1
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Current dependence of the negative magnetoresistance in superconducting NbN nanowires. Sci Rep 2022; 12:22027. [PMID: 36539457 PMCID: PMC9767931 DOI: 10.1038/s41598-022-26475-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Magnetoresistance measurements in amorphous NbN nanowires show that transport current affects their negative magnetoresistance (nMR) in a manner qualitatively similar to temperature. In particular, the current suppresses the nMR and, beyond a certain level it eliminates the effect altogether. As the temperature dependence of the nMR effect is more pronounced at low currents, similarly the current dependence of the effect is more pronounced at low temperatures. These results are discussed in terms of the phenomenological model which attributes the nMR to the interplay between the resistance originating from the rate of phase slips via the Josephson relation and the Ohmic contribution from quasiparticles charge imbalance that accompany fluctuations of the order parameter in the nanowire.
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2
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Chen J, Xu W, Tan Z, Pan Z, Zhu P, Liao ZM, Yu D. Superconducting Proximity in Intrinsic Magnetic Topological Insulator MnBi 2Te 4-NbN Hybrid Device Modulated by Coulomb Blockade Effect. NANO LETTERS 2022; 22:6484-6491. [PMID: 35926195 DOI: 10.1021/acs.nanolett.2c00948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The combination of nontrivial topology, magnetism, and superconductivity could offer the potential to realize exotic excitations of quasiparticles. MnBi2Te4, as an intrinsic magnetic topological insulator, may be a good platform to create Majorana fermions if coupled to an s-wave superconductor. Here, we report the transport properties of a MnBi2Te4-NbN hybrid device. This device exhibits clear Coulomb blockade oscillations. We observe a large zero-bias conductance peak that exists over considerable changes in gate voltage, magnetic field, and temperature, which is interpreted as a not fully developed supercurrent. The zero-bias peak shows a nonmonotonic evolution with a magnetic field and an abrupt π phase shift with changing temperature. Zero-energy bound states and a topological phase transition may exist in this hybrid system. Our results provide the first experimental investigation into the properties of the intrinsic magnetic topological insulator/superconductor hybrid structures modulated by the Coulomb blockade effect.
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Affiliation(s)
- Jingjing Chen
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenzheng Xu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Zhenbing Tan
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
| | - Zhencun Pan
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Pengfei Zhu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Sato Y, Ueda K, Takeshige Y, Kamata H, Li K, Samuelson L, Xu HQ, Matsuo S, Tarucha S. Quasiparticle Trapping at Vortices Producing Josephson Supercurrent Enhancement. PHYSICAL REVIEW LETTERS 2022; 128:207001. [PMID: 35657870 DOI: 10.1103/physrevlett.128.207001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/04/2022] [Indexed: 06/15/2023]
Abstract
The Josephson junction of a strong spin-orbit material under a magnetic field is a promising Majorana fermion candidate. Supercurrent enhancement by a magnetic field has been observed in the InAs nanowire Josephson junctions and assigned to a topological transition. In this work we observe a similar phenomenon but discuss the nontopological origin by considering the trapping of quasiparticles by vortices that penetrate the superconductor under a finite magnetic field. This assignment is supported by the observed hysteresis of the switching current when sweeping up and down the magnetic field. Our experiment shows the importance of quasiparticles in superconducting devices with a magnetic field, which can provide important insights for the design of qubits using superconductors.
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Affiliation(s)
- Yosuke Sato
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Kento Ueda
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yuusuke Takeshige
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Hiroshi Kamata
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université Paris Diderot, Sorbonne Paris Cité, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Kan Li
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices and School of Electronics, Peking University, Beijing 100871, China
| | - Lars Samuelson
- Division of Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan, Shenzhen, Guangdong 518055, China
| | - H Q Xu
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices and School of Electronics, Peking University, Beijing 100871, China
- Division of Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Sadashige Matsuo
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Seigo Tarucha
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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4
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Zhang E, Xu X, Huang C, Zou YC, Ai L, Liu S, Leng P, Jia Z, Zhang Y, Zhao M, Li Z, Yang Y, Liu J, Haigh SJ, Mao Z, Xiu F. Magnetic-Field-Induced Re-entrance of Superconductivity in Ta 2PdS 5 Nanostrips. NANO LETTERS 2021; 21:288-297. [PMID: 33346673 DOI: 10.1021/acs.nanolett.0c03655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The motion of Abrikosov vortices is the dominant origin of dissipation in type II superconductors subjected to a magnetic field, which leads to a finite electrical resistance. It is generally believed that the increase in the magnetic field results in the aggravation of energy dissipation through the increase in vortex density. Here, we show a distinctive re-entrance of the dissipationless state in quasi-one-dimensional superconducting Ta2PdS5 nanostrips. Utilizing magnetotransport measurements, we unveil a prominent magnetoresistance drop with the increase in the magnetic field below the superconducting transition temperature, manifesting itself as a giant re-entrance to the superconducting phase. Time-dependent Ginzburg-Landau calculations show that this is originated from the suppression of the vortex motion by the increased energy barrier on the edges. Interestingly, both our experiments and simulations demonstrate that this giant re-entrance of superconductivity occurs only in certain geometrical regimes because of the finite size of the vortex.
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Affiliation(s)
- Enze Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Xian Xu
- School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Ce Huang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Yi-Chao Zou
- School of Materials, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Linfeng Ai
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Shanshan Liu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Pengliang Leng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Zehao Jia
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Yuda Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Minhao Zhao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Zihan Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Yunkun Yang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Jinyu Liu
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, United States
| | - Sarah J Haigh
- School of Materials, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Zhiqiang Mao
- Department of Physics, Penn State University, State College, Pennsylvania 16801, United States
| | - Faxian Xiu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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5
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Tiira J, Strambini E, Amado M, Roddaro S, San-Jose P, Aguado R, Bergeret FS, Ercolani D, Sorba L, Giazotto F. Magnetically-driven colossal supercurrent enhancement in InAs nanowire Josephson junctions. Nat Commun 2017; 8:14984. [PMID: 28401951 PMCID: PMC5394342 DOI: 10.1038/ncomms14984] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 02/19/2017] [Indexed: 11/21/2022] Open
Abstract
The Josephson effect is a fundamental quantum phenomenon where a dissipationless supercurrent is introduced in a weak link between two superconducting electrodes by Andreev reflections. The physical details and topology of the junction drastically modify the properties of the supercurrent and a strong enhancement of the critical supercurrent is expected to occur when the topology of the junction allows an emergence of Majorana bound states. Here we report charge transport measurements in mesoscopic Josephson junctions formed by InAs nanowires and Ti/Al superconducting leads. Our main observation is a colossal enhancement of the critical supercurrent induced by an external magnetic field applied perpendicular to the substrate. This striking and anomalous supercurrent enhancement cannot be described by any known conventional phenomenon of Josephson junctions. We consider these results in the context of topological superconductivity, and show that the observed critical supercurrent enhancement is compatible with a magnetic field-induced topological transition. Physical details of a Josephson junction may drastically modify the properties of supercurrent. Here, the authors observe a colossal enhancement of the critical supercurrent in a Josephson junction subject to a perpendicular magnetic field, indicating topological phase transitions.
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Affiliation(s)
- J Tiira
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - E Strambini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - M Amado
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.,Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 OFS, UK
| | - S Roddaro
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - P San-Jose
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - R Aguado
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - F S Bergeret
- Centro de Fisica de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, E-20018 San Sebastian, Spain.,Donostia International Physics Center (DIPC), E-20018 San Sebastian, Spain
| | - D Ercolani
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - L Sorba
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - F Giazotto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
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6
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Mitra S, Tewari GC, Mahalu D, Shahar D. Negative Magnetoresistance in Amorphous Indium Oxide Wires. Sci Rep 2016; 6:37687. [PMID: 27876859 PMCID: PMC5120288 DOI: 10.1038/srep37687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/01/2016] [Indexed: 11/08/2022] Open
Abstract
We study magneto-transport properties of several amorphous Indium oxide nanowires of different widths. The wires show superconducting transition at zero magnetic field, but, there exist a finite resistance at the lowest temperature. The R(T) broadening was explained by available phase slip models. At low field, and far below the superconducting critical temperature, the wires with diameter equal to or less than 100 nm, show negative magnetoresistance (nMR). The magnitude of nMR and the crossover field are found to be dependent on both temperature and the cross-sectional area. We find that this intriguing behavior originates from the interplay between two field dependent contributions.
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Affiliation(s)
- Sreemanta Mitra
- The Weizmann Institute of Science, Department of Condensed Matter Physics, Rehovot, 76100, Israel
| | - Girish C Tewari
- The Weizmann Institute of Science, Department of Condensed Matter Physics, Rehovot, 76100, Israel
| | - Diana Mahalu
- The Weizmann Institute of Science, Department of Condensed Matter Physics, Rehovot, 76100, Israel
| | - Dan Shahar
- The Weizmann Institute of Science, Department of Condensed Matter Physics, Rehovot, 76100, Israel
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7
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Yang Y, Fedorov G, Shafranjuk SE, Klapwijk TM, Cooper BK, Lewis RM, Lobb CJ, Barbara P. Electronic Transport and Possible Superconductivity at Van Hove Singularities in Carbon Nanotubes. NANO LETTERS 2015; 15:7859-7866. [PMID: 26506109 DOI: 10.1021/acs.nanolett.5b02564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Van Hove singularities (VHSs) are a hallmark of reduced dimensionality, leading to a divergent density of states in one and two dimensions and predictions of new electronic properties when the Fermi energy is close to these divergences. In carbon nanotubes, VHSs mark the onset of new subbands. They are elusive in standard electronic transport characterization measurements because they do not typically appear as notable features and therefore their effect on the nanotube conductance is largely unexplored. Here we report conductance measurements of carbon nanotubes where VHSs are clearly revealed by interference patterns of the electronic wave functions, showing both a sharp increase of quantum capacitance, and a sharp reduction of energy level spacing, consistent with an upsurge of density of states. At VHSs, we also measure an anomalous increase of conductance below a temperature of about 30 K. We argue that this transport feature is consistent with the formation of Cooper pairs in the nanotube.
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Affiliation(s)
- Y Yang
- Department of Physics, Georgetown University , Washington, District of Columbia 20057, United States
| | - G Fedorov
- Department of Physics, Georgetown University , Washington, District of Columbia 20057, United States
| | - S E Shafranjuk
- Department of Physics and Astronomy, Northwestern University , Evanston, Illinois 60208, United States
| | - T M Klapwijk
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
- Laboratory for Quantum Limited Devices, Physics Department, Moscow State Pedagogical University , 29 Malaya Pirogovskaya Street, Moscow, 119992, Russia
| | - B K Cooper
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
| | - R M Lewis
- Department of Physics, CNAM, and JQI , University of Maryland , College Park, Maryland 20742, United States
| | - C J Lobb
- Department of Physics, CNAM, and JQI , University of Maryland , College Park, Maryland 20742, United States
| | - P Barbara
- Department of Physics, Georgetown University , Washington, District of Columbia 20057, United States
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8
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Ning W, Yu H, Liu Y, Han Y, Wang N, Yang J, Du H, Zhang C, Mao Z, Liu Y, Tian M, Zhang Y. Superconductor-insulator transition in quasi-one-dimensional single-crystal Nb₂PdS₅ nanowires. NANO LETTERS 2015; 15:869-75. [PMID: 25575045 DOI: 10.1021/nl503538s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Superconductor-insulator transition (SIT) in one-dimensional (1D) nanowires attracts great attention in the past decade and remains an open question since contrasting results were reported in nanowires with different morphologies (i.e., granular, polycrystalline, or amorphous) or environments. Nb2PdS5 is a recently discovered low-dimensional superconductor with typical quasi-1D chain structure. By decreasing the wire diameter in the range of 100-300 nm, we observed a clear SIT with a 1D transport character driven by both the cross-sectional area and external magnetic field. We also found that the upper critical magnetic field (Hc2) decreases with the reduction of nanowire cross-sectional area. The temperature dependence of the resistance below Tc can be described by the thermally activated phase slip (TAPS) theory without any signature of quantum phase slips (QPS). These findings demonstrated that the enhanced Coulomb interactions with the shrinkage of the wire diameter competes with the interchain Josephson-like coupling may play a crucial role on the SIT in quasi-1D system.
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Affiliation(s)
- Wei Ning
- High Magnetic Field Laboratory, Chinese Academy of Sciences , Hefei 230031 Anhui, People's Republic of China
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9
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Kim T, Chamberlin RV, Bird JP. Large magnetoresistance of nickel-silicide nanowires: non-equilibrium heating of magnetically-coupled dangling bonds. NANO LETTERS 2013; 13:1106-1110. [PMID: 23421719 DOI: 10.1021/nl3044585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We demonstrate large (>100%) time-dependent magnetoresistance in nickel-silicide nanowires and develop a thermodynamic model for this behavior. The model describes nonequilibrium heating of localized spins in an increasing magnetic field. We find a strong interaction between spins but no long-range magnetic order. The spins likely come from unpaired dangling bonds in the interfacial layers of the nanowires. The model indicates that although these bonds couple weakly to a thermal bath, they dominate the nanowire resistance.
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Affiliation(s)
- T Kim
- Department of Electrical Engineering, Arizona State University, Tempe, Arizona 85287-5706, United States
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10
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Magnetic field-induced dissipation-free state in superconducting nanostructures. Nat Commun 2013; 4:1437. [DOI: 10.1038/ncomms2437] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 01/02/2013] [Indexed: 11/08/2022] Open
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11
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Kim H, Jamali S, Rogachev A. Superconductor-insulator transition in long MoGe nanowires. PHYSICAL REVIEW LETTERS 2012; 109:027002. [PMID: 23030196 DOI: 10.1103/physrevlett.109.027002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Indexed: 06/01/2023]
Abstract
The properties of one-dimensional superconducting wires depend on physical processes with different characteristic lengths. To identify the process dominant in the critical regime we have studied the transport properties of very narrow (9-20 nm) MoGe wires fabricated by advanced electron-beam lithography in a wide range of lengths, 1-25 μm. We observed that the wires undergo a superconductor-insulator transition (SIT) that is controlled by cross sectional area of a wire and possibly also by the width-to-thickness ratio. The mean-field critical temperature decreases exponentially with the inverse of the wire cross section. We observed that a qualitatively similar superconductor-insulator transition can be induced by an external magnetic field. Our results are not consistent with any currently known theory of the SIT. Some long superconducting MoGe nanowires can be identified as localized superconductors; namely, in these wires the one-electron localization length is much smaller than the length of a wire.
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Affiliation(s)
- Hyunjeong Kim
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
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12
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Del Maestro A, Rosenow B, Hoyos JA, Vojta T. Dynamical conductivity at the dirty superconductor-metal quantum phase transition. PHYSICAL REVIEW LETTERS 2010; 105:145702. [PMID: 21230844 DOI: 10.1103/physrevlett.105.145702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Indexed: 05/30/2023]
Abstract
We study the transport properties of ultrathin disordered nanowires in the neighborhood of the superconductor-metal quantum phase transition. To this end we combine numerical calculations with analytical strong-disorder renormalization group results. The quantum critical conductivity at zero temperature diverges logarithmically as a function of frequency. In the metallic phase, it obeys activated scaling associated with an infinite-randomness quantum critical point. We extend the scaling theory to higher dimensions and discuss implications for experiments.
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Affiliation(s)
- Adrian Del Maestro
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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13
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Chen Y, Snyder SD, Goldman AM. Magnetic-field-induced superconducting state in Zn nanowires driven in the normal state by an electric current. PHYSICAL REVIEW LETTERS 2009; 103:127002. [PMID: 19792453 DOI: 10.1103/physrevlett.103.127002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Revised: 07/02/2009] [Indexed: 05/28/2023]
Abstract
Four-terminal resistance measurements have been carried out on Zn nanowires formed using electron-beam lithography. When driven resistive by current, these wires reenter the superconducting state upon application of small magnetic fields. The data are qualitatively different from those of previous experiments on superconducting nanowires, which revealed either negative magnetoresistance near T_{c} or high-magnetic-field-enhanced critical currents.
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Affiliation(s)
- Yu Chen
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
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14
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Bluhm H, Bert JA, Koshnick NC, Huber ME, Moler KA. Spinlike susceptibility of metallic and insulating thin films at low temperature. PHYSICAL REVIEW LETTERS 2009; 103:026805. [PMID: 19659233 DOI: 10.1103/physrevlett.103.026805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Indexed: 05/28/2023]
Abstract
Susceptibility measurements of patterned thin films at sub-K temperatures were carried out using a scanning SQUID microscope that can resolve signals corresponding to a few hundred Bohr magnetons. Several metallic and insulating thin films, even oxide-free Au films, show a paramagnetic response with a temperature dependence that indicates unpaired spins as the origin. The observed response exhibits a measurable out-of-phase component, which implies that these spins will create 1/f-like magnetic noise. The measured spin density is consistent with recent explanations of low frequency flux noise in SQUIDs and superconducting qubits in terms of spin fluctuations, and suggests that such unexpected spins may be even more ubiquitous than already indicated by earlier measurements. Our measurements set several constraints on the nature of these spins.
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Affiliation(s)
- Hendrik Bluhm
- Department of Physics, Stanford University, Stanford, California 94305, USA
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15
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Kim T, Chamberlin RV, Bennett PA, Bird JP. Dynamical characteristics of the giant magneto-resistance of epitaxial silicide nanowires. NANOTECHNOLOGY 2009; 20:135401. [PMID: 19420499 DOI: 10.1088/0957-4484/20/13/135401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We study the dynamical properties of a hugely hysteretic magneto-resistance in epitaxially formed silicide nanowires, and propose a model for this remarkable effect in which it is attributed to the collective interactions among interfacial spins associated with dangling bonds. According to our model, the dynamic character of this effect reflects a competitive tendency for the interfacial spins to align in different collective configurations (random, ordered, and multi-domain). Our work thus provides a dramatic demonstration of how the collective interactions among interfacial spins can modify the properties of nonmagnetic nanostructures.
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Affiliation(s)
- T Kim
- Department of Electrical Engineering, Arizona State University, Tempe, AZ 85287-5706, USA
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16
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Bollinger AT, Dinsmore RC, Rogachev A, Bezryadin A. Determination of the superconductor-insulator phase diagram for one-dimensional wires. PHYSICAL REVIEW LETTERS 2008; 101:227003. [PMID: 19113514 DOI: 10.1103/physrevlett.101.227003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 03/18/2008] [Indexed: 05/27/2023]
Abstract
We establish the superconductor-insulator phase diagram for quasi-one-dimensional wires by measuring a large set of MoGe nanowires. This diagram is roughly consistent with the Chakravarty-Schmid-Bulgadaev phase boundary, namely, with the critical resistance being equal to RQ=h/4e2. Deviations from this boundary for a small fraction of the samples prompt us to suggest an alternative phase diagram, which matches the data exactly. Transport properties of wires in the superconducting phase are dominated by phase slips, whereas insulating nanowires exhibit a weak Coulomb blockade behavior.
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Affiliation(s)
- A T Bollinger
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3080, USA
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17
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Kumar N, Tian ML, Wang JG, Watts W, Kindt J, Mallouk TE, Chan MHW. Investigation of superconductivity in electrochemically fabricated AuSn nanowires. NANOTECHNOLOGY 2008; 19:365704. [PMID: 21828885 DOI: 10.1088/0957-4484/19/36/365704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have fabricated intermetallic AuSn nanowires by electrochemical deposition in porous polycarbonate membranes. By controlling the deposition parameters, nanowires of a single intermetallic phase, namely AuSn, can be fabricated. AuSn nanowires are found to be crystalline and fairly resistant to oxidation. Electrical transport measurements on arrays of nanowires showed a superconducting transition temperature, T(c)∼1.5 K. In addition, four-probe measurements were made on individual freestanding nanowires with electrodes formed by a focused ion beam (FIB). Results from the two sets of measurements are found to be in close agreement.
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Affiliation(s)
- Nitesh Kumar
- Center for Nanoscale Science, Pennsylvania State University, University Park, PA 16802, USA. Department of Physics, Pennsylvania State University, University Park, PA 16802, USA
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18
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Del Maestro A, Rosenow B, Müller M, Sachdev S. Infinite randomness fixed point of the superconductor-metal quantum phase transition. PHYSICAL REVIEW LETTERS 2008; 101:035701. [PMID: 18764263 DOI: 10.1103/physrevlett.101.035701] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 04/20/2008] [Indexed: 05/26/2023]
Abstract
We examine the influence of quenched disorder on the superconductor-metal transition, as described by a theory of overdamped Cooper pairs which repel each other. The self-consistent pairing eigenmodes of a quasi-one-dimensional wire are determined numerically. Our results support the recent proposal by Hoyos et al. [Phys. Rev. Lett. 99, 230601 (2007)10.1103/PhysRevLett.99.230601] that the transition is characterized by the same strong-disorder fixed point describing the onset of ferromagnetism in the random quantum Ising chain in a transverse field.
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Affiliation(s)
- Adrian Del Maestro
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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19
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Sendelbach S, Hover D, Kittel A, Mück M, Martinis JM, McDermott R. Magnetism in SQUIDs at millikelvin temperatures. PHYSICAL REVIEW LETTERS 2008; 100:227006. [PMID: 18643451 DOI: 10.1103/physrevlett.100.227006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Indexed: 05/17/2023]
Abstract
We have characterized the temperature dependence of the flux threading dc SQUIDs cooled to millikelvin temperatures. The flux increases as 1/T as temperature is lowered; moreover, the flux change is proportional to the density of trapped vortices. The data are compatible with the thermal polarization of surface spins in the trapped fields of the vortices. In the absence of trapped flux, we observe evidence of spin-glass freezing at low temperature. These results suggest an explanation for the universal 1/f flux noise in SQUIDs and superconducting qubits.
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Affiliation(s)
- S Sendelbach
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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20
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Li JM. Extracting superconducting single-crystal Nb mesowires out of NbSe2 by a crystal-lattice collapse method. NANO LETTERS 2008; 8:1382-1385. [PMID: 18380485 DOI: 10.1021/nl0801273] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The author reports a conceptually new approach to superconducting niobium (Nb) mesowires in high yields from layered compounds (NbSe2) by solid-state pyrolysis. High-resolution transmission electron microscopy and selected-area electron diffraction demonstrate that the mesowires are single crystalline, grow along the [001] direction, and have specific facets. Unlike the previous electrodeposition routes within templates, a possible vapor-solid interaction mechanism was first proposed for component-selective epitaxial growth of one-dimensional Nb lattices where vapor-assisted collapse of NbSe2 crystal structure occurs through disposing of Se vapor phase matrix at enhanced temperatures.
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Affiliation(s)
- Jian-Min Li
- Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China.
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21
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Xu K, Heath JR. Controlled fabrication and electrical properties of long quasi-one-dimensional superconducting nanowire arrays. NANO LETTERS 2008; 8:136-141. [PMID: 18052403 DOI: 10.1021/nl072227z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report a general method for reliably fabricating quasi-one-dimensional superconducting nanowire arrays, with good control over nanowire cross section and length, and with full compatibility with device processing methods. We investigate Nb nanowires with individual nanowire cross sectional areas that range from bulklike to 10 x 11 nm, and with lengths from 1 to 100 microm. Nanowire size effects are systematically studied. In particular, a comprehensive investigation of influence of nanowire length on superconductivity is reported for the first time. All results are interpreted within the context of phase-slip models.
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Affiliation(s)
- Ke Xu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 127-72, Pasadena, California 91125, USA
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