1
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Yu S, Chen L, Pan Y, Wang Y, Zhang D, Wu G, Fan X, Liu X, Wu L, Zhang L, Peng W, Ren J, Wang Z. Gate-Tunable Critical Current of the Three-Dimensional Niobium Nanobridge Josephson Junction. NANO LETTERS 2023; 23:8043-8049. [PMID: 37592211 DOI: 10.1021/acs.nanolett.3c02015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Recent studies have shown that the critical currents of several metallic superconducting nanowires and Dayem bridges can be locally tuned by using a gate voltage (Vg). Here, we report a gate-tunable Josephson junction structure constructed from a three-dimensional (3D) niobium nanobridge junction (NBJ) with a voltage gate on top. Measurements up to 6 K showed that the critical current of this structure can be tuned to zero by increasing Vg. The critical gate voltage was reduced to 16 V and may possibly be reduced further by reducing the thickness of the insulation layer between the gate and the NBJ. Furthermore, the flux modulation generated by Josephson interference of two parallel 3D NBJs can also be tuned by using Vg in a similar manner. Therefore, we believe that this gate-tunable Josephson junction structure is promising for superconducting circuit fabrication at high integration levels.
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Affiliation(s)
- Shujie Yu
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Lei Chen
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yinping Pan
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - Yue Wang
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Denghui Zhang
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Guangting Wu
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xinxin Fan
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyu Liu
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - Ling Wu
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - Lu Zhang
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Peng
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Ren
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Wang
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology(SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
- School of Physical Science and Technology, Shanghai Tech University, Shanghai 200031, China
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2
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Elalaily T, Berke M, Kedves M, Fülöp G, Scherübl Z, Kanne T, Nygård J, Makk P, Csonka S. Signatures of Gate-Driven Out-of-Equilibrium Superconductivity in Ta/InAs Nanowires. ACS NANO 2023; 17:5528-5535. [PMID: 36912466 PMCID: PMC10062030 DOI: 10.1021/acsnano.2c10877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Understanding the microscopic origin of the gate-controlled supercurrent (GCS) in superconducting nanobridges is crucial for engineering superconducting switches suitable for a variety of electronic applications. The origin of GCS is controversial, and various mechanisms have been proposed to explain it. In this work, we have investigated the GCS in a Ta layer deposited on the surface of InAs nanowires. Comparison between switching current distributions at opposite gate polarities and between the gate dependence of two opposite side gates with different nanowire-gate spacings shows that the GCS is determined by the power dissipated by the gate leakage. We also found a substantial difference between the influence of the gate and elevated bath temperature on the magnetic field dependence of the supercurrent. Detailed analysis of the switching dynamics at high gate voltages shows that the device is driven into the multiple phase slips regime by high-energy fluctuations arising from the leakage current.
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Affiliation(s)
- Tosson Elalaily
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Müegyetem rkp. 3., H-1111 Budapest, Hungary
- MTA-BME
Superconducting Nanoelectronics Momentum Research Group, Müegyetem rkp. 3., H-1111 Budapest, Hungary
- Department
of Physics, Faculty of Science, Tanta University, Al-Geish St., 31527 Tanta, Gharbia, Egypt
| | - Martin Berke
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Müegyetem rkp. 3., H-1111 Budapest, Hungary
- MTA-BME
Superconducting Nanoelectronics Momentum Research Group, Müegyetem rkp. 3., H-1111 Budapest, Hungary
| | - Máté Kedves
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Müegyetem rkp. 3., H-1111 Budapest, Hungary
- MTA-BME
Correlated van der Waals Structures Momentum Research Group, Müegyetem rkp. 3., H-1111 Budapest, Hungary
| | - Gergő Fülöp
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Müegyetem rkp. 3., H-1111 Budapest, Hungary
- MTA-BME
Superconducting Nanoelectronics Momentum Research Group, Müegyetem rkp. 3., H-1111 Budapest, Hungary
| | - Zoltán Scherübl
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Müegyetem rkp. 3., H-1111 Budapest, Hungary
- MTA-BME
Superconducting Nanoelectronics Momentum Research Group, Müegyetem rkp. 3., H-1111 Budapest, Hungary
| | - Thomas Kanne
- Center
for Quantum Devices and Nano-Science Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen, Denmark
| | - Jesper Nygård
- Center
for Quantum Devices and Nano-Science Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen, Denmark
| | - Péter Makk
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Müegyetem rkp. 3., H-1111 Budapest, Hungary
- MTA-BME
Correlated van der Waals Structures Momentum Research Group, Müegyetem rkp. 3., H-1111 Budapest, Hungary
| | - Szabolcs Csonka
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Müegyetem rkp. 3., H-1111 Budapest, Hungary
- MTA-BME
Superconducting Nanoelectronics Momentum Research Group, Müegyetem rkp. 3., H-1111 Budapest, Hungary
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3
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Ritter MF, Crescini N, Haxell DZ, Hinderling M, Riel H, Bruder C, Fuhrer A, Nichele F. Out-of-equilibrium phonons in gated superconducting switches. NATURE ELECTRONICS 2022; 5:71-77. [PMID: 35310295 PMCID: PMC8885403 DOI: 10.1038/s41928-022-00721-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 01/19/2022] [Indexed: 06/13/2023]
Abstract
Recent experiments have suggested that superconductivity in metallic nanowires can be suppressed by the application of modest gate voltages. The source of this gate action has been debated and either attributed to an electric-field effect or to small leakage currents. Here we show that the suppression of superconductivity in titanium nitride nanowires on silicon substrates does not depend on the presence or absence of an electric field at the nanowire, but requires a current of high-energy electrons. The suppression is most efficient when electrons are injected into the nanowire, but similar results are obtained when electrons are passed between two remote electrodes. This is explained by the decay of high-energy electrons into phonons, which propagate through the substrate and affect superconductivity in the nanowire by generating quasiparticles. By studying the switching probability distribution of the nanowire, we also show that high-energy electron emission leads to a much broader phonon energy distribution compared with the case where superconductivity is suppressed by Joule heating near the nanowire.
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Affiliation(s)
- M. F. Ritter
- IBM Quantum, IBM Research—Zurich, Rüschlikon, Switzerland
| | - N. Crescini
- IBM Quantum, IBM Research—Zurich, Rüschlikon, Switzerland
| | - D. Z. Haxell
- IBM Quantum, IBM Research—Zurich, Rüschlikon, Switzerland
| | - M. Hinderling
- IBM Quantum, IBM Research—Zurich, Rüschlikon, Switzerland
| | - H. Riel
- IBM Quantum, IBM Research—Zurich, Rüschlikon, Switzerland
| | - C. Bruder
- Department of Physics, University of Basel, Basel, Switzerland
| | - A. Fuhrer
- IBM Quantum, IBM Research—Zurich, Rüschlikon, Switzerland
| | - F. Nichele
- IBM Quantum, IBM Research—Zurich, Rüschlikon, Switzerland
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4
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Paolucci F, Crisá F, De Simoni G, Bours L, Puglia C, Strambini E, Roddaro S, Giazotto F. Electrostatic Field-Driven Supercurrent Suppression in Ionic-Gated Metallic Superconducting Nanotransistors. NANO LETTERS 2021; 21:10309-10314. [PMID: 34851117 DOI: 10.1021/acs.nanolett.1c03481] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent experiments have shown the possibility of tuning the transport properties of metallic nanosized superconductors through a gate voltage. These results renewed the longstanding debate on the interaction between electrostatic fields and superconductivity. Indeed, different works suggested competing mechanisms as the cause of the effect: an unconventional electric field-effect or quasiparticle injection. Here, we provide conclusive evidence for the electrostatic-field-driven control of the supercurrent in metallic nanosized superconductors, by realizing ionic-gated superconducting field-effect nanotransistors (ISFETs) where electron injection is impossible. Our Nb ISFETs show giant suppression of the superconducting critical current of up to ∼45%. Moreover, the bipolar supercurrent suppression observed in different ISFETs, together with invariant critical temperature and normal-state resistance, also excludes conventional charge accumulation/depletion. Therefore, the microscopic explanation of this effect calls upon a novel theory able to describe the nontrivial interaction of static electric fields with conventional superconductivity.
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Affiliation(s)
- Federico Paolucci
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Francesco Crisá
- Department of Physics "E. Fermi", Universitá di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
| | - Giorgio De Simoni
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Lennart Bours
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Claudio Puglia
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Elia Strambini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Stefano Roddaro
- Department of Physics "E. Fermi", Universitá di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
| | - Francesco Giazotto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, I-56127 Pisa, Italy
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5
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Elalaily T, Kürtössy O, Scherübl Z, Berke M, Fülöp G, Lukács IE, Kanne T, Nygård J, Watanabe K, Taniguchi T, Makk P, Csonka S. Gate-Controlled Supercurrent in Epitaxial Al/InAs Nanowires. NANO LETTERS 2021; 21:9684-9690. [PMID: 34726405 PMCID: PMC8631737 DOI: 10.1021/acs.nanolett.1c03493] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Gate-controlled supercurrent (GCS) in superconducting nanobridges has recently attracted attention as a means to create superconducting switches. Despite the clear advantages for applications, the microscopic mechanism of this effect is still under debate. In this work, we realize GCS for the first time in a highly crystalline superconductor epitaxially grown on an InAs nanowire. We show that the supercurrent in the epitaxial Al layer can be switched to the normal state by applying ≃±23 V on a bottom gate insulated from the nanowire by a crystalline hBN layer. Our extensive study of the temperature and magnetic field dependencies suggests that the electric field is unlikely to be the origin of GCS in our device. Though hot electron injection alone cannot explain our experimental findings, a very recent non-equilibrium phonons based picture is compatible with most of our results.
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Affiliation(s)
- Tosson Elalaily
- Department
of Physics and Nanoelectronics “Momentum” Research Group
of the Hungarian Academy of Sciences, Budapest
University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
- Department
of Physics, Faculty of Science, Tanta University, Al-Geish Street, 31527 Tanta, Gharbia, Egypt
| | - Olivér Kürtössy
- Department
of Physics and Nanoelectronics “Momentum” Research Group
of the Hungarian Academy of Sciences, Budapest
University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
| | - Zoltán Scherübl
- Department
of Physics and Nanoelectronics “Momentum” Research Group
of the Hungarian Academy of Sciences, Budapest
University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
- Université
Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, 38000 Grenoble, France
| | - Martin Berke
- Department
of Physics and Nanoelectronics “Momentum” Research Group
of the Hungarian Academy of Sciences, Budapest
University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
| | - Gergö Fülöp
- Department
of Physics and Nanoelectronics “Momentum” Research Group
of the Hungarian Academy of Sciences, Budapest
University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
| | - István Endre Lukács
- Center
for Energy Research, Institute of Technical
Physics and Material Science, Konkoly-Thege Miklós út 29-33., H-1121 Budapest, Hungary
| | - Thomas Kanne
- Center for
Quantum Devices and Nano-Science Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Jesper Nygård
- Center for
Quantum Devices and Nano-Science Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Péter Makk
- Department
of Physics and Nanoelectronics “Momentum” Research Group
of the Hungarian Academy of Sciences, Budapest
University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
| | - Szabolcs Csonka
- Department
of Physics and Nanoelectronics “Momentum” Research Group
of the Hungarian Academy of Sciences, Budapest
University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
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6
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De Simoni G, Battisti S, Ligato N, Mercaldo MT, Cuoco M, Giazotto F. Gate Control of the Current-Flux Relation of a Josephson Quantum Interferometer Based on Proximitized Metallic Nanojuntions. ACS APPLIED ELECTRONIC MATERIALS 2021; 3:3927-3935. [PMID: 36247495 PMCID: PMC9555709 DOI: 10.1021/acsaelm.1c00508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We demonstrate an Al superconducting quantum interference device in which the Josephson junctions are implemented through gate-controlled proximity Cu mesoscopic weak links. This specific kind of metallic weak links behaves analogously to genuine superconducting metals in terms of the response to electrostatic gating and provides a good performance in terms of current-modulation visibility. We show that through the application of a static gate voltage we can modify the interferometer current-flux relation in a fashion that seems compatible with the introduction of π-channels within the gated weak link. Our results suggest that the microscopic mechanism at the origin of the suppression of the switching current in the interferometer is apparently phase coherent, resulting in an overall damping of the superconducting phase rigidity. We finally tackle the performance of the interferometer in terms of responsivity to magnetic flux variations in the dissipative regime and discuss the practical relevance of gated proximity-based all-metallic SQUIDs for magnetometry at the nanoscale.
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Affiliation(s)
- Giorgio De Simoni
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - Sebastiano Battisti
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
- Department
of Physics “E. Fermi”, Universitá
di Pisa, Largo Pontecorvo
3, I-56127 Pisa, Italy
| | - Nadia Ligato
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - Maria Teresa Mercaldo
- Dipartimento
di Fisica “E. R. Caianiello”, Universitá di Salerno, Fisciano, Salerno IT-84084, Italy
| | | | - Francesco Giazotto
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
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7
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Golokolenov I, Guthrie A, Kafanov S, Pashkin YA, Tsepelin V. On the origin of the controversial electrostatic field effect in superconductors. Nat Commun 2021; 12:2747. [PMID: 33980842 PMCID: PMC8115342 DOI: 10.1038/s41467-021-22998-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 03/30/2021] [Indexed: 11/09/2022] Open
Abstract
Superconducting quantum devices offer numerous applications, from electrical metrology and magnetic sensing to energy-efficient high-end computing and advanced quantum information processing. The key elements of quantum circuits are (single and double) Josephson junctions controllable either by electric current or magnetic field. The voltage control, commonly used in semiconductor-based devices via the electrostatic field effect, would be far more versatile and practical. Hence, the field effect recently reported in superconducting devices may revolutionise the whole field of superconductor electronics provided it is confirmed. Here we show that the suppression of the critical current attributed to the field effect, can be explained by quasiparticle excitations in the constriction of superconducting devices. Our results demonstrate that a miniscule leakage current between the gate and the constriction of devices perfectly follows the Fowler-Nordheim model of electron field emission from a metal electrode and injects quasiparticles with energies sufficient to weaken or even suppress superconductivity. A recent report on electrostatic field effect in superconducting devices provides a high potential for advanced quantum technology, but it remains controversial. Here, the authors report that the suppression of critical current, which was attributed to the field effect, can instead be explained by quasiparticle excitations in the constriction of superconducting devices.
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Affiliation(s)
- I Golokolenov
- Department of Physics, Lancaster University, Lancaster, UK.,P. L. Kapitza Institute for Physical Problems of RAS, Moscow, Russia.,National Research University Higher School of Economics, Moscow, Russia
| | - A Guthrie
- Department of Physics, Lancaster University, Lancaster, UK
| | - S Kafanov
- Department of Physics, Lancaster University, Lancaster, UK.
| | - Yu A Pashkin
- Department of Physics, Lancaster University, Lancaster, UK.
| | - V Tsepelin
- Department of Physics, Lancaster University, Lancaster, UK
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8
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Solinas P, Amoretti A, Giazotto F. Sauter-Schwinger Effect in a Bardeen-Cooper-Schrieffer Superconductor. PHYSICAL REVIEW LETTERS 2021; 126:117001. [PMID: 33798345 DOI: 10.1103/physrevlett.126.117001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/01/2020] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
Since the 1960s a deep and surprising connection has followed the development of superconductivity and quantum field theory. The Anderson-Higgs mechanism and the similarities between the Dirac and Bogoliubov-de Gennes equations are the most intriguing examples. In this last analogy, the massive Dirac particle is identified with a quasiparticle excitation and the fermion mass energy with the superconducting gap energy. Here we follow further this parallelism and show that it predicts an outstanding phenomenon: the superconducting Sauter-Schwinger effect. As in the quantum electrodynamics Schwinger effect, where an electron-positron couple is created from the vacuum by an intense electric field, we show that an electrostatic field can generate two coherent excitations from the superconducting ground-state condensate. Differently from the dissipative thermal excitation, these form a new macroscopically coherent and dissipationless state. We discuss how the superconducting state is weakened by the creation of this kind of excitations. In addition to shedding a different light and suggesting a method for the experimental verification of the Sauter-Schwinger effect, our results pave the way to the understanding and exploitation of the interaction between superconductors and electric fields.
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Affiliation(s)
- P Solinas
- Dipartimento di Fisica, Università di Genova, via Dodecaneso 33, I-16146 Genova, Italy
- INFN-Sezione di Genova, via Dodecaneso 33, I-16146 Genova, Italy
| | - A Amoretti
- Dipartimento di Fisica, Università di Genova, via Dodecaneso 33, I-16146 Genova, Italy
- INFN-Sezione di Genova, via Dodecaneso 33, I-16146 Genova, Italy
| | - F Giazotto
- NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
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9
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Puglia C, De Simoni G, Giazotto F. Gate Control of Superconductivity in Mesoscopic All-Metallic Devices. MATERIALS (BASEL, SWITZERLAND) 2021; 14:1243. [PMID: 33807981 PMCID: PMC7961734 DOI: 10.3390/ma14051243] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/24/2021] [Accepted: 02/28/2021] [Indexed: 11/16/2022]
Abstract
The possibility to tune, through the application of a control gate voltage, the superconducting properties of mesoscopic devices based on Bardeen-Cooper-Schrieffer metals was recently demonstrated. Despite the extensive experimental evidence obtained on different materials and geometries, a description of the microscopic mechanism at the basis of such an unconventional effect has not been provided yet. This work discusses the technological potential of gate control of superconductivity in metallic superconductors and revises the experimental results, which provide information regarding a possible thermal origin of the effect: first, we review experiments performed on high-critical-temperature elemental superconductors (niobium and vanadium) and show how devices based on these materials can be exploited to realize basic electronic tools, such as a half-wave rectifier. Second, we discuss the origin of the gating effect by showing gate-driven suppression of the supercurrent in a suspended titanium wire and by providing a comparison between thermal and electric switching current probability distributions. Furthermore, we discuss the cold field-emission of electrons from the gate employing finite element simulations and compare the results with experimental data. In our view, the presented data provide a strong indication regarding the unlikelihood of the thermal origin of the gating effect.
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Affiliation(s)
- Claudio Puglia
- Department of Physics, University of Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
- NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy; (G.D.S.); (F.G.)
| | - Giorgio De Simoni
- NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy; (G.D.S.); (F.G.)
| | - Francesco Giazotto
- NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy; (G.D.S.); (F.G.)
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10
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Rocci M, Suri D, Kamra A, Takamura Y, Nemes NM, Martinez JL, Hernandez MG, Moodera JS. Large Enhancement of Critical Current in Superconducting Devices by Gate Voltage. NANO LETTERS 2021; 21:216-221. [PMID: 33275436 DOI: 10.1021/acs.nanolett.0c03547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Significant control over the properties of a high-carrier density superconductor via an applied electric field has been considered infeasible due to screening of the field over atomic length scales. Here, we demonstrate an enhancement of up to 30% in critical current in a back-gate tunable NbN micro- and nano superconducting bridges. Our suggested plausible mechanism of this enhancement in critical current based on surface nucleation and pinning of Abrikosov vortices is consistent with expectations and observations for type-II superconductor films with thicknesses comparable to their coherence length. Furthermore, we demonstrate an applied electric field-dependent infinite electroresistance and hysteretic resistance. Our work presents an electric field driven enhancement in the superconducting property in type-II superconductors which is a crucial step toward the understanding of field-effects on the fundamental properties of a superconductor and its exploitation for logic and memory applications in a superconductor-based low-dissipation digital computing paradigm.
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Affiliation(s)
- Mirko Rocci
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - Dhavala Suri
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Akashdeep Kamra
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Yota Takamura
- School of Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Norbert M Nemes
- GFMC, Departamento de Física de Materiales, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Jose L Martinez
- Instituto de Ciencia de Materiales de Madrid, C.S.I.C., Cantoblanco, E-28049 Madrid, Spain
| | - Mar Garcia Hernandez
- Instituto de Ciencia de Materiales de Madrid, C.S.I.C., Cantoblanco, E-28049 Madrid, Spain
| | - Jagadeesh S Moodera
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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11
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Rocci M, De Simoni G, Puglia C, Esposti DD, Strambini E, Zannier V, Sorba L, Giazotto F. Gate-Controlled Suspended Titanium Nanobridge Supercurrent Transistor. ACS NANO 2020; 14:12621-12628. [PMID: 32822153 DOI: 10.1021/acsnano.0c05355] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Under standard conditions, the electrostatic field-effect is negligible in conventional metals and was expected to be completely ineffective also in superconducting metals. This common belief was recently put under question by a family of experiments that displayed full gate-voltage-induced suppression of critical current in superconducting all-metallic gated nanotransistors. To date, the microscopic origin of this phenomenon is under debate, and trivial explanations based on heating effects given by the negligible electron leakage from the gates should be excluded. Here, we demonstrate the control of the supercurrent in fully suspended superconducting nanobridges. Our advanced nanofabrication methods allow us to build suspended superconducting Ti-based supercurrent transistors which show ambipolar and monotonic full suppression of the critical current for gate voltages of VGC ≃ 18 V and for temperatures up to ∼80% of the critical temperature. The suspended device architecture minimizes the electron-phonon interaction between the superconducting nanobridge and the substrate, and therefore, it rules out any possible contribution stemming from charge injection into the insulating substrate. Besides, our finite element method simulations of vacuum electron tunneling from the gate to the bridge and thermal considerations rule out the cold-electron field emission as a possible driving mechanism for the observed phenomenology. Our findings promise a better understanding of the field effect in superconducting metals.
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Affiliation(s)
- Mirko Rocci
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - Giorgio De Simoni
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - Claudio Puglia
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
- Department of Physics "E. Fermi", Università di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
| | - Davide Degli Esposti
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
- Department of Physics "E. Fermi", Università di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
| | - Elia Strambini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - Valentina Zannier
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - Lucia Sorba
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
| | - Francesco Giazotto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
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Paolucci F, Vischi F, De Simoni G, Guarcello C, Solinas P, Giazotto F. Field-Effect Controllable Metallic Josephson Interferometer. NANO LETTERS 2019; 19:6263-6269. [PMID: 31461290 DOI: 10.1021/acs.nanolett.9b02369] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Gate-tunable Josephson junctions (JJs) are the backbone of superconducting classical and quantum computation. Typically, these systems exploit low-charge-concentration materials and present technological difficulties limiting their scalability. Surprisingly, electric field modulation of a supercurrent in metallic wires and JJs has been recently demonstrated. Here, we report the realization of titanium-based monolithic interferometers which allow tuning both JJs independently via voltage bias applied to capacitively coupled electrodes. Our experiments demonstrate full control of the amplitude of the switching current (Is) and of the superconducting phase across the single JJ in a wide range of temperatures. Astoundingly, by gate-biasing a single junction, the maximum achievable total Is is suppressed down to values much lower than the critical current of a single JJ. A theoretical model including gate-induced phase fluctuations on a single junction accounts for our experimental findings. This class of quantum interferometers could represent a breakthrough for several applications such as digital electronics, quantum computing, sensitive magnetometry, and single-photon detection.
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Affiliation(s)
- Federico Paolucci
- INFN Sezione di Pisa , Largo Bruno Pontecorvo 3 , I-56127 Pisa , Italy
- NEST , Instituto Nanoscienze-CNR and Scuola Normale Superiore , I-56127 Pisa , Italy
| | - Francesco Vischi
- NEST , Instituto Nanoscienze-CNR and Scuola Normale Superiore , I-56127 Pisa , Italy
- Dipartimento di Fisica , Università di Pisa , Largo Pontecorvo 3 , I-56127 Pisa , Italy
| | - Giorgio De Simoni
- NEST , Instituto Nanoscienze-CNR and Scuola Normale Superiore , I-56127 Pisa , Italy
| | - Claudio Guarcello
- NEST , Instituto Nanoscienze-CNR and Scuola Normale Superiore , I-56127 Pisa , Italy
| | - Paolo Solinas
- SPIN-CNR , Via Dodecaneso 33 , I-16146 Genova , Italy
| | - Francesco Giazotto
- NEST , Instituto Nanoscienze-CNR and Scuola Normale Superiore , I-56127 Pisa , Italy
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