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Haxell DZ, Coraiola M, Sabonis D, Hinderling M, Ten Kate SC, Cheah E, Krizek F, Schott R, Wegscheider W, Belzig W, Cuevas JC, Nichele F. Microwave-induced conductance replicas in hybrid Josephson junctions without Floquet-Andreev states. Nat Commun 2023; 14:6798. [PMID: 37884490 PMCID: PMC10603169 DOI: 10.1038/s41467-023-42357-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 10/09/2023] [Indexed: 10/28/2023] Open
Abstract
Light-matter coupling allows control and engineering of complex quantum states. Here we investigate a hybrid superconducting-semiconducting Josephson junction subject to microwave irradiation by means of tunnelling spectroscopy of the Andreev bound state spectrum and measurements of the current-phase relation. For increasing microwave power, discrete levels in the tunnelling conductance develop into a series of equally spaced replicas, while the current-phase relation changes amplitude and skewness, and develops dips. Quantitative analysis of our results indicates that conductance replicas originate from photon assisted tunnelling of quasiparticles into Andreev bound states through the tunnelling barrier. Despite strong qualitative similarities with proposed signatures of Floquet-Andreev states, our study rules out this scenario. The distortion of the current-phase relation is explained by the interaction of Andreev bound states with microwave photons, including a non-equilibrium Andreev bound state occupation. The techniques outlined here establish a baseline to study light-matter coupling in hybrid nanostructures and distinguish photon assisted tunnelling from Floquet-Andreev states in mesoscopic devices.
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Affiliation(s)
| | - Marco Coraiola
- IBM Research Europe-Zurich, 8803, Rüschlikon, Switzerland
| | | | | | | | - Erik Cheah
- Laboratory for Solid State Physics, ETH Zürich, 8093, Zürich, Switzerland
| | - Filip Krizek
- IBM Research Europe-Zurich, 8803, Rüschlikon, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, 8093, Zürich, Switzerland
| | - Rüdiger Schott
- Laboratory for Solid State Physics, ETH Zürich, 8093, Zürich, Switzerland
| | - Werner Wegscheider
- Laboratory for Solid State Physics, ETH Zürich, 8093, Zürich, Switzerland
| | - Wolfgang Belzig
- Fachbereich Physik, Universität Konstanz, D-78457, Konstanz, Germany
| | - Juan Carlos Cuevas
- Fachbereich Physik, Universität Konstanz, D-78457, Konstanz, Germany
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049, Madrid, Spain
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Baumgartner C, Fuchs L, Frész L, Reinhardt S, Gronin S, Gardner GC, Manfra MJ, Paradiso N, Strunk C. Josephson Inductance as a Probe for Highly Ballistic Semiconductor-Superconductor Weak Links. PHYSICAL REVIEW LETTERS 2021; 126:037001. [PMID: 33543978 DOI: 10.1103/physrevlett.126.037001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
We present simultaneous measurements of Josephson inductance and dc transport characteristics of ballistic Josephson junctions based upon an epitaxial Al-InAs heterostructure. The Josephson inductance at finite current bias directly reveals the current-phase relation. The proximity-induced gap, the critical current and the average value of the transparency τ[over ¯] are extracted without need for phase bias, demonstrating, e.g., a near-unity value of τ[over ¯]=0.94. Our method allows us to probe the devices deeply in the nondissipative regime, where ordinary transport measurements are featureless. In perpendicular magnetic field the junctions show a nearly perfect Fraunhofer pattern of the critical current, which is insensitive to the value of τ[over ¯]. In contrast, the signature of supercurrent interference in the inductance turns out to be extremely sensitive to τ[over ¯].
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Affiliation(s)
- Christian Baumgartner
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, 93040 Regensburg, Germany
| | - Lorenz Fuchs
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, 93040 Regensburg, Germany
| | - Linus Frész
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, 93040 Regensburg, Germany
| | - Simon Reinhardt
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, 93040 Regensburg, Germany
| | - Sergei Gronin
- Microsoft Quantum Purdue, Purdue University, West Lafayette, Indiana 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Geoffrey C Gardner
- Microsoft Quantum Purdue, Purdue University, West Lafayette, Indiana 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 USA
| | - Michael J Manfra
- Microsoft Quantum Purdue, Purdue University, West Lafayette, Indiana 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, USA
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Nicola Paradiso
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, 93040 Regensburg, Germany
| | - Christoph Strunk
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, 93040 Regensburg, Germany
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Lee GH, Lee HJ. Proximity coupling in superconductor-graphene heterostructures. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:056502. [PMID: 29451135 DOI: 10.1088/1361-6633/aaafe1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This review discusses the electronic properties and the prospective research directions of superconductor-graphene heterostructures. The basic electronic properties of graphene are introduced to highlight the unique possibility of combining two seemingly unrelated physics, superconductivity and relativity. We then focus on graphene-based Josephson junctions, one of the most versatile superconducting quantum devices. The various theoretical methods that have been developed to describe graphene Josephson junctions are examined, together with their advantages and limitations, followed by a discussion on the advances in device fabrication and the relevant length scales. The phase-sensitive properties and phase-particle dynamics of graphene Josephson junctions are examined to provide an understanding of the underlying mechanisms of Josephson coupling via graphene. Thereafter, microscopic transport of correlated quasiparticles produced by Andreev reflections at superconducting interfaces and their phase-coherent behaviors are discussed. Quantum phase transitions studied with graphene as an electrostatically tunable 2D platform are reviewed. The interplay between proximity-induced superconductivity and the quantum-Hall phase is discussed as a possible route to study topological superconductivity and non-Abelian physics. Finally, a brief summary on the prospective future research directions is given.
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Affiliation(s)
- Gil-Ho Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea. Department of Physics, Harvard University, Cambridge, MA 02138, United States of America
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Exciting Andreev pairs in a superconducting atomic contact. Nature 2013; 499:312-5. [DOI: 10.1038/nature12315] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/16/2013] [Indexed: 11/08/2022]
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Gustavsson S, Oliver WD. Andreev states taken to the next level. Nature 2013; 499:286-7. [DOI: 10.1038/499286a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Dassonneville B, Ferrier M, Guéron S, Bouchiat H. Dissipation and supercurrent fluctuations in a diffusive normal-metal-superconductor ring. PHYSICAL REVIEW LETTERS 2013; 110:217001. [PMID: 23745912 DOI: 10.1103/physrevlett.110.217001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 06/02/2023]
Abstract
A mesoscopic hybrid normal-metal-superconductor ring is characterized by a dense Andreev spectrum with a flux dependent minigap. To probe the dynamics of such a ring, we measure its linear response to a high frequency flux, in a wide frequency range, with a multimode superconducting resonator. We find that the current response contains, besides the well-known dissipationless Josephson contribution, a large dissipative component. At high frequency compared to the minigap and low temperature, we find that the dissipation is due to transitions across the minigap. In contrast, at lower frequency there is a range of temperature for which dissipation is caused predominantly by the relaxation of the Andreev states' population. This dissipative response, related via the fluctuation dissipation theorem to a nonintuitive zero frequency thermal noise of supercurrent, is characterized by a phase dependence dominated by its second harmonic, as predicted long ago but never observed thus far.
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Affiliation(s)
- B Dassonneville
- LPS, University of Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France
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Voutilainen J, Virtanen P, Heikkilä TT. Absorption of heat into a superconductor-normal metal-superconductor junction from a fluctuating environment. PHYSICAL REVIEW LETTERS 2012; 109:067002. [PMID: 23006295 DOI: 10.1103/physrevlett.109.067002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Indexed: 06/01/2023]
Abstract
We study a diffusive superconductor-normal-metal-superconductor junction in an environment with intrinsic incoherent fluctuations which couple to the junction through an electromagnetic field. When the temperature of the junction differs from that of the environment, this coupling leads to an energy transfer between the two systems, taking the junction out of equilibrium. We describe this effect in the linear response regime and show that the change in the supercurrent induced by this coupling leads to qualitative changes in the current-phase relation and, for a certain range of parameters, an increase in the critical current of the junction. In addition to normal metals, similar effects can be expected also in other conducting weak links.
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Affiliation(s)
- J Voutilainen
- Low Temperature Laboratory, Aalto University, Aalto, Finland
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Probing the dynamics of Andreev states in a coherent normal/superconducting ring. Sci Rep 2011; 1:3. [PMID: 22355522 PMCID: PMC3210693 DOI: 10.1038/srep00003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 04/28/2011] [Accepted: 05/03/2011] [Indexed: 11/08/2022] Open
Abstract
The supercurrent that establishes between two superconductors connected through a normal N mesoscopic link is carried by quasiparticule states localized within the link, the "Andreev bound states (ABS)". Whereas the dc properties of this supercurrent in SNS junctions are now well understood, its dynamical properties are still an unresolved issue. In this letter we probe this dynamics by inductively coupling an NS ring to a multimode superconducting resonator, thereby implementing both a phase bias and current detection at high frequency. Whereas at very low temperatures we essentially measure the phase derivative of the supercurrent, at higher temperature we find a surprisingly strong frequency dependence in the current response of the ring: the ABS do not follow adiabatically the phase modulation. This experiment also illustrates a new tool to probe the fundamental time scales of phase coherent systems that are decoupled from macroscopic normal contacts and thermal baths.
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Virtanen P, Heikkilä TT, Bergeret FS, Cuevas JC. Theory of microwave-assisted supercurrent in diffusive SNS junctions. PHYSICAL REVIEW LETTERS 2010; 104:247003. [PMID: 20867329 DOI: 10.1103/physrevlett.104.247003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2010] [Indexed: 05/29/2023]
Abstract
The observation of very large microwave-enhanced critical currents in superconductor-normal-metal-superconductor (SNS) junctions at temperatures well below the critical temperature of the electrodes has remained without a satisfactory theoretical explanation for more than three decades. Here we present a theory of the supercurrent in diffusive SNS junctions under microwave irradiation based on the quasiclassical Green's function formalism. We show that the enhancement of the critical current is due to the energy redistribution of the quasiparticles in the normal wire induced by the electromagnetic field. The theory provides predictions across a wide range of temperatures, frequencies, and radiation powers, both for the critical current and the current-phase relationship.
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Affiliation(s)
- Pauli Virtanen
- Low Temperature Laboratory, Aalto University School of Science and Technology, P.O. Box 15100, FI-00076 AALTO, Finland
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