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Zhang L, Kang C, Liu C, Wang K, Zhang W. Two-dimensional superconducting nature of Bi 2Sr 2CaCu 2O 8+δ thin films revealed by BKT transition. RSC Adv 2023; 13:25797-25803. [PMID: 37664203 PMCID: PMC10468687 DOI: 10.1039/d3ra02701e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/15/2023] [Indexed: 09/05/2023] Open
Abstract
High-quality Bi2Sr2CaCu2O8+δ superconducting thin films are successfully grown on a SrTiO3 substrate by the Pulsed Laser Deposition technique. Superconducting critical transition temperatures Tc,zero have reached up to 85 K by using optimized growth parameters. In addition, we demonstrated the two-dimensional nature of the superconductivity of thin films by virtue of exhibiting Berezinskii-Kosterlitz-Thouless (BKT) physics and anisotropic magnetic response. Furthermore, three distinct regimes are identified based on the analysis of direct current resistance. The non-Fermi liquid phase and BKT phase fluctuation zone almost perfectly merge together, which implies that the system undergoes a unique topological state that is determined by the BKT phase fluctuation preceding the onset of the superconducting state. The emergence of such a topological state radically differentiates from the three-dimensional superconducting transition, which spontaneously breaks the gauge symmetry. The current studies on the Bi2Sr2CaCu2O8+δ superconducting thin films provide some new insights for understanding the rich quantum states of matter that emerge in the vicinity of the superconducting phase transition and highlight the significant role of BKT fluctuation on two-dimensional superconducting transition.
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Affiliation(s)
- Liping Zhang
- School of Future Technology, Henan University Zhengzhou 450046 China
| | - Chaoyang Kang
- School of Future Technology, Henan University Zhengzhou 450046 China
| | - Chengyan Liu
- School of Future Technology, Henan University Zhengzhou 450046 China
| | - Kai Wang
- Center for Topological Functional Materials, Henan University Kaifeng 475004 China
| | - Weifeng Zhang
- School of Future Technology, Henan University Zhengzhou 450046 China
- Institute of Quantum Materials and Physics, Henan Academy of Sciences Zhengzhou 450046 China
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2
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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.
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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
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3
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Yoshida T, Daido A, Yanase Y, Kawakami N. Fate of Majorana Modes in CeCoIn_{5}/YbCoIn_{5} Superlattices: A Test Bed for the Reduction of Topological Classification. PHYSICAL REVIEW LETTERS 2017; 118:147001. [PMID: 28430503 DOI: 10.1103/physrevlett.118.147001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Indexed: 06/07/2023]
Abstract
In this paper, we propose CeCoIn_{5}/YbCoIn_{5} superlattice systems as a test bed for the reduction of topological classification in free fermions. We find that the system with a quadlayer of CeCoIn_{5} shows a topological crystalline superconducting phase with the mirror Chern number eight at the noninteracting level. Furthermore, we demonstrate that in the presence of two-body interactions, gapless edge modes are no longer protected by the symmetry in the system with a quadlayer, but are protected in the system with a bilayer or trilayer. This clearly exemplifies the reduction of topological classification from Z⊕Z to Z⊕Z_{8}.
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Affiliation(s)
- Tsuneya Yoshida
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Akito Daido
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Youichi Yanase
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Norio Kawakami
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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Shimozawa M, Goh SK, Shibauchi T, Matsuda Y. From Kondo lattices to Kondo superlattices. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:074503. [PMID: 27275757 DOI: 10.1088/0034-4885/79/7/074503] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The realization of new classes of ground states in strongly correlated electron systems continues to be a major issue in condensed matter physics. Heavy fermion materials, whose electronic structure is essentially three-dimensional, are one of the most suitable systems for obtaining novel electronic states because of their intriguing properties associated with many-body effects. Recently, a state-of-the-art molecular beam epitaxy technique was developed to reduce the dimensionality of heavy electron systems by fabricating artificial superlattices that include heavy fermion compounds; this approach can produce a new type of electronic state in two-dimensional (2D) heavy fermion systems. In artificial superlattices of the antiferromagnetic heavy fermion compound CeIn3 and the conventional metal LaIn3, the magnetic order is suppressed by a reduction in the thickness of the CeIn3 layers. In addition, the 2D confinement of heavy fermions leads to enhancement of the effective electron mass and deviation from the standard Fermi liquid electronic properties, which are both associated with the dimensional tuning of quantum criticality. In the superconducting superlattices of the heavy fermion superconductor CeCoIn5 and nonmagnetic metal YbCoIn5, signatures of superconductivity are observed even at the thickness of one unit-cell layer of CeCoIn5. The most remarkable feature of this 2D heavy fermion superconductor is that the thickness reduction of the CeCoIn5 layers changes the temperature and angular dependencies of the upper critical field significantly. This result is attributed to a substantial suppression of the Pauli pair-breaking effect through the local inversion symmetry breaking at the interfaces of CeCoIn5 block layers. The importance of the inversion symmetry breaking in this system has also been supported by site-selective nuclear magnetic resonance spectroscopy, which can resolve spectroscopic information from each layer separately, even within the same CeCoIn5 block layer. In addition, recent experiments involving CeCoIn5/YbCoIn5 superlattices have shown that the degree of the inversion symmetry breaking and, in turn, the Rashba splitting are controllable, offering the prospect of achieving even more fascinating superconducting states. Thus, these Kondo superlattices pave the way for the exploration of unconventional metallic and superconducting states.
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Affiliation(s)
- Masaaki Shimozawa
- The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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5
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Ishii T, Toda R, Hanaoka Y, Tokiwa Y, Shimozawa M, Kasahara Y, Endo R, Terashima T, Nevidomskyy AH, Shibauchi T, Matsuda Y. Tuning the Magnetic Quantum Criticality of Artificial Kondo Superlattices CeRhIn_{5}/YbRhIn_{5}. PHYSICAL REVIEW LETTERS 2016; 116:206401. [PMID: 27258878 DOI: 10.1103/physrevlett.116.206401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Indexed: 06/05/2023]
Abstract
The effects of reduced dimensions and the interfaces on antiferromagnetic quantum criticality are studied in epitaxial Kondo superlattices, with alternating n layers of heavy-fermion antiferromagnet CeRhIn_{5} and seven layers of normal metal YbRhIn_{5}. As n is reduced, the Kondo coherence temperature is suppressed due to the reduction of effective Kondo screening. The Néel temperature is gradually suppressed as n decreases and the quasiparticle mass is strongly enhanced, implying dimensional control toward a quantum critical point. Magnetotransport measurements reveal that a quantum critical point is reached for the n=3 superlattice by applying small magnetic fields. Remarkably, the anisotropy of the quantum critical field is opposite to the expectations from the magnetic susceptibility in bulk CeRhIn_{5}, suggesting that the Rashba spin-orbit interaction arising from the inversion symmetry breaking at the interface plays a key role for tuning the quantum criticality in the two-dimensional Kondo lattice.
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Affiliation(s)
- T Ishii
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - R Toda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Hanaoka
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Tokiwa
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
- Research Center for Low Temperature and Materials Science, Kyoto University, Kyoto 606-8501, Japan
| | - M Shimozawa
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Y Kasahara
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - R Endo
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Terashima
- Research Center for Low Temperature and Materials Science, Kyoto University, Kyoto 606-8501, Japan
| | - A H Nevidomskyy
- Department of Physics and Astronomy, Rice University, 6100 Main Street, Houston, Texas 77005, USA
| | - T Shibauchi
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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Herranz G, Singh G, Bergeal N, Jouan A, Lesueur J, Gázquez J, Varela M, Scigaj M, Dix N, Sánchez F, Fontcuberta J. Engineering two-dimensional superconductivity and Rashba spin-orbit coupling in LaAlO₃/SrTiO₃ quantum wells by selective orbital occupancy. Nat Commun 2015; 6:6028. [PMID: 25583368 PMCID: PMC4308716 DOI: 10.1038/ncomms7028] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/03/2014] [Indexed: 11/09/2022] Open
Abstract
The discovery of two-dimensional electron gases (2DEGs) at oxide interfaces-involving electrons in narrow d-bands-has broken new ground, enabling the access to correlated states that are unreachable in conventional semiconductors based on s- and p- electrons. There is a growing consensus that emerging properties at these novel quantum wells-such as 2D superconductivity and magnetism-are intimately connected to specific orbital symmetries in the 2DEG sub-band structure. Here we show that crystal orientation allows selective orbital occupancy, disclosing unprecedented ways to tailor the 2DEG properties. By carrying out electrostatic gating experiments in LaAlO3/SrTiO3 wells of different crystal orientations, we show that the spatial extension and anisotropy of the 2D superconductivity and the Rashba spin-orbit field can be largely modulated by controlling the 2DEG sub-band filling. Such an orientational tuning expands the possibilities for electronic engineering of 2DEGs at LaAlO3/SrTiO3 interfaces.
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Affiliation(s)
- Gervasi Herranz
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain
| | - Gyanendra Singh
- LPEM-UMR8213/CNRS-ESPCI ParisTech-UPMC, PSL University, 10 rue Vauquelin, 75005 Paris, France
| | - Nicolas Bergeal
- LPEM-UMR8213/CNRS-ESPCI ParisTech-UPMC, PSL University, 10 rue Vauquelin, 75005 Paris, France
| | - Alexis Jouan
- LPEM-UMR8213/CNRS-ESPCI ParisTech-UPMC, PSL University, 10 rue Vauquelin, 75005 Paris, France
| | - Jérôme Lesueur
- LPEM-UMR8213/CNRS-ESPCI ParisTech-UPMC, PSL University, 10 rue Vauquelin, 75005 Paris, France
| | - Jaume Gázquez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain
| | - María Varela
- 1] Materials Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA [2] GFMC, Department de Fisica Aplicada III &Instituto Pluridisciplinar, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Mateusz Scigaj
- 1] Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain [2] Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Catalonia, Spain
| | - Nico Dix
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain
| | - Florencio Sánchez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain
| | - Josep Fontcuberta
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain
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7
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Shimozawa M, Goh SK, Endo R, Kobayashi R, Watashige T, Mizukami Y, Ikeda H, Shishido H, Yanase Y, Terashima T, Shibauchi T, Matsuda Y. Controllable Rashba spin-orbit interaction in artificially engineered superlattices involving the heavy-fermion superconductor CeCoIn5. PHYSICAL REVIEW LETTERS 2014; 112:156404. [PMID: 24785062 DOI: 10.1103/physrevlett.112.156404] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Indexed: 06/03/2023]
Abstract
By using a molecular beam epitaxy technique, we fabricate a new type of superconducting superlattices with controlled atomic layer thicknesses of alternating blocks between the heavy-fermion superconductor CeCoIn5, which exhibits a strong Pauli pair-breaking effect, and nonmagnetic metal YbCoIn5. The introduction of the thickness modulation of YbCoIn5 block layers breaks the inversion symmetry centered at the superconducting block of CeCoIn5. This configuration leads to dramatic changes in the temperature and angular dependence of the upper critical field, which can be understood by considering the effect of the Rashba spin-orbit interaction arising from the inversion symmetry breaking and the associated weakening of the Pauli pair-breaking effect. Since the degree of thickness modulation is a design feature of this type of superlattices, the Rashba interaction and the nature of pair breaking are largely tunable in these modulated superlattices with strong spin-orbit coupling.
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Affiliation(s)
- M Shimozawa
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - S K Goh
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan and Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - R Endo
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - R Kobayashi
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Watashige
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Mizukami
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - H Ikeda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - H Shishido
- Department of Physics and Electronics, Osaka Prefecture University, Osaka 599-8531, Japan
| | - Y Yanase
- Department of Physics, Niigata University, Niigata 950-2181, Japan
| | - T Terashima
- Research Center for Low Temperature and Materials Science, Kyoto University, Kyoto 606-8501, Japan
| | - T Shibauchi
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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Goh SK, Mizukami Y, Shishido H, Watanabe D, Yasumoto S, Shimozawa M, Yamashita M, Terashima T, Yanase Y, Shibauchi T, Buzdin AI, Matsuda Y. Anomalous upper critical field in CeCoIn5/YbCoIn5 superlattices with a Rashba-type heavy Fermion interface. PHYSICAL REVIEW LETTERS 2012; 109:157006. [PMID: 23102358 DOI: 10.1103/physrevlett.109.157006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Indexed: 06/01/2023]
Abstract
We report a highly unusual angular variation of the upper critical field (H(c2)) in epitaxial superlattices CeCoIn(5)(n)/YbCoIn(5)(5), formed by alternating layers of n and a 5 unit-cell thick heavy-fermion superconductor CeCoIn(5) with a strong Pauli effect and normal metal YbCoIn(5), respectively. For the n=3 superlattice, H(c2)(θ) changes smoothly as a function of the field angle θ. However, close to the superconducting transition temperature, H(c2)(θ) exhibits a cusp near the parallel field (θ=0°). This cusp behavior disappears for n=4 and 5 superlattices. This sudden disappearance suggests the relative dominance of the orbital depairing effect in the n=3 superlattice, which may be due to the suppression of the Pauli effect in a system with local inversion symmetry breaking. Taking into account the temperature dependence of H(c2)(θ) as well, our results suggest that some exotic superconducting states, including a helical superconducting state, might be realized at high magnetic fields.
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Affiliation(s)
- S K Goh
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan
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Fellows JM, Carr ST, Hooley CA, Schmalian J. Unbinding of giant vortices in states of competing order. PHYSICAL REVIEW LETTERS 2012; 109:155703. [PMID: 23102335 DOI: 10.1103/physrevlett.109.155703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Indexed: 06/01/2023]
Abstract
We consider a two-dimensional system with two order parameters, one with O(2) symmetry and one with O(M), near a point in parameter space where they couple to become a single O(2+M) order. While the O(2) sector supports vortex excitations, these vortices must somehow disappear as the high symmetry point is approached. We develop a variational argument which shows that the size of the vortex cores diverges as 1/√Δ and the Berezinskii-Kosterlitz-Thouless transition temperature of the O(2) order vanishes as 1/ln(1/Δ), where Δ denotes the distance from the high-symmetry point. Our physical picture is confirmed by a renormalization group analysis which gives further logarithmic corrections, and demonstrates full symmetry restoration within the cores.
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Affiliation(s)
- J M Fellows
- School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom
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