFL), Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, Netherlands
| | | | | |
Collapse
|
15
|
Böhmer AE, Kreisel A. Nematicity, magnetism and superconductivity in FeSe. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:023001. [PMID: 29240560 DOI: 10.1088/1361-648x/aa9caa] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Iron-based superconductors are well known for their complex interplay between structure, magnetism and superconductivity. FeSe offers a particularly fascinating example. This material has been intensely discussed because of its extended nematic phase, whose relationship with magnetism is not obvious. Superconductivity in FeSe is highly tunable, with the superconducting transition temperature, T c, ranging from 8 K in bulk single crystals at ambient pressure to almost 40 K under pressure or in intercalated systems, and to even higher temperatures in thin films. In this topical review, we present an overview of nematicity, magnetism and superconductivity, and discuss the interplay of these phases in FeSe. We focus on bulk FeSe and the effects of physical pressure and chemical substitutions as tuning parameters. The experimental results are discussed in the context of the well-studied iron-pnictide superconductors and interpretations from theoretical approaches are presented.
Collapse
Affiliation(s)
- Anna E Böhmer
- Ames Laboratory, US DOE, Ames, IA 50011, United States of America
| | | |
Collapse
|
16
|
Grinenko V, Iida K, Kurth F, Efremov DV, Drechsler SL, Cherniavskii I, Morozov I, Hänisch J, Förster T, Tarantini C, Jaroszynski J, Maiorov B, Jaime M, Yamamoto A, Nakamura I, Fujimoto R, Hatano T, Ikuta H, Hühne R. Selective mass enhancement close to the quantum critical point in BaFe 2(As 1-x P x ) 2. Sci Rep 2017; 7:4589. [PMID: 28676703 PMCID: PMC5496881 DOI: 10.1038/s41598-017-04724-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/15/2017] [Indexed: 11/09/2022] Open
Abstract
A quantum critical point (QCP) is currently being conjectured for the BaFe2(As1-x P x )2 system at the critical value x c ≈ 0.3. In the proximity of a QCP, all thermodynamic and transport properties are expected to scale with a single characteristic energy, given by the quantum fluctuations. Such a universal behavior has not, however, been found in the superconducting upper critical field H c2. Here we report H c2 data for epitaxial thin films extracted from the electrical resistance measured in very high magnetic fields up to 67 Tesla. Using a multi-band analysis we find that H c2 is sensitive to the QCP, implying a significant charge carrier effective mass enhancement at the doping-induced QCP that is essentially band-dependent. Our results point to two qualitatively different groups of electrons in BaFe2(As1-x P x )2. The first one (possibly associated to hot spots or whole Fermi sheets) has a strong mass enhancement at the QCP, and the second one is insensitive to the QCP. The observed duality could also be present in many other quantum critical systems.
Collapse
Affiliation(s)
- V Grinenko
- Institute for Solid State Physics, TU Dresden, 01069, Dresden, Germany. .,IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany. .,Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
| | - K Iida
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany.,Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - F Kurth
- Institute for Solid State Physics, TU Dresden, 01069, Dresden, Germany.,IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - D V Efremov
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - S-L Drechsler
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - I Cherniavskii
- Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russian Federation
| | - I Morozov
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany.,Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russian Federation
| | - J Hänisch
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany.,Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - T Förster
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01314, Dresden, Germany
| | - C Tarantini
- NHMFL, Florida State University, Tallahassee, FL, 32310, USA
| | - J Jaroszynski
- NHMFL, Florida State University, Tallahassee, FL, 32310, USA
| | - B Maiorov
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - M Jaime
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - A Yamamoto
- Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo, 184-8588, Japan
| | - I Nakamura
- Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - R Fujimoto
- Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - T Hatano
- Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - H Ikuta
- Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - R Hühne
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| |
Collapse
|
17
|
Majumder M, Ghoshray A, Khuntia P, Mazumdar C, Poddar A, Baenitz M, Ghoshray K. Absence of low energy magnetic spin-fluctuations in isovalently and aliovalently doped LaCo2B2 superconducting compounds. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:345701. [PMID: 27355521 DOI: 10.1088/0953-8984/28/34/345701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Magnetization, resistivity and (11)B, (59)Co NMR measurements have been performed on the Pauli paramagnet [Formula: see text], and the superconductors [Formula: see text] ([Formula: see text] K) and [Formula: see text] ([Formula: see text] K). The site selective NMR experiment reveals the multiband nature of the Fermi surface in these systems. The temperature independent Knight shift and 1/T 1 T clearly indicate the absence of correlated low energy magnetic spin-fluctuations in the normal state, which is in contrast to other Fe-based pnictides. The density of states (DOS) of Co 3d electrons has been enhanced in superconducting [Formula: see text] and [Formula: see text] with respect to the non superconducting reference compound [Formula: see text]. The occurrence of superconductivity is related to the DOS enhancement.
Collapse
Affiliation(s)
- M Majumder
- ECMP Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700064, India. Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | | | | | | | | | | | | |
Collapse
|
18
|
Dioguardi AP, Kissikov T, Lin CH, Shirer KR, Lawson MM, Grafe HJ, Chu JH, Fisher IR, Fernandes RM, Curro NJ. NMR Evidence for Inhomogeneous Nematic Fluctuations in BaFe_{2}(As_{1-x}P_{x})_{2}. PHYSICAL REVIEW LETTERS 2016; 116:107202. [PMID: 27015507 DOI: 10.1103/physrevlett.116.107202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Indexed: 06/05/2023]
Abstract
We present evidence for nuclear spin-lattice relaxation driven by glassy nematic fluctuations in isovalent P-doped BaFe_{2}As_{2} single crystals. Both the ^{75}As and ^{31}P sites exhibit a stretched-exponential relaxation similar to the electron-doped systems. By comparing the hyperfine fields and the relaxation rates at these sites we find that the As relaxation cannot be explained solely in terms of magnetic spin fluctuations. We demonstrate that nematic fluctuations couple to the As nuclear quadrupolar moment and can explain the excess relaxation. These results suggest that glassy nematic dynamics are a common phenomenon in the iron-based superconductors.
Collapse
Affiliation(s)
- A P Dioguardi
- Department of Physics, University of California, Davis, California 95616, USA
| | - T Kissikov
- Department of Physics, University of California, Davis, California 95616, USA
| | - C H Lin
- Department of Physics, University of California, Davis, California 95616, USA
| | - K R Shirer
- Department of Physics, University of California, Davis, California 95616, USA
| | - M M Lawson
- Department of Physics, University of California, Davis, California 95616, USA
| | - H-J Grafe
- IFW Dresden, Institute for Solid State Research, P.O. Box 270116, D-01171 Dresden, Germany
| | - J-H Chu
- Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
- Stanford Institute of Energy and Materials Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - I R Fisher
- Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
- Stanford Institute of Energy and Materials Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - N J Curro
- Department of Physics, University of California, Davis, California 95616, USA
| |
Collapse
|
19
|
Wiecki P, Roy B, Johnston DC, Bud'ko SL, Canfield PC, Furukawa Y. Competing Magnetic Fluctuations in Iron Pnictide Superconductors: Role of Ferromagnetic Spin Correlations Revealed by NMR. PHYSICAL REVIEW LETTERS 2015; 115:137001. [PMID: 26451577 DOI: 10.1103/physrevlett.115.137001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Indexed: 06/05/2023]
Abstract
In the iron pnictide superconductors, theoretical calculations have consistently shown enhancements of the static magnetic susceptibility at both the stripe-type antiferromagnetic and in-plane ferromagnetic (FM) wave vectors. However, the possible existence of FM fluctuations has not yet been examined from a microscopic point of view. Here, using ^{75}As NMR data, we provide clear evidence for the existence of FM spin correlations in both the hole- and electron-doped BaFe_{2}As_{2} families of iron-pnictide superconductors. These FM fluctuations appear to compete with superconductivity and are thus a crucial ingredient to understanding the variability of T_{c} and the shape of the superconducting dome in these and other iron-pnictide families.
Collapse
Affiliation(s)
- P Wiecki
- The Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - B Roy
- The Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - D C Johnston
- The Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - S L Bud'ko
- The Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - P C Canfield
- The Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Y Furukawa
- The Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| |
Collapse
|
20
|
Hu D, Lu X, Zhang W, Luo H, Li S, Wang P, Chen G, Han F, Banjara SR, Sapkota A, Kreyssig A, Goldman AI, Yamani Z, Niedermayer C, Skoulatos M, Georgii R, Keller T, Wang P, Yu W, Dai P. Structural and Magnetic Phase Transitions near Optimal Superconductivity in BaFe2(As(1-x)Px)2. PHYSICAL REVIEW LETTERS 2015; 114:157002. [PMID: 25933332 DOI: 10.1103/physrevlett.114.157002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Indexed: 06/04/2023]
Abstract
We use nuclear magnetic resonance (NMR), high-resolution x-ray, and neutron scattering studies to study structural and magnetic phase transitions in phosphorus-doped BaFe2(As(1-x)P(x)2. Previous transport, NMR, specific heat, and magnetic penetration depth measurements have provided compelling evidence for the presence of a quantum critical point (QCP) near optimal superconductivity at x=0.3. However, we show that the tetragonal-to-orthorhombic structural (T{s}) and paramagnetic to antiferromagnetic (AF, TN) transitions in BaFe2(As(1-x)Px)2 are always coupled and approach T{N}≈T{s}≥T{c} (≈29 K) for x=0.29 before vanishing abruptly for x≥0.3. These results suggest that AF order in BaFe_{2}(As(1-x)Px)2 disappears in a weakly first-order fashion near optimal superconductivity, much like the electron-doped iron pnictides with an avoided QCP.
Collapse
Affiliation(s)
- Ding Hu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xingye Lu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wenliang Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Huiqian Luo
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shiliang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
| | - Peipei Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Genfu Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Fei Han
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Shree R Banjara
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A Sapkota
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A Kreyssig
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A I Goldman
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Z Yamani
- Canadian Neutron Beam Centre, National Research Council, Chalk River, Ontario K0J 1P0, Canada
| | - Christof Niedermayer
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Markos Skoulatos
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Robert Georgii
- Heinz Maier-Leibnitz Zentrum, Technische Universität München, D-85748 Garching, Germany
| | - T Keller
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Max Planck Society Outstation at the Forschungsneutronenquelle Heinz Maier-Leibnitz (MLZ), D-85747 Garching, Germany
| | - Pengshuai Wang
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Weiqiang Yu
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Pengcheng Dai
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| |
Collapse
|
21
|
Zhi HZ, Imai T, Ning FL, Bao JK, Cao GH. NMR investigation of the quasi-one-dimensional superconductor K(2)Cr(3)As(3). PHYSICAL REVIEW LETTERS 2015; 114:147004. [PMID: 25910155 DOI: 10.1103/physrevlett.114.147004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Indexed: 06/04/2023]
Abstract
We report ^{75}As NMR measurements on the new quasi-one-dimensional superconductor K_{2}Cr_{3}As_{3} (T_{c}∼6.1 K) [J. K. Bao et al., Phys. Rev. X 5, 011013 (2015)]. We found evidence for strong enhancement of Cr spin fluctuations above T_{c} in the [Cr_{3}As_{3}]_{∞} double-walled subnanotubes based on the nuclear spin-lattice relaxation rate 1/T_{1}. The power-law temperature dependence, 1/T_{1}T∼T^{-γ} (γ∼0.25), is consistent with the Tomonaga-Luttinger liquid. Moreover, absence of the Hebel-Slichter coherence peak of 1/T_{1} just below T_{c} suggests an unconventional nature of superconductivity.
Collapse
Affiliation(s)
- H Z Zhi
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S4M1, Canada
| | - T Imai
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S4M1, Canada
- Canadian Institute for Advanced Research, Toronto, Ontario M5G1Z8, Canada
| | - F L Ning
- Department of Physics, Zhejiang University, Hangzhou 310027, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jin-Ke Bao
- Department of Physics, Zhejiang University, Hangzhou 310027, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Guang-Han Cao
- Department of Physics, Zhejiang University, Hangzhou 310027, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| |
Collapse
|
22
|
Kotegawa H, Nakahara S, Akamatsu R, Tou H, Sugawara H, Harima H. Detection of an unconventional superconducting phase in the vicinity of the strong first-order magnetic transition in CrAs using (75)As-nuclear quadrupole resonance. PHYSICAL REVIEW LETTERS 2015; 114:117002. [PMID: 25839303 DOI: 10.1103/physrevlett.114.117002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Indexed: 06/04/2023]
Abstract
Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure P(c) between the helimagnetic (HM) and paramagnetic (PM) phases, a phase separation is observed. The large internal field remaining in the phase-separated HM state indicates that the HM phase disappears through a strong first-order transition. This indicates the absence of a quantum critical point in CrAs; however, the nuclear spin-lattice relaxation rate 1/T(1) reveals that substantial magnetic fluctuations are present in the PM state. The absence of a coherence effect in 1/T(1) in the superconducting state provides evidence that CrAs is the first Cr-based unconventional superconductor.
Collapse
Affiliation(s)
| | - Shingo Nakahara
- Department of Physics, Kobe University, Kobe 657-8501, Japan
| | - Rui Akamatsu
- Department of Physics, Kobe University, Kobe 657-8501, Japan
| | - Hideki Tou
- Department of Physics, Kobe University, Kobe 657-8501, Japan
| | | | - Hisatomo Harima
- Department of Physics, Kobe University, Kobe 657-8501, Japan
| |
Collapse
|
23
|
Putzke C, Walmsley P, Fletcher JD, Malone L, Vignolles D, Proust C, Badoux S, See P, Beere HE, Ritchie DA, Kasahara S, Mizukami Y, Shibauchi T, Matsuda Y, Carrington A. Anomalous critical fields in quantum critical superconductors. Nat Commun 2014; 5:5679. [PMID: 25477044 PMCID: PMC4268691 DOI: 10.1038/ncomms6679] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 10/28/2014] [Indexed: 11/22/2022] Open
Abstract
Fluctuations around an antiferromagnetic quantum critical point (QCP) are believed to lead to unconventional superconductivity and in some cases to high-temperature superconductivity. However, the exact mechanism by which this occurs remains poorly understood. The iron-pnictide superconductor BaFe2(As1−xPx)2 is perhaps the clearest example to date of a high-temperature quantum critical superconductor, and so it is a particularly suitable system to study how the quantum critical fluctuations affect the superconducting state. Here we show that the proximity of the QCP yields unexpected anomalies in the superconducting critical fields. We find that both the lower and upper critical fields do not follow the behaviour, predicted by conventional theory, resulting from the observed mass enhancement near the QCP. Our results imply that the energy of superconducting vortices is enhanced, possibly due to a microscopic mixing of antiferromagnetism and superconductivity, suggesting that a highly unusual vortex state is realized in quantum critical superconductors. Superconductivity in the iron pnictides is believed to be related to quantum critical fluctuations. Putzke et al. observe unexpected anomalies in the critical fields of BaFe2(As1−xPx)2 that emerge close to its magnetic critical point, which they argue is a generic feature of quantum critical superconductivity.
Collapse
Affiliation(s)
- C Putzke
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
| | - P Walmsley
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
| | - J D Fletcher
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK
| | - L Malone
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
| | - D Vignolles
- Laboratoire National des Champs Magnétiques Intenses (CNRS-INSA-UJF-UPS), 31400 Toulouse, France
| | - C Proust
- Laboratoire National des Champs Magnétiques Intenses (CNRS-INSA-UJF-UPS), 31400 Toulouse, France
| | - S Badoux
- Laboratoire National des Champs Magnétiques Intenses (CNRS-INSA-UJF-UPS), 31400 Toulouse, France
| | - P See
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK
| | - H E Beere
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
| | - D A Ritchie
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
| | - S Kasahara
- Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Y Mizukami
- 1] Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan [2] Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - T Shibauchi
- 1] Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan [2] Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - A Carrington
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
| |
Collapse
|
24
|
Hoffmann AV, Hlukhyy V, Fässler TF. Synthesis, Structure, and Chemical Bonding in CaCoSi. Z Anorg Allg Chem 2014. [DOI: 10.1002/zaac.201400356] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
25
|
Wu JJ, Lin JF, Wang XC, Liu QQ, Zhu JL, Xiao YM, Chow P, Jin CQ. Magnetic and structural transitions of SrFe2As2 at high pressure and low temperature. Sci Rep 2014; 4:3685. [PMID: 24418845 PMCID: PMC3890939 DOI: 10.1038/srep03685] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/04/2013] [Indexed: 12/02/2022] Open
Abstract
One of key issues in studying iron based superconductors is to understand how the magnetic phase of the parent compounds evolves. Here we report the systematic investigation of paramagnetic to antiferromagnetic and tetragonal to orthorhombic structural transitions of “122” SrFe2As2 parent compound using combined high resolution synchrotron Mössbauer spectroscopy and x-ray diffraction techniques in a cryogenically cooled high pressure diamond anvil cell. It is found that although the two transitions are coupled at 205 K at ambient pressure, they are concurrently suppressed to much lower temperatures near a quantum critical pressure of approximately 4.8 GPa where the antiferromagnetic state transforms into bulk superconducting state. Our results indicate that the lattice distortions and magnetism jointly play a critical role in inducing superconductivity in iron based compounds.
Collapse
Affiliation(s)
- J J Wu
- 1] Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China [2] Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, TX 78712, USA
| | - J F Lin
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, TX 78712, USA
| | - X C Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Q Q Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - J L Zhu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Y M Xiao
- HPCAT, Carnegie Institution of Washington, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - P Chow
- HPCAT, Carnegie Institution of Washington, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - C Q Jin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| |
Collapse
|
26
|
Dioguardi AP, Crocker J, Shockley AC, Lin CH, Shirer KR, Nisson DM, Lawson MM, apRoberts-Warren N, Canfield PC, Bud'ko SL, Ran S, Curro NJ. Coexistence of cluster spin glass and superconductivity in Ba(Fe(1-x)Co(x))2As2 for 0.060≤x≤0.071. PHYSICAL REVIEW LETTERS 2013; 111:207201. [PMID: 24289706 DOI: 10.1103/physrevlett.111.207201] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 09/24/2013] [Indexed: 06/02/2023]
Abstract
We present 75As nuclear magnetic resonance data from measurements of a series of Ba(Fe(1-x)Co(x))2As2 crystals with 0.00≤x≤0.075 that reveals the coexistence of frozen antiferromagnetic domains and superconductivity for 0.060≤x≤0.071. Although bulk probes reveal no long range antiferromagnetic order beyond x=0.06, we find that the local spin dynamics reveal no qualitative change across this transition. The characteristic domain sizes vary by more than an order of magnitude, reaching a maximum variation at x=0.06. This inhomogeneous glassy dynamics may be an intrinsic response to the competition between superconductivity and antiferromagnetism in this system.
Collapse
Affiliation(s)
- A P Dioguardi
- Department of Physics, University of California, Davis, California 95616, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Nomoto T, Ikeda H. Effect of magnetic criticality and Fermi-surface topology on the magnetic penetration depth. PHYSICAL REVIEW LETTERS 2013; 111:167001. [PMID: 24182292 DOI: 10.1103/physrevlett.111.167001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 08/31/2013] [Indexed: 06/02/2023]
Abstract
We investigate the effect of antiferromagnetic (AF) quantum criticality on the magnetic penetration depth λ(T) in line-nodal superconductors, including the cuprates, the iron pnictides, and the heavy-fermion superconductors. The critical magnetic fluctuation renormalizes the current vertex and drastically enhances the zero-temperature penetration depth λ(0), which is more remarkable in the iron-pnictide case due to the Fermi-surface topology. Additional temperature (T) dependence of the current renormalization makes the expected T-linear behavior at low temperatures approach T(1.5) asymptotically. These anomalous behaviors are consistent with experimental observations. We stress that λ(T) is a good probe to detect the AF quantum critical point in the superconducting state.
Collapse
Affiliation(s)
- Takuya Nomoto
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | | |
Collapse
|
28
|
Fernandes RM, Böhmer AE, Meingast C, Schmalian J. Scaling between magnetic and lattice fluctuations in iron pnictide superconductors. PHYSICAL REVIEW LETTERS 2013; 111:137001. [PMID: 24116808 DOI: 10.1103/physrevlett.111.137001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 08/05/2013] [Indexed: 06/02/2023]
Abstract
The phase diagram of the iron arsenides is dominated by a magnetic and a structural phase transition, which need to be suppressed in order for superconductivity to appear. The proximity between the two transition temperature lines indicates correlation between these two phases, whose nature remains unsettled. Here, we find a scaling relation between nuclear magnetic resonance and shear modulus data in the tetragonal phase of electron-doped Ba(Fe1-xCox)2As2 compounds. Because the former probes the strength of magnetic fluctuations while the latter is sensitive to orthorhombic fluctuations, our results provide strong evidence for a magnetically driven structural transition.
Collapse
Affiliation(s)
- Rafael M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55116, USA
| | | | | | | |
Collapse
|
29
|
Dai YM, Xu B, Shen B, Xiao H, Wen HH, Qiu XG, Homes CC, Lobo RPSM. Hidden T-linear scattering rate in Ba0.6K0.4Fe2As2 revealed by optical spectroscopy. PHYSICAL REVIEW LETTERS 2013; 111:117001. [PMID: 24074114 DOI: 10.1103/physrevlett.111.117001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Indexed: 06/02/2023]
Abstract
The optical properties of Ba0.6K0.4Fe2As2 have been determined in the normal state for a number of temperatures over a wide frequency range. Two Drude terms, representing two groups of carriers with different scattering rates (1/τ), well describe the real part of the optical conductivity σ1(ω). A "broad" Drude component results in an incoherent background with a T-independent 1/τb, while a "narrow" Drude component reveals a T-linear 1/τn resulting in a resistivity ρn≡1/σ1n(ω→0) also linear in temperature. An arctan(T) low-frequency spectral weight is also strong evidence for a T-linear 1/τ. A comparison to other materials with similar behavior suggests that the T-linear 1/τn and ρn in Ba0.6K0.4Fe2As2 originate from scattering from spin fluctuations and hence that an antiferromagnetic quantum critical point is likely to exist in the superconducting dome.
Collapse
Affiliation(s)
- Y M Dai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China and LPEM, ESPCI-ParisTech, CNRS, UPMC, 10 rue Vauquelin, F-75231 Paris Cedex 5, France and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Quantum criticality in electron-doped BaFe2−xNixAs2. Nat Commun 2013; 4:2265. [PMID: 23945701 DOI: 10.1038/ncomms3265] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 07/08/2013] [Indexed: 11/08/2022] Open
|
31
|
Walmsley P, Putzke C, Malone L, Guillamón I, Vignolles D, Proust C, Badoux S, Coldea AI, Watson MD, Kasahara S, Mizukami Y, Shibauchi T, Matsuda Y, Carrington A. Quasiparticle mass enhancement close to the quantum critical point in BaFe2(As(1-x)P(x))2. PHYSICAL REVIEW LETTERS 2013; 110:257002. [PMID: 23829753 DOI: 10.1103/physrevlett.110.257002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/10/2013] [Indexed: 06/02/2023]
Abstract
We report a combined study of the specific heat and de Haas-van Alphen effect in the iron-pnictide superconductor BaFe2(As(1-x)P(x))2. Our data when combined with results for the magnetic penetration depth give compelling evidence for the existence of a quantum critical point close to x=0.30 which affects the majority of the Fermi surface by enhancing the quasiparticle mass. The results show that the sharp peak in the inverse superfluid density seen in this system results from a strong increase in the quasiparticle mass at the quantum critical point.
Collapse
Affiliation(s)
- P Walmsley
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Jiang S, Jeevan HS, Dong J, Gegenwart P. Thermopower as a sensitive probe of electronic nematicity in iron pnictides. PHYSICAL REVIEW LETTERS 2013; 110:067001. [PMID: 23432292 DOI: 10.1103/physrevlett.110.067001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Indexed: 06/01/2023]
Abstract
We study the in-plane anisotropy of the thermoelectric power and electrical resistivity on detwinned single crystals of isovalent substituted EuFe(2)(As(1-x)P(x))(2). Compared to the resistivity anisotropy, the thermopower anisotropy is more pronounced and clearly visible already at temperatures much above the structural and magnetic phase transitions. Most remarkably, the thermopower anisotropy changes sign below the structural transition. This is associated with the interplay of two contributions due to anisotropic scattering and orbital polarization, which dominate at high and low temperatures, respectively.
Collapse
Affiliation(s)
- Shuai Jiang
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany
| | | | | | | |
Collapse
|
33
|
Ma L, Ji GF, Dai J, Lu XR, Eom MJ, Kim JS, Normand B, Yu W. Microscopic Coexistence of Superconductivity and Antiferromagnetism in Underdoped Ba(Fe(1-x)Ru(x))2As2. PHYSICAL REVIEW LETTERS 2012; 109:197002. [PMID: 23215417 DOI: 10.1103/physrevlett.109.197002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Indexed: 06/01/2023]
Abstract
We use (75)As nuclear magnetic resonance to investigate the local electronic properties of Ba(Fe(1-x)Ru(x))(2)As(2) (x = 0.23). We find two phase transitions: to antiferromagnetism at T(N) ≈ 60 K and to superconductivity at T(C) ≈ 15 K. Below T(N), our data show that the system is fully magnetic, with a commensurate antiferromagnetic structure and a moment of 0.4μ(B)/Fe. The spin-lattice relaxation rate 1/(75)T(1) is large in the magnetic state, indicating a high density of itinerant electrons induced by Ru doping. On cooling below T(C), 1/(75)T(1) on the magnetic sites falls sharply, providing unambiguous evidence for the microscopic coexistence of antiferromagnetism and superconductivity.
Collapse
Affiliation(s)
- Long Ma
- Department of Physics, Renmin University of China, Beijing 100872, China
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Mukuda H, Furukawa S, Kinouchi H, Yashima M, Kitaoka Y, Shirage PM, Eisaki H, Iyo A. High-Tc nodeless s±-wave superconductivity in (Y,La)FeAsO(1-y) with Tc=50 K:75As-NMR study. PHYSICAL REVIEW LETTERS 2012; 109:157001. [PMID: 23102353 DOI: 10.1103/physrevlett.109.157001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Indexed: 06/01/2023]
Abstract
We report on an (75)As-NMR study on the Fe-pnictide high-T(c) superconductor Y(0.95)La(0.05)FeAsO(1-y) (Y(0.95)La(0.05)1111) with T(c)=50 K that includes no magnetic rare-earth elements. The measurement of the nuclear-spin lattice-relaxation rate (75)(1/T(1)) has revealed that the nodeless bulk superconductivity takes place at T(c)=50 K while antiferromagnetic spin fluctuations develop moderately in the normal state. These features are consistently described by the multiple fully gapped s(±)-wave model based on the Fermi-surface nesting. Incorporating the theory based on band calculations, we propose that the reason that T(c)=50 K in Y(0.95)La(0.05)1111 is larger than T(c)=28 K in La1111 is that the Fermi-surface multiplicity is maximized, and hence the Fermi-surface nesting condition is better than that in La1111.
Collapse
Affiliation(s)
- H Mukuda
- Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Hashimoto K, Cho K, Shibauchi T, Kasahara S, Mizukami Y, Katsumata R, Tsuruhara Y, Terashima T, Ikeda H, Tanatar MA, Kitano H, Salovich N, Giannetta RW, Walmsley P, Carrington A, Prozorov R, Matsuda Y. A sharp peak of the zero-temperature penetration depth at optimal composition in BaFe2(As(1-x)P(x))2. Science 2012; 336:1554-7. [PMID: 22723416 DOI: 10.1126/science.1219821] [Citation(s) in RCA: 243] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In a superconductor, the ratio of the carrier density, n, to its effective mass, m*, is a fundamental property directly reflecting the length scale of the superfluid flow, the London penetration depth, λ(L). In two-dimensional systems, this ratio n/m* (~1/λ(L)(2)) determines the effective Fermi temperature, T(F). We report a sharp peak in the x-dependence of λ(L) at zero temperature in clean samples of BaFe(2)(As(1)(-x)P(x))(2) at the optimum composition x = 0.30, where the superconducting transition temperature T(c) reaches a maximum of 30 kelvin. This structure may arise from quantum fluctuations associated with a quantum critical point. The ratio of T(c)/T(F) at x = 0.30 is enhanced, implying a possible crossover toward the Bose-Einstein condensate limit driven by quantum criticality.
Collapse
Affiliation(s)
- K Hashimoto
- Department of Physics, Kyoto University, Kyoto, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Moon SJ, Schafgans AA, Kasahara S, Shibauchi T, Terashima T, Matsuda Y, Tanatar MA, Prozorov R, Thaler A, Canfield PC, Sefat AS, Mandrus D, Basov DN. Infrared measurement of the pseudogap of P-doped and Co-doped high-temperature BaFe2As2 superconductors. PHYSICAL REVIEW LETTERS 2012; 109:027006. [PMID: 23030200 DOI: 10.1103/physrevlett.109.027006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Indexed: 06/01/2023]
Abstract
We report on infrared studies of charge dynamics in a prototypical pnictide system: the BaFe2As2 family. Our experiments have identified hallmarks of the pseudogap state in the BaFe2As2 system that mirror the spectroscopic manifestations of the pseudogap in the cuprates. The magnitude of the infrared pseudogap is in accord with that of the spin-density-wave gap of the parent compound. By monitoring the superconducting gap of both P- and Co-doped compounds, we find that the infrared pseudogap is unrelated to superconductivity. The appearance of the pseudogap is found to correlate with the evolution of the antiferromagnetic fluctuations associated with the spin-density-wave instability. The strong-coupling analysis of infrared data further reveals the interdependence between the magnetism and the pseudogap in the iron pnictides.
Collapse
Affiliation(s)
- S J Moon
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Electronic nematicity above the structural and superconducting transition in BaFe2(As(1-x)P(x))2. Nature 2012; 486:382-5. [PMID: 22722198 DOI: 10.1038/nature11178] [Citation(s) in RCA: 369] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 05/01/2012] [Indexed: 11/08/2022]
Abstract
Electronic nematicity, a unidirectional self-organized state that breaks the rotational symmetry of the underlying lattice, has been observed in the iron pnictide and copper oxide high-temperature superconductors. Whether nematicity plays an equally important role in these two systems is highly controversial. In iron pnictides, the nematicity has usually been associated with the tetragonal-to-orthorhombic structural transition at temperature T(s). Although recent experiments have provided hints of nematicity, they were performed either in the low-temperature orthorhombic phase or in the tetragonal phase under uniaxial strain, both of which break the 90° rotational C(4) symmetry. Therefore, the question remains open whether the nematicity can exist above T(s) without an external driving force. Here we report magnetic torque measurements of the isovalent-doping system BaFe(2)(As(1-x)P(x))(2), showing that the nematicity develops well above T(s) and, moreover, persists to the non-magnetic superconducting regime, resulting in a phase diagram similar to the pseudogap phase diagram of the copper oxides. By combining these results with synchrotron X-ray measurements, we identify two distinct temperatures-one at T*, signifying a true nematic transition, and the other at T(s) (<T*), which we show not to be a true phase transition, but rather what we refer to as a 'meta-nematic transition', in analogy to the well-known meta-magnetic transition in the theory of magnetism.
Collapse
|
38
|
Luo H, Zhang R, Laver M, Yamani Z, Wang M, Lu X, Wang M, Chen Y, Li S, Chang S, Lynn JW, Dai P. Coexistence and competition of the short-range incommensurate antiferromagnetic order with the superconducting state of BaFe(2-x)Ni(x)As2. PHYSICAL REVIEW LETTERS 2012; 108:247002. [PMID: 23004310 DOI: 10.1103/physrevlett.108.247002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 03/12/2012] [Indexed: 06/01/2023]
Abstract
Superconductivity in the iron pnictides develops near antiferromagnetism, and the antiferromagnetic (AF) phase appears to overlap with the superconducting phase in some materials such as BaFe(2-x)T(x)As2 (where T=Co or Ni). Here we use neutron scattering to demonstrate that genuine long-range AF order and superconductivity do not coexist in BaFe(2-x)Ni(x)As2 near optimal superconductivity. In addition, we find a first-order-like AF-to-superconductivity phase transition with no evidence for a magnetic quantum critical point. Instead, the data reveal that incommensurate short-range AF order coexists and competes with superconductivity, where the AF spin correlation length is comparable to the superconducting coherence length.
Collapse
Affiliation(s)
- Huiqian Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Guo J, Chen XJ, Dai J, Zhang C, Guo J, Chen X, Wu Q, Gu D, Gao P, Yang L, Yang K, Dai X, Mao HK, Sun L, Zhao Z. Pressure-driven quantum criticality in iron-selenide superconductors. PHYSICAL REVIEW LETTERS 2012; 108:197001. [PMID: 23003077 DOI: 10.1103/physrevlett.108.197001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 02/16/2012] [Indexed: 06/01/2023]
Abstract
We report a finding of a pressure-induced quantum critical transition in K0.8Fe(x)Se2 (x = 1.7 and 1.78) superconductors through in situ high-pressure electrical transport and x-ray diffraction measurements in diamond anvil cells. Transitions from metallic Fermi liquid behavior to non-Fermi liquid behavior and from antiferromagnetism to paramagnetism are found in the pressure range of 9.2-10.3 GPa, in which superconductivity tends to disappear. The change around the quantum critical point from the coexisting antiferromagnetism state and the Fermi liquid behavior to the paramagnetism state and the non-Fermi liquid behavior in the iron-selenide superconductors demonstrates a unique mechanism for their quantum critical transition.
Collapse
Affiliation(s)
- Jing Guo
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Oka T, Li Z, Kawasaki S, Chen GF, Wang NL, Zheng GQ. Antiferromagnetic spin fluctuations above the dome-shaped and full-gap superconducting states of LaFeAsO1-xFx revealed by (75)As-nuclear quadrupole resonance. PHYSICAL REVIEW LETTERS 2012; 108:047001. [PMID: 22400880 DOI: 10.1103/physrevlett.108.047001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 07/09/2011] [Indexed: 05/31/2023]
Abstract
We report a systematic study by (75)As nuclear-quadrupole resonance in LaFeAsO(1-x)F(x). The antiferromagnetic spin fluctuation found above the magnetic ordering temperature T(N) = 58 K for x = 0.03 persists in the regime 0.04 ≤ x ≤ 0.08, where superconductivity sets in. A dome-shaped x dependence of the superconducting transition temperature T(c) is found, with the highest T(c) = 27 K at x = 0.06, which is realized under significant antiferromagnetic spin fluctuation. With increasing x further, the antiferromagnetic spin fluctuation decreases, and so does T(c). These features resemble closely the cuprates La(2-x)Sr(x)CuO(4). In x = 0.06, the spin-lattice relaxation rate (1/T(1)) below T(c) decreases exponentially down to 0.13T(c), which unambiguously indicates that the energy gaps are fully opened. The temperature variation of 1/T(1) below T(c) is rendered nonexponential for other x by impurity scattering.
Collapse
Affiliation(s)
- T Oka
- Department of Physics, Okayama University, Okayama 700-8530, Japan
| | | | | | | | | | | |
Collapse
|
41
|
Dey T, Khuntia P, Mahajan AV, Sharma S, Bharathi A. (75)As NMR study of antiferromagnetic fluctuations in Ba(Fe(1-x)Ru(x))(2)As(2). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:475701. [PMID: 22056991 DOI: 10.1088/0953-8984/23/47/475701] [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
The evolution of (75)As NMR parameters with composition and temperature was probed in the Ba(Fe(1-x)Ru(x))(2)As(2) system where Fe is replaced by isovalent Ru. While the Ru end member was found to be a conventional Fermi liquid, the composition (x = 0.5) corresponding to the highest T(c) (20 K) in this system shows an upturn in the (75)As [Formula: see text] below about 80 K, evidencing the presence of antiferromagnetic (AFM) fluctuations. These results are similar to those obtained in another system with isovalent substitution, BaFe(2)(As(1-x)P(x))(2) (Nakai et al 2010 Phys. Rev. Lett. 105 107003) and point to a possible role of AFM fluctuations in driving superconductivity.
Collapse
Affiliation(s)
- Tusharkanti Dey
- Department of Physics, IIT Bombay, Powai, Mumbai 400076, India
| | | | | | | | | |
Collapse
|
42
|
Kinouchi H, Mukuda H, Yashima M, Kitaoka Y, Shirage PM, Eisaki H, Iyo A. Antiferromagnetic spin fluctuations and unconventional nodeless superconductivity in an iron-based new superconductor (Ca4Al2O(6-y))(Fe2As2): 75As nuclear quadrupole resonance study. PHYSICAL REVIEW LETTERS 2011; 107:047002. [PMID: 21867031 DOI: 10.1103/physrevlett.107.047002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Indexed: 05/31/2023]
Abstract
We report 75As nuclear quadrupole resonance studies on (Ca4Al2O(6-y))(Fe2As2) with T(c) = 27 K. Measurement of nuclear-spin-relaxation rate 1/T1 has revealed a significant development of two-dimensional antiferromagnetic spin fluctuations down to T(c) in association with the smallest As-Fe-As bond angle. Below T(c), the temperature dependence of 1/T1 without any trace of the coherence peak is well accounted for by a nodeless s(±)-wave multiple-gaps model. From the fact that its T(c) is comparable to T(c) = 28 K in the optimally doped LaFeAsO(1-y) in which antiferromagnetic spin fluctuations are not dominant, we remark that antiferromagnetic spin fluctuations are not a unique factor for enhancing T(c) among Fe-based superconductors, but a condition for optimizing superconductivity should be addressed from the lattice structure point of view.
Collapse
Affiliation(s)
- H Kinouchi
- Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan.
| | | | | | | | | | | | | |
Collapse
|
43
|
Giovannetti G, Ortix C, Marsman M, Capone M, van den Brink J, Lorenzana J. Proximity of iron pnictide superconductors to a quantum tricritical point. Nat Commun 2011; 2:398. [PMID: 21772269 PMCID: PMC3160143 DOI: 10.1038/ncomms1407] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 06/20/2011] [Indexed: 11/13/2022] Open
Abstract
In several materials, unconventional superconductivity appears nearby a quantum phase transition where long-range magnetic order vanishes as a function of a control parameter like charge doping, pressure or magnetic field. The nature of the quantum phase transition is of key relevance, because continuous transitions are expected to favour superconductivity, due to strong fluctuations. Discontinuous transitions, on the other hand, are not expected to have a similar role. Here we determine the nature of the magnetic quantum phase transition, which occurs as a function of doping, in the iron-based superconductor LaFeAsO(1-x)F(x). We use constrained density functional calculations that provide ab initio coefficients for a Landau order parameter analysis. The outcome is intriguing, as this material turns out to be remarkably close to a quantum tricritical point, where the transition changes from continuous to discontinuous, and several susceptibilities diverge simultaneously. We discuss the consequences for superconductivity and the phase diagram.
Collapse
Affiliation(s)
- Gianluca Giovannetti
- Dipartimento di Fisica, Università di Roma 'La Sapienza', P. Aldo Moro 2, Roma 00185, Italy
- Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Università di Roma 'La Sapienza', P. Aldo Moro 2, Roma 00185, Italy
- Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, SISSA, Via Bonomea 265, 34136 Trieste, Italy
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Condensed Matter Sector, Via Bonomea 265, Trieste 34136, SISSA, Via Bonomea 265, 34136 Trieste, Italy
| | - Carmine Ortix
- Institute for Theoretical Solid State Physics, IFW-Dresden, PF 270116, Dresden 01171, Germany
| | - Martijn Marsman
- Faculty of Physics and Center for Computational Materials Science, University Vienna, Sensengasse 8/12, Vienna A-1090, Austria
| | - Massimo Capone
- Dipartimento di Fisica, Università di Roma 'La Sapienza', P. Aldo Moro 2, Roma 00185, Italy
- Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, SISSA, Via Bonomea 265, 34136 Trieste, Italy
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Condensed Matter Sector, Via Bonomea 265, Trieste 34136, SISSA, Via Bonomea 265, 34136 Trieste, Italy
| | - Jeroen van den Brink
- Institute for Theoretical Solid State Physics, IFW-Dresden, PF 270116, Dresden 01171, Germany
| | - José Lorenzana
- Dipartimento di Fisica, Università di Roma 'La Sapienza', P. Aldo Moro 2, Roma 00185, Italy
- Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Università di Roma 'La Sapienza', P. Aldo Moro 2, Roma 00185, Italy
| |
Collapse
|
44
|
Abrahams E, Si Q. Quantum criticality in the iron pnictides and chalcogenides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:223201. [PMID: 21593557 DOI: 10.1088/0953-8984/23/22/223201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Superconductivity in the iron pnictides and chalcogenides arises at the border of antiferromagnetism, which raises the question of the role of quantum criticality. In this topical review, we describe the theoretical work that led to the prediction of a magnetic quantum critical point arising out of a competition between electronic localization and itinerancy, and the proposal for accessing it by using isoelectronic P substitution for As in the undoped iron pnictides. We go on to compile the emerging experimental evidence in support of the existence of such a quantum critical point in isoelectronically tuned iron pnictides. We close by discussing the implications of these results for the physics of the iron pnictides and chalcogenides.
Collapse
Affiliation(s)
- Elihu Abrahams
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095, USA.
| | | |
Collapse
|
45
|
Yu W, Ma L, He JB, Wang DM, Xia TL, Chen GF, Bao W. 77Se NMR study of the pairing symmetry and the spin dynamics in K(y)Fe(2-x)Se2. PHYSICAL REVIEW LETTERS 2011; 106:197001. [PMID: 21668191 DOI: 10.1103/physrevlett.106.197001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Indexed: 05/30/2023]
Abstract
We present a 77Se NMR study of the newly discovered iron selenide superconductor K(y)Fe(2-x)Se2, in which T(c) = 32 K. Below T(c), the Knight shift 77K drops sharply with temperature, providing strong evidence for singlet pairing. Above T(c), Korringa-type relaxation indicates Fermi-liquid behavior. Our experimental results set strict constraints on the nature of possible theories for the mechanism of high-T(c) superconductivity in this iron selenide system.
Collapse
Affiliation(s)
- Weiqiang Yu
- Department of Physics, Renmin University of China, Beijing 100872, China.
| | | | | | | | | | | | | |
Collapse
|