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Araujo CILD, Virtanen P, Spies M, González-Orellana C, Kerschbaumer S, Ilyn M, Rogero C, Heikkilä TT, Giazotto F, Strambini E. Superconducting spintronic heat engine. Nat Commun 2024; 15:4823. [PMID: 38844436 PMCID: PMC11156981 DOI: 10.1038/s41467-024-49052-z] [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: 12/06/2023] [Accepted: 05/23/2024] [Indexed: 06/09/2024] Open
Abstract
Heat engines are key devices that convert thermal energy into usable energy. Strong thermoelectricity, at the basis of electrical heat engines, is present in superconducting spin tunnel barriers at cryogenic temperatures where conventional semiconducting or metallic technologies cease to work. Here we realize a superconducting spintronic heat engine consisting of a ferromagnetic insulator/superconductor/insulator/ferromagnet tunnel junction (EuS/Al/AlOx/Co). The efficiency of the engine is quantified for bath temperatures ranging from 25 mK up to 800 mK, and at different load resistances. Moreover, we show that the sign of the generated thermoelectric voltage can be inverted according to the parallel or anti-parallel orientation of the two ferromagnetic layers, EuS and Co. This realizes a thermoelectric spin valve controlling the sign and strength of the Seebeck coefficient, thereby implementing a thermoelectric memory cell. We propose a theoretical model that allows describing the experimental data and predicts the engine efficiency for different device parameters.
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Affiliation(s)
- Clodoaldo Irineu Levartoski de Araujo
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
- Departamento de Fìsica, Laboratório de Spintrônica e Nanomagnetismo, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Pauli Virtanen
- Department of Physics and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.
| | - Maria Spies
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Carmen González-Orellana
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Donostia-San Sebastián, Spain
| | - Samuel Kerschbaumer
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Donostia-San Sebastián, Spain
| | - Maxim Ilyn
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Donostia-San Sebastián, Spain
| | - Celia Rogero
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain
| | - Tero Tapio Heikkilä
- Department of Physics and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Francesco Giazotto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Elia Strambini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy.
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2
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Aceves Rodriguez UA, Guimarães F, Brinker S, Lounis S. Magnetic exchange interactions at the proximity of a superconductor. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:295801. [PMID: 38471158 DOI: 10.1088/1361-648x/ad32de] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 03/12/2024] [Indexed: 03/14/2024]
Abstract
Interfacing magnetism with superconductivity gives rise to a wonderful playground for intertwining key degrees of freedom: Cooper pairs, spin, charge, and spin-orbit interaction, from which emerge a wealth of exciting phenomena, fundamental in the nascent field of superconducting spinorbitronics and topological quantum technologies. Magnetic exchange interactions (MEIs), being isotropic or chiral such as the Dzyaloshinskii-Moriya interactions, are vital in establishing the magnetic behavior at these interfaces as well as in dictating not only complex transport phenomena, but also the manifestation of topologically trivial or non-trivial objects. Here, we propose a methodology enabling the extraction of the tensor of MEI from electronic structure simulations accounting for superconductivity. We apply our scheme to the case of a Mn layer deposited on Nb(110) surface and explore proximity-induced impact on the MEI. The latter are weakly modified by a realistic electron-phonon coupling. However, tuning the superconducting order parameter, we unveil potential change of the magnetic order accompanied with chirality switching, as induced by the interplay of spin-orbit interaction and Cooper pairing. Owing to its simple formulation, our methodology can be readily implemented in state-of-the-art frameworks capable of tackling superconductivity and magnetism. We thus foresee implications in the simulations and prediction of topological superconducting bits as well as of cryogenic superconducting hybrid devices involving magnetic units.
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Affiliation(s)
- Uriel A Aceves Rodriguez
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
- Faculty of Physics & CENIDE, University of Duisburg-Essen, 47053 Duisburg, Germany
| | - Filipe Guimarães
- Jülich Supercomputing Centre, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
| | - Sascha Brinker
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
| | - Samir Lounis
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
- Faculty of Physics & CENIDE, University of Duisburg-Essen, 47053 Duisburg, Germany
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3
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Gao Y, Zhang X, Yi Z, Liu L, Chi F. Thermophase Seebeck Coefficient in Hybridized Superconductor-Quantum-Dot-Superconductor Josephson Junction Side-Coupled to Majorana Nanowire. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2489. [PMID: 37686996 PMCID: PMC10490436 DOI: 10.3390/nano13172489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 09/10/2023]
Abstract
The dc Josephson current is generated from phase difference between two superconductors separated by a mesoscopic thin film (Josephson junction) without external bias voltage. In the presence of a temperature gradient across the superconductors, a thermal phase is induced under the condition of open circuit. This is very similar to the Seebeck effect in the usual thermoelectric effect, and the thermal phase is thus named as thermophase Seebeck coefficient (TPSC). Here we find obvious enhancement and sign change of the TPSC unique to the Josephson junction composing of two superconductors connected to a semiconductor quantum dot (QD), which is additionally side-coupled to a nanowire hosting Majorana bound states (MBSs), the system denoted by S-MQD-S. These result arise from the newly developed states near the Fermi level of the superconductors due to the QD-MBS hybridization when the dot level is within the superconducting gap. The sign change of the TPSC provides a strong evidence of the existence of MBSs, and is absent if the QD is coupled to regular fermion, such as another QD (system denoted by S-DQD-S). We show that the magnitude and sign of the TPSC are sensitive to the physical quantities including interaction strength between the QD and MBSs, direct overlap between the MBSs, system equilibrium temperature, as well as hopping amplitude between the QD and the superconductors. The obtained results are explained with the help of the current-carrying density of the states (CCDOS), and may be useful in interdisciplinary research areas of Josephson and Majorana physics.
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Affiliation(s)
- Yumei Gao
- School of Electronic and Information Engineering, UEST of China, Zhongshan Institute, Zhongshan 528400, China; (Y.G.); (Z.Y.); (L.L.)
| | - Xiaoyan Zhang
- College of Science, North China Institute of Science and Technology, Beijing 101601, China
| | - Zichuan Yi
- School of Electronic and Information Engineering, UEST of China, Zhongshan Institute, Zhongshan 528400, China; (Y.G.); (Z.Y.); (L.L.)
| | - Liming Liu
- School of Electronic and Information Engineering, UEST of China, Zhongshan Institute, Zhongshan 528400, China; (Y.G.); (Z.Y.); (L.L.)
| | - Feng Chi
- School of Electronic and Information Engineering, UEST of China, Zhongshan Institute, Zhongshan 528400, China; (Y.G.); (Z.Y.); (L.L.)
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4
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Lu B, Ikegaya S, Burset P, Tanaka Y, Nagaosa N. Tunable Josephson Diode Effect on the Surface of Topological Insulators. PHYSICAL REVIEW LETTERS 2023; 131:096001. [PMID: 37721825 DOI: 10.1103/physrevlett.131.096001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/27/2023] [Accepted: 08/02/2023] [Indexed: 09/20/2023]
Abstract
The Josephson rectification effect, where the resistance is finite in one direction while zero in the other, has been recently realized experimentally. The resulting Josephson diode has many potential applications on superconducting devices, including quantum computers. Here, we theoretically show that a superconductor-normal metal-superconductor Josephson junction diode on the two-dimensional surface of a topological insulator has large tunability. The magnitude and sign of the diode quality factor strongly depend on the external magnetic field, gate voltage, and the length of the junction. Such rich properties stem from the interplay between different current-phase relations for the multiple transverse transport channels, and can be used for designing realistic superconducting diode devices.
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Affiliation(s)
- Bo Lu
- Center for Joint Quantum Studies, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, Tianjin University, Tianjin 300354, China
| | - Satoshi Ikegaya
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
- Institute for Advanced Research, Nagoya University, Nagoya 464-8601, Japan
| | - Pablo Burset
- Department of Theoretical Condensed Matter Physics, Condensed Matter Physics Center (IFIMAC) and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Yukio Tanaka
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
- Research Center for Crystalline Materials Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Naoto Nagaosa
- Center for Emergent Matter Science (CEMS), RIKEN, Wako, Saitama 351-0198, Japan
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Chiles J, Arnault EG, Chen CC, Larson TFQ, Zhao L, Watanabe K, Taniguchi T, Amet F, Finkelstein G. Nonreciprocal Supercurrents in a Field-Free Graphene Josephson Triode. NANO LETTERS 2023. [PMID: 37191404 DOI: 10.1021/acs.nanolett.3c01276] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Superconducting diodes are proposed nonreciprocal circuit elements that should exhibit nondissipative transport in one direction while being resistive in the opposite direction. Multiple examples of such devices have emerged in the past couple of years; however, their efficiency is typically limited, and most of them require a magnetic field to function. Here we present a device that achieves efficiencies approaching 100% while operating at zero field. Our samples consist of a network of three graphene Josephson junctions linked by a common superconducting island, to which we refer as a Josephson triode. The three-terminal nature of the device inherently breaks the inversion symmetry, and the control current applied to one of the contacts breaks the time-reversal symmetry. The triode's utility is demonstrated by rectifying a small (nA scale amplitude) applied square wave. We speculate that devices of this type could be realistically employed in the modern quantum circuits.
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Affiliation(s)
- John Chiles
- Department of Physics, Duke University, Durham, North Carolina 27701, United States
| | - Ethan G Arnault
- Department of Physics, Duke University, Durham, North Carolina 27701, United States
| | - Chun-Chia Chen
- Department of Physics, Duke University, Durham, North Carolina 27701, United States
| | - Trevyn F Q Larson
- Department of Physics, Duke University, Durham, North Carolina 27701, United States
| | - Lingfei Zhao
- Department of Physics, Duke University, Durham, North Carolina 27701, United States
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba 305-0044, Japan
| | | | - François Amet
- Department of Physics and Astonomy, Appalachian State University, Boone, North Carolina 28607, United States
| | - Gleb Finkelstein
- Department of Physics, Duke University, Durham, North Carolina 27701, United States
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6
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Ramallo MV. Superconductivity in Nanosystems: A Fruitful Path to New Phenomenology in Quantum Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:592. [PMID: 36770553 PMCID: PMC9921788 DOI: 10.3390/nano13030592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
In the recent years, the landscape of the research in superconductivity has experienced a progressive focus on varied superconducting systems, which share as common primary characteristics the reduction of some of their dimensionalities and the emergence of qualitatively novel phenomenology with respect to bulk superconducting materials [...].
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Affiliation(s)
- Manuel V. Ramallo
- Quantum Materials and Photonics Research Group (QMatterPhotonics), Department of Particle Physics, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain; or
- Instituto de Materiais (iMATUS), University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
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7
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Souto RS, Leijnse M, Schrade C. Josephson Diode Effect in Supercurrent Interferometers. PHYSICAL REVIEW LETTERS 2022; 129:267702. [PMID: 36608204 DOI: 10.1103/physrevlett.129.267702] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 10/10/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
A Josephson diode is a nonreciprocal circuit element that supports a larger dissipationless supercurrent in one direction than in the other. In this Letter, we propose a class of Josephson diodes based on supercurrent interferometers composed of Andreev bound state Josephson junctions or interacting quantum dot Josephson junctions, which are not diodes themselves but possess nonsinusoidal current-phase relations. We show that such Josephson diodes have several important advantages, like being electrically tunable and requiring only time-reversal breaking by a magnetic flux. We also show that our diodes have a characteristic ac response, revealed by the Shapiro steps. Even the simplest realization of our Josephson diode paradigm that relies on only two junctions can achieve efficiencies of up to ∼40% and, interestingly, far greater efficiencies are achievable by concatenating interferometer loops. We hope that our Letter will stimulate the search for highly tunable Josephson diode effects in Josephson devices based semiconductor-superconductor hybrids, 2d materials, and topological insulators, where nonsinusoidal current-phase relations were recently observed.
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Affiliation(s)
- Rubén Seoane Souto
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Division of Solid State Physics and NanoLund, Lund University, S-22100 Lund, Sweden
| | - Martin Leijnse
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Division of Solid State Physics and NanoLund, Lund University, S-22100 Lund, Sweden
| | - Constantin Schrade
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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Bauriedl L, Bäuml C, Fuchs L, Baumgartner C, Paulik N, Bauer JM, Lin KQ, Lupton JM, Taniguchi T, Watanabe K, Strunk C, Paradiso N. Supercurrent diode effect and magnetochiral anisotropy in few-layer NbSe2. Nat Commun 2022; 13:4266. [PMID: 35871226 PMCID: PMC9308774 DOI: 10.1038/s41467-022-31954-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 07/07/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractNonreciprocal transport refers to charge transfer processes that are sensitive to the bias polarity. Until recently, nonreciprocal transport was studied only in dissipative systems, where the nonreciprocal quantity is the resistance. Recent experiments have, however, demonstrated nonreciprocal supercurrent leading to the observation of a supercurrent diode effect in Rashba superconductors. Here we report on a supercurrent diode effect in NbSe2 constrictions obtained by patterning NbSe2 flakes with both even and odd layer number. The observed rectification is a consequence of the valley-Zeeman spin-orbit interaction. We demonstrate a rectification efficiency as large as 60%, considerably larger than the efficiency of devices based on Rashba superconductors. In agreement with recent theory for superconducting transition metal dichalcogenides, we show that the effect is driven by the out-of-plane component of the magnetic field. Remarkably, we find that the effect becomes field-asymmetric in the presence of an additional in-plane field component transverse to the current direction. Supercurrent diodes offer a further degree of freedom in designing superconducting quantum electronics with the high degree of integrability offered by van der Waals materials.
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Turini B, Salimian S, Carrega M, Iorio A, Strambini E, Giazotto F, Zannier V, Sorba L, Heun S. Josephson Diode Effect in High-Mobility InSb Nanoflags. NANO LETTERS 2022; 22:8502-8508. [PMID: 36285780 PMCID: PMC9650771 DOI: 10.1021/acs.nanolett.2c02899] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/21/2022] [Indexed: 05/27/2023]
Abstract
We report nonreciprocal dissipation-less transport in single ballistic InSb nanoflag Josephson junctions. Applying an in-plane magnetic field, we observe an inequality in supercurrent for the two opposite current propagation directions. Thus, these devices can work as Josephson diodes, with dissipation-less current flowing in only one direction. For small fields, the supercurrent asymmetry increases linearly with external field, and then it saturates as the Zeeman energy becomes relevant, before it finally decreases to zero at higher fields. The effect is maximum when the in-plane field is perpendicular to the current vector, which identifies Rashba spin-orbit coupling as the main symmetry-breaking mechanism. While a variation in carrier concentration in these high-quality InSb nanoflags does not significantly influence the supercurrent asymmetry, it is instead strongly suppressed by an increase in temperature. Our experimental findings are consistent with a model for ballistic short junctions and show that the diode effect is intrinsic to this material.
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Affiliation(s)
- Bianca Turini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127Pisa, Italy
| | - Sedighe Salimian
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127Pisa, Italy
| | | | - Andrea Iorio
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127Pisa, Italy
| | - Elia Strambini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127Pisa, Italy
| | - Francesco Giazotto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127Pisa, Italy
| | - Valentina Zannier
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127Pisa, Italy
| | - Lucia Sorba
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127Pisa, Italy
| | - Stefan Heun
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127Pisa, Italy
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