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Pankratov AL, Gordeeva AV, Revin LS, Ladeynov DA, Yablokov AA, Kuzmin LS. Approaching microwave photon sensitivity with Al Josephson junctions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:582-589. [PMID: 35874437 PMCID: PMC9273979 DOI: 10.3762/bjnano.13.50] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Here, we experimentally test the applicability of an aluminium Josephson junction of a few micrometers size as a single photon counter in the microwave frequency range. We have measured the switching from the superconducting to the resistive state through the absorption of 10 GHz photons. The dependence of the switching probability on the signal power suggests that the switching is initiated by the simultaneous absorption of three and more photons, with a dark count time above 0.01 s.
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Affiliation(s)
- Andrey L Pankratov
- Nizhny Novgorod State Technical University n.a. R.E. Alekseev, GSP-41, Nizhny Novgorod, 603950, Russia
- Institute for Physics of Microstructures of RAS, GSP-105, Nizhny Novgorod, 603950, Russia
- Lobachevsky State University of Nizhny Novgorod, 603950, Nizhny Novgorod, Russia
| | - Anna V Gordeeva
- Nizhny Novgorod State Technical University n.a. R.E. Alekseev, GSP-41, Nizhny Novgorod, 603950, Russia
- Institute for Physics of Microstructures of RAS, GSP-105, Nizhny Novgorod, 603950, Russia
| | - Leonid S Revin
- Nizhny Novgorod State Technical University n.a. R.E. Alekseev, GSP-41, Nizhny Novgorod, 603950, Russia
- Institute for Physics of Microstructures of RAS, GSP-105, Nizhny Novgorod, 603950, Russia
| | - Dmitry A Ladeynov
- Nizhny Novgorod State Technical University n.a. R.E. Alekseev, GSP-41, Nizhny Novgorod, 603950, Russia
- Institute for Physics of Microstructures of RAS, GSP-105, Nizhny Novgorod, 603950, Russia
- Lobachevsky State University of Nizhny Novgorod, 603950, Nizhny Novgorod, Russia
| | - Anton A Yablokov
- Nizhny Novgorod State Technical University n.a. R.E. Alekseev, GSP-41, Nizhny Novgorod, 603950, Russia
- Institute for Physics of Microstructures of RAS, GSP-105, Nizhny Novgorod, 603950, Russia
| | - Leonid S Kuzmin
- Nizhny Novgorod State Technical University n.a. R.E. Alekseev, GSP-41, Nizhny Novgorod, 603950, Russia
- Chalmers University of Technology, 41296, Gothenburg, Sweden
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2
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Petkovic I, Lollo A, Harris JGE. Phase-Slip Statistics of a Single Isolated Flux-Biased Superconducting Ring. PHYSICAL REVIEW LETTERS 2020; 125:067002. [PMID: 32845664 DOI: 10.1103/physrevlett.125.067002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
We describe measurements of the thermally activated transitions between fluxoid states of a single isolated superconducting ring. We compare these measurements with theoretical predictions in which all of the relevant parameters are determined via independent characterization of the same ring. This no-free-parameters comparison shows qualitative agreement over a wide range of temperatures. We discuss possible origins for the remaining discrepancies between the data and theory, in particular the choice of model for the superconducting order parameter's damping.
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Affiliation(s)
- I Petkovic
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06520, USA
| | - A Lollo
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06520, USA
| | - J G E Harris
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06520, USA
- Department of Applied Physics, Yale University, 15 Prospect Street, New Haven, Connecticut 06520, USA
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3
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Revin LS, Pankratov AL, Gordeeva AV, Yablokov AA, Rakut IV, Zbrozhek VO, Kuzmin LS. Microwave photon detection by an Al Josephson junction. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:960-965. [PMID: 32647595 PMCID: PMC7323616 DOI: 10.3762/bjnano.11.80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 06/10/2020] [Indexed: 05/14/2023]
Abstract
An aluminium Josephson junction (JJ), with a critical current suppressed by a factor of three compared with the maximal value calculated from the gap, is experimentally investigated for application as a threshold detector for microwave photons. We present the preliminary results of measurements of the lifetime of the superconducting state and the probability of switching by a 9 GHz external signal. We found an anomalously large lifetime, not described by the Kramers' theory for the escape time over a barrier under the influence of fluctuations. We explain it by the phase diffusion regime, which is evident from the temperature dependence of the switching current histograms. Therefore, phase diffusion allows for a significant improvement of the noise immunity of a device, radically decreasing the dark count rate, but it will also decrease the single-photon sensitivity of the considered threshold detector. Quantization of the switching probability tilt as a function of the signal attenuation for various bias currents through the JJ is observed, which resembles the differentiation between N and N + 1 photon absorption.
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Affiliation(s)
- Leonid S Revin
- Institute for Physics of Microstructures of RAS, GSP-105, Nizhny Novgorod, 603950, Russia
- Center of Cryogenic Nanoelectronics, Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia
| | - Andrey L Pankratov
- Institute for Physics of Microstructures of RAS, GSP-105, Nizhny Novgorod, 603950, Russia
- Center of Cryogenic Nanoelectronics, Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia
- Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Anna V Gordeeva
- Center of Cryogenic Nanoelectronics, Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia
| | - Anton A Yablokov
- Institute for Physics of Microstructures of RAS, GSP-105, Nizhny Novgorod, 603950, Russia
- Center of Cryogenic Nanoelectronics, Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia
| | - Igor V Rakut
- Center of Cryogenic Nanoelectronics, Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia
- Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Victor O Zbrozhek
- Center of Cryogenic Nanoelectronics, Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia
| | - Leonid S Kuzmin
- Center of Cryogenic Nanoelectronics, Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia
- Chalmers University of Technology, SE-41296 Gothenburg, Sweden
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4
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Ridderbos J, Brauns M, Shen J, de Vries FK, Li A, Bakkers EPAM, Brinkman A, Zwanenburg FA. Josephson Effect in a Few-Hole Quantum Dot. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802257. [PMID: 30260519 DOI: 10.1002/adma.201802257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/11/2018] [Indexed: 06/08/2023]
Abstract
A Ge-Si core-shell nanowire is used to realize a Josephson field-effect transistor with highly transparent contacts to superconducting leads. By changing the electric field, access to two distinct regimes, not combined before in a single device, is gained: in the accumulation mode the device is highly transparent and the supercurrent is carried by multiple subbands, while near depletion, the supercurrent is carried by single-particle levels of a strongly coupled quantum dot operating in the few-hole regime. These results establish Ge-Si nanowires as an important platform for hybrid superconductor-semiconductor physics and Majorana fermions.
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Affiliation(s)
- Joost Ridderbos
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Matthias Brauns
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Jie Shen
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA, Delft, The Netherlands
| | - Folkert K de Vries
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA, Delft, The Netherlands
| | - Ang Li
- Department of Applied Physics, Eindhoven University of Technology, Postbox 513, 5600 MB, Eindhoven, The Netherlands
| | - Erik P A M Bakkers
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA, Delft, The Netherlands
- Department of Applied Physics, Eindhoven University of Technology, Postbox 513, 5600 MB, Eindhoven, The Netherlands
| | - Alexander Brinkman
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Floris A Zwanenburg
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
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Gill ST, Damasco J, Janicek BE, Durkin MS, Humbert V, Gazibegovic S, Car D, Bakkers EPAM, Huang PY, Mason N. Selective-Area Superconductor Epitaxy to Ballistic Semiconductor Nanowires. NANO LETTERS 2018; 18:6121-6128. [PMID: 30200769 DOI: 10.1021/acs.nanolett.8b01534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Semiconductor nanowires such as InAs and InSb are promising materials for studying Majorana zero modes and demonstrating non-Abelian particle exchange relevant for topological quantum computing. While evidence for Majorana bound states in nanowires has been shown, the majority of these experiments are marked by significant disorder. In particular, the interfacial inhomogeneity between the superconductor and nanowire is strongly believed to be the main culprit for disorder and the resulting "soft superconducting gap" ubiquitous in tunneling studies of hybrid semiconductor-superconductor systems. Additionally, a lack of ballistic transport in nanowire systems can create bound states that mimic Majorana signatures. We resolve these problems through the development of selective-area epitaxy of Al to InSb nanowires, a technique applicable to other nanowires and superconductors. Epitaxial InSb-Al devices generically possess a hard superconducting gap and demonstrate ballistic 1D superconductivity and near-perfect transmission of supercurrents in the single mode regime, requisites for engineering and controlling 1D topological superconductivity. Additionally, we demonstrate that epitaxial InSb-Al superconducting island devices, the building blocks for Majorana-based quantum computing applications, prepared using selective-area epitaxy can achieve micron-scale ballistic 1D transport. Our results pave the way for the development of networks of ballistic superconducting electronics for quantum device applications.
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Affiliation(s)
| | | | | | | | | | - Sasa Gazibegovic
- QuTech and Kavli Institute of NanoScience , Delft University of Technology , 2600 GA Delft , The Netherlands
- Department of Applied Physics , Eindhoven University of Technology , 5600 MB Eindhoven , The Netherlands
| | - Diana Car
- QuTech and Kavli Institute of NanoScience , Delft University of Technology , 2600 GA Delft , The Netherlands
- Department of Applied Physics , Eindhoven University of Technology , 5600 MB Eindhoven , The Netherlands
| | - Erik P A M Bakkers
- QuTech and Kavli Institute of NanoScience , Delft University of Technology , 2600 GA Delft , The Netherlands
- Department of Applied Physics , Eindhoven University of Technology , 5600 MB Eindhoven , The Netherlands
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6
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Borzenets IV, Coskun UC, Mebrahtu HT, Bomze YV, Smirnov AI, Finkelstein G. Phonon bottleneck in graphene-based Josephson junctions at millikelvin temperatures. PHYSICAL REVIEW LETTERS 2013; 111:027001. [PMID: 23889431 DOI: 10.1103/physrevlett.111.027001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/21/2013] [Indexed: 06/02/2023]
Abstract
We examine the nature of the transitions between the normal and superconducting branches in superconductor-graphene-superconductor Josephson junctions. We attribute the hysteresis between the switching (superconducting to normal) and retrapping (normal to superconducting) transitions to electron overheating. In particular, we demonstrate that the retrapping current corresponds to the critical current at an elevated temperature, where the heating is caused by the retrapping current itself. The superconducting gap in the leads suppresses the hot electron outflow, allowing us to further study electron thermalization by phonons at low temperatures (T≲1 K). The relationship between the applied power and the electron temperature was found to be P∝T3, which we argue is consistent with cooling due to electron-phonon interactions.
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Affiliation(s)
- I V Borzenets
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
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7
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Longobardi L, Massarotti D, Stornaiuolo D, Galletti L, Rotoli G, Lombardi F, Tafuri F. Direct transition from quantum escape to a phase diffusion regime in YBaCuO biepitaxial Josephson junctions. PHYSICAL REVIEW LETTERS 2012; 109:050601. [PMID: 23006159 DOI: 10.1103/physrevlett.109.050601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Indexed: 05/27/2023]
Abstract
Dissipation encodes the interaction of a quantum system with the environment and regulates the activation regimes of a Brownian particle. We have engineered grain boundary biepitaxial YBaCuO junctions to drive a direct transition from a quantum activated running state to a phase diffusion regime. The crossover to the quantum regime is tuned by the magnetic field and dissipation is described by a fully consistent set of junction parameters. To unravel phase dynamics in moderately damped systems is of general interest for advances in the comprehension of retrapping phenomena and in view of quantum hybrid technology.
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Affiliation(s)
- Luigi Longobardi
- Seconda Universitá degli Studi di Napoli, Dipartimento di Ingegneria dell'Informazione, Aversa, Italy.
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8
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Bomze Y, Hey R, Grahn HT, Teitsworth SW. Noise-induced current switching in semiconductor superlattices: observation of nonexponential kinetics in a high-dimensional system. PHYSICAL REVIEW LETTERS 2012; 109:026801. [PMID: 23030192 DOI: 10.1103/physrevlett.109.026801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Indexed: 06/01/2023]
Abstract
We report on measurements of first-passage-time distributions associated with current switching in weakly coupled GaAs/AlAs superlattices driven by shot noise, a system that is both far from equilibrium and high dimensional. Static current-voltage (I-V) characteristics exhibit multiple current branches and bistability; precision, high-bandwidth current switching data are collected in response to steps in the applied voltage to final voltages V1 near the end of a current branch. For a range of V1 values, the measured switching times vary stochastically. At short times (≲10 μs), the switching time distributions decay exponentially, while at longer times the distributions develop nonexponential tails that follow an approximate power law over several decades. The power law decay behavior is attributed to the presence of multiple switching pathways, which may arise from small spatial variations in the superlattice growth parameters.
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Affiliation(s)
- Yu Bomze
- Department of Physics, Duke University, Box 90305, Durham, North Carolina 27708-0305, USA
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9
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Yu HF, Zhu XB, Peng ZH, Tian Y, Cui DJ, Chen GH, Zheng DN, Jing XN, Lu L, Zhao SP, Han S. Quantum phase diffusion in a small underdamped Josephson junction. PHYSICAL REVIEW LETTERS 2011; 107:067004. [PMID: 21902362 DOI: 10.1103/physrevlett.107.067004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Indexed: 05/27/2023]
Abstract
Quantum phase diffusion in a small underdamped Nb/AlO(x)/Nb junction (∼0.4 μm(2)) is demonstrated in a wide temperature range of 25-140 mK where macroscopic quantum tunneling (MQT) is the dominant escape mechanism. We propose a two-step transition model to describe the switching process in which the escape rate out of the potential well and the transition rate from phase diffusion to the running state are considered. The transition rate extracted from the experimental switching current distribution follows the predicted Arrhenius law in the thermal regime but is greatly enhanced when MQT becomes dominant.
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Affiliation(s)
- H F Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, China
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10
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De Franceschi S, Kouwenhoven L, Schönenberger C, Wernsdorfer W. Hybrid superconductor-quantum dot devices. NATURE NANOTECHNOLOGY 2010; 5:703-711. [PMID: 20852639 DOI: 10.1038/nnano.2010.173] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Advances in nanofabrication techniques have made it possible to make devices in which superconducting electrodes are connected to non-superconducting nanostructures such as quantum dots. The properties of these hybrid devices result from a combination of a macroscopic quantum phenomenon involving large numbers of electrons (superconductivity) and the ability to control single electrons, offered by quantum dots. Here we review research into electron transport and other fundamental processes that have been studied in these devices. We also describe potential applications, such as a transistor in which the direction of a supercurrent can be reversed by adding just one electron to a quantum dot.
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Affiliation(s)
- Silvano De Franceschi
- SPSMS/LaTEQS, CEA-INAC/UJF-Grenoble 1, 17 Rue des Martyrs, 38054 Grenoble Cedex 9, France.
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11
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Pan C, Tan X, Yu Y, Sun G, Kang L, Xu W, Chen J, Wu P. Resonant activation through effective temperature oscillation in a Josephson tunnel junction. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:030104. [PMID: 19391880 DOI: 10.1103/physreve.79.030104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Indexed: 05/27/2023]
Abstract
We experimentally investigated the thermal escape from a metastable state in a Josephson tunnel junction subjected to an oscillating effective temperature. A minimum of the average escape time is observed at certain oscillation frequency. Our results confirm that the resonant activation can be caused not only by the oscillating barrier but also by the oscillating temperature. The linear dependence of the minimum average escape time on the resonant frequency suggests that the correlation between the oscillation and the escape process leads to the resonant escape.
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Affiliation(s)
- Cheng Pan
- Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
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12
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Cleuziou JP, Wernsdorfer W, Andergassen S, Florens S, Bouchiat V, Ondarçuhu T, Monthioux M. Gate-tuned high frequency response of carbon nanotube Josephson junctions. PHYSICAL REVIEW LETTERS 2007; 99:117001. [PMID: 17930461 DOI: 10.1103/physrevlett.99.117001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Indexed: 05/25/2023]
Abstract
Carbon nanotube Josephson junctions in the open quantum dot limit are fabricated using Pd/Al bilayer electrodes, and exhibit gate-controlled superconducting switching currents. Shapiro voltage steps can be observed under radio frequency current excitations, with a damping of the phase dynamics that strongly depends on the gate voltage. These measurements are described by a standard resistively and capacitively shunted junction model showing that the switching currents from the superconducting to the normal state are close to the critical current of the junction. The effective dynamical capacitance of the nanotube junction is found to be strongly gate dependent, suggesting a diffusive contact of the nanotube.
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Affiliation(s)
- J-P Cleuziou
- Université de Toulouse, CEMES-CNRS, BP 94347, 31055 Toulouse Cedex 4, France
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13
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Cleuziou JP, Wernsdorfer W, Bouchiat V, Ondarçuhu T, Monthioux M. Carbon nanotube superconducting quantum interference device. NATURE NANOTECHNOLOGY 2006; 1:53-59. [PMID: 18654142 DOI: 10.1038/nnano.2006.54] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 08/30/2006] [Indexed: 05/26/2023]
Abstract
A superconducting quantum interference device (SQUID) with single-walled carbon nanotube (CNT) Josephson junctions is presented. Quantum confinement in each junction induces a discrete quantum dot (QD) energy level structure, which can be controlled with two lateral electrostatic gates. In addition, a backgate electrode can vary the transparency of the QD barriers, thus permitting change in the hybridization of the QD states with the superconducting contacts. The gates are also used to directly tune the quantum phase interference of the Cooper pairs circulating in the SQUID ring. Optimal modulation of the switching current with magnetic flux is achieved when both QD junctions are in the 'on' or 'off' state. In particular, the SQUID design establishes that these CNT Josephson junctions can be used as gate-controlled pi-junctions; that is, the sign of the current-phase relation across the CNT junctions can be tuned with a gate voltage. The CNT-SQUIDs are sensitive local magnetometers, which are very promising for the study of magnetization reversal of an individual magnetic particle or molecule placed on one of the two CNT Josephson junctions.
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Affiliation(s)
- J-P Cleuziou
- Centre d'Elaboration des Matériaux et d'Etudes Structurales, CEMES-CNRS, 29 rue Jeanne Marvig, 31055 Toulouse Cedex 4, France
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14
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Krasnov VM, Bauch T, Intiso S, Hürfeld E, Akazaki T, Takayanagi H, Delsing P. Collapse of thermal activation in moderately damped Josephson junctions. PHYSICAL REVIEW LETTERS 2005; 95:157002. [PMID: 16241753 DOI: 10.1103/physrevlett.95.157002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Indexed: 05/05/2023]
Abstract
We study switching current statistics in moderately damped Nb-InAs-Nb and intrinsic Bi2Sr2CaCu2O8+delta) Josephson junctions. A paradoxical collapse of thermal activation with increasing temperature is reported and explained by the interplay of two conflicting consequences of thermal fluctuations, which can both assist in premature escape and help in retrapping back into the stationary state. We analyze the influence of dissipation on the thermal escape by tuning damping with a gate voltage, magnetic field, temperature, and an in situ capacitor.
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Affiliation(s)
- V M Krasnov
- Department of Physics, Stockholm University, Albanova University Center, SE-10691 Stockholm, Sweden
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15
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Koval Y, Fistul MV, Ustinov AV. Enhancement of Josephson phase diffusion by microwaves. PHYSICAL REVIEW LETTERS 2004; 93:087004. [PMID: 15447218 DOI: 10.1103/physrevlett.93.087004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Indexed: 05/24/2023]
Abstract
We report an experimental and theoretical study of the phase diffusion in small Josephson junctions under microwave irradiation. A peculiar enhancement of the phase diffusion by microwaves is observed. The enhancement manifests itself by a pronounced current peak in the current-voltage characteristics. The voltage position V(top) of the peak increases with the power P of microwave radiation as V(top) proportional to sqrt[P], while its current amplitude weakly decreases with P. As the microwave frequency increases, the peak feature evolves into Shapiro steps with a finite slope. Our theoretical analysis, taking into account the enhancement of incoherent superconducting current by multiphoton absorption, is in good agreement with experimental data.
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Affiliation(s)
- Y Koval
- Physikalisches Institut III, Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany
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16
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Kraut S, Feudel U. Enhancement of noise-induced escape through the existence of a chaotic saddle. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:015204. [PMID: 12636550 DOI: 10.1103/physreve.67.015204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2002] [Indexed: 05/24/2023]
Abstract
We study the noise-induced escape process in a prototype dissipative nonequilibrium system, the Ikeda map. In the presence of a chaotic saddle embedded in the basin of attraction of the metastable state, we find the novel phenomenon of a strong enhancement of noise-induced escape. This result is established by employing the theory of quasipotentials. Our finding is of general validity and should be experimentally observable.
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Affiliation(s)
- Suso Kraut
- Institut für Physik, Universität Potsdam, Postfach 601553, D-14415 Potsdam, Germany
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17
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Steinbach A, Joyez P, Cottet A, Esteve D, Devoret MH, Huber ME, Martinis JM. Direct measurement of the Josephson supercurrent in an ultrasmall Josephson junction. PHYSICAL REVIEW LETTERS 2001; 87:137003. [PMID: 11580618 DOI: 10.1103/physrevlett.87.137003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2001] [Indexed: 05/23/2023]
Abstract
We have measured the supercurrent flowing through a nonhysteretic, ultrasmall, voltage-biased Josephson junction. In contrast with experiments performed so far on hysteretic Josephson junctions, we find a supercurrent peak whose maximum I(s max) increases as the temperature T decreases. The asymptotic T = 0 value of I(s max) agrees with the junction Ambegaokar-Baratoff critical current, as predicted by theory.
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Affiliation(s)
- A Steinbach
- Service de Physique de l'Etat Condensé, CEA-Saclay, F-91191 Gif-sur-Yvette, France
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18
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Goffman MF, Cron R, Joyez P, Devoret MH, Esteve D, Urbina C. Supercurrent in atomic point contacts and andreev states. PHYSICAL REVIEW LETTERS 2000; 85:170-173. [PMID: 10991186 DOI: 10.1103/physrevlett.85.170] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/1999] [Indexed: 05/23/2023]
Abstract
We have measured the supercurrent in aluminum atomic point contacts containing a small number of well characterized conduction channels. For most contacts, the measured supercurrent is adequately described by the opposite contributions of two thermally populated Andreev bound states per conduction channel. However, for contacts containing an almost perfectly transmitted channel 0.9</=tau</=1 the measured supercurrent is higher than expected, a fact that we attribute to nonadiabatic transitions between bound states.
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Affiliation(s)
- MF Goffman
- Service de Physique de l'Etat Condense, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex, France
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