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Wang Y, Yang SY, Sivakumar PK, Ortiz BR, Teicher SML, Wu H, Srivastava AK, Garg C, Liu D, Parkin SSP, Toberer ES, McQueen T, Wilson SD, Ali MN. Anisotropic proximity-induced superconductivity and edge supercurrent in Kagome metal, K 1-xV 3Sb 5. SCIENCE ADVANCES 2023; 9:eadg7269. [PMID: 37436976 DOI: 10.1126/sciadv.adg7269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/12/2023] [Indexed: 07/14/2023]
Abstract
Materials with Kagome nets are of particular importance for their potential combination of strong correlation, exotic magnetism, and electronic topology. KV3Sb5 was discovered to be a layered topological metal with a Kagome net of vanadium. Here, we fabricated Josephson Junctions of K1-xV3Sb5 and induced superconductivity over long junction lengths. Through magnetoresistance and current versus phase measurements, we observed a magnetic field sweeping direction-dependent magnetoresistance and an anisotropic interference pattern with a Fraunhofer pattern for in-plane magnetic field but a suppression of critical current for out-of-plane magnetic field. These results indicate an anisotropic internal magnetic field in K1-xV3Sb5 that influences the superconducting coupling in the junction, possibly giving rise to spin-triplet superconductivity. In addition, the observation of long-lived fast oscillations shows evidence of spatially localized conducting channels arising from edge states. These observations pave the way for studying unconventional superconductivity and Josephson device based on Kagome metals with electron correlation and topology.
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Affiliation(s)
- Yaojia Wang
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Shuo-Ying Yang
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
| | - Pranava K Sivakumar
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
| | - Brenden R Ortiz
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Samuel M L Teicher
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Heng Wu
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Abhay K Srivastava
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
| | - Chirag Garg
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
- IBM Almaden Research Center, San Jose, CA 95120, USA
| | - Defa Liu
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
| | | | | | - Stephen D Wilson
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Mazhar N Ali
- Max Planck Institute of Microstructure Physics, 06108 Halle, Saxony-Anhalt, Germany
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
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Camargo BC, Gierłowski P, Kuzmiak M, de Jesus RF, Onufriienko O, Szabó P, Kopelevich Y. Macroscopic-ranged proximity effect in graphite. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:495602. [PMID: 34496351 DOI: 10.1088/1361-648x/ac24c5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
We report proximity-induced superconducting features over macroscopic lengths in highly oriented pyrolytic graphite. The phenomenon is triggered when electrical currents are injected in the material through superconducting electrodes, few millimeters apart from each other. Such a large range is anomalous, as proximity-induced features in normal conductors hardly surpass few micrometers. The results can be explained as due to the presence of pre-existing superconductivity in graphite on small, localized regions.
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Affiliation(s)
- Bruno Cury Camargo
- Faculty of Physics, University of Warsaw, Ul. Pasteura 5, 02-093 Warsaw, Poland
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02-668 Warsaw, Poland
| | - Piotr Gierłowski
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02-668 Warsaw, Poland
| | - Marek Kuzmiak
- Centre of Low Temperature Physics, Institute of Experimental Physics, Slovak Academy of Sciences, 04001 Košice, Slovakia
- Faculty of Electrical Engineering and Informatics, Technical University, 04001 Košice, Slovakia
| | | | - Oleksandr Onufriienko
- Centre of Low Temperature Physics, Institute of Experimental Physics, Slovak Academy of Sciences, 04001 Košice, Slovakia
| | - Pavol Szabó
- Centre of Low Temperature Physics, Institute of Experimental Physics, Slovak Academy of Sciences, 04001 Košice, Slovakia
| | - Yakov Kopelevich
- Universidade Estadual de Campinas-UNICAMP, Instituto de Fisica Gleb Wattaghin, R. Sergio Buarque de Holanda 777, 13083-859 Campinas, Brazil
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Ahmadkhani S, Hosseini MV. Superconducting proximity effect in flat band systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:315504. [PMID: 32224514 DOI: 10.1088/1361-648x/ab849a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/30/2020] [Indexed: 06/10/2023]
Abstract
We study theoretically proximity-induced superconductivity and its inverse effect in dice lattice flat band model by considering Josephson junction with an s-wave pairing in the superconducting leads. Using self-consistent tight-binding Bogoliubov-de Gennes method, we show that there is a critical value for chemical potential of the superconductors depending on paring interaction strength over which for undoped normal region the proximity effect is enhanced. Whereas if the supserconductor chemical potential is less than the critical one the proximity effect decreases regardless of normal region doping and in the meanwhile, the pairing amplitude of superconducting region increases significantly. Furthermore, we unveil that the supercurrent passing through the junction is large (vanishingly small) when the superconductor chemical potential is smaller (larger) than the critical value which increases as a function of normal region chemical potential.
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Affiliation(s)
- Somayeh Ahmadkhani
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan 45371-38791, Iran
| | - Mir Vahid Hosseini
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan 45371-38791, Iran
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4
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Perron JK, Kimball MO, Gasparini FM. A review of giant correlation-length effects via proximity and weak-links coupling in a critical system: 4He near the superfluid transition. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:114501. [PMID: 31437826 DOI: 10.1088/1361-6633/ab3df5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We review measurements of 4He near the superfluid transition in arrangements whereby an array of weak links couple relatively larger, more bulk-like 4He regions. In contrast to experiments which focus on the dependence of the superflow on the chemical potential difference across the links, these studies focus on the specific heat of both the weak links and that of the larger coupled regions, as well as the behavior of the superfluid fraction within the weak links. The data show unexpected results which reflect a very long range coupling as well as modification of the weak link itself due to the proximity to bulk-like helium. One finds that while the three-dimensional correlation length [Formula: see text], where [Formula: see text], is involved in these long-range effects, the distance over which these can be seen is of the order of 100 to 1000 times [Formula: see text]. These results call into question our understanding of the meaning of the correlation length at a critical point as the 'range' over which information can propagate. These studies are the first to measure the thermodynamic properties of weak links for a critical system where fluctuations are important. They differ in essential ways with expectations from mean-field considerations. We compare results with other 4He measurements, with superconductors and the theoretical calculations of the Ising model.
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Affiliation(s)
- J K Perron
- Department of Physics, California State University San Marcos, San Marcos, CA 92069, United States of America
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Electron pairing in the pseudogap state revealed by shot noise in copper oxide junctions. Nature 2019; 572:493-496. [PMID: 31435059 DOI: 10.1038/s41586-019-1486-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/18/2019] [Indexed: 11/08/2022]
Abstract
In the quest to understand high-temperature superconductivity in copper oxides, debate has been focused on the pseudogap-a partial energy gap that opens over portions of the Fermi surface in the 'normal' state above the bulk critical temperature1. The pseudogap has been attributed to precursor superconductivity, to the existence of preformed pairs and to competing orders such as charge-density waves1-4. A direct determination of the charge of carriers as a function of temperature and bias could help resolve among these alternatives. Here we report measurements of the shot noise of tunnelling current in high-quality La2-xSrxCuO4/La2CuO4/La2-xSrxCuO4 (LSCO/LCO/LSCO) heterostructures fabricated using atomic layer-by-layer molecular beam epitaxy at several doping levels. The data delineate three distinct regions in the bias voltage-temperature space. Well outside the superconducting gap region, the shot noise agrees quantitatively with independent tunnelling of individual charge carriers. Deep within the superconducting gap, shot noise is greatly enhanced, reminiscent of multiple Andreev reflections5-7. Above the critical temperature and extending to biases much larger than the superconducting gap, there is a broad region in which the noise substantially exceeds theoretical expectations for single-charge tunnelling, indicating pairing of charge carriers. These pairs are detectable deep into the pseudogap region of temperature and bias. The presence of these pairs constrains current models of the pseudogap and broken symmetry states, while phase fluctuations limit the domain of superconductivity.
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Pavlov DP, Zagidullin RR, Mukhortov VM, Kabanov VV, Adachi T, Kawamata T, Koike Y, Mamin RF. Fabrication of High-Temperature Quasi-Two-Dimensional Superconductors at the Interface of a Ferroelectric Ba_{0.8}Sr_{0.2}TiO_{3} Film and an Insulating Parent Compound of La_{2}CuO_{4}. PHYSICAL REVIEW LETTERS 2019; 122:237001. [PMID: 31298885 DOI: 10.1103/physrevlett.122.237001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 01/29/2019] [Indexed: 06/10/2023]
Abstract
We report the first observation of superconductivity in a heterostructure consisting of an insulating ferroelectric film (Ba_{0.8}Sr_{0.2}TiO_{3}) grown on an insulating parent compound of La_{2}CuO_{4} with [001] orientation. The heterostructure was prepared by magnetron sputtering on a nonatomically flat surface with inhomogeneities of the order of 1-2 nm. The measured superconducting transition temperature T_{c} is about 30 K. We have shown that superconductivity is confined near the interface region. Application of a weak magnetic field perpendicular to the interface leads to the appearance of the finite resistance. That confirms the quasi-two-dimensional nature of the superconductive state. The proposed concept promises ferroelectrically controlled interface superconductivity which offers the possibility of novel design of electronic devices.
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Affiliation(s)
- Dmitrii P Pavlov
- Zavoisky Physical-Technical Institute, FRC KazanSC of RAS, 420029 Kazan, Russia
| | - Rustem R Zagidullin
- Zavoisky Physical-Technical Institute, FRC KazanSC of RAS, 420029 Kazan, Russia
| | | | - Viktor V Kabanov
- Zavoisky Physical-Technical Institute, FRC KazanSC of RAS, 420029 Kazan, Russia
- Department for Complex Matter, Jozef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Tadashi Adachi
- Department of Engineering and Applied Sciences, Sophia University, 102-8554 Tokyo, Japan
| | - Takayuki Kawamata
- Department of Applied Physics, Tohoku University, 980-8579 Sendai, Japan
| | - Yoji Koike
- Department of Applied Physics, Tohoku University, 980-8579 Sendai, Japan
| | - Rinat F Mamin
- Zavoisky Physical-Technical Institute, FRC KazanSC of RAS, 420029 Kazan, Russia
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7
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Abstract
Although giant proximity effect (GPE) can shed important information on understanding superconducting pairing mechanisms and superconducting electronics, reports on the GPE are few because the fabrication of the junctions with GPE is technologically difficult. Here, we report a GPE in the single-crystalline MgB2 bilayers (S'/S), where the S' is the damaged MgB2 layer by cobalt (Co)-ion irradiation and the S is the undamaged MgB2 layer. Superconducting properties of the S' is remarkably degraded by the irradiation, whereas those of the S is uninfluenced by the irradiation. The degraded superconductivity in the S' is fully recovered by increasing the thickness of undamaged MgB2 layer S despite almost ten times larger thickness ~ 95 nm of S' than the superconducting coherence length ξab(0) ~ 8.5 nm of the S, indicating a presence of GPE in the S'/S MgB2 bilayers. A diffusion of electrons in the S' into the S can reduce a pair breaking scattering in the S', and the similar electronic structures of S' and S layers and a finite attractive electron-electron interaction in the S' are thought to be origins of unpredicted GPE between the same superconducting materials. Both upper critical field (μ0Hc2) and in-field critical current density (Jc) of S'/S bilayers show a significant enhancement, representing a strong correlation between S' and S. These discoveries provide the blue print to the design of the superconducting multilayers for fundamental researches on the mechanism of the GPE as well as their technological applications.
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8
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Li Q, He C, Wang Y, Liu E, Wang M, Wang Y, Zeng J, Ma Z, Cao T, Yi C, Wang N, Watanabe K, Taniguchi T, Shao L, Shi Y, Chen X, Liang SJ, Wang QH, Miao F. Proximity-Induced Superconductivity with Subgap Anomaly in Type II Weyl Semi-Metal WTe 2. NANO LETTERS 2018; 18:7962-7968. [PMID: 30403355 DOI: 10.1021/acs.nanolett.8b03924] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Due to the nontrivial topological band structure in type II Weyl semi-metal tungsten ditelluride (WTe2), unconventional properties may emerge in its superconducting phase. While realizing intrinsic superconductivity has been challenging in the type II Weyl semi-metal WTe2, the proximity effect may open an avenue for the realization of superconductivity. Here, we report the observation of proximity-induced superconductivity with a long coherence length along the c axis in WTe2 thin flakes based on a WTe2/NbSe2 van der Waals heterostructure. Interestingly, we also observe anomalous oscillations of the differential resistance during the transition from the superconducting to the normal state. Theoretical calculations show excellent agreement with experimental results, revealing that such a subgap anomaly is the intrinsic property of WTe2 in superconducting state induced by the proximity effect. Our findings enrich the understanding of the superconducting phase of type II Weyl semi-metals and pave the way for their future applications in topological quantum computing.
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Affiliation(s)
- Qiao Li
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Chaocheng He
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Yaojia Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Erfu Liu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Miao Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Yu Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Junwen Zeng
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Zecheng Ma
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Tianjun Cao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Changjiang Yi
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | | | - Kenji Watanabe
- National Institute for Materials Science , 1-1 Namiki Tsukuba , Ibaraki 305-0044 , Japan
| | - Takashi Taniguchi
- National Institute for Materials Science , 1-1 Namiki Tsukuba , Ibaraki 305-0044 , Japan
| | - Lubing Shao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Youguo Shi
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | | | - Shi-Jun Liang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Qiang-Hua Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Feng Miao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
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Paull OHC, Pan AV, Causer GL, Fedoseev SA, Jones A, Liu X, Rosenfeld A, Klose F. Field dependence of the ferromagnetic/superconducting proximity effect in a YBCO/STO/LCMO multilayer. NANOSCALE 2018; 10:18995-19003. [PMID: 29845139 DOI: 10.1039/c8nr01210e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The interaction between superconductivity and magnetism in spatially confined heterostructures of thin film multilayers is investigated in the ferromagnetic manganite La2/3Ca1/3MnO3 (LCMO) and the high-temperature superconductor YBa2Cu3O7-δ (YBCO) mediated by an intermediate insulating SrTiO3 (STO) layer. The STO layer is used to mediate and tune the range of interactions between the ferromagnet and superconductor. A magnetically depleted layer with zero-magnetisation within the LCMO layer is shown by polarised neutron reflectometry measurements. This zero-magnetisation layer is caused by the onset of superconductivity in YBCO despite being separated by an insulating layer with a thickness much larger than the superconducting coherence length. The magnetic field dependence of this interaction is also explored. We show that the magnetism of the depleted layer can be restored by applying a magnetic field that partially destroys the superconductivity in YBCO, restricting the electronic interaction between the materials.
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Affiliation(s)
- Oliver H C Paull
- Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia.
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10
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ON the Nature of Ionic Liquid Gating of La2−xSrxCuO4. Int J Mol Sci 2018; 19:ijms19020566. [PMID: 29438349 PMCID: PMC5855788 DOI: 10.3390/ijms19020566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 02/07/2018] [Accepted: 02/09/2018] [Indexed: 01/19/2023] Open
Abstract
Ionic liquids have recently been used as means of modulating the charge carrier properties of cuprates. The mechanism behind it, however, is still a matter of debate. In this paper we report experiments on ionic liquid gated ultrathin La2−xSrxCuO4 films. Our results show that the electrostatic part of gating has limited influence in the conductance of the cuprate in the gate voltage range of 0 to −2 V. A non-electrostatic mechanism takes over for gate voltages below −2 V. This mechanism most likely changes the oxygen concentration of the film. The results presented are in line with previous X-ray based studies on ionic liquid gating induced oxygenation of the cuprate materials YBa2Cu3O7−x and La2−xSrxCuO4.
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11
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Frano A, Blanco-Canosa S, Schierle E, Lu Y, Wu M, Bluschke M, Minola M, Christiani G, Habermeier HU, Logvenov G, Wang Y, van Aken PA, Benckiser E, Weschke E, Le Tacon M, Keimer B. Long-range charge-density-wave proximity effect at cuprate/manganate interfaces. NATURE MATERIALS 2016; 15:831-834. [PMID: 27322824 DOI: 10.1038/nmat4682] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 05/25/2016] [Indexed: 06/06/2023]
Abstract
The interplay between charge density waves (CDWs) and high-temperature superconductivity is currently under intense investigation. Experimental research on this issue is difficult because CDW formation in bulk copper oxides is strongly influenced by random disorder, and a long-range-ordered CDW state in high magnetic fields is difficult to access with spectroscopic and diffraction probes. Here we use resonant X-ray scattering in zero magnetic field to show that interfaces with the metallic ferromagnet La2/3Ca1/3MnO3 greatly enhance CDW formation in the optimally doped high-temperature superconductor YBa2Cu3O6+δ (δ ∼ 1), and that this effect persists over several tens of nanometres. The wavevector of the incommensurate CDW serves as an internal calibration standard of the charge carrier concentration, which allows us to rule out any significant influence of oxygen non-stoichiometry, and to attribute the observed phenomenon to a genuine electronic proximity effect. Long-range proximity effects induced by heterointerfaces thus offer a powerful method to stabilize the charge-density-wave state in the cuprates and, more generally, to manipulate the interplay between different collective phenomena in metal oxides.
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Affiliation(s)
- A Frano
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie, Wilhelm-Conrad-Röntgen-Campus BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - S Blanco-Canosa
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - E Schierle
- Helmholtz-Zentrum Berlin für Materialien und Energie, Wilhelm-Conrad-Röntgen-Campus BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Y Lu
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - M Wu
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - M Bluschke
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie, Wilhelm-Conrad-Röntgen-Campus BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - M Minola
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - G Christiani
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - H U Habermeier
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - G Logvenov
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Y Wang
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - P A van Aken
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - E Benckiser
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - E Weschke
- Helmholtz-Zentrum Berlin für Materialien und Energie, Wilhelm-Conrad-Röntgen-Campus BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - M Le Tacon
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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12
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Kloss T, Montiel X, de Carvalho VS, Freire H, Pépin C. Charge orders, magnetism and pairings in the cuprate superconductors. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:084507. [PMID: 27427401 DOI: 10.1088/0034-4885/79/8/084507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We review the recent developments in the field of cuprate superconductors with special focus on the recently observed charge order in the underdoped compounds. We introduce new theoretical developments following the study of the antiferromagnetic quantum critical point in two dimensions, in which preemptive orders in both charge and superconducting (SC) sectors emerge, that are in turn related by an SU(2) symmetry. We consider the implications of this proliferation of orders in the underdoped region, and provide a study of the type of fluctuations which characterize the SU(2) symmetry. We identify an intermediate energy scale where the SC fluctuations are dominant and argue that they are unstable towards the formation of a resonant excitonic state at the pseudogap temperature T (*). We discuss the implications of this scenario for a few key experiments.
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Affiliation(s)
- T Kloss
- IPhT, L'Orme des Merisiers, CEA-Saclay, 91191 Gif-sur-Yvette, France
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13
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Kirzhner T, Koren G. Pairing and the phase diagram of the normal coherence length ξN(T, x) above Tc of La(2-x)Sr(x)CuO4 thin films probed by the Josephson effect. Sci Rep 2014; 4:6244. [PMID: 25175417 PMCID: PMC4150101 DOI: 10.1038/srep06244] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/08/2014] [Indexed: 11/09/2022] Open
Abstract
The long range proximity effect in high-Tc c-axis Josephson junctions with a high-Tc barrier of lower Tc is still a puzzling phenomenon. It leads to supercurrents in junctions with much thicker barriers than would be allowed by the conventional proximity effect. Here we measured the T − x (Temperature-doping level) phase diagram of the barrier coherence length ξN(T, x), and found an enhancement of ξN at moderate under-doping and high temperatures. This indicates that a possible origin of the long range proximity effect in the cuprate barrier is the conjectured pre-formed pairs in the pseudogap regime, which increase the length scale over which superconducting correlations survive in the seemingly normal barrier. In more details, we measured the supercurrents Ic of Superconducting - Normal - Superconducting SNS c-axis junctions, where S was optimally doped Y Ba2Cu3O7−δ below Tc (90 K) and N was La2−xSrxCuO4 above its Tc (<25 K) but in the pseudogap regime. From the exponential decay of Ic(T) ∝ exp[−d/ξN(T)], where d is the barrier thickness, the ξN(T) values were extracted. By repeating these measurements for different barrier doping levels x, the whole phase diagram of ξN(T, x) was obtained.
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Affiliation(s)
- Tal Kirzhner
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Gad Koren
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
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Proximity-induced high-temperature superconductivity in the topological insulators Bi2Se3 and Bi2Te3. Nat Commun 2012; 3:1056. [DOI: 10.1038/ncomms2042] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 08/01/2012] [Indexed: 11/08/2022] Open
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Perron JK, Gasparini FM. Critical point coupling and proximity effects in 4He at the superfluid transition. PHYSICAL REVIEW LETTERS 2012; 109:035302. [PMID: 22861866 DOI: 10.1103/physrevlett.109.035302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Indexed: 06/01/2023]
Abstract
We report measurements of the superfluid fraction ρ(s)/ρ and specific heat c(p) near the superfluid transition of 4He when confined in an array of (2 μm)3 boxes at a separation of S=2 μm and coupled through a 32.5 nm film. We find that c(p) is strongly enhanced when compared with data where coupling is not present. An analysis of this excess signal shows that it is proportional to the finite-size correlation length in the boxes ξ(t,L), and it is measurable as far as S/ξ∼30-50. We obtain ξ(0,L) and the scaling function (within a constant) for ξ(t,L) in an L3 box geometry. Furthermore, we find that ρ(s)/ρ of the film persists a full decade closer to the bulk transition temperature T(λ) than a film uninfluenced by proximity effects. This excess in ρ(s)/ρ is measurable even when S/ξ>100, which cannot be understood on the basis of mean field theory.
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Affiliation(s)
- Justin K Perron
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA.
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16
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The Meissner effect in a strongly underdoped cuprate above its critical temperature. Nat Commun 2011; 2:272. [PMID: 21505428 PMCID: PMC3104550 DOI: 10.1038/ncomms1273] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 03/11/2011] [Indexed: 12/02/2022] Open
Abstract
The Meissner effect and associated perfect 'bulk' diamagnetism together with zero resistance and gap opening are characteristic features of the superconducting state. In the pseudogap state of cuprates, unusual diamagnetic signals and anomalous proximity effects have been detected, but a Meissner effect has never been observed. Here we probe the local diamagnetic response in the normal state of an underdoped La1.94Sr0.06CuO4 layer (Tc′≤5 K), which is brought into close contact with two nearly optimally doped La1.84Sr0.16CuO4 layers (Tc≈32 K). We show that the entire 'barrier' layer of thickness, much larger than the typical c axis coherence lengths of cuprates, exhibits a Meissner effect at temperatures above Tc′ but below Tc. The temperature dependence of the effective penetration depth and superfluid density in different layers indicates that superfluidity with long-range phase coherence is induced in the underdoped layer by the proximity to optimally doped layers, but this induced order is sensitive to thermal excitation. In the pseudogap state of cuprates, although diamagnetic signals have been detected, a Meissner effect has never been observed. Morenzoni and colleagues probe the local diamagnetic response in the normal state of an underdoped layer showing that a 'barrier' layer exhibits a Meissner effect.
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Inhomogeneity, dynamical symmetry, and complexity in high-temperature superconductors: Reconciling a universal phase diagram with rich local disorder. CHINESE SCIENCE BULLETIN-CHINESE 2011. [DOI: 10.1007/s11434-010-4282-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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Gomez JA, Larkin I, Schwingenschlögl U. Relaxation of the electronic states at a thin-layer YBa2Cu3O7/PrBa2Cu3O7 interface. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.09.077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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19
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Parker CV, Pushp A, Pasupathy AN, Gomes KK, Wen J, Xu Z, Ono S, Gu G, Yazdani A. Nanoscale proximity effect in the high-temperature superconductor Bi{2}Sr{2}CaCu{2}O{8+delta} using a scanning tunneling microscope. PHYSICAL REVIEW LETTERS 2010; 104:117001. [PMID: 20366497 DOI: 10.1103/physrevlett.104.117001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Indexed: 05/29/2023]
Abstract
High-temperature cuprate superconductors exhibit extremely local nanoscale phenomena and strong sensitivity to doping. While other experiments have looked at nanoscale interfaces between layers of different dopings, we focus on the interplay between naturally inhomogeneous nanoscale regions. Using scanning tunneling microscopy to carefully track the same region of the sample as a function of temperature, we show that regions with weak superconductivity can persist to elevated temperatures if bordered by regions of strong superconductivity. This suggests that it may be possible to increase the maximum possible transition temperature by controlling the distribution of dopants.
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Affiliation(s)
- Colin V Parker
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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Zhang Y, Yang H, Li M, Sun B, Qi Y. Improvement of multiple oxide properties: effect of gel processes on the quality of Bi2Sr2CaCu2O8 + δ superconducting powders. CrystEngComm 2010. [DOI: 10.1039/b927276c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Smadici S, Lee JCT, Wang S, Abbamonte P, Logvenov G, Gozar A, Cavellin CD, Bozovic I. Superconducting transition at 38 K in insulating-overdoped La2CuO4-La1.64Sr0.36CuO4 superlattices: evidence for interface electronic redistribution from resonant soft X-ray scattering. PHYSICAL REVIEW LETTERS 2009; 102:107004. [PMID: 19392148 DOI: 10.1103/physrevlett.102.107004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Indexed: 05/27/2023]
Abstract
We use resonant soft x-ray scattering (RSXS) to quantify the hole distribution in a superlattice of insulating La2CuO4 (LCO) and overdoped La2-xSrxCuO4 (LSCO). Despite its nonsuperconducting constituents, this structure is superconducting with T_{c}=38 K. We found that the conducting holes redistribute electronically from LSCO to the LCO layers. The LCO layers were found to be optimally doped, suggesting they are the main drivers of superconductivity. Our results demonstrate the utility of RSXS for separating electronic from structural effects at oxide interfaces.
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Affiliation(s)
- S Smadici
- Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
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Yan XZ, Ting CS. Supercurrent transferring through c-axis cuprate Josephson junctions with thick normal-metal bridge. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:035701. [PMID: 21817282 DOI: 10.1088/0953-8984/21/3/035701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
With a simple but exactly solvable model, we investigate the supercurrent transferring through the c-axis cuprate superconductor-normal metal-superconductor junctions with the clean normal metal much thicker than its coherence length. It is shown that the supercurrent as a function of thickness of the normal metal decreases much slower than the exponential decaying expected by the proximity effect. The present result may account for the giant proximity effect observed in the c-axis cuprate SNS junctions.
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Affiliation(s)
- Xin-Zhong Yan
- Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing 100190, People's Republic of China
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24
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Altfeder IB, Chen DM. Anisotropic charge ordering on the gallium surface. PHYSICAL REVIEW LETTERS 2008; 101:136405. [PMID: 18851471 DOI: 10.1103/physrevlett.101.136405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Indexed: 05/26/2023]
Abstract
Low-temperature scanning tunneling microscopy of atomically flat Ga(001) islands revealed the 2D electronic superlattice composed of stripe domains. Tunnel spectroscopy of these surface electrons indicates the formation of a 2D charge-ordered state of Wigner-crystal type driven by competition of short-range and long-range Coulomb energies. At the boundaries of stripe domains the energy spectra exhibit splitting due to charged excitonic states and shift due to charge doping, altogether indicating the self-assembly of 1D hole stripes. The size distribution of stripe domains is broadened around 4a.
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Affiliation(s)
- I B Altfeder
- Rowland Institute at Harvard, Harvard University, Cambridge, Massachusetts 02142, USA
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Marchand D, Covaci L, Berciu M, Franz M. Giant proximity effect in a phase-fluctuating superconductor. PHYSICAL REVIEW LETTERS 2008; 101:097004. [PMID: 18851642 DOI: 10.1103/physrevlett.101.097004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Indexed: 05/26/2023]
Abstract
When a tunneling barrier between two superconductors is formed by a normal material that would be a superconductor in the absence of phase fluctuations, the resulting Josephson effect can undergo an enormous enhancement. We establish this novel proximity effect by a general argument as well as a numerical simulation and argue that it may underlie recent experimental observations of the giant proximity effect between two cuprate superconductors separated by a barrier made of the same material rendered normal by severe underdoping.
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Affiliation(s)
- Dominic Marchand
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada V6T 1Z1
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Clayhold JA, Kerns BM, Schroer MD, Rench DW, Logvenov G, Bollinger AT, Bozovic I. Combinatorial measurements of Hall effect and resistivity in oxide films. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:033908. [PMID: 18377026 DOI: 10.1063/1.2901622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A system for the simultaneous measurement of the Hall effect in 31 different locations as well as the measurement of the resistivity in 30 different locations on a single oxide thin film grown with a composition gradient is described. Considerations for designing and operating a high-throughput system for characterizing highly conductive oxides with Hall coefficients as small as 10(-10) m3/C are discussed. Results from measurements on films grown using combinatorial molecular beam epitaxy show the usefulness of characterizing combinatorial libraries via both the resistivity and the Hall effect.
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Affiliation(s)
- J A Clayhold
- Department of Physics, Miami University, Oxford, Ohio 45056, USA
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Komissinskiy P, Ovsyannikov GA, Borisenko IV, Kislinskii YV, Constantinian KY, Zaitsev AV, Winkler D. Josephson effect in hybrid oxide heterostructures with an antiferromagnetic layer. PHYSICAL REVIEW LETTERS 2007; 99:017004. [PMID: 17678184 DOI: 10.1103/physrevlett.99.017004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Revised: 04/30/2007] [Indexed: 05/16/2023]
Abstract
Josephson coupling between an s- and d-wave superconductor through a 50 nm thick Ca1-xSrxCuO2 antiferromagnetic layer was observed for the hybrid Nb/Au/Ca1-xSrxCuO2/YBa2Cu3O7-delta heterostructures and investigated as a function of temperature, magnetic field, and applied millimeter-wave electromagnetic radiation. The magnetic field dependence of the supercurrent I(c)(H) exhibits anomalously rapid oscillations, which is the first experimental evidence of the theoretically predicted giant magneto-oscillations in Josephson junctions with antiferromagnetic interlayers.
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Affiliation(s)
- P Komissinskiy
- Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Moscow, Russia
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Abstract
A wide variety of experimental results and theoretical investigations in recent years have convincingly demonstrated that several transition metal oxides and other materials have dominant states that are not spatially homogeneous. This occurs in cases in which several physical interactions-spin, charge, lattice, and/or orbital-are simultaneously active. This phenomenon causes interesting effects, such as colossal magnetoresistance, and it also appears crucial to understand the high-temperature superconductors. The spontaneous emergence of electronic nanometer-scale structures in transition metal oxides, and the existence of many competing states, are properties often associated with complex matter where nonlinearities dominate, such as soft materials and biological systems. This electronic complexity could have potential consequences for applications of correlated electronic materials, because not only charge (semiconducting electronic), or charge and spin (spintronics) are of relevance, but in addition the lattice and orbital degrees of freedom are active, leading to giant responses to small perturbations. Moreover, several metallic and insulating phases compete, increasing the potential for novel behavior.
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Affiliation(s)
- Elbio Dagotto
- Department of Physics, University of Tennessee (UT), Knoxville, TN 37996-1200, USA. Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6393, USA
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