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Sobral Rey L, Ohnmacht DC, Winkelmann CB, Siewert J, Belzig W, Scheer E. Interplay of Andreev Reflection and Coulomb Blockade in Hybrid Superconducting Single-Electron Transistors. PHYSICAL REVIEW LETTERS 2024; 132:057001. [PMID: 38364128 DOI: 10.1103/physrevlett.132.057001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/29/2023] [Accepted: 12/22/2023] [Indexed: 02/18/2024]
Abstract
We study the interplay between Coulomb blockade and superconductivity in a tunable superconductor-superconductor-normal-metal single-electron transistor. The device is realized by connecting the superconducting island via an oxide barrier to the normal-metal lead and with a break junction to the superconducting lead. The latter enables Cooper pair transport and (multiple) Andreev reflection. We show that these processes are relevant also far above the superconducting gap and that signatures of Coulomb blockade may reoccur at high bias while they are absent for small bias in the strong-coupling regime. Our experimental findings agree with simulations using a rate equation approach in combination with the full counting statistics of multiple Andreev reflection.
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Affiliation(s)
- Laura Sobral Rey
- Physics Department, University of Konstanz, 78457 Konstanz, Germany
| | | | - Clemens B Winkelmann
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Jens Siewert
- University of the Basque Country UPV/EHU and EHU Quantum Center, 48080 Bilbao, Spain
- Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Wolfgang Belzig
- Physics Department, University of Konstanz, 78457 Konstanz, Germany
| | - Elke Scheer
- Physics Department, University of Konstanz, 78457 Konstanz, Germany
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2
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Huang MZ, Mohan J, Visuri AM, Fabritius P, Talebi M, Wili S, Uchino S, Giamarchi T, Esslinger T. Superfluid Signatures in a Dissipative Quantum Point Contact. PHYSICAL REVIEW LETTERS 2023; 130:200404. [PMID: 37267563 DOI: 10.1103/physrevlett.130.200404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/13/2023] [Accepted: 04/13/2023] [Indexed: 06/04/2023]
Abstract
We measure superfluid transport of strongly interacting fermionic lithium atoms through a quantum point contact with local, spin-dependent particle loss. We observe that the characteristic non-Ohmic superfluid transport enabled by high-order multiple Andreev reflections transitions into an excess Ohmic current as the dissipation strength exceeds the superfluid gap. We develop a model with mean-field reservoirs connected via tunneling to a dissipative site. Our calculations in the Keldysh formalism reproduce the observed nonequilibrium particle current, yet do not fully explain the observed loss rate or spin current.
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Affiliation(s)
- Meng-Zi Huang
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - Jeffrey Mohan
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - Anne-Maria Visuri
- Physikalisches Institut, University of Bonn, Nussallee 12, 53115 Bonn, Germany
| | - Philipp Fabritius
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - Mohsen Talebi
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - Simon Wili
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - Shun Uchino
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
| | - Thierry Giamarchi
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Tilman Esslinger
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
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3
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Ptaszyński K. Bounds on skewness and kurtosis of steady-state currents. Phys Rev E 2022; 106:024119. [PMID: 36109909 DOI: 10.1103/physreve.106.024119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Current fluctuations are a powerful tool to unravel the underlying physics of the observed transport process. This work discusses some general properties of the third and the fourth current cumulant (skewness and kurtosis) related to dynamics and thermodynamics of a transport setup. Specifically, several distinct bounds on these quantities are either analytically derived or numerically conjectured, which are applicable to (1) noninteracting fermionic systems, (2) noninteracting bosonic systems, (3) thermally driven classical Markovian systems, and (4) unicyclic Markovian networks. Finally, it is demonstrated that violation of the obtained inequalities can provide a broad spectrum of information about the physics of the analyzed system; e.g., it can enable one to infer the presence of interactions or unitary dynamics, unravel the topology of the Markovian network, or characterize the nature of thermodynamic forces driving the system. In particular, relevant information about the microscopic dynamics can be gained even at equilibrium when the current variance-a standard measure of current fluctuations-is determined mostly by the thermal noise.
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Affiliation(s)
- Krzysztof Ptaszyński
- Institute of Molecular Physics, Polish Academy of Sciences, Mariana Smoluchowskiego 17, 60-179 Poznań, Poland
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Ko W, Lado JL, Maksymovych P. Noncontact Andreev Reflection as a Direct Probe of Superconductivity on the Atomic Scale. NANO LETTERS 2022; 22:4042-4048. [PMID: 35549356 DOI: 10.1021/acs.nanolett.2c00697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Direct detection of superconductivity has long been a key strength of point-contact Andreev reflection. However, its applicability to atomic-scale imaging is limited by the mechanical contact of the Andreev probe. To this end, we present a new method to probe Andreev reflection in a tunnel junction, leveraging tunneling spectroscopy and junction tunability to achieve quantitative detection of Andreev scattering. This method enables unambiguous assignment of superconducting origins of current-carrying excitations, as well as detection of higher order Andreev processes in atomic-scale junctions. We furthermore revealed distinct sensitivity of Andreev reflection to natural defects, such as step edges, even in classical superconductors. The methodology opens a new path to nano- and atomic-scale imaging of superconducting properties, including disordered superconductors and proximity to phase transitions.
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Affiliation(s)
- Wonhee Ko
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jose L Lado
- Department of Applied Physics, Aalto University, 02150 Espoo, Finland
| | - Petro Maksymovych
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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5
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Pinsolle E, Houle S, Lupien C, Reulet B. Non-Gaussian Current Fluctuations in a Short Diffusive Conductor. PHYSICAL REVIEW LETTERS 2018; 121:027702. [PMID: 30085754 DOI: 10.1103/physrevlett.121.027702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Indexed: 06/08/2023]
Abstract
We report the measurement of the third moment of current fluctuations in a short metallic wire at low temperature. The data are deduced from the statistics of voltage fluctuations across the conductor using a careful determination of environmental contributions. Our results at low bias agree very well with theoretical predictions for coherent transport with no fitting parameter. By increasing the bias voltage we explore the crossover from elastic to inelastic transport.
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Affiliation(s)
- Edouard Pinsolle
- Institut Quantique, Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Samuel Houle
- Institut Quantique, Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Christian Lupien
- Institut Quantique, Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Bertrand Reulet
- Institut Quantique, Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
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Maisi VF, Kambly D, Flindt C, Pekola JP. Full counting statistics of Andreev tunneling. PHYSICAL REVIEW LETTERS 2014; 112:036801. [PMID: 24484157 DOI: 10.1103/physrevlett.112.036801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Indexed: 06/03/2023]
Abstract
We employ a single-charge counting technique to measure the full counting statistics of Andreev events in which Cooper pairs are either produced from electrons that are reflected as holes at a superconductor-normal-metal interface or annihilated in the reverse process. The full counting statistics consists of quiet periods with no Andreev processes, interrupted by the tunneling of a single electron that triggers an avalanche of Andreev events giving rise to strongly super-Poissonian distributions.
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Affiliation(s)
- Ville F Maisi
- Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland and Centre for Metrology and Accreditation (MIKES), P.O. Box 9, 02151 Espoo, Finland
| | - Dania Kambly
- Département de Physique Théorique, Université de Genève, 1211 Genève, Switzerland
| | - Christian Flindt
- Département de Physique Théorique, Université de Genève, 1211 Genève, Switzerland
| | - Jukka P Pekola
- Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland
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Jung M, Noh H, Doh YJ, Song W, Chong Y, Choi MS, Yoo Y, Seo K, Kim N, Woo BC, Kim B, Kim J. Superconducting junction of a single-crystalline au nanowire for an ideal Josephson device. ACS NANO 2011; 5:2271-2276. [PMID: 21355535 DOI: 10.1021/nn1035679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report on the fabrication and measurements of a superconducting junction of a single-crystalline Au nanowire, connected to Al electrodes. The current-voltage characteristic curve shows a clear supercurrent branch below the superconducting transition temperature of Al and quantized voltage plateaus on application of microwave radiation, as expected from Josephson relations. Highly transparent (0.95) contacts very close to an ideal limit of 1 are formed at the interface between the normal metal (Au) and the superconductor (Al). The very high transparency is ascribed to the single crystallinity of a Au nanowire and the formation of an oxide-free contact between Au and Al. The subgap structures of the differential conductance are well explained by coherent multiple Andreev reflections (MAR), the hallmark of mesoscopic Josephson junctions. These observations demonstrate that single crystalline Au nanowires can be employed to develop novel quantum devices utilizing coherent electrical transport.
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Affiliation(s)
- Minkyung Jung
- Korea Research Institute of Standards and Science, Daejeon 305-600, Korea
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Belzig W. Device physics: super-semiconducting nanowires. NATURE NANOTECHNOLOGY 2006; 1:167-168. [PMID: 18654178 DOI: 10.1038/nnano.2006.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Levy Yeyati A, Cuevas JC, Martín-Rodero A. Dynamical coulomb blockade of multiple Andreev reflections. PHYSICAL REVIEW LETTERS 2005; 95:056804. [PMID: 16090903 DOI: 10.1103/physrevlett.95.056804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Indexed: 05/03/2023]
Abstract
We analyze the dynamical Coulomb blockade of multiple Andreev reflections (MAR) in a superconducting quantum point contact coupled to a macroscopic impedance. We find that at very low transmission the blockade scales as n2 with n = Int(2delta/eV), where V is the bias voltage and delta is the superconducting gap, as it would correspond to the occurrence of shots of charge ne. For higher transmission the blockade is reduced because of both the Pauli principle and the elastic renormalization of the MAR probability, and for certain voltage regions it may even become an anti-blockade; i.e., the current is enhanced due to the coupling with the electromagnetic environment.
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Affiliation(s)
- A Levy Yeyati
- Departamento de Física Teórica de la Materia Condensada CV, Universidad Autónoma de Madrid, E28049 Madrid, Spain
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Komnik A, Gogolin AO. Full counting statistics for the Kondo dot. PHYSICAL REVIEW LETTERS 2005; 94:216601. [PMID: 16090336 DOI: 10.1103/physrevlett.94.216601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Indexed: 05/03/2023]
Abstract
The generating function for the cumulants of charge current distribution is calculated for two generalized Majorana resonant level models: the Kondo dot at the Toulouse point and the resonant level embedded in a Luttinger liquid with the interaction parameter g=1/2. We find that the low-temperature nonequilibrium transport in the Kondo case occurs via tunneling of physical electrons as well as by coherent transmission of electron pairs. We calculate the third cumulant ("skewness") explicitly and analyze it for different couplings, temperatures, and magnetic fields. For the g=1/2 setup the statistics simplifies and is given by a modified version of the Levitov-Lesovik formula.
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Affiliation(s)
- A Komnik
- Physikalisches Institut, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany
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Pilgram S, Samuelsson P. Noise and full counting statistics of incoherent multiple Andreev reflection. PHYSICAL REVIEW LETTERS 2005; 94:086806. [PMID: 15783919 DOI: 10.1103/physrevlett.94.086806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Indexed: 05/24/2023]
Abstract
We present a general theory for the full counting statistics of multiple Andreev reflections in incoherent superconducting-normal-superconducting contacts. The theory, based on a stochastic path integral approach, is applied to a superconductor-double-barrier system. It is found that all cumulants of the current show a pronounced subharmonic gap structure at voltages V=2Delta/en. For low voltages V<<Delta/e, the counting statistics results from diffusion of multiple charges in energy space, giving the pth cumulant Q(p) proportional, variantV(2-p), diverging for p> or =3. We show that this low-voltage result holds for a large class of incoherent superconducting-normal-superconducting contacts.
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Affiliation(s)
- S Pilgram
- Département de Physique Théorique, Universitè de Genéve, CH-1211, Genève 4, Switzerland
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