1
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Sekiguchi F, Narita H, Hirori H, Ono T, Kanemitsu Y. Anomalous behavior of critical current in a superconducting film triggered by DC plus terahertz current. Nat Commun 2024; 15:4435. [PMID: 38789464 PMCID: PMC11126563 DOI: 10.1038/s41467-024-48738-8] [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: 12/03/2023] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
The critical current in a superconductor (SC) determines the performance of many SC devices, including SC diodes which have attracted recent attention. Hitherto, studies of SC diodes are limited in the DC-field measurements, and their performance under a high-frequency current remains unexplored. Here, we conduct the first investigation on the interaction between the DC and terahertz (THz) current in a SC artificial superlattice. We found that the DC critical current is sensitively modified by THz pulse excitations in a nontrivial manner. In particular, at low-frequency THz excitations below the SC gap, the critical current becomes sensitive to the THz-field polarization direction. Furthermore, we observed anomalous behavior in which a supercurrent flows with an amplitude larger than the modified critical current. Assuming that vortex depinning determines the critical current, we show that the THz-current-driven vortex dynamics reproduce the observed behavior. While the delicate nonreciprocity in the critical current is obscured by the THz pulse excitations, the interplay between the DC and THz current causes a non-monotonic SC/normal-state switching with current amplitude, which can pave a pathway to developing SC devices with novel functionalities.
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Affiliation(s)
- Fumiya Sekiguchi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.
| | - Hideki Narita
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Hideki Hirori
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Teruo Ono
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Yoshihiko Kanemitsu
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.
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2
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Reinhardt S, Ascherl T, Costa A, Berger J, Gronin S, Gardner GC, Lindemann T, Manfra MJ, Fabian J, Kochan D, Strunk C, Paradiso N. Link between supercurrent diode and anomalous Josephson effect revealed by gate-controlled interferometry. Nat Commun 2024; 15:4413. [PMID: 38782910 PMCID: PMC11116472 DOI: 10.1038/s41467-024-48741-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: 12/05/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
In Josephson diodes the asymmetry between positive and negative current branch of the current-phase relation leads to a polarity-dependent critical current and Josephson inductance. The supercurrent nonreciprocity can be described as a consequence of the anomalous Josephson effect -a φ0-shift of the current-phase relation- in multichannel ballistic junctions with strong spin-orbit interaction. In this work, we simultaneously investigate φ0-shift and supercurrent diode efficiency on the same Josephson junction by means of a superconducting quantum interferometer. By electrostatic gating, we reveal a direct link between φ0-shift and diode effect. Our findings show that spin-orbit interaction in combination with a Zeeman field plays an important role in determining the magnetochiral anisotropy and the supercurrent diode effect.
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Affiliation(s)
- S Reinhardt
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - T Ascherl
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - A Costa
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
| | - J Berger
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - S Gronin
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - G C Gardner
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - T Lindemann
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - M J Manfra
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
- School of Materials Engineering, Purdue University, West Lafayette, IN, USA
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
| | - J Fabian
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
| | - D Kochan
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
- Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
- Center for Quantum Frontiers of Research and Technology (QFort), National Cheng Kung University, Tainan, Taiwan
| | - C Strunk
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - N Paradiso
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany.
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3
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Asaba T, Naritsuka M, Asaeda H, Kosuge Y, Ikemori S, Suetsugu S, Kasahara Y, Kohsaka Y, Terashima T, Daido A, Yanase Y, Matsuda Y. Evidence for a finite-momentum Cooper pair in tricolor d-wave superconducting superlattices. Nat Commun 2024; 15:3861. [PMID: 38719822 PMCID: PMC11078924 DOI: 10.1038/s41467-024-47875-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 04/09/2024] [Indexed: 05/12/2024] Open
Abstract
Fermionic superfluidity with a nontrivial Cooper-pairing, beyond the conventional Bardeen-Cooper-Schrieffer state, is a captivating field of study in quantum many-body systems. In particular, the search for superconducting states with finite-momentum pairs has long been a challenge, but establishing its existence has long suffered from the lack of an appropriate probe to reveal its momentum. Recently, it has been proposed that the nonreciprocal electron transport is the most powerful probe for the finite-momentum pairs, because it directly couples to the supercurrents. Here we reveal such a pairing state by the non-reciprocal transport on tricolor superlattices with strong spin-orbit coupling combined with broken inversion-symmetry consisting of atomically thin d-wave superconductor CeCoIn5. We find that while the second-harmonic resistance exhibits a distinct dip anomaly at the low-temperature (T)/high-magnetic field (H) corner in the HT-plane for H applied to the antinodal direction of the d-wave gap, such an anomaly is absent for H along the nodal direction. By carefully isolating extrinsic effects due to vortex dynamics, we reveal the presence of a non-reciprocal response originating from intrinsic superconducting properties characterized by finite-momentum pairs. We attribute the high-field state to the helical superconducting state, wherein the phase of the order parameter is spontaneously spatially modulated.
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Affiliation(s)
- T Asaba
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan.
| | - M Naritsuka
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
- RIKEN Center for Emergent Matter Science, Wako, Saitama, 351-0198, Japan
| | - H Asaeda
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Kosuge
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - S Ikemori
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - S Suetsugu
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Kasahara
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Kohsaka
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - T Terashima
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - A Daido
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Yanase
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan.
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4
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Coraiola M, Svetogorov AE, Haxell DZ, Sabonis D, Hinderling M, Ten Kate SC, Cheah E, Krizek F, Schott R, Wegscheider W, Cuevas JC, Belzig W, Nichele F. Flux-Tunable Josephson Diode Effect in a Hybrid Four-Terminal Josephson Junction. ACS NANO 2024; 18:9221-9231. [PMID: 38488287 DOI: 10.1021/acsnano.4c01642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
We investigate the direction-dependent switching current in a flux-tunable four-terminal Josephson junction defined in an InAs/Al two-dimensional heterostructure. The device exhibits the Josephson diode effect with switching currents that depend on the sign of the bias current. The superconducting diode efficiency, reaching a maximum of |η| ≈ 34%, is widely tunable─both in amplitude and sign─as a function of magnetic fluxes and gate voltages. Our observations are supported by a circuit model of three parallel Josephson junctions with nonsinusoidal current-phase relation. With respect to conventional Josephson interferometers, phase-tunable multiterminal Josephson junctions enable large diode efficiencies in structurally symmetric devices, where local magnetic fluxes generated on the chip break both time-reversal and spatial symmetries. Our work presents an approach for developing Josephson diodes with wide-range tunability that do not rely on exotic materials.
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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
- Institute of Physics, Czech Academy of Sciences, 162 00 Prague, Czech Republic
| | - Rüdiger Schott
- Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich, Switzerland
| | - Werner Wegscheider
- Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich, Switzerland
| | - 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
| | - Wolfgang Belzig
- Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
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5
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Kim JK, Jeon KR, Sivakumar PK, Jeon J, Koerner C, Woltersdorf G, Parkin SSP. Intrinsic supercurrent non-reciprocity coupled to the crystal structure of a van der Waals Josephson barrier. Nat Commun 2024; 15:1120. [PMID: 38321041 PMCID: PMC10847146 DOI: 10.1038/s41467-024-45298-9] [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: 05/27/2023] [Accepted: 01/17/2024] [Indexed: 02/08/2024] Open
Abstract
Non-reciprocal electronic transport in a spatially homogeneous system arises from the simultaneous breaking of inversion and time-reversal symmetries. Superconducting and Josephson diodes, a key ingredient for future non-dissipative quantum devices, have recently been realized. Only a few examples of a vertical superconducting diode effect have been reported and its mechanism, especially whether intrinsic or extrinsic, remains elusive. Here we demonstrate a substantial supercurrent non-reciprocity in a van der Waals vertical Josephson junction formed with a Td-WTe2 barrier and NbSe2 electrodes that clearly reflects the intrinsic crystal structure of Td-WTe2. The Josephson diode efficiency increases with the Td-WTe2 thickness up to critical thickness, and all junctions, irrespective of the barrier thickness, reveal magneto-chiral characteristics with respect to a mirror plane of Td-WTe2. Our results, together with the twist-angle-tuned magneto-chirality of a Td-WTe2 double-barrier junction, show that two-dimensional materials promise vertical Josephson diodes with high efficiency and tunability.
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Affiliation(s)
- Jae-Keun Kim
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany.
| | - Kun-Rok Jeon
- Department of Physics, Chung-Ang University (CAU), Seoul, 06974, Republic of Korea
| | - Pranava K Sivakumar
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Jaechun Jeon
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Chris Koerner
- Department of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120, Halle, Germany
| | - Georg Woltersdorf
- Department of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120, Halle, Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany.
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6
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Virtanen P, Heikkilä TT. Nonreciprocal Josephson Linear Response. PHYSICAL REVIEW LETTERS 2024; 132:046002. [PMID: 38335348 DOI: 10.1103/physrevlett.132.046002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 12/22/2023] [Indexed: 02/12/2024]
Abstract
We consider the finite-frequency response of multiterminal Josephson junctions and show how nonreciprocity in them can show up at linear response, in contrast to the static Josephson diodes featuring nonlinear nonreciprocity. At finite frequencies, the response contains dynamic contributions to the Josephson admittance, featuring the effects of Andreev bound state transitions along with Berry phase effects, and reflecting the breaking of the same symmetries as in Josephson diodes. We show that outside exact Andreev resonances, the junctions feature nonreciprocal reactive response. As a result, the microwave transmission through those systems is nondissipative, and the electromagnetic scattering can approach complete nonreciprocity. Besides providing information about the nature of the weak link energy levels, the nonreciprocity can be utilized to create nondissipative and small-scale on-chip circulators whose operation requires only rather small magnetic fields.
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Affiliation(s)
- Pauli Virtanen
- Department of Physics and Nanoscience Center, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 University of Jyväskylä, Finland
| | - Tero T Heikkilä
- Department of Physics and Nanoscience Center, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 University of Jyväskylä, Finland
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7
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Banerjee S, Scheurer MS. Enhanced Superconducting Diode Effect due to Coexisting Phases. PHYSICAL REVIEW LETTERS 2024; 132:046003. [PMID: 38335356 DOI: 10.1103/physrevlett.132.046003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 12/14/2023] [Indexed: 02/12/2024]
Abstract
The superconducting diode effect refers to an asymmetry in the critical supercurrent J_{c}(n[over ^]) along opposite directions, J_{c}(n[over ^])≠J_{c}(-n[over ^]). While the basic symmetry requirements for this effect are known, it is, for junction-free systems, difficult to capture within current theoretical models the large current asymmetries J_{c}(n[over ^])/J_{c}(-n[over ^]) recently observed in experiment. We here propose and develop a theory for an enhancement mechanism of the diode effect arising from spontaneous symmetry breaking. We show-both within a phenomenological and a microscopic theory-that there is a coupling of the supercurrent and the underlying symmetry-breaking order parameter. This coupling can enhance the current asymmetry significantly. Our work might not only provide a possible explanation for recent experiments on trilayer graphene but also pave the way for future realizations of the superconducting diode effect with large current asymmetries.
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Affiliation(s)
- Sayan Banerjee
- Institute for Theoretical Physics III, University of Stuttgart, 70550 Stuttgart, Germany and Institute for Theoretical Physics, University of Innsbruck, Innsbruck A-6020, Austria
| | - Mathias S Scheurer
- Institute for Theoretical Physics III, University of Stuttgart, 70550 Stuttgart, Germany and Institute for Theoretical Physics, University of Innsbruck, Innsbruck A-6020, Austria
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8
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Banerjee A, Geier M, Rahman MA, Thomas C, Wang T, Manfra MJ, Flensberg K, Marcus CM. Phase Asymmetry of Andreev Spectra from Cooper-Pair Momentum. PHYSICAL REVIEW LETTERS 2023; 131:196301. [PMID: 38000437 DOI: 10.1103/physrevlett.131.196301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 08/10/2023] [Accepted: 10/16/2023] [Indexed: 11/26/2023]
Abstract
In analogy to conventional semiconductor diodes, the Josephson diode exhibits superconducting properties that are asymmetric in applied bias. The effect has been investigated in a number of systems recently, and requires a combination of broken time-reversal and inversion symmetries. We demonstrate a dual of the usual Josephson diode effect, a nonreciprocal response of Andreev bound states to a superconducting phase difference across the normal region of a superconductor-normal-superconductor Josephson junction, fabricated using an epitaxial InAs/Al heterostructure. Phase asymmetry of the subgap Andreev spectrum is absent in the absence of in-plane magnetic field and reaches a maximum at 0.15 T applied in the plane of the junction transverse to the current direction. We interpret the phase diode effect in this system as resulting from finite-momentum Cooper pairing due to orbital coupling to the in-plane magnetic field. At higher magnetic fields, we observe a sign reversal of the diode effect that appears together with a reopening of the spectral gap. Within our model, the sign reversal of the diode effect at higher fields is correlated with a topological phase transition that requires Zeeman and spin-orbit interactions in addition to orbital coupling.
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Affiliation(s)
- Abhishek Banerjee
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Max Geier
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Md Ahnaf Rahman
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Candice Thomas
- Department of Physics and Astronomy, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Tian Wang
- Department of Physics and Astronomy, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Michael J Manfra
- Department of Physics and Astronomy, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
- School of Materials Engineering, and School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Karsten Flensberg
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Charles M Marcus
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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9
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Costa A, Baumgartner C, Reinhardt S, Berger J, Gronin S, Gardner GC, Lindemann T, Manfra MJ, Fabian J, Kochan D, Paradiso N, Strunk C. Sign reversal of the Josephson inductance magnetochiral anisotropy and 0-π-like transitions in supercurrent diodes. NATURE NANOTECHNOLOGY 2023; 18:1266-1272. [PMID: 37430040 DOI: 10.1038/s41565-023-01451-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 06/09/2023] [Indexed: 07/12/2023]
Abstract
The recent discovery of the intrinsic supercurrent diode effect, and its prompt observation in a rich variety of systems, has shown that non-reciprocal supercurrents naturally emerge when both space-inversion and time-inversion symmetries are broken. In Josephson junctions, non-reciprocal supercurrent can be conveniently described in terms of spin-split Andreev states. Here we demonstrate a sign reversal of the Josephson inductance magnetochiral anisotropy, a manifestation of the supercurrent diode effect. The asymmetry of the Josephson inductance as a function of the supercurrent allows us to probe the current-phase relation near equilibrium, and to probe jumps in the junction ground state. Using a minimal theoretical model, we can then link the sign reversal of the inductance magnetochiral anisotropy to the so-called 0-π-like transition, a predicted but still elusive feature of multichannel junctions. Our results demonstrate the potential of inductance measurements as sensitive probes of the fundamental properties of unconventional Josephson junctions.
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Affiliation(s)
- A Costa
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
| | - C Baumgartner
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - S Reinhardt
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - J Berger
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - S Gronin
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - G C Gardner
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - T Lindemann
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - M J Manfra
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
- School of Materials Engineering, Purdue University, West Lafayette, IN, USA
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
| | - J Fabian
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
| | - D Kochan
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
- Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - N Paradiso
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany.
| | - C Strunk
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
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10
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Narita H, Ishizuka J, Kan D, Shimakawa Y, Yanase Y, Ono T. Magnetization Control of Zero-Field Intrinsic Superconducting Diode Effect. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2304083. [PMID: 37410358 DOI: 10.1002/adma.202304083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/28/2023] [Accepted: 07/03/2023] [Indexed: 07/07/2023]
Abstract
The superconducting diode effect (SDE), which causes a superconducting state in one direction and a normal-conducting state in another, has significant potential for developing ultralow power consumption circuits and non-volatile memory. However, the practical control of the SDE necessities the precise tuning of current, temperature, magnetic field, or magnetism. Therefore, the mechanisms of the SDE must be understood to develop novel materials and devices capable of realizing the SDE under more controlled and robust conditions. This study demonstrates an intrinsic zero-field SDE with an efficiency of up to 40% in Fe/Pt-inserted non-centrosymmetric Nb/V/Ta superconducting artificial superlattices. The polarity and magnitude of the zero-field SDE are controllable by the direction of magnetization, indicating that the effective exchange field acts on Cooper pairs. Furthermore, the first-principles calculation indicates that the SDE can be enhanced by an asymmetric configuration of proximity induced magnetic moments in superconducting layers, which induces a magnetic toroidal moment. This study has important implications regarding the development of novel materials and devices that can effectively control the SDE. Moreover, the magnetization control of the SDE is expected to aid in the designing of superconducting quantum devices and establishing a material platform for topological superconductors.
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Affiliation(s)
- Hideki Narita
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Jun Ishizuka
- Faculty of Engineering, Niigata University, Ikarashi, Niigata, 950-2181, Japan
| | - Daisuke Kan
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
- Center for Spintronics Research Network, Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Yuichi Shimakawa
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
- Center for Spintronics Research Network, Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Youichi Yanase
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
- Institute for Molecular Science, Okazaki, 444-0867, Japan
| | - Teruo Ono
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
- Center for Spintronics Research Network, Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
- Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, Toyonaka, 560-0043, Japan
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11
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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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12
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Hou Y, Nichele F, Chi H, Lodesani A, Wu Y, Ritter MF, Haxell DZ, Davydova M, Ilić S, Glezakou-Elbert O, Varambally A, Bergeret FS, Kamra A, Fu L, Lee PA, Moodera JS. Ubiquitous Superconducting Diode Effect in Superconductor Thin Films. PHYSICAL REVIEW LETTERS 2023; 131:027001. [PMID: 37505965 DOI: 10.1103/physrevlett.131.027001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 05/09/2023] [Indexed: 07/30/2023]
Abstract
The macroscopic coherence in superconductors supports dissipationless supercurrents that could play a central role in emerging quantum technologies. Accomplishing unequal supercurrents in the forward and backward directions would enable unprecedented functionalities. This nonreciprocity of critical supercurrents is called the superconducting (SC) diode effect. We demonstrate the strong SC diode effect in conventional SC thin films, such as niobium and vanadium, employing external magnetic fields as small as 1 Oe. Interfacing the SC layer with a ferromagnetic semiconductor EuS, we further accomplish the nonvolatile SC diode effect reaching a giant efficiency of 65%. By careful control experiments and theoretical modeling, we demonstrate that the critical supercurrent nonreciprocity in SC thin films could be easily accomplished with asymmetrical vortex edge and surface barriers and the universal Meissner screening current governing the critical currents. Our engineering of the SC diode effect in simple systems opens the door for novel technologies while revealing the ubiquity of the Meissner screening effect induced SC diode effect in superconducting films, and it should be eliminated with great care in the search for exotic superconducting states harboring finite-momentum Cooper pairing.
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Affiliation(s)
- Yasen Hou
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Fabrizio Nichele
- IBM Research Europe - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Hang Chi
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- U.S. Army DEVCOM Army Research Laboratory, Adelphi, Maryland 20783, USA
| | - Alessandro Lodesani
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Yingying Wu
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Markus F Ritter
- IBM Research Europe - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Daniel Z Haxell
- IBM Research Europe - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Margarita Davydova
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Stefan Ilić
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Pº Manuel de Lardizabal 5, Donostia-San Sebastián 20018, Spain
| | | | | | - F Sebastian Bergeret
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Pº Manuel de Lardizabal 5, Donostia-San Sebastián 20018, Spain
- Donostia International Physics Center (DIPC), Donostia-San Sebastián 20018, Spain
| | - Akashdeep Kamra
- Condensed Matter Physics Center (IFIMAC) and Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Patrick A Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jagadeesh S Moodera
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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13
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Xie YM, Law KT. Orbital Fulde-Ferrell Pairing State in Moiré Ising Superconductors. PHYSICAL REVIEW LETTERS 2023; 131:016001. [PMID: 37478419 DOI: 10.1103/physrevlett.131.016001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/09/2023] [Indexed: 07/23/2023]
Abstract
In this Letter, we study superconducting moiré homobilayer transition metal dichalcogenides where the Ising spin-orbit coupling (SOC) is much larger than the moiré bandwidth. We call such noncentrosymmetric superconductors, moiré Ising superconductors. Because of the large Ising SOC, the depairing effect caused by the Zeeman field is negligible and the in-plane upper critical field (B_{c2}) is determined by the orbital effects. This allows us to study the effect of large orbital fields. Interestingly, when the applied in-plane field is larger than the conventional orbital B_{c2}, a finite-momentum pairing phase would appear which we call the orbital Fulde-Ferrell (FF) state. In this state, the Cooper pairs acquire a net momentum of 2q_{B}, where 2q_{B}=eBd is the momentum shift caused by the magnetic field B and d denotes the layer separation. This orbital field-driven FF state is different from the conventional FF state driven by Zeeman effects in Rashba superconductors. Remarkably, we predict that the FF pairing would result in a giant superconducting diode effect under electric gating when layer asymmetry is induced. An upturn of the B_{c2} as the temperature is lowered, coupled with the giant superconducting diode effect, would allow the detection of the orbital FF state.
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Affiliation(s)
- Ying-Ming Xie
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - K T Law
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
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14
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He JJ, Tanaka Y, Nagaosa N. The supercurrent diode effect and nonreciprocal paraconductivity due to the chiral structure of nanotubes. Nat Commun 2023; 14:3330. [PMID: 37286618 DOI: 10.1038/s41467-023-39083-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 05/30/2023] [Indexed: 06/09/2023] Open
Abstract
The phenomenon that critical supercurrents along opposite directions become unequal is called the supercurrent diode effect (SDE). It has been observed in various systems and can often be understood by combining spin-orbit coupling and Zeeman field, which break the spatial-inversion and time-reversal symmetries, respectively. Here, we theoretically investigate another mechanism of breaking these symmetries and predict the existence of the SDE in chiral nanotubes without spin-orbit coupling. The symmetries are broken by the chiral structure and a magnetic flux through the tube. With a generalized Ginzburg-Landau theory, we obtain the main features of the SDE in its dependence on system parameters. We further show that the same Ginzburg-Landau free energy leads to another important manifestation of the nonreciprocity in superconducting systems, i.e., the nonreciprocal paraconductivity (NPC) slightly above the transition temperature. Our study suggests a new class of realistic platforms to investigate nonreciprocal properties of superconducting materials. It also provides a theoretical link between the SDE and the NPC, which were often studied separately.
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Affiliation(s)
- James Jun He
- Hefei National Laboratory, Hefei, Anhui, 230088, China.
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| | - Yukio Tanaka
- Department of Applied Physics, Nagoya University, Nagoya, 464-8603, Japan
| | - Naoto Nagaosa
- Center for Emergent Matter Science (CEMS), RIKEN, Wako, Saitama, 351-0198, Japan
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15
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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: 1] [Impact Index Per Article: 1.0] [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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16
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Steiner JF, Melischek L, Trahms M, Franke KJ, von Oppen F. Diode Effects in Current-Biased Josephson Junctions. PHYSICAL REVIEW LETTERS 2023; 130:177002. [PMID: 37172233 DOI: 10.1103/physrevlett.130.177002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 04/07/2023] [Indexed: 05/14/2023]
Abstract
Current-biased Josephson junctions exhibit hysteretic transitions between dissipative and superconducting states as characterized by switching and retrapping currents. Here, we develop a theory for diodelike effects in the switching and retrapping currents of weakly damped Josephson junctions. We find that while the diodelike behavior of switching currents is rooted in asymmetric current-phase relations, nonreciprocal retrapping currents originate in asymmetric quasiparticle currents. These different origins also imply distinctly different symmetry requirements. We illustrate our results by a microscopic model for junctions involving a single magnetic atom. Our theory provides significant guidance in identifying the microscopic origin of nonreciprocities in Josephson junctions.
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Affiliation(s)
- Jacob F Steiner
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Larissa Melischek
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Martina Trahms
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | | | - Felix von Oppen
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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17
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Gutfreund A, Matsuki H, Plastovets V, Noah A, Gorzawski L, Fridman N, Yang G, Buzdin A, Millo O, Robinson JWA, Anahory Y. Direct observation of a superconducting vortex diode. Nat Commun 2023; 14:1630. [PMID: 36959184 PMCID: PMC10036628 DOI: 10.1038/s41467-023-37294-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 03/09/2023] [Indexed: 03/25/2023] Open
Abstract
The interplay between magnetism and superconductivity can lead to unconventional proximity and Josephson effects. A related phenomenon that has recently attracted considerable attention is the superconducting diode effect, in which a nonreciprocal critical current emerges. Although superconducting diodes based on superconductor/ferromagnet (S/F) bilayers were demonstrated more than a decade ago, the precise underlying mechanism remains unclear. While not formally linked to this effect, the Fulde-Ferrell-Larkin-Ovchinikov (FFLO) state is a plausible mechanism due to the twofold rotational symmetry breaking caused by the finite center-of-mass-momentum of the Cooper pairs. Here, we directly observe asymmetric vortex dynamics that uncover the mechanism behind the superconducting vortex diode effect in Nb/EuS (S/F) bilayers. Based on our nanoscale SQUID-on-tip (SOT) microscope and supported by in-situ transport measurements, we propose a theoretical model that captures our key results. The key conclusion of our model is that screening currents induced by the stray fields from the F layer are responsible for the measured nonreciprocal critical current. Thus, we determine the origin of the vortex diode effect, which builds a foundation for new device concepts.
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Affiliation(s)
- Alon Gutfreund
- The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
| | - Hisakazu Matsuki
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, CB3 0FS, United Kingdom
| | - Vadim Plastovets
- LOMA UMR-CNRS 5798, University of Bordeaux, Talence, F-33405, France
| | - Avia Noah
- The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Laura Gorzawski
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, CB3 0FS, United Kingdom
| | - Nofar Fridman
- The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Guang Yang
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, CB3 0FS, United Kingdom
| | - Alexander Buzdin
- LOMA UMR-CNRS 5798, University of Bordeaux, Talence, F-33405, France
| | - Oded Millo
- The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Jason W A Robinson
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, CB3 0FS, United Kingdom.
| | - Yonathan Anahory
- The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
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18
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Sundaresh A, Väyrynen JI, Lyanda-Geller Y, Rokhinson LP. Diamagnetic mechanism of critical current non-reciprocity in multilayered superconductors. Nat Commun 2023; 14:1628. [PMID: 36959191 PMCID: PMC10036566 DOI: 10.1038/s41467-023-36786-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 02/14/2023] [Indexed: 03/25/2023] Open
Abstract
The suggestion that non-reciprocal critical current (NRC) may be an intrinsic property of non-centrosymmetric superconductors has generated renewed theoretical and experimental interest motivated by an analogy with the non-reciprocal resistivity due to the magnetochiral effect in uniform materials with broken spatial and time-reversal symmetry. Theoretically it has been understood that terms linear in the Cooper pair momentum do not contribute to NRC, although the role of higher-order terms remains unclear. In this work we show that critical current non-reciprocity is a generic property of multilayered superconductor structures in the presence of magnetic field-generated diamagnetic currents. In the regime of an intermediate coupling between the layers, the Josephson vortices are predicted to form at high fields and currents. Experimentally, we report the observation of NRC in nanowires fabricated from InAs/Al heterostructures. The effect is independent of the crystallographic orientation of the wire, ruling out an intrinsic origin of NRC. Non-monotonic NRC evolution with magnetic field is consistent with the generation of diamagnetic currents and formation of the Josephson vortices. This extrinsic NRC mechanism can be used to design novel devices for superconducting circuits.
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Affiliation(s)
- Ananthesh Sundaresh
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
| | - Jukka I Väyrynen
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
| | - Yuli Lyanda-Geller
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
| | - Leonid P Rokhinson
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA.
- Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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19
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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: 12] [Impact Index Per Article: 6.0] [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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20
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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: 20] [Impact Index Per Article: 10.0] [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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21
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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: 11] [Impact Index Per Article: 5.5] [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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22
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Jeon KR, Kim JK, Yoon J, Jeon JC, Han H, Cottet A, Kontos T, Parkin SSP. Zero-field polarity-reversible Josephson supercurrent diodes enabled by a proximity-magnetized Pt barrier. NATURE MATERIALS 2022; 21:1008-1013. [PMID: 35798947 DOI: 10.1038/s41563-022-01300-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Simultaneous breaking of inversion and time-reversal symmetries in a conductor yields a non-reciprocal electronic transport1-3, known as the diode or rectification effect, that is, low (ideally zero) conductance in one direction and high (ideally infinite) conductance in the other. So far, most of the diode effects observed in non-centrosymmetric polar/superconducting conductors4-7 and Josephson junctions8-10 require external magnetic fields to break the time-reversal symmetry. Here we report zero-field polarity-switchable Josephson supercurrent diodes, in which a proximity-magnetized Pt layer by ferrimagnetic insulating Y3Fe5O12 serves as the Rashba(-type) Josephson barrier. The zero-field diode efficiency of our proximity-engineered device reaches up to ±35% at 2 K, with a clear square-root dependence on temperature. Measuring in-plane field-strength/angle dependences and comparing with Cu-inserted control junctions, we demonstrate that exchange spin-splitting11-13 and Rashba(-type) spin-orbit coupling13-15 at the Pt/Y3Fe5O12 interface are key for the zero-field giant rectification efficiency. Our achievement advances the development of field-free absolute Josephson diodes.
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Affiliation(s)
- Kun-Rok Jeon
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany.
- Department of Physics, Chung-Ang University (CAU), Seoul, Republic of Korea.
| | - Jae-Keun Kim
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | - Jiho Yoon
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | - Jae-Chun Jeon
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | - Hyeon Han
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | - Audrey Cottet
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, France
| | - Takis Kontos
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, France
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany.
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23
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Davydova M, Prembabu S, Fu L. Universal Josephson diode effect. SCIENCE ADVANCES 2022; 8:eabo0309. [PMID: 35675396 PMCID: PMC9176746 DOI: 10.1126/sciadv.abo0309] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 04/19/2022] [Indexed: 05/27/2023]
Abstract
We propose a universal mechanism for the Josephson diode effect in short Josephson junctions. The proposed mechanism is due to finite Cooper pair momentum and is a manifestation of simultaneous breaking of inversion and time-reversal symmetries. The diode efficiency is up to 40%, which corresponds to an asymmetry between the critical currents in opposite directions Ic+/Ic- ≈ 230%. We show that this arises from both the Doppler shift of the Andreev bound state energies and the phase-independent asymmetric current from the continuum. Last, we propose a simple scheme for achieving finite-momentum pairing, which does not rely on spin-orbit coupling and thus greatly expands existing platforms for the observation of supercurrent diode effects.
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Affiliation(s)
- Margarita Davydova
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Saranesh Prembabu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Liang Fu
- Corresponding author. (M.D.); (L.F.)
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