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Marín-Suárez M, Peltonen JT, Pekola JP. Active Quasiparticle Suppression in a Non-Equilibrium Superconductor. NANO LETTERS 2020; 20:5065-5071. [PMID: 32551699 PMCID: PMC7467774 DOI: 10.1021/acs.nanolett.0c01264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/09/2020] [Indexed: 06/11/2023]
Abstract
Quasiparticle (qp) poisoning is a major issue that impairs the operation of various superconducting devices. Even though these devices are often operated at temperatures well below the critical point where the number density of excitations is expected to be exponentially suppressed, their bare operation and stray microwave radiation excite the non-equilibrium qp's. Here we use voltage-biased superconducting junctions to demonstrate and quantify qp extraction in the turnstile operation of a superconductor-insulator-normal metal-insulator-superconductor single-electron transistor. In this operation regime, excitations are injected into the superconducting leads at a rate proportional to the driving frequency. We reach a reduction of density by an order of magnitude even for the highest injection rate of 2.4 × 108 qp's per second when extraction is turned on.
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Affiliation(s)
- Marco Marín-Suárez
- Pico group, QTF Centre of
Excellence, Department of Applied Physics, Aalto University, FI-000 76 Aalto, Finland
| | - Joonas T. Peltonen
- Pico group, QTF Centre of
Excellence, Department of Applied Physics, Aalto University, FI-000 76 Aalto, Finland
| | - Jukka P. Pekola
- Pico group, QTF Centre of
Excellence, Department of Applied Physics, Aalto University, FI-000 76 Aalto, Finland
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Taupin M, Khaymovich IM, Meschke M, Mel'nikov AS, Pekola JP. Tunable quasiparticle trapping in Meissner and vortex states of mesoscopic superconductors. Nat Commun 2016; 7:10977. [PMID: 26980225 PMCID: PMC4799370 DOI: 10.1038/ncomms10977] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/08/2016] [Indexed: 11/28/2022] Open
Abstract
Nowadays, superconductors serve in numerous applications, from high-field magnets to ultrasensitive detectors of radiation. Mesoscopic superconducting devices, referring to those with nanoscale dimensions, are in a special position as they are easily driven out of equilibrium under typical operating conditions. The out-of-equilibrium superconductors are characterized by non-equilibrium quasiparticles. These extra excitations can compromise the performance of mesoscopic devices by introducing, for example, leakage currents or decreased coherence time in quantum devices. By applying an external magnetic field, one can conveniently suppress or redistribute the population of excess quasiparticles. In this article, we present an experimental demonstration and a theoretical analysis of such effective control of quasiparticles, resulting in electron cooling both in the Meissner and vortex states of a mesoscopic superconductor. We introduce a theoretical model of quasiparticle dynamics, which is in quantitative agreement with the experimental data. Excessive excitation induced by overheating may deteriorate the resistance-free operation of superconductor-based devices. Here, Taupin et al. propose an effective control of excess quasiparticles and their spatial distribution in a mesoscopic superconducting disc by applying a small magnetic field.
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Affiliation(s)
- M Taupin
- Low Temperature Laboratory, Department of Applied Physics, Aalto University School of Science, P.O. Box 13500, FI-00076 Aalto, Finland
| | - I M Khaymovich
- Low Temperature Laboratory, Department of Applied Physics, Aalto University School of Science, P.O. Box 13500, FI-00076 Aalto, Finland.,Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, 603950 Nizhni Novgorod, Russia
| | - M Meschke
- Low Temperature Laboratory, Department of Applied Physics, Aalto University School of Science, P.O. Box 13500, FI-00076 Aalto, Finland
| | - A S Mel'nikov
- Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, 603950 Nizhni Novgorod, Russia.,Lobachevsky State University of Nizhni Novgorod, 23 Prospekt Gagarina, 603950 Nizhni Novgorod, Russia
| | - J P Pekola
- Low Temperature Laboratory, Department of Applied Physics, Aalto University School of Science, P.O. Box 13500, FI-00076 Aalto, Finland
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Microwave-stimulated superconductivity due to presence of vortices. Sci Rep 2015; 5:9187. [PMID: 25778446 PMCID: PMC4361862 DOI: 10.1038/srep09187] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 02/20/2015] [Indexed: 11/08/2022] Open
Abstract
The response of superconducting devices to electromagnetic radiation is a core concept implemented in diverse applications, ranging from the currently used voltage standard to single photon detectors in astronomy. Suprisingly, a sufficiently high power subgap radiation may stimulate superconductivity itself. The possibility of stimulating type II superconductors, in which the radiation may interact also with vortex cores, remains however unclear. Here we report on superconductivity enhanced by GHz radiation in type II superconducting Pb films in the presence of vortices. The stimulation effect is more clearly observed in the upper critical field and less pronounced in the critical temperature. The magnetic field dependence of the vortex related microwave losses in a film with periodic pinning reveals a reduced dissipation of mobile vortices in the stimulated regime due to a reduction of the core size. Results of numerical simulations support the validy of this conclusion. Our findings may have intriguing connections with holographic superconductors in which the possibility of stimulation is under current debate.
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Wenner J, Yin Y, Lucero E, Barends R, Chen Y, Chiaro B, Kelly J, Lenander M, Mariantoni M, Megrant A, Neill C, O'Malley PJJ, Sank D, Vainsencher A, Wang H, White TC, Cleland AN, Martinis JM. Excitation of superconducting qubits from hot nonequilibrium quasiparticles. PHYSICAL REVIEW LETTERS 2013; 110:150502. [PMID: 25167235 DOI: 10.1103/physrevlett.110.150502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 03/04/2013] [Indexed: 06/03/2023]
Abstract
Superconducting qubits probe environmental defects such as nonequilibrium quasiparticles, an important source of decoherence. We show that "hot" nonequilibrium quasiparticles, with energies above the superconducting gap, affect qubits differently from quasiparticles at the gap, implying qubits can probe the dynamic quasiparticle energy distribution. For hot quasiparticles, we predict a non-negligible increase in the qubit excited state probability Pe. By injecting hot quasiparticles into a qubit, we experimentally measure an increase of Pe in semiquantitative agreement with the model and rule out the typically assumed thermal distribution.
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Affiliation(s)
- J Wenner
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Yi Yin
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Erik Lucero
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - R Barends
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Yu Chen
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - B Chiaro
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - J Kelly
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - M Lenander
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Matteo Mariantoni
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
| | - A Megrant
- Department of Physics, University of California, Santa Barbara, California 93106, USA and Department of Materials, University of California, Santa Barbara, California 93106, USA
| | - C Neill
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - P J J O'Malley
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - D Sank
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A Vainsencher
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - H Wang
- Department of Physics, University of California, Santa Barbara, California 93106, USA and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - T C White
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
| | - John M Martinis
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
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Golubov AA, Brinkman A, Tanaka Y, Mazin II, Dolgov OV. Andreev spectra and subgap bound states in multiband superconductors. PHYSICAL REVIEW LETTERS 2009; 103:077003. [PMID: 19792677 DOI: 10.1103/physrevlett.103.077003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Indexed: 05/28/2023]
Abstract
A theory of Andreev conductance is formulated for junctions involving normal metals (N) and multiband superconductors (S) and applied to the case of superconductors with nodeless extended s(+/-)-wave order parameter symmetry, as possibly realized in the recently discovered ferropnictides. We find qualitative differences from tunneling into s-wave or d-wave superconductors that may help to identify such a state. First, interband interference leads to a suppression of Andreev reflection in the case of a highly transparent N/S interface and to a current deficit in the tunneling regime. Second, surface bound states may appear, both at zero and at nonzero energies.
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Affiliation(s)
- A A Golubov
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
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Rajauria S, Luo PS, Fournier T, Hekking FWJ, Courtois H, Pannetier B. Electron and phonon cooling in a superconductor-normal-metal-superconductor tunnel junction. PHYSICAL REVIEW LETTERS 2007; 99:047004. [PMID: 17678393 DOI: 10.1103/physrevlett.99.047004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 05/08/2007] [Indexed: 05/16/2023]
Abstract
We present evidence for the cooling of normal-metal phonons, in addition to the well-known electron cooling, by electron tunneling in a superconductor-normal-metal-superconductor tunnel junction. The normal-metal electron temperature is extracted by comparing the device current-voltage characteristics to the theoretical prediction. We use a quantitative model for the heat transfer that includes the electron-phonon coupling in the normal metal and the Kapitza resistance between the substrate and the metal. It gives a very good fit to the data and enables us to extract an effective phonon temperature in the normal metal.
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Affiliation(s)
- Sukumar Rajauria
- Institut Néel, CNRS and Université Joseph Fourier, 25 Avenue des Martyrs, BP 166, 38042 Grenoble, France
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Giazotto F, Taddei F, Fazio R, Beltram F. Manipulating nonequilibrium magnetism through superconductors. PHYSICAL REVIEW LETTERS 2005; 95:066804. [PMID: 16090974 DOI: 10.1103/physrevlett.95.066804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Indexed: 05/03/2023]
Abstract
Electrostatic control of the magnetization of a normal mesoscopic conductor is analyzed in a hybrid superconductor-normal-conductor-superconductor system. This effect stems from the interplay between the nonequilibrium condition in the normal region and the Zeeman splitting of the quasi-particle density of states of the superconductor subjected to a static in-plane magnetic field. Unexpected spin-dependent effects such as magnetization suppression, diamagnetic-like response of the susceptibility, as well as spin-polarized current generation are the most remarkable features presented. The impact of scattering events is evaluated and lets us show that this effect is compatible with realistic material properties and fabrication techniques.
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Giazotto F, Heikkilä TT, Taddei F, Fazio R, Pekola JP, Beltram F. Tailoring Josephson coupling through superconductivity-induced nonequilibrium. PHYSICAL REVIEW LETTERS 2004; 92:137001. [PMID: 15089638 DOI: 10.1103/physrevlett.92.137001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Indexed: 05/24/2023]
Abstract
The distinctive quasiparticle distribution existing under nonequilibrium in a superconductor-insulator-normal metal-insulator-superconductor mesoscopic line is proposed as a novel tool to control the supercurrent intensity in a long Josephson weak link. We present a description of this system in the framework of the diffusive-limit quasiclassical Green-function theory and take into account the effects of inelastic scattering with arbitrary strength. Supercurrent enhancement and suppression, including a marked transition to a pi junction, are striking features leading to a fully tunable structure.
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Affiliation(s)
- F Giazotto
- NEST-INFM & Scuola Normale Superiore, I-56126 Pisa, Italy.
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