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41 results on '"Hervé Courtois"'

1. Probing magnetism of individual nano-structures using Nb μ -SQUIDs in hysteresis free mode

Author

Hervé Courtois, Ganesh Kotagiri, Rini Ganguly, Clemens Winkelmann, Anjan K. Gupta, Harsh Parashari, Sagar Paul, Department of Physics [Kanpur], Indian Institute of Technology Kanpur (IIT Kanpur), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)

Subjects
010302 applied physics, Permalloy, Materials science, Condensed matter physics, Magnetism, Magnetometer, Nucleation, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Magnetic flux, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Electronic, Optical and Magnetic Materials, law.invention, Hysteresis, law, Condensed Matter::Superconductivity, 0103 physical sciences, Nano, 0210 nano-technology, Anisotropy, ComputingMilieux_MISCELLANEOUS
Abstract

The magnetization reversal of an individual magnetic nano-structure has been best studied using a μ -SQUID. An optimum inductive shunt helps in eliminating the hysteresis in μ -SQUID’s current voltage characteristics, giving thus a direct voltage readout of magnetic flux with high bandwidth and sensitivity. Here we report on a new μ -SQUID magnetometry setup for studying the magnetism of individual magnetic nano-structures. The switching field anisotropy of Permalloy nano-needles was studied using both hysteretic and non–hysteretic μ -SQUID modes. The observed anisotropy fits well the magnetization reversal through curling mode under the Neel-Brown model as well as micromagnetic simulations. The latter show a reversal through vortex nucleation and annihilation whose signatures we observe through minor hysteresis loops in experiments. Some preliminary magnetization reversal studies on Fe3O4 nano-particles using a non–hysteretic μ -SQUID mode are also briefly discussed.

Published
2020
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2. Nonlinear thermovoltage in a single-electron transistor

Author

Jukka P. Pekola, Paolo Andrea Erdman, Joonas T. Peltonen, Bibek Bhandari, Hervé Courtois, Bivas Dutta, Rosario Fazio, Fabio Taddei, NEST - Scuola Normale Superiore and Istituto Nanoscienze-CNR, Department of Applied Physics [Aalto], Aalto University, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Abdus Salam International Centre for Theoretical Physics [Trieste] (ICTP), Fondation Nanosciences - Grenoble, Quantum Phenomena and Devices, National Enterprise for nanoScience and nanoTechnology, National Research Council of Italy, Université Grenoble Alpes, CNR-ENEA-EURATOM Association, Centre of Excellence in Quantum Technology, QTF, Department of Applied Physics, Aalto-yliopisto, Erdman, P. A., Peltonen, J. T., Bhandari, B., Dutta, B., Courtois, H., Fazio, R., Taddei, F., and Pekola, J. P.

Subjects
Materials science, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, law.invention, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Temperature difference, Sensitivity (control systems), [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], [PHYS]Physics [physics], Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, ta114, Transistor, Charge current, Coulomb blockade, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Nonlinear system, 0210 nano-technology, Free parameter
Abstract

We perform direct thermovoltage measurements in a single-electron transistor, using on-chip local thermometers, both in the linear and non-linear regimes. Using a model which accounts for co-tunneling, we find excellent agreement with the experimental data with no free parameters even when the temperature difference is larger than the average temperature (far-from-linear regime). This allows us to confirm the sensitivity of the thermovoltage on co-tunneling and to find that in the non-linear regime the temperature of the metallic island is a crucial parameter. Surprisingly, the metallic island tends to overheat even at zero net charge current, resulting in a reduction of the thermovoltage., 10 pages, 4 figures

Published
2019
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3. Magnetic-field-induced transition in a quantum dot coupled to a superconductor

Author

A. Garcia Corral, Serge Florens, D. M. T. van Zanten, Hervé Courtois, Clemens Winkelmann, Katharina J. Franke, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Fachbereich Physik [Berlin], Freie Universität Berlin, and Théorie Quantique des Circuits (ThQC)

Subjects
Coulomb blockade, Kondo effect, FOS: Physical sciences, 02 engineering and technology, Proximity effect, 01 natural sciences, Andreev reflection, Condensed Matter::Superconductivity, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Proximity effect (superconductivity), Singlet state, 010306 general physics, Computer Science::Databases, Spin-½, Physics, Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, High Energy Physics::Phenomenology, 500 Naturwissenschaften und Mathematik::530 Physik::530 Physik, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Magnetic field, STATES, Condensed Matter::Strongly Correlated Electrons, Impurities in superconductors, 0210 nano-technology, Magnetic impurity
Abstract

The magnetic moment of a quantum dot can be screened by its coupling to a superconducting reservoir, depending on the hierarchy of the superconducting gap and the relevant Kondo scale. This screening-unscreening transition can be driven by electrostatic gating, tunnel coupling, and, as we demonstrate here, magnetic field. We perform high-resolution spectroscopy of subgap excitations near the screening-unscreening transition of asymmetric superconductor - quantum dot - superconductor (S-QD-S) junctions formed by the electromigration technique. Our measurements reveal a re-entrant phase boundary determined by the competition between Zeeman energy and gap reduction with magnetic field. We further track the evolution of the phase transition with increasing temperature, which is also evidenced by thermal replicas of subgap states., 15 pages, including Supp. Info. file

Published
2020
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4. Stochastic resonance in thermally bistable Josephson weak-links and micro-SQUIDs

Author

Rini Ganguly, Sagar Paul, Anjan K. Gupta, Ganesh Kotagiri, Hervé Courtois, and Clemens Winkelmann

Subjects
Physics, Condensed matter physics, Bistability, Condensed Matter - Mesoscale and Nanoscale Physics, Statistical Mechanics (cond-mat.stat-mech), Stochastic resonance, Condensed Matter - Superconductivity, Sinusoidal excitation, General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 01 natural sciences, Signal, Magnetic field, Superconductivity (cond-mat.supr-con), Hysteresis, 0103 physical sciences, Thermal, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, 0210 nano-technology, Condensed Matter - Statistical Mechanics, Voltage
Abstract

Constriction-based Josephson weak-links display a thermal bi-stability between two states exhibiting zero and finite voltages. This manifests in experiments either as hysteresis in weak-links current voltage characteristics or as random telegraphic signal in voltage. In the latter case, a noise-driven amplification of a sinusoidal excitation of the device is observed, at frequencies matching the characteristic switching frequency in telegraphic signal, a phenomenon known as stochastic resonance. The observed behavior is understood using a two-state model of stochastic resonance and is exploited to illustrate an enhanced signal-to-noise-ratio in a micro-SQUID as a magnetic field sensor., Comment: 23 pages, 7 figures, suppl. info. available on request

Published
2020
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5. Non-invasive nanoscale potentiometry and ballistic transport in epigraphene nanoribbons

Author

David Wander, Clemens Winkelmann, Vladimir Prudkovskiy, Hervé Courtois, Walt A. de Heer, Alessandro de Cecco, Rini Ganguly, Claire Berger, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), Georgia Institute of Technology [Atlanta], and Circuits électroniques quantiques Alpes (QuantECA)

Subjects
Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Mechanical Engineering, Non invasive, FOS: Physical sciences, Bioengineering, Nanotechnology, 02 engineering and technology, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electron transport chain, ballistic transport, Ballistic conduction, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Metrics & More Article Recommendations Epigraphene, General Materials Science, scanning tunneling potentiometry, 0210 nano-technology, Nanoscopic scale, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Graphene nanoribbons, graphene nanoribbons, Electronic properties
Abstract

International audience; The recent observation of non-classical electron transport regimes in two-dimensional materials has called for new high-resolution non-invasive techniques to locally probe electronic properties. We introduce a novel hybrid scanning probe technique to map the local resistance and electrochemical potential with nm-and µV resolution, and we apply it to study epigraphene nanoribbons grown on the sidewalls of SiC sub-strate steps. Remarkably, the potential drop is non uniform along the ribbons, and µm-long segments show no potential variation with distance. The potential maps are in excellent agreement with measurements of the local resistance. This reveals ballistic transport (removed "in ambient conditions"), compatible with micrometer-long room-temperature electronic mean free paths.

Published
2020
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6. Direct Probe of the Seebeck Coefficient in a Kondo-Correlated Single-Quantum-Dot Transistor

Author

Hervé Courtois, Paolo Andrea Erdman, Danial Majidi, Bivas Dutta, Clemens Winkelmann, T. A. Costi, Alvaro García Corral, Serge Florens, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Théorie Quantique des Circuits (ThQC)

Subjects
Materials science, FOS: Physical sciences, Bioengineering, 02 engineering and technology, law.invention, Condensed Matter::Materials Science, law, Seebeck coefficient, Condensed Matter::Superconductivity, Thermoelectric effect, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, ComputingMilieux_MISCELLANEOUS, Quantum tunnelling, Spin-½, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Mechanical Engineering, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Quantum dot, Thermoelectricity, quantum transport, Kondo effect, Density of states, ddc:660, Condensed Matter::Strongly Correlated Electrons, Kondo effect, Scanning tunneling microscope, 0210 nano-technology
Abstract

We report on the first measurement of the Seebeck coefficient in a tunnel-contacted and gate-tunable individual single-quantum dot junction in the Kondo regime, fabricated using the electromigration technique. This fundamental thermoelectric parameter is obtained by directly monitoring the magnitude of the voltage induced in response to a temperature difference across the junction, while keeping a zero net tunneling current through the device. In contrast to bulk materials and single molecules probed in a scanning tunneling microscopy (STM) configuration, investigating the thermopower in nanoscale electronic transistors benefits from the electric tunability to showcase prominent quantum effects. Here, striking sign changes of the Seebeck coefficient are induced by varying the temperature, depending on the spin configuration in the quantum dot. The comparison with numerical renormalization group (NRG) calculations demonstrates that the tunneling density of states is generically asymmetric around the Fermi level in the leads, both in the cotunneling and Kondo regimes.

Published
2019
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7. Full electrostatic control of quantum interference in an extended trenched Josephson junction

Author

Giorgio Biasiol, Hervé Courtois, Fabio Beltram, Fabio Taddei, Stefan Heun, Stefano Guiducci, Matteo Carrega, NEST - Scuola Normale Superiore and Istituto Nanoscienze-CNR, NEST-INFM (INFM), Istituto Nazionale di Fisica Nucleare (INFN), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), NEST and Scuola Normale Superiore, CNR-INFM, Laboratorio Nazionale TASC (TASC), Consiglio Nazionale delle Ricerche [Roma] (CNR)-INFM, Guiducci, S., Carrega, M., Taddei, F., Biasiol, G., Courtois, H., Beltram, F., and Heun, S.

Subjects
Josephson effect, FOS: Physical sciences, 02 engineering and technology, Interference (wave propagation), 01 natural sciences, Settore FIS/03 - Fisica della Materia, Condensed Matter::Superconductivity, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Quantum well, Quantum computer, Physics, Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Magnetic field, Semiconductor, Modulation, Optoelectronics, 0210 nano-technology, business
Abstract

Hybrid semiconductor/superconductor devices constitute an important platform for a wide range of applications, from quantum computing to topological-state-based architectures. Here, we demonstrate full modulation of the interference pattern in a superconducting interference device with two parallel islands of ballistic InAs quantum wells separated by a trench, by acting independently on two side gates. This so far unexplored geometry enables us to tune the device with high precision from a SQUID-like to a Fraunhofer-type behavior simply by electrostatic gating, without the need for an additional in-plane magnetic field. These measurements are successfully analyzed within a theoretical model of an extended tunnel Josephson junction, taking into account the focusing factor of the setup. The impact of these results on the design of novel devices is discussed. Hybrid semiconductor/superconductor devices constitute an important platform for a wide range of applications, from quantum computing to topological-state-based architectures. Here, we demonstrate full modulation of the interference pattern in a superconducting interference device with two parallel islands of ballistic InAs quantum wells separated by a trench, by acting independently on two side gates. This so far unexplored geometry enables us to tune the device with high precision from a SQUID-like to a Fraunhofer-type behavior simply by electrostatic gating, without the need for an additional in-plane magnetic field. These measurements are successfully analyzed within a theoretical model of an extended tunnel Josephson junction, taking into account the focusing factor of the setup. The impact of these results on the design of novel devices is discussed.

Published
2019
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8. Elimination of thermal bistability in superconducting weak links by an inductive shunt

Author

Thierry Dauxois, Clemens Winkelmann, Hervé Courtois, Anjan K. Gupta, Hillol Biswas, Sourav Biswas, Department of Physics [Kanpur], Indian Institute of Technology Kanpur (IIT Kanpur), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Superconductivity, Bistability, Condensed matter physics, Condensed Matter - Superconductivity, FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Superconductivity (cond-mat.supr-con), Nonlinear system, Condensed Matter::Superconductivity, 0103 physical sciences, Thermal, Dissipative system, 010306 general physics, 0210 nano-technology, Quantum, Shunt (electrical), Voltage
Abstract

The quantum phase-coherent behavior of superconducting weak links (WL) is often quenched in the finite voltage state, due to the heat dissipation and related thermal hysteresis. The latter can be reduced by improving heat evacuation and/or by lowering the critical current, so that a phase-dynamic regime is obtained, albeit over a narrow bias-current and temperature range. Here we demonstrate that an inductive shunt with well-chosen parameters introduces unexpected nonlinear dynamics that destabilize an otherwise stable fixed point in the dissipative branch. This leads to a nonhysteretic behavior with large voltage oscillations in intrinsically hysteretic WL-based micron-size superconducting quantum interference devices. A dynamic thermal model quantitatively describes our observations and further allows us to elaborate on the optimal shunting conditions., The model section has been revised in the latest version, 9 pages, 11 figures

Published
2018
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9. Josephson Coupling in the Dissipative State of a Thermally Hysteretic $\mu$-SQUID

Author

Hervé Courtois, Sourav Biswas, Clemens Winkelmann, Anjan K. Gupta, Department of Physics [Kanpur], Indian Institute of Technology Kanpur (IIT Kanpur), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Physics, Superconductivity, Condensed matter physics, Condensed Matter - Superconductivity, Supercurrent, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 01 natural sciences, Magnetic flux, law.invention, Pi Josephson junction, SQUID, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Amplitude, law, Condensed Matter::Superconductivity, 0103 physical sciences, Dissipative system, 010306 general physics, 0210 nano-technology, Dimensionless quantity
Abstract

Micron-sized superconducting interference devices ($\mu$-SQUIDs) based on constrictions optimized for minimizing thermal runaway are shown to exhibit voltage oscillations with applied magnetic flux despite their hysteretic behavior. We explain this remarkable feature by a significant supercurrent contribution surviving deep into the resistive state, due to efficient heat evacuation. A resistively shunted junction model, complemented by a thermal balance determining the amplitude of the critical current, describes well all experimental observations, including the flux modulation of the (dynamic) retrapping current and voltage by introducing a single dimensionless parameter. Thus hysteretic $\mu$-SQUIDs can be operated in the voltage read-out mode with a faster response. The quantitative modeling of this regime incorporating both heating and phase dynamics paves the way for further optimization of $\mu$-SQUIDs for nano-magnetism., Comment: 10 pages, 11 figures, Revised

Published
2017
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10. Thermal Conductance of a Single-Electron Transistor

Author

Clemens Winkelmann, Daniil S. Antonenko, Björn Kubala, Hervé Courtois, Bivas Dutta, Jürgen König, Matthias Meschke, Mikhail A. Skvortsov, Joonas T. Peltonen, Jukka P. Pekola, Department of Applied Physics, Skolkovo Institute of Science and Technology, Ulm University, University of Duisburg-Essen, Université Grenoble Alpes, Aalto-yliopisto, Aalto University, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Low Temperature Laboratory, TKK, Skolkovo Institute of Science and Technology [Moscow] (Skoltech), L.D. Landau Institute for Theoretical Physics of RAS, Russian Academy of Sciences [Moscow] (RAS), Moscow Institute of Physics and Technology [Moscow] (MIPT), Aalto University School of Science and Technology [Aalto, Finland], Universität Ulm - Ulm University [Ulm, Allemagne], and Universität Duisburg-Essen [Essen]

Subjects
General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, 7. Clean energy, law.invention, Thermal conductivity, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Physics, Heat current, ta114, Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Transistor, Coulomb blockade, Charge (physics), Physik (inkl. Astronomie), 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Threshold voltage, 0210 nano-technology, Degeneracy (mathematics), Voltage
Abstract

We report on combined measurements of heat and charge transport through a single-electron transistor. The device acts as a heat switch actuated by the voltage applied on the gate. The Wiedemann-Franz law for the ratio of heat and charge conductances is found to be systematically violated away from the charge degeneracy points. The observed deviation agrees well with the theoretical expectation. With large temperature drop between the source and drain, the heat current away from degeneracy deviates from the standard quadratic dependence in the two temperatures., Comment: 5 pages, 4 figures + supplementary material

Published
2017
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11. High-performance electronic cooling with superconducting tunnel junctions

Author

Jukka P. Pekola, Clemens Winkelmann, Hervé Courtois, Hung Q. Nguyen, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Aalto university low temperature physics (Aalto), Aalto University, Centre National de la Recherche Scientifique (CNRS), Department of Applied Physics, and Aalto-yliopisto

Subjects
Jonctions tunnel, Electronic cooling, Materials science, Band gap, Energy Engineering and Power Technology, FOS: Physical sciences, 02 engineering and technology, Physics and Astronomy(all), 01 natural sciences, 7. Clean energy, Superconducting tunnel junctions, Superconducting tunnel jonctions, Superconductivity (cond-mat.supr-con), Tunnel junction, Condensed Matter::Superconductivity, 0103 physical sciences, Cooling power, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Superconductivity, Range (particle radiation), Thermo-electricity, Thermoélectricité, ta114, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Condensed Matter - Superconductivity, General Engineering, Refroidissement électronique, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Tunnel barrier, Optoelectronics, 0210 nano-technology, business, Voltage
Abstract

When biased at a voltage just below a superconductor's energy gap, a tunnel junction between this superconductor and a normal metal cools the latter. While the study of such devices has long been focussed to structures of submicron size and consequently cooling power in the picoWatt range, we have led a thorough study of devices with a large cooling power up to the nanoWatt range. Here we describe how their performance can be optimized by using a quasi-particle drain and tuning the cooling junctions' tunnel barrier., in Comptes Rendus Physique, Elsevier Masson, 2016

Published
2016
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12. Equal variations of the Fermi level and work function in graphene at the nanoscale

Author

Johann Coraux, Clemens Winkelmann, Benjamin Grévin, Sylvain Martin, Sayanti Samaddar, Hervé Courtois, Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Systèmes hybrides de basse dimensionnalité (NEEL - HYBRID), Service des Basses Températures (SBT ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Nano-Electronique Quantique et Spectroscopie (QuNES), Systèmes hybrides de basse dimensionnalité (HYBRID), and Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Kelvin probe force microscope, Materials science, Condensed matter physics, Graphene, business.industry, Scanning tunneling spectroscopy, Fermi level, Quantum oscillations, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, law.invention, symbols.namesake, Semiconductor, law, 0103 physical sciences, symbols, General Materials Science, Work function, 010306 general physics, 0210 nano-technology, business, Fermi gas, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

International audience; If surface effects are neglected, any change of the Fermi level in a semiconductor is expected to result in an equal and opposite change of the work function. This is however not observed in general in three-dimensional semiconductors, because of Fermi level pinning at the surface. By combining Kelvin Probe Force Microscopy and Scanning Tunneling Spectroscopy on single layer graphene, we measure both the local work function and the charge carrier density. The one-to-one equivalence of changes in the Fermi level and the work function is demonstrated to accurately hold in single layer graphene down to the nanometer scale.

Published
2016
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13. Interplay between electron overheating and ac Josephson effect

Author

A. De Cecco, Hervé Courtois, Benjamin Sacépé, Clemens Winkelmann, K. Le Calvez, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and ANR-12-BS10-0007,NANOQUARTETS,Production de Quartets d'Electrons dans des Bijonctions Josephson(2012)

Subjects
Josephson effect, Phonon, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 02 engineering and technology, Electron, 7. Clean energy, 01 natural sciences, Superconductivity (cond-mat.supr-con), Pi Josephson junction, Condensed Matter::Superconductivity, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, 010306 general physics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Overheating (electricity), Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Condensed Matter - Superconductivity, 021001 nanoscience & nanotechnology, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Amplitude, 0210 nano-technology, Microwave, Excitation
Abstract

International audience; We study the response of high-critical current proximity Josephson junctions to a microwave excitation. Electron over-heating in such devices is known to create hysteretic dc voltage-current characteristics. Here we demonstrate that it also strongly influences the ac response. The interplay of electron over-heating and ac Josephson dynamics is revealed by the evolution of the Shapiro steps with the microwave drive amplitude. Extending the resistively shunted Josephson junction model by including a thermal balance for the electronic bath coupled to phonons, a strong electron over-heating is obtained.

Published
2016
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14. Single Quantum Level Electron Turnstile

Author

Jukka P. Pekola, Hervé Courtois, Denis M. Basko, D. M. T. van Zanten, Ivan M. Khaymovich, Clemens Winkelmann, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de physique et modélisation des milieux condensés (LPM2C), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institute for Physics of Microstructures of the RAS, Russian Academy of Sciences [Moscow] (RAS), Low Temperature Laboratory, TKK, Université Grenoble Alpes, CNRS, Department of Applied Physics, Aalto-yliopisto, and Aalto University

Subjects
Superconductivity, Physics, ta114, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, FOS: Physical sciences, General Physics and Astronomy, Quantum level, 02 engineering and technology, Electron, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Conventional superconductor, Turnstile, Quantum dot, Condensed Matter::Superconductivity, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Quasiparticle, 010306 general physics, 0210 nano-technology, Realization (systems)
Abstract

We report on the realization of a single-electron source, where current is transported through a single-level quantum dot (Q) tunnel coupled to two superconducting leads (S). When driven with an ac gate voltage, the experiment demonstrates electron turnstile operation. Compared to the more conventional superconductor-normal-metal-superconductor turnstile, our superconductor-quantum-dot-superconductor device presents a number of novel properties, including higher immunity to the unavoidable presence of nonequilibrium quasiparticles in superconducting leads. Moreover, we demonstrate its ability to deliver electrons with a very narrow energy distribution.

Published
2016
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15. Quantum Coherence of the Quartet Scheme Observed by Shapiro Resonance Under Radio-Frequency Irradiation in Three Terminal Josephson Junctions

Author

Andreas Pfeffer, F. Lefloch, Hervé Courtois, J. E. Duvauchelle, Laboratoire de Transport Electronique Quantique et Supraconductivité (LaTEQS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES)

Subjects
Superconductivity, Physics, Josephson effect, [PHYS]Physics [physics], Condensed matter physics, Resonance, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Pi Josephson junction, Condensed Matter::Superconductivity, 0103 physical sciences, Radio frequency, Electrical and Electronic Engineering, Cooper pair, 010306 general physics, 0210 nano-technology, Quantum, Coherence (physics)
Abstract

International audience; We have investigated three-terminal superconductor (S)-normal metal (N)-superconductor (S) Josephson junctions. In a geometry where a T-shaped normal metal (Cu) is connected to three superconducting reservoirs (Al), new subgap structures appear in the differential resistance when the bias voltages on two of the three terminals compensate each other exactly. These features correspond to the correlated motion of Cooper pairs within the structure. They are consistent with the prediction of quartets formed by the simultaneous splitting of two Cooper pairs at one of the superconducting contacts and the emission of two phase correlated Cooper pairs in the two other electrodes. To test the quantum coherence of such mechanism, we have studied the effect of a radio-frequency irradiation at 14 GHz down to 100 mK. Well known Shapiro steps involving two terminals are measured, and in particular, half-integer steps are observed. This is consistent with the transfer of two Cooper pairs between two terminals. This paper reveals that the quartet resonances also show Shapiro steps in agreement with the quartet mechanism. Our findings confirm the quartet scenario and demonstrate its coherent nature.

Published
2016
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16. Random telegraphic voltage noise due to thermal bi-stability in a superconducting weak link

Author

Hervé Courtois, Anjan K. Gupta, Sourav Biswas, Nikhil Kumar, Clemens Winkelmann, Department of Physics [Kanpur], Indian Institute of Technology Kanpur (IIT Kanpur), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Physics, Superconductivity, [PHYS]Physics [physics], Resistive touchscreen, Condensed matter physics, Biasing, 02 engineering and technology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, Signal, Noise (electronics), Telegraphic speech, Control theory, 0103 physical sciences, Time domain, 010306 general physics, 0210 nano-technology, Voltage
Abstract

We investigated the random telegraphic voltage noise signal in the hysteretic bi-stable state of a superconducting weak link device. Fluctuation induced random switching between zero voltage state and non-zero-voltage state gives rise to a random telegraphic voltage signal in time domain. This telegraphic noise is used to find the mean lifetime of each of the two states. The mean life time in the zero voltage state is found to decrease with increasing bias current while that of resistive state increases and thus the two cross at certain bias current. We qualitatively discuss this observed switching behavior as arising from the bi-stable nature.

Published
2016
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17. Charge Puddles in Graphene Near the Dirac Point

Author

Sayanti Samaddar, Clemens Winkelmann, Indra Yudhistira, Hervé Courtois, Shaffique Adam, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and National University of Singapore (NUS)

Subjects
Materials science, General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, Electron, 01 natural sciences, law.invention, symbols.namesake, law, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, Spectroscopy, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Mesoscopic physics, Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Graphene, Fermi level, Charge (physics), 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Amplitude, symbols, Scanning tunneling microscope, 0210 nano-technology
Abstract

International audience; The charge carrier density in graphene on a dielectric substrate such as SiO2 displays inho-mogeneities, the so-called charge puddles. Because of the linear dispersion relation in monolayer graphene, the puddles are predicted to grow near charge neutrality, a markedly distinct property from conventional two-dimensional electron gases. By performing scanning tunneling mi-croscopy/spectroscopy on a mesoscopic graphene device, we directly observe the puddles' growth, both in spatial extent and in amplitude, as the Fermi level approaches the Dirac point. Self-consistent screening theory provides a unified description of both the macroscopic transport properties and the microscopically observed charge disorder.

Published
2015
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18. Reversibility Of Superconducting Nb Weak Links Driven By The Proximity Effect In A Quantum Interference Device

Author

Thierry Fournier, Hervé Courtois, Nikhil Kumar, Clemens Winkelmann, Anjan K. Gupta, Department of Physics [Kanpur], Indian Institute of Technology Kanpur (IIT Kanpur), Nanofab (Nanofab), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Nano-Electronique Quantique et Spectroscopie (QuNES)

Subjects
Physics, Superconductivity, Condensed matter physics, Condensed Matter - Superconductivity, Phase (waves), FOS: Physical sciences, General Physics and Astronomy, Nanotechnology, 02 engineering and technology, 021001 nanoscience & nanotechnology, Small amplitude, 01 natural sciences, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], 3. Good health, Superconductivity (cond-mat.supr-con), Condensed Matter::Superconductivity, Heat generation, 0103 physical sciences, Thermal, Quantum interference, Proximity effect (superconductivity), Critical current, 010306 general physics, 0210 nano-technology
Abstract

We demonstrate the role of proximity effect in the thermal hysteresis of superconducting constrictions. From the analysis of successive thermal instabilities in the transport characteristics of micron-size superconducting quantum interference devices with a well-controlled geometry, we obtain a complete picture of the different thermal regimes. These determine whether the junctions are hysteretic or not. Below the superconductor critical temperature, the critical current switches from a classical weak-link behavior to one driven by the proximity effect. The associated small amplitude of the critical current makes it robust with respect to the heat generation by phase-slips, leading to a non-hysteretic behavior., 6 pages, 5 figures, including Supplementary Information

Published
2015
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19. Long-ranged magnetic proximity effects in noble metal-doped cobalt probed with spin- dependent tunnelling

Author

Hervé Courtois, Mihai Gabureac, Donald A. Mac Laren, Christopher M. Marrows, School of Physics and Astronomy [Leeds], University of Leeds, SUPA School of Physics and Astronomy [Glasgow], University of Glasgow, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), European Project: 26472,SFINX, Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)

Subjects
Length scale, Materials science, Magnetoresistance, FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, 01 natural sciences, Superconductivity (cond-mat.supr-con), symbols.namesake, Condensed Matter::Materials Science, 0103 physical sciences, Exponential decay, 010306 general physics, Quantum tunnelling, Superconductivity, Condensed Matter - Materials Science, Spin polarization, Condensed matter physics, Magnetic circular dichroism, Condensed Matter - Superconductivity, Fermi level, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], symbols, 0210 nano-technology
Abstract

International audience; We inserted non-magnetic layers of Au and Cu into sputtered AlOx-based magnetic tunnel junctions and Meservey-Tedrow junctions in order to study their effect on tunnelling magnetoresistance (TMR) and spin polarization (TSP). When either Au or Cu are inserted into a Co/AlOx interface, we find that TMR and TSP remain finite and measurable for thicknesses up to several nanometres. High-resolution transmission electron microscopy shows that the Cu and Au interface layers are fully continuous when their thickness exceeds ∼3 nm, implying that spin-polarized carriers penetrate the interface noble metal to dis- tances exceeding this value. A power law model based on exchange scattering is found to fit the data better than a phenomenological exponential decay. The discrepancy between these length scales and the much shorter ones reported from x-ray magnetic circular dichroism studies of magnetic proximitization is ascribed to the fact that our tunnelling transport measurements selectively probe s-like electrons close to the Fermi level. When a 0.1 nm thick Cu or Au layer is inserted within the Co, we find that the suppression of TMR and TSP is restored on a length scale of ≲1 nm, indicating that this is a sufficient quantity of Co to form a fully spin-polarized band structure at the interface with the tunnel barrier.

Published
2014
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20. Modulating charge density and inelastic optical response in graphene by atmospheric pressure localized intercalation through wrinkles

Author

Sayanti Samaddar, Hervé Courtois, Olivier Renault, Amina Kimouche, Olivier Fruchart, Clemens Winkelmann, Johann Coraux, Systèmes hybrides de basse dimensionnalité (NEEL - HYBRID), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), Micro et NanoMagnétisme (NEEL - MNM), Systèmes hybrides de basse dimensionnalité (HYBRID), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Nano-Electronique Quantique et Spectroscopie (QuNES), and Micro et NanoMagnétisme (MNM)

Subjects
Materials science, Oxide, STM, FOS: Physical sciences, Nanotechnology, 02 engineering and technology, Substrate (electronics), Chemical vapor deposition, doping, 01 natural sciences, STS, law.invention, chemistry.chemical_compound, symbols.namesake, law, intercalation, 0103 physical sciences, General Materials Science, 010306 general physics, Raman, Graphene oxide paper, Condensed Matter - Materials Science, Atmospheric pressure, Graphene, graphene, XPEEM, Materials Science (cond-mat.mtrl-sci), General Chemistry, 021001 nanoscience & nanotechnology, chemistry, Chemical physics, symbols, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], AFM, 0210 nano-technology, Raman spectroscopy, Graphene nanoribbons
Abstract

The intercalation of an oxide barrier between graphene and its metallic substrate for chem- ical vapor deposition is a contamination-free alternative to the transfer of graphene to dielectric supports, usually needed for the realization of electronic devices. Low-cost pro- cesses, especially at atmospheric pressure, are desirable but whether they are achievable remains an open question. Combining complementary microscopic analysis, providing structural, electronic, vibrational, and chemical information, we demonstrate the spontaneous reactive intercalation of 1.5 nm-thick oxide ribbons between graphene and an iridium substrate, at atmospheric pressure and room temperature. We discover that oxygen-containing molecules needed for forming the ribbons are supplied through the graphene wrinkles, which act as tunnels for the efficient diffusion of molecules entering their free end. The intercalated oxide ribbons are found to modify the graphene-support interaction, leading to the formation of quasi-free-standing high quality graphene whose charge density is modulated in few 10-100 nm-wide ribbons by a few 10^12 cm-2, where the inelastic optical response is changed, due to a softening of vibrational modes - red-shifts of Raman G and 2D bands by 6 and 10 cm-1, respectively., Comment: Carbon (2013) available online

Published
2014
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21. Trapping hot quasi-particles in a high-power superconducting electronic cooler

Author

Jukka P. Pekola, Hervé Courtois, V. J. Kauppila, Clemens Winkelmann, Thomas Aref, Hung Q. Nguyen, Matthias Meschke, Department of Applied Physics, Aalto-yliopisto, Aalto University, Low Temperature Laboratory, TKK, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), European Project, Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Perustieteiden korkeakoulu, School of Science, and Teknillisen fysiikan laitos

Subjects
FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, Trapping, 7. Clean energy, 01 natural sciences, Quasi particles, superconducting electrodes, Superconductivity (cond-mat.supr-con), Condensed Matter::Superconductivity, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Cooling power, 010306 general physics, Physics, Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics, tunnel barriers, business.industry, Condensed Matter - Superconductivity, 021001 nanoscience & nanotechnology, Power (physics), [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Tunnel barrier, Electrode, Optoelectronics, metallic drains, Thermal model, hybrid superconducting electronic coolers, 0210 nano-technology, business
Abstract

International audience; The performance of hybrid superconducting electronic coolers is usually limited by the accumulation of hot quasi-particles in the superconducting leads. This issue is all the more stringent in large-scale and high-power devices, as required by applications. Introducing a metallic drain connected to the superconducting electrodes via a fine-tuned tunnel barrier, we efficiently remove quasi-particles and obtain electronic cooling from 300 mK down to 130 mK with a 400 pW cooling power. A simple thermal model accounts for the experimental observations.

Published
2013
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22. Niobium-based superconducting nano-devices fabrication using all-metal suspended masks

Author

Clemens Winkelmann, Hervé Courtois, Sayanti Samaddar, Aurelien Fay, D. M. T. van Zanten, Benjamin Sacépé, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), European Project: 264034,EC:FP7:PEOPLE,FP7-PEOPLE-2010-ITN,Q-NET(2011), and Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES)

Subjects
Fabrication, Nano devices, Niobium, chemistry.chemical_element, FOS: Physical sciences, Bioengineering, 02 engineering and technology, 01 natural sciences, Metal, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, Electrical and Electronic Engineering, 010306 general physics, Lithography, Superconductivity, Physics, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Mechanical Engineering, General Chemistry, 021001 nanoscience & nanotechnology, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Characterization (materials science), chemistry, Resist, Mechanics of Materials, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], visual_art, visual_art.visual_art_medium, Optoelectronics, 0210 nano-technology, business
Abstract

We report a novel method for the fabrication of superconducting nano-devices based on niobium. The well-known difficulties of lithographic patterning of high-quality niobium are overcome by replacing the usual organic resist mask by a metallic one. The quality of the fabrication procedure is demonstrated by the realization and characterization of long and narrow superconducting lines and niobium-gold-niobium proximity SQUIDs.

Published
2013
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23. Efficiency of Quasiparticle Evacuation in Superconducting Devices

Author

Sukumar Rajauria, Bernard Pannetier, Philippe Gandit, Hervé Courtois, Frank W. J. Hekking, Laetitia Pascal, Circuits électroniques quantiques Alpes (QuantECA), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Hélium : du fondamental aux applications (HELFA), Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Nano-Electronique Quantique et Spectroscopie (QuNES), European Project, Circuits électroniques quantiques Alpes (NEEL - QuantECA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Hélium : du fondamental aux applications (NEEL - HELFA), and Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES)

Subjects
Superconductivity, Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 01 natural sciences, Electronic, Optical and Magnetic Materials, Condensed Matter::Superconductivity, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quasiparticle, Condensed Matter::Strongly Correlated Electrons, 010306 general physics, 0210 nano-technology, Voltage
Abstract

We have studied the diffusion of excess quasiparticles in a current-biased superconductor strip in proximity to a metallic trap junction. In particular, we have measured accurately the superconductor temperature at a near-gap injection voltage. By analyzing our data quantitatively, we provide a full description of the spatial distribution of excess quasiparticles in the superconductor. We show that a metallic trap junction contributes significantly to the evacuation of excess quasiparticles., Comment: 4 pages, 4 figures

Published
2012
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24. Noise Correlations in Three-Terminal Diffusive Superconductor-Normal Metal-Superconductor Nanostructures

Author

Olivier Coupiac, Hervé Courtois, François Lefloch, Bhaskar Kaviraj, Laboratoire de Transport Electronique Quantique et Supraconductivité (LaTEQS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), ANR, Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nanostructure, General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Andreev reflection, Metal, Superconductivity (cond-mat.supr-con), Current noise, Condensed Matter::Superconductivity, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Superconductivity, Physics, Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Superconductivity, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Terminal (electronics), visual_art, visual_art.visual_art_medium, 0210 nano-technology, Noise (radio)
Abstract

We present measurements of current noise and cross-correlations in three-terminal Superconductor-Normal metal-Superconductor (S-N-S) nanostructures that are potential solid-state entanglers thanks to Andreev reflections at the N-S interfaces. The noise correlation measurements spanned from the regime where electron-electron interactions are relevant to the regime of Incoherent Multiple Andreev Reflection (IMAR). In the latter regime, negative cross-correlations are observed in samples with closely-spaced junctions., Include Supplemental Material

Published
2011
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25. Circuit approach to photonic heat transport

Author

Hervé Courtois, Frank W. J. Hekking, Laetitia Pascal, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et modélisation des milieux condensés (LPM2C), and Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photon, Thermodynamics, FOS: Physical sciences, 02 engineering and technology, Heat transfer coefficient, 01 natural sciences, 7. Clean energy, Superconductivity (cond-mat.supr-con), 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, Electrical impedance, Physics, Coupling, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Condensed Matter - Superconductivity, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Computational physics, Nonlinear system, Thermal radiation, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Heat transfer, Photonics, 0210 nano-technology, business
Abstract

We discuss the heat transfer by photons between two metals coupled by a linear element with a reactive impedance. Using a simple circuit approach, we calculate the spectral power transmitted from one resistor to the other and find that it is determined by the photon transmission coefficient, which depends on the impedances of the metals and the coupling element. We study the total photonic power flow for different coupling impedances, both in the linear regime, where the temperature difference between the metals is small, and in the non-linear regime of large temperature differences., Comment: 6 pages, 6 figures

Published
2011
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26. Hysteresis in superconducting short weak links and $\mu$-SQUIDs

Author

Dibyendu Hazra, Laetitia Pascal, Hervé Courtois, Anjan K. Gupta, Department of Physics [Kanpur], Indian Institute of Technology Kanpur (IIT Kanpur), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)

Subjects
Superconductivity, Josephson effect, Physics, Condensed matter physics, Magnetometer, Condensed Matter - Superconductivity, Order (ring theory), 02 engineering and technology, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, law.invention, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Hysteresis, Thermal conductivity, law, Condensed Matter::Superconductivity, 0103 physical sciences, Linear approximation, 010306 general physics, 0210 nano-technology
Abstract

Thermal hysteresis in a micron-size Superconducting Quantum Interference Device ($\mu$-SQUID), with weak links as Josephson junctions, is an obstacle for improving its performance for magnetometery. Following the "hot-spot" model of Skocpol et al. [J. Appl. Phys. {\bf 45}, 4054 (1974)] and by incorporating the temperature dependence of thermal conductivity of superconductor using a linear approximation, we find a much better agreement with the observed temperature dependence of the retrapping current in short superconducting Nb-based weak links and $\mu$-SQUIDs. In addition, using the temperature dependence of the critical current, we find that above a certain temperature hysteresis disappears. We analyze the current-voltage characteristics and the weak link temperature variation in both the hysteretic and non-hysteretic regimes. We also discuss the effect of the weak link geometry in order to widen the temperature range of hysteresis-free operation., Comment: 11 pages, 12 figures

Published
2010
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27. Nanocrystalline boron-doped diamond films, a mixture of BCS-like and non-BCS-like superconducting grains

Author

Etienne Bustarret, Daniel Araujo, Philipp Achatz, Oliver A. Williams, Hervé Courtois, F. Dahlem, Semi-conducteurs à large bande interdite (SC2G), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Institute for Materials Research, Hasselt University (UHasselt), Departamento Ciencia de los Materiales e IMyQI, Universidad de Cádiz (UCA), Nano-Electronique Quantique et Spectroscopie (QuNES), and Publica

Subjects
Materials science, Scanning tunneling spectroscopy, STM, 02 engineering and technology, doping, engineering.material, 01 natural sciences, law.invention, Condensed Matter::Materials Science, diamond, law, Condensed Matter::Superconductivity, 0103 physical sciences, Materials Chemistry, Proximity effect (superconductivity), disorder system, Electrical and Electronic Engineering, 010306 general physics, Superconductivity, Condensed matter physics, superconductivity, Doping, Diamond, Surfaces and Interfaces, BCS theory, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Nanocrystalline material, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], proximity effect, engineering, Scanning tunneling microscope, 0210 nano-technology
Abstract

International audience; Scanning tunneling topography and spectroscopy are performed below 100 mK on granular nanocrystalline boron-doped diamond (BDD) films. We found the superconductivity behavior to follow mainly the granular features of the BDD films. The temperature dependence of the local differential conductance spectra shows our nanocrystalline BDD films as made of grains with a supercondutivity either BCS-like or non-BCS-like. Such a distribution is not discernible in transport measurements, which present a sharp macroscopic superconducting transition at a temperature of a few Kelvins. Our local scanning tunneling microscopies also confirm the good coupling between these grains: only a few opaque interfaces are detected. Such a transparency of intergrain interfaces is responsible for a proximity effect in weakly superconductive grains and an inverse proximity effect in strongly superconducting grains.

Published
2010
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28. Spatially correlated microstructure and superconductivity in polycrystalline boron-doped diamond

Author

Oliver A. Williams, Daniel Araujo, Philipp Achatz, Hervé Courtois, F. Dahlem, Etienne Bustarret, Publica, Semi-conducteurs à large bande interdite (SC2G), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Institute for Materials Research, Hasselt University (UHasselt), Departamento Ciencia de los Materiales e IMyQI, Universidad de Cádiz (UCA), and Nano-Electronique Quantique et Spectroscopie (QuNES)

Subjects
Materials science, FOS: Physical sciences, 02 engineering and technology, engineering.material, 01 natural sciences, Superconductivity (cond-mat.supr-con), Condensed Matter::Materials Science, Condensed Matter::Superconductivity, 0103 physical sciences, Proximity effect (superconductivity), 010306 general physics, QC, Quantum tunnelling, Superconductivity, Condensed matter physics, Condensed Matter - Superconductivity, Diamond, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Microstructure, Electronic, Optical and Magnetic Materials, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Amplitude, Transmission electron microscopy, engineering, Crystallite, 0210 nano-technology
Abstract

International audience; Scanning tunneling spectroscopies are performed below 100~mK on nano-crystalline boron-doped diamond films characterized by Transmission Electron Microscopy and transport measurements. We demonstrate a strong correlation between the local superconductivity strength and the granular structure of the films. The study of the spectral shape, amplitude and temperature dependence of the superconductivity gap enables us to differentiate intrinsically superconducting grains that follow the BCS model, from grains showing a different behavior involving the superconducting proximity effect.

Published
2010
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29. Electron cooling by diffusive normal metal–superconductor tunnel junctions

Author

Hervé Courtois, Frank W. J. Hekking, Andrey S. Vasenko, E. V. Bezuglyi, Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), European Project, Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)

Subjects
Superconductivity, Materials science, Condensed matter physics, Condensed Matter - Superconductivity, FOS: Physical sciences, 02 engineering and technology, Electron, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Andreev reflection, law.invention, Superconductivity (cond-mat.supr-con), [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], law, Condensed Matter::Superconductivity, 0103 physical sciences, Heat transfer, Electrode, Electric current, 010306 general physics, 0210 nano-technology, Joule heating, Electron cooling
Abstract

We investigate heat and charge transport in NN'IS tunnel junctions in the diffusive limit. Here N and S are massive normal and superconducting electrodes (reservoirs), N' is a normal metal strip, and I is an insulator. The flow of electric current in such structures at subgap bias is accompanied by heat transfer from the normal metal into the superconductor, which enables refrigeration of electrons in the normal metal. We show that the two-particle current due to Andreev reflection generates Joule heating, which is deposited in the N electrode and dominates over the single-particle cooling at low enough temperatures. This results in the existence of a limiting temperature for refrigeration. We consider different geometries of the contact: one-dimensional and planar, which is commonly used in the experiments. We also discuss the applicability of our results to a double-barrier SINIS microcooler., Comment: 9 pages, 4 figures, submitted to Phys. Rev. B

Published
2010
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30. Quasiparticle diffusion based heating in superconductor tunneling micro-coolers

Author

Hervé Courtois, Bernard Pannetier, Sukumar Rajauria, Circuits électroniques quantiques Alpes (QuantECA), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Nano-Electronique Quantique et Spectroscopie (QuNES)

Subjects
Materials science, FOS: Physical sciences, 02 engineering and technology, Cooling effect, 01 natural sciences, Tunnel junction, Condensed Matter::Superconductivity, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Diffusion (business), 010306 general physics, Quantum tunnelling, Superconductivity, Condensed Matter - Materials Science, Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Detector, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Electronic, Optical and Magnetic Materials, Quasiparticle, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Superconducting tunnel junction, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology
Abstract

In a hybrid Superconductor - Insulator - Normal metal tunnel junction biased just below the gap, the extraction of hot electrons out of the normal metal results in electronic cooling effect. The quasiparticles injected in the superconductor accumulate near the tunnel interface, thus increasing the effective superconductor temperature. We propose a simple model for the diffusion of excess quasiparticles in a superconducting strip with an additional trap junction. This diffusion model has a complete analytic solution, which depends on experimentally accessible parameters. We find that the accumulated quasiparticles near the junction reduce the efficiency of the device. This study is also relevant to more general situations making use of superconducting tunnel junctions, as low temperature detectors., 4 pages, 3 figures

Published
2009
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31. Calorimetric readout of a superconducting proximity-effect thermometer

Author

Joonas T. Peltonen, Jukka P. Pekola, Hervé Courtois, Matthias Meschke, Low Temperature Laboratory, TKK, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and ANR-07-NANO-0011,ELEC-EPR,Electronic EPR Source(2007)

Subjects
Superconductivity, Josephson effect, Resistive touchscreen, Materials science, Condensed matter physics, Condensed Matter - Superconductivity, Supercurrent, FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 01 natural sciences, Atomic and Molecular Physics, and Optics, Superconductivity (cond-mat.supr-con), [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Thermometer, Condensed Matter::Superconductivity, 0103 physical sciences, Proximity effect (superconductivity), General Materials Science, 010306 general physics, 0210 nano-technology, Joule heating, Voltage
Abstract

A proximity-effect thermometer measures the temperature dependent critical supercurrent in a long superconductor - normal metal - superconductor (SNS) Josephson junction. Typically, the transition from the superconducting to the normal state is detected by monitoring the appearance of a voltage across the junction. We describe a new approach to detect the transition based on the temperature increase in the resistive state due to Joule heating. Our method increases the sensitivity and is especially applicable for temperatures below about 300 mK., 10 pages, 5 figures. To appear in the proceedings of the Conference on Micro- and Nanocryogenics (LT25 satellite) organized in Espoo, Finland (2008)

Published
2009
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32. Spin-Valve Effect of the Spin Accumulation Resistance in a Double Ferromagnet - Superconductor Junction

Author

B. Gilles, Hervé Courtois, Bernard Pannetier, Sukumar Rajauria, Thierry Crozes, P. S. Luo, Champion, Yannick, Nanofab (Nanofab), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Science et Ingénierie des Matériaux et Procédés (SIMaP), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Institut National Polytechnique de Grenoble (INPG), Circuits électroniques quantiques Alpes (QuantECA), Nano-Electronique Quantique et Spectroscopie (QuNES), ANR-07-NANO-0011,ELEC-EPR,Electronic EPR Source(2007), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National Polytechnique de Grenoble (INPG)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nanostructure, Materials science, Spin valve, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Superconductivity (cond-mat.supr-con), Magnetization, Condensed Matter::Materials Science, Condensed Matter::Superconductivity, 0103 physical sciences, Proximity effect (superconductivity), 010306 general physics, ComputingMilieux_MISCELLANEOUS, Spin-½, Superconductivity, [CHIM.MATE] Chemical Sciences/Material chemistry, Condensed matter physics, Condensed Matter - Superconductivity, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Electronic, Optical and Magnetic Materials, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Ferromagnetism, Electrode, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology
Abstract

International audience; We have measured the transport properties of Ferromagnet - Superconductor nanostructures, where two superconducting aluminum (Al) electrodes are connected through two ferromagnetic iron (Fe) ellipsoids in parallel. We find that, below the superconducting critical temperature of Al, the resistance depends on the relative alignment of the ferromagnets' magnetization. This spin-valve effect is analyzed in terms of spin accumulation in the superconducting electrode submitted to inverse proximity effect.

Published
2008
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33. Andreev current-induced dissipation in a hybrid superconducting tunnel junction

Author

Hervé Courtois, Frank W. J. Hekking, Bernard Pannetier, Philippe Gandit, Thierry Fournier, Sukumar Rajauria, Circuits électroniques quantiques Alpes (QuantECA), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Hélium : du fondamental aux applications (HELFA), Nanofab (Nanofab), Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and Nano-Electronique Quantique et Spectroscopie (QuNES)

Subjects
Superconductivity, Materials science, Condensed matter physics, Condensed Matter - Superconductivity, FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, Dissipation, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 01 natural sciences, 7. Clean energy, Superconductivity (cond-mat.supr-con), [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Tunnel junction, Condensed Matter::Superconductivity, 0103 physical sciences, Quasiparticle, Superconducting tunnel junction, Current (fluid), 010306 general physics, 0210 nano-technology, Joule heating, Quantum tunnelling
Abstract

International audience; We have studied hybrid superconducting micro-coolers made of a double Superconductor-Insulator-Normal metal tunnel junction. Under subgap conditions, the Andreev current is found to dominate the single-particle tunnel current. We show that the Andreev current introduces additional dissipation in the normal metal equivalent to Joule heating. By analyzing quantitatively the heat balance in the system, we provide a full description of the evolution of the electronic temperature with the voltage. The dissipation induced by the Andreev current is found to dominate the quasiparticle tunneling-based cooling over a large bias range.

Published
2008
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34. Origin of Hysteresis in a Proximity Josephson Junction

Author

Hervé Courtois, Jukka P. Pekola, Matthias Meschke, Joonas T. Peltonen, Perustieteiden korkeakoulu, School of Science, Department of Applied Physics, Teknillisen fysiikan laitos, Aalto-yliopisto, Aalto University, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Low Temperature Laboratory, TKK, and ANR-07-NANO-0011,ELEC-EPR,Electronic EPR Source(2007)

Subjects
Josephson effect, Materials science, Thermal resistance, General Physics and Astronomy, metals, FOS: Physical sciences, 02 engineering and technology, superconductors, 01 natural sciences, Pi Josephson junction, normal-metal-superconductor, Superconductivity (cond-mat.supr-con), tunneling, junctions, Josephson junction, Condensed Matter::Superconductivity, 0103 physical sciences, 010306 general physics, Superconductivity, Resistive touchscreen, Condensed matter physics, Condensed Matter - Superconductivity, Physics, temperature, 021001 nanoscience & nanotechnology, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Hysteresis, hysteresis, Electrode, Electron temperature, 0210 nano-technology
Abstract

International audience; We investigate hysteresis in the transport properties of Superconductor - Normal metal - Superconductor (S-N-S) junctions at low temperatures by measuring directly the electron temperature in the normal metal. Our results demonstrate unambiguously that the hysteresis results from an increase of the normal metal electron temperature once the junction switches to the resistive state. In our geometry, the electron temperature increase is governed by the thermal resistance of the superconducting electrodes of the junction.

Published
2008
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35. Inherent thermometry in a hybrid superconducting tunnel junction

Author

Frank W. J. Hekking, Sukumar Rajauria, Hervé Courtois, Philippe Gandit, Bernard Pannetier, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Circuits électroniques quantiques Alpes (QuantECA), Hélium : du fondamental aux applications (HELFA), Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and ANR-07-NANO-0011,ELEC-EPR,Electronic EPR Source(2007)

Subjects
Materials science, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Andreev reflection, law.invention, Superconductivity (cond-mat.supr-con), law, Tunnel junction, Condensed Matter::Superconductivity, 0103 physical sciences, General Materials Science, 010306 general physics, Quantum tunnelling, Superconductivity, Condensed matter physics, Condensed Matter - Superconductivity, Biasing, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Atomic and Molecular Physics, and Optics, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Electron temperature, Superconducting tunnel junction, 0210 nano-technology, Electron cooling
Abstract

International audience; We discuss inherent thermometry in a Superconductor - Normal metal - Superconductor tunnel junction. In this configuration, the energy selectivity of single-particle tunneling can provide a significant electron cooling, depending on the bias voltage. The usual approach for measuring the electron temperature consists in using an additional pair of superconducting tunnel junctions as probes. In this paper, we discuss our experiment performed on a different design with no such thermometer. The quasi-equilibrium in the central metallic island is discussed in terms of a kinetic equation including injection and relaxation terms. We determine the electron temperature by comparing the micro-cooler experimental current-voltage characteristic with isothermal theoretical predictions. The limits of validity of this approach, due to the junctions asymmetry, the Andreev reflection or the presence of sub-gap states are discussed.

Published
2008
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36. Laser induced resonance shifts of single molecules self-coupled by a metallic surface

Author

O. Labeau, Hervé Courtois, Brahim Lounis, Girish S. Agarwal, Ph. Tamarat, Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Department of Physics, Oklahoma State university, Oklahoma State University [Stillwater], and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)

Subjects
Materials science, Dephasing, General Physics and Astronomy, 02 engineering and technology, 01 natural sciences, Molecular physics, law.invention, Quality (physics), Nuclear magnetic resonance, law, 0103 physical sciences, boundary conditions, Molecule, high resolution spectroscopy, Physics::Atomic Physics, 010306 general physics, Quantum optics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], 33.80.32.70.Jz, 33.50.j, 42.50.p, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], Resonance, 021001 nanoscience & nanotechnology, Laser, Dipole, single molecule detection, oscillating electric dipole, 0210 nano-technology, Excitation
Abstract

The spectral properties of single molecules placed near a metallic surface are investigated at low temperatures. Because of the high quality factor of the optical resonance, a laser-induced shift of the molecular lines is evidenced for the first time. The shift dependence on the laser excitation intensity and on the dephasing rate of the transition dipole is studied. A simple theoretical model of a laser-driven molecule self-coupled by a mirror is developed to qualitatively interpret the observations.

Published
2007
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37. Electron and phonon Cooling in a Superconductor - Normal Metal - Superconductor Tunnel Junction

Author

Sukumar Rajauria, Pengshun Luo, Hervé Courtois, Bernard Pannetier, Thierry Fournier, Frank W. J. Hekking, Circuits électroniques quantiques Alpes (QuantECA), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Nanofab (Nanofab), Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Nano-Electronique Quantique et Spectroscopie (QuNES), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)

Subjects
Materials science, Phonon, FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, Electron, 01 natural sciences, law.invention, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Tunnel junction, law, Condensed Matter::Superconductivity, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Interfacial thermal resistance, 010306 general physics, Quantum tunnelling, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Superconductivity, Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 3. Good health, Heat transfer, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, Electron cooling
Abstract

We present evidence for the cooling of normal metal phonons 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 phonon cooling that includes the electron-phonon coupling in the normal metal and the Kapitza resistance between the substrate and the metal. It gives an excellent fit to the data and enables us to extract an effective phonon temperature in the normal metal., 4 pages, 5 figures

Published
2006
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38. Combined scanning force microscopy and scanning tunneling spectroscopy of an electronic nano-circuit at very low temperature

Author

Julien Senzier, Hervé Courtois, Pengshun Luo, Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)

Subjects
Materials science, Microscope, Physics and Astronomy (miscellaneous), Scanning tunneling spectroscopy, Quartz tuning fork, FOS: Physical sciences, PACS numbers: 07.79.-v, 74.78.Na, 07.20.Mc, 02 engineering and technology, Substrate (electronics), 01 natural sciences, law.invention, Superconductivity (cond-mat.supr-con), law, Tunnel junction, Condensed Matter::Superconductivity, 0103 physical sciences, Nano, Scanning Force Microscopy, 010306 general physics, Superconductivity, Condensed matter physics, business.industry, Condensed Matter - Superconductivity, 021001 nanoscience & nanotechnology, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Optoelectronics, 0210 nano-technology, business
Abstract

We demonstrate the combination of scanning force microscopy and scanning tunneling spectroscopy in a local probe microscope operating at very low temperature (60 mK). This local probe uses a quartz tuning fork ensuring high tunnel junction stability. We performed the spatially-resolved spectroscopic study of a superconducting nano-circuit patterned on an insulating substrate. Significant deviations from the BCS prediction are observed., 4 pages

Published
2006
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39. Etching suspended superconducting tunnel junctions from a multilayer

Author

Clemens Winkelmann, Laetitia Pascal, Hervé Courtois, Olivier Buisson, B. Gilles, Hung Q. Nguyen, Z. H. Peng, Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Circuits électroniques quantiques Alpes (NEEL - QuantECA), Science et Ingénierie des Matériaux et Procédés (SIMaP), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National Polytechnique de Grenoble (INPG)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), European Project: 228464,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2008-1,MICROKELVIN(2009), Nano-Electronique Quantique et Spectroscopie (QuNES), and Circuits électroniques quantiques Alpes (QuantECA)

Subjects
Josephson effect, Fabrication, Materials science, Physics and Astronomy (miscellaneous), FOS: Physical sciences, Physics::Optics, Nanotechnology, 02 engineering and technology, 01 natural sciences, law.invention, Superconductivity (cond-mat.supr-con), law, Etching (microfabrication), Condensed Matter::Superconductivity, parasitic diseases, 0103 physical sciences, Thermal, 010306 general physics, Superconductivity, business.industry, Condensed Matter - Superconductivity, technology, industry, and agriculture, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Computer Science::Other, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Optoelectronics, Superconducting tunnel junction, Photolithography, 0210 nano-technology, business, Voltage
Abstract

A method to fabricate large-area superconducting hybrid tunnel junctions with a suspended central normal metal part is presented. The samples are fabricated by combining photo-lithography and chemical etch of a superconductor—insulator—normal metal multilayer. The process involves few fabrication steps, is reliable and produces extremely high-quality tunnel junctions. Under an appropriate voltage bias, a significant electronic cooling is demonstrated. We analyze semi-quantitatively the thermal behavior of a typical device.

Published
2012
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40. Hybrid superconducting nanostructures: very low temperature local probing and noise

Author

F. Lefloch, Hervé Courtois, Claude Chapelier, Klaus Hasselbach, Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de Transport Electronique Quantique et Supraconductivité (LaTEQS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Magnétisme et Supraconductivité (NEEL - MagSup), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Magnétisme et Supraconductivité (MagSup)

Subjects
Josephson effect, Superconductivity, Mesoscopic physics, Materials science, Condensed matter physics, Diamond, Bioengineering, 02 engineering and technology, engineering.material, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Andreev reflection, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Tunnel effect, Tunnel junction, Condensed Matter::Superconductivity, 0103 physical sciences, Materials Chemistry, engineering, Electrical and Electronic Engineering, 010306 general physics, 0210 nano-technology, Quantum tunnelling
Abstract

International audience; We review the topic of hybrid superconducting nanostructures by introducing the basic physical concepts and describing recent key experimental results. We discuss the superconductivity nucleation in mesoscopic structures, the vortex lattice imaging in doped diamond films, the superconducting proximity effect, multiple Andreev reflection in Josephson junctions and the electronic micro-cooling in hybrid tunnel junctions. An emphasis is put on very low temperature local probes and noise measurement techniques developed in Grenoble.

Published
2010
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41. Quantum Confinement Suppressing Electronic Heat Flow below the Wiedemann–Franz Law

Author

Danial Majidi, Martin Josefsson, Mukesh Kumar, Martin Leijnse, Lars Samuelson, Hervé Courtois, Clemens B. Winkelmann, and Ville F. Maisi

Subjects
scattering theory, Letter, Condensed Matter - Mesoscale and Nanoscale Physics, heat transport quantum dot junction scattering theory Wiedemann−Franz law, Mechanical Engineering, FOS: Physical sciences, Bioengineering, 02 engineering and technology, General Chemistry, quantum dot junction, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 7. Clean energy, 01 natural sciences, Wiedemann−Franz law, Condensed Matter::Materials Science, Condensed Matter::Superconductivity, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, 010306 general physics, 0210 nano-technology, heat transport
Abstract

The Wiedemann–Franz law states that the charge conductance and the electronic contribution to the heat conductance are proportional. This sets stringent constraints on efficiency bounds for thermoelectric applications, which seek a large charge conduction in response to a small heat flow. We present experiments based on a quantum dot formed inside a semiconducting InAs nanowire transistor, in which the heat conduction can be tuned significantly below the Wiedemann–Franz prediction. Comparison with scattering theory shows that this is caused by quantum confinement and the resulting energy-selective transport properties of the quantum dot. Our results open up perspectives for tailoring independently the heat and electrical conduction properties in semiconductor nanostructures.

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