1
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Matsuo S, Imoto T, Yokoyama T, Sato Y, Lindemann T, Gronin S, Gardner GC, Manfra MJ, Tarucha S. Phase engineering of anomalous Josephson effect derived from Andreev molecules. SCIENCE ADVANCES 2023; 9:eadj3698. [PMID: 38091387 PMCID: PMC10848717 DOI: 10.1126/sciadv.adj3698] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 11/14/2023] [Indexed: 02/12/2024]
Abstract
A Josephson junction (JJ) is a key device for developing superconducting circuits, wherein a supercurrent in the JJ is controlled by the phase difference between the two superconducting electrodes. When two JJs sharing one superconducting electrode are coherently coupled and form the Andreev molecules, a supercurrent of one JJ is expected to be nonlocally controlled by the phase difference of another JJ. Here, we evaluate the supercurrent in one of the coupled two JJs as a function of local and nonlocal phase differences. Consequently, the results exhibit that the nonlocal phase control generates a finite supercurrent even when the local phase difference is zero. In addition, an offset of the local phase difference giving the JJ ground state depends on the nonlocal phase difference. These features demonstrate the anomalous Josephson effect realized by the nonlocal phase control. Our results provide a useful concept for engineering superconducting devices such as phase batteries and dissipationless rectifiers.
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Affiliation(s)
- Sadashige Matsuo
- Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Takaya Imoto
- Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan
- Department of Applied Physics, Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601, Japan
| | - Tomohiro Yokoyama
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Yosuke Sato
- Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Tyler Lindemann
- Birck Nanotechnology Center, Purdue University,, West Lafayette, IN 47907, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, USA
| | - Sergei Gronin
- Birck Nanotechnology Center, Purdue University,, West Lafayette, IN 47907, USA
| | - Geoffrey C. Gardner
- Birck Nanotechnology Center, Purdue University,, West Lafayette, IN 47907, USA
| | - Michael J. Manfra
- Birck Nanotechnology Center, Purdue University,, West Lafayette, IN 47907, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, USA
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Seigo Tarucha
- Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing, RIKEN, Wako, Saitama 351-0198, Japan
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2
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Matsuo S, Imoto T, Yokoyama T, Sato Y, Lindemann T, Gronin S, Gardner GC, Nakosai S, Tanaka Y, Manfra MJ, Tarucha S. Phase-dependent Andreev molecules and superconducting gap closing in coherently-coupled Josephson junctions. Nat Commun 2023; 14:8271. [PMID: 38092786 PMCID: PMC10719386 DOI: 10.1038/s41467-023-44111-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
The Josephson junction (JJ) is an essential element of superconducting (SC) devices for both fundamental and applied physics. The short-range coherent coupling of two adjacent JJs forms Andreev molecule states (AMSs), which provide a new ingredient to engineer exotic SC phenomena such as topological SC states and Andreev qubits. Here we provide tunneling spectroscopy measurements on a device consisting of two electrically controllable planar JJs sharing a single SC electrode. We discover that Andreev spectra in the coupled JJ are highly modulated from those in the single JJs and possess phase-dependent AMS features reproduced in our numerical calculation. Notably, the SC gap closing due to the AMS formation is experimentally observed. Our results help in understanding SC transport derived from the AMS and promoting the use of AMS physics to engineer topological SC states and quantum information devices.
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Affiliation(s)
- Sadashige Matsuo
- Center for Emergent Matter Science, RIKEN, Saitama, 351-0198, Japan.
| | - Takaya Imoto
- Center for Emergent Matter Science, RIKEN, Saitama, 351-0198, Japan
- Department of Applied Physics, Tokyo University of Science, Tokyo, 162-8601, Japan
| | - Tomohiro Yokoyama
- Department of Materials Engineering Science, Osaka University, Osaka, 560-8531, Japan.
| | - Yosuke Sato
- Center for Emergent Matter Science, RIKEN, Saitama, 351-0198, Japan
| | - Tyler Lindemann
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, IN, 47907, USA
| | - Sergei Gronin
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, IN, 47907, USA
| | - Geoffrey C Gardner
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, IN, 47907, USA
| | - Sho Nakosai
- Department of Applied Physics, Nagoya University, Nagoya, 464-8603, Japan
| | - Yukio Tanaka
- Department of Applied Physics, Nagoya University, Nagoya, 464-8603, Japan
| | - Michael J Manfra
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, IN, 47907, USA
- School of Materials Engineering, Purdue University, West Lafayette, Indiana, IN, 47907, USA
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, IN, 47907, USA
| | - Seigo Tarucha
- Center for Emergent Matter Science, RIKEN, Saitama, 351-0198, Japan.
- RIKEN Center for Quantum Computing, RIKEN, Saitama, 351-0198, Japan.
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3
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Scheppe AD, Pak MV. Perturbing finite temperature multicomponent DFT 1D Kohn-Sham systems: Peierls gap & Kohn anomaly. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:075401. [PMID: 37921113 DOI: 10.1088/1361-648x/ad08eb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 11/01/2023] [Indexed: 11/04/2023]
Abstract
One of the greatest challenges when designing new technologies that make use of non-trivial quantum materials is the difficulty associated with predicting material-specific properties, such as critical temperature, gap parameter, etc. There is naturally a great amount of interest in these types of condensed matter systems because of their application to quantum sensing, quantum electronics, and quantum computation; however, they are exceedingly difficult to address from first principles because of the famous many-body problem. For this reason, a full electron-nuclear quantum calculation will likely remain completely out of reach for the foreseeable future. A practical alternative is provided by finite temperature, multi component density functional theory, which is a formally exact method of computing the equilibrium state energy of a many-body quantum system. In this work, we use this construction alongside a perturbative scheme to demonstrate that the phenomena Peierls effect and Kohn anomaly are both natural features of the Kohn-Sham (KS) equations without additional structure needed. We find the temperature dependent ionic density for a simple 1D lattice which is then used to derive the ionic densities temperature dependent affect on the electronic band structure. This is accomplished by Fourier transforming the ionic density term found within this KS electronic equation. Using the Peierls effect phonon distortion gap openings in relation to the Fermi level, we then perturb the KS ionic equation with a conduction electron density, deriving the Kohn anomaly. This provides a workable predictive strategy for interesting electro-phonon related material properties which could be extended to 2D and 3D real materials while retaining the otherwise complicated temperature dependence.
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Affiliation(s)
- Adrian D Scheppe
- Department of Physics, Air Force Institute of Technology, 2950 Hobson Way, Wright-Patterson AFB, OH 45433, United States of America
| | - Michael V Pak
- Department of Physics, Air Force Institute of Technology, 2950 Hobson Way, Wright-Patterson AFB, OH 45433, United States of America
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4
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Coraiola M, Haxell DZ, Sabonis D, Weisbrich H, Svetogorov AE, Hinderling M, Ten Kate SC, Cheah E, Krizek F, Schott R, Wegscheider W, Cuevas JC, Belzig W, Nichele F. Phase-engineering the Andreev band structure of a three-terminal Josephson junction. Nat Commun 2023; 14:6784. [PMID: 37880228 PMCID: PMC10600130 DOI: 10.1038/s41467-023-42356-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 10/09/2023] [Indexed: 10/27/2023] Open
Abstract
In hybrid Josephson junctions with three or more superconducting terminals coupled to a semiconducting region, Andreev bound states may form unconventional energy band structures, or Andreev matter, which are engineered by controlling superconducting phase differences. Here we report tunnelling spectroscopy measurements of three-terminal Josephson junctions realised in an InAs/Al heterostructure. The three terminals are connected to form two loops, enabling independent control over two phase differences and access to a synthetic Andreev band structure in the two-dimensional phase space. Our results demonstrate a phase-controlled Andreev molecule, originating from two discrete Andreev levels that spatially overlap and hybridise. Signatures of hybridisation are observed in the form of avoided crossings in the spectrum and band structure anisotropies in the phase space, all explained by a numerical model. Future extensions of this work could focus on addressing spin-resolved energy levels, ground state fermion parity transitions and Weyl bands in multiterminal geometries.
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Affiliation(s)
- Marco Coraiola
- IBM Research Europe-Zurich, 8803, Rüschlikon, Switzerland
| | | | | | - Hannes Weisbrich
- Fachbereich Physik, Universität Konstanz, D-78457, Konstanz, Germany
| | | | | | | | - 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
- 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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Gupta M, Graziano GV, Pendharkar M, Dong JT, Dempsey CP, Palmstrøm C, Pribiag VS. Gate-tunable superconducting diode effect in a three-terminal Josephson device. Nat Commun 2023; 14:3078. [PMID: 37248246 DOI: 10.1038/s41467-023-38856-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/11/2023] [Indexed: 05/31/2023] Open
Abstract
The phenomenon of non-reciprocal critical current in a Josephson device, termed the Josephson diode effect, has garnered much recent interest. Realization of the diode effect requires inversion symmetry breaking, typically obtained by spin-orbit interactions. Here we report observation of the Josephson diode effect in a three-terminal Josephson device based upon an InAs quantum well two-dimensional electron gas proximitized by an epitaxial aluminum superconducting layer. We demonstrate that the diode efficiency in our devices can be tuned by a small out-of-plane magnetic field or by electrostatic gating. We show that the Josephson diode effect in these devices is a consequence of the artificial realization of a current-phase relation that contains higher harmonics. We also show nonlinear DC intermodulation and simultaneous two-signal rectification, enabled by the multi-terminal nature of the devices. Furthermore, we show that the diode effect is an inherent property of multi-terminal Josephson devices, establishing an immediately scalable approach by which potential applications of the Josephson diode effect can be realized, agnostic to the underlying material platform. These Josephson devices may also serve as gate-tunable building blocks in designing topologically protected qubits.
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Affiliation(s)
- Mohit Gupta
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Gino V Graziano
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mihir Pendharkar
- Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
- Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Jason T Dong
- Materials Department, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Connor P Dempsey
- Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Chris Palmstrøm
- Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
- Materials Department, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
- California NanoSystems Institute, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Vlad S Pribiag
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA.
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6
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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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7
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Graziano GV, Gupta M, Pendharkar M, Dong JT, Dempsey CP, Palmstrøm C, Pribiag VS. Selective control of conductance modes in multi-terminal Josephson junctions. Nat Commun 2022; 13:5933. [PMID: 36209199 PMCID: PMC9547902 DOI: 10.1038/s41467-022-33682-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 09/29/2022] [Indexed: 11/18/2022] Open
Abstract
The Andreev bound state spectra of multi-terminal Josephson junctions form an artificial band structure, which is predicted to host tunable topological phases under certain conditions. However, the number of conductance modes between the terminals of a multi-terminal Josephson junction must be few in order for this spectrum to be experimentally accessible. In this work, we employ a quantum point contact geometry in three-terminal Josephson devices to demonstrate independent control of conductance modes between each pair of terminals and access to the single-mode regime coexistent with the presence of superconducting coupling. These results establish a full platform on which to realize tunable Andreev bound state spectra in multi-terminal Josephson junctions.
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Affiliation(s)
- Gino V Graziano
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mohit Gupta
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mihir Pendharkar
- Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
- Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Jason T Dong
- Materials Department, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Connor P Dempsey
- Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Chris Palmstrøm
- Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
- Materials Department, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
- California NanoSystems Institute, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Vlad S Pribiag
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA.
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8
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Arnault EG, Idris S, McConnell A, Zhao L, Larson TFQ, Watanabe K, Taniguchi T, Finkelstein G, Amet F. Dynamical Stabilization of Multiplet Supercurrents in Multiterminal Josephson Junctions. NANO LETTERS 2022; 22:7073-7079. [PMID: 35997531 DOI: 10.1021/acs.nanolett.2c01999] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The dynamical properties of multiterminal Josephson junctions (MT-JJs) have attracted interest, driven by the promise of new insights into synthetic topological phases of matter and Floquet states. This effort has culminated in the discovery of Cooper multiplets in which the splitting of a Cooper pair is enabled via a series of Andreev reflections that entangle four (or more) electrons. Here, we show that multiplet resonances can also emerge as a consequence of the three-terminal circuit model. The supercurrent appears due to correlated phase dynamics at values that correspond to the multiplet condition nV1 = -mV2 of applied bias. Multiplet resonances are seen in nanofabricated three-terminal graphene JJs, analog three-terminal JJ circuits, and circuit simulations. The stabilization of the supercurrent is purely dynamical, and a close analog to Kapitza's inverted pendulum problem. We describe parameter considerations that optimize the detection of the multiplet lines both for design of future devices.
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Affiliation(s)
- Ethan G Arnault
- Department of Physics, Duke University, Durham, North Carolina 27701, United States
| | - Sara Idris
- Department of Physics and Astonomy, Appalachian State University, Boone, North Carolina 28607 United States
| | - Aeron McConnell
- Department of Physics and Astonomy, Appalachian State University, Boone, North Carolina 28607 United States
| | - Lingfei Zhao
- 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
| | - Kenji Watanabe
- Advanced Materials Laboratory, NIMS, Tsukuba, 305-0044, Japan
| | | | - Gleb Finkelstein
- Department of Physics, Duke University, Durham, North Carolina 27701, United States
| | - François Amet
- Department of Physics and Astonomy, Appalachian State University, Boone, North Carolina 28607 United States
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9
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Zhu Z, Kim S, Lei S, Schoop LM, Cava RJ, Ong NP. Phase tuning of multiple Andreev reflections of Dirac fermions and the Josephson supercurrent in Al-MoTe 2-Al junctions. Proc Natl Acad Sci U S A 2022; 119:e2204468119. [PMID: 35867759 PMCID: PMC9282224 DOI: 10.1073/pnas.2204468119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/18/2022] [Indexed: 11/22/2022] Open
Abstract
When an electron is incident on a superconductor from a metal, it is reflected as a hole in a process called Andreev reflection. If the metal N is sandwiched between two superconductors S in an SNS junction, multiple Andreev reflections (MARs) occur. We have found that, in SNS junctions with high transparency ([Formula: see text]) based on the Dirac semimetal MoTe2, the MAR features are observed with exceptional resolution. By tuning the phase difference [Formula: see text] between the bracketing Al superconductors, we establish that the MARs coexist with a Josephson supercurrent [Formula: see text]. As we vary the junction voltage V, the supercurrent amplitude [Formula: see text] varies in step with the MAR order n, revealing a direct relation between them. Two successive Andreev reflections serve to shuttle a Cooper pair across the junction. If the pair is shuttled coherently, it contributes to [Formula: see text]. The experiment measures the fraction of pairs shuttled coherently vs. V. Surprisingly, superconductivity in MoTe2 does not affect the MAR features.
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Affiliation(s)
- Zheyi Zhu
- Department of Physics, Princeton University, Princeton, NJ 08544
| | - Stephan Kim
- Department of Physics, Princeton University, Princeton, NJ 08544
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ 08544
| | - Shiming Lei
- Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - Leslie M. Schoop
- Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - N. P. Ong
- Department of Physics, Princeton University, Princeton, NJ 08544
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10
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Huang KF, Ronen Y, Mélin R, Feinberg D, Watanabe K, Taniguchi T, Kim P. Evidence for 4e charge of Cooper quartets in a biased multi-terminal graphene-based Josephson junction. Nat Commun 2022; 13:3032. [PMID: 35641534 PMCID: PMC9156765 DOI: 10.1038/s41467-022-30732-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 05/16/2022] [Indexed: 11/18/2022] Open
Abstract
In a Josephson junction (JJ) at zero bias, Cooper pairs are transported between two superconducting contacts via the Andreev bound states (ABSs) formed in the Josephson channel. Extending JJs to multiple superconducting contacts, the ABSs in the Josephson channel can coherently hybridize Cooper pairs among different superconducting electrodes. Biasing three-terminal JJs with antisymmetric voltages, for example, results in a direct current (DC) of Cooper quartet (CQ), which involves a four-fermion entanglement. Here, we report half a flux periodicity in the interference of CQ formed in graphene based multi-terminal (MT) JJs with a magnetic flux loop. We observe that the quartet differential conductance associated with supercurrent exhibits magneto-oscillations associated with a charge of 4e, thereby presenting evidence for interference between different CQ processes. The CQ critical current shows non-monotonic bias dependent behavior, which can be modeled by transitions between Floquet-ABSs. Our experimental observation for voltage-tunable non-equilibrium CQ-ABS in flux-loop-JJs significantly extends our understanding of MT-JJs, enabling future design of topologically unique ABS spectrum.
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Affiliation(s)
- Ko-Fan Huang
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Yuval Ronen
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Régis Mélin
- Université Grenoble-Alpes, CNRS, Grenoble INP, Institut NEEL, 38000, Grenoble, France
| | - Denis Feinberg
- Université Grenoble-Alpes, CNRS, Grenoble INP, Institut NEEL, 38000, Grenoble, France
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.
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11
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Arnault EG, Larson TFQ, Seredinski A, Zhao L, Idris S, McConnell A, Watanabe K, Taniguchi T, Borzenets I, Amet F, Finkelstein G. Multiterminal Inverse AC Josephson Effect. NANO LETTERS 2021; 21:9668-9674. [PMID: 34779633 DOI: 10.1021/acs.nanolett.1c03474] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
When a Josephson junction is exposed to microwave radiation, it undergoes the inverse AC Josephson effect─the phase of the junction locks to the drive frequency. As a result, the I-V curves of the junction acquire "Shapiro steps" of quantized voltage. If the junction has three or more superconducting contacts, coupling between different pairs of terminals must be taken into account and the state of the junction evolves in a phase space of higher dimensionality. Here, we study the multiterminal inverse AC Josephson effect in a graphene sample with three superconducting terminals. We observe robust fractional Shapiro steps and correlated switching events, which can only be explained by considering the device as a completely connected Josephson network. We successfully simulate the observed behaviors using a modified two-dimensional RCSJ model. Our results suggest that multiterminal Josephson junctions are a playground to study highly connected nonlinear networks with novel topologies.
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Affiliation(s)
- Ethan G Arnault
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Trevyn F Q Larson
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Andrew Seredinski
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
- School of Sciences and Humanities, Wentworth Institute of Technology, Boston, Massachusetts 02115, United States
| | - Lingfei Zhao
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Sara Idris
- Department of Physics and Astronomy, Appalachian State University, Boone, North Carolina 28607, United States
| | - Aeron McConnell
- Department of Physics and Astronomy, Appalachian State University, Boone, North Carolina 28607, United States
| | - Kenji Watanabe
- Advanced Materials Laboratory, NIMS, Tsukuba 305-0044, Japan
| | | | - Ivan Borzenets
- Department of Physics, City University of Hong Kong, Kowloon, Hong Kong SAR
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, United States
| | - François Amet
- Department of Physics and Astronomy, Appalachian State University, Boone, North Carolina 28607, United States
| | - Gleb Finkelstein
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
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12
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Lin P, Fang F, Zhang L, Li Y, Wang K. Various Nodal Lines in P6 3/mmc-type TiTe Topological Metal and its (001) Surface State. Front Chem 2021; 9:755350. [PMID: 34650960 PMCID: PMC8510513 DOI: 10.3389/fchem.2021.755350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 09/10/2021] [Indexed: 11/13/2022] Open
Abstract
Searching for existing topological materials is a hot topic in quantum and computational chemistry. This study uncovers P63/mmc type TiTe compound—an existing material—is a newly discovered topological metal that hosts the various type of nodal line states. Different nodal line states normally exhibit different properties; they may have their individual applications. We report that TiTe hosts I, II, and hybrid type nodal line (NL) states at its ground state without chemical doping and strain engineering effects. Specifically, two type I NLs, two hybrid-type NLs, and one Γ—centered type II NL can be found in the kz = 0 plane. Moreover, the spin-orbit coupling induced gaps for these NLs are very small and within acceptable limits. The surface states of the TiTe (001) plane were determined to provide strong evidence for the appearance of the three types of NLs in TiTe. We also provide a reference for the data of the dynamic and mechanical properties of TiTe. We expect that the proposed NL states in TiTe can be obtained in future experiments.
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Affiliation(s)
- Peng Lin
- Engineering and Technology Center, The Fourth Medical College of Harbin Medical University, Harbin, China
| | - Fang Fang
- Engineering and Technology Center, The Fourth Medical College of Harbin Medical University, Harbin, China
| | - Li Zhang
- Changchun Institute of Technology, Changchun, China
| | - Yang Li
- Engineering and Technology Center, The Fourth Medical College of Harbin Medical University, Harbin, China.,Nanoscience and Engineering and Technology Electrophysiology Research Center, The Fourth Medical College of Harbin Medical University, Harbin, China
| | - Kai Wang
- Engineering and Technology Center, The Fourth Medical College of Harbin Medical University, Harbin, China.,Nanoscience and Engineering and Technology Electrophysiology Research Center, The Fourth Medical College of Harbin Medical University, Harbin, China
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13
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Preliminary demonstration of a persistent Josephson phase-slip memory cell with topological protection. Nat Commun 2021; 12:5200. [PMID: 34465775 PMCID: PMC8408200 DOI: 10.1038/s41467-021-25209-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 07/09/2021] [Indexed: 11/08/2022] Open
Abstract
Superconducting computing promises enhanced computational power in both classical and quantum approaches. Yet, scalable and fast superconducting memories are not implemented. Here, we propose a fully superconducting memory cell based on the hysteretic phase-slip transition existing in long aluminum nanowire Josephson junctions. Embraced by a superconducting ring, the memory cell codifies the logic state in the direction of the circulating persistent current, as commonly defined in flux-based superconducting memories. But, unlike the latter, the hysteresis here is a consequence of the phase-slip occurring in the long weak link and associated to the topological transition of its superconducting gap. This disentangles our memory scheme from the large-inductance constraint, thus enabling its miniaturization. Moreover, the strong activation energy for phase-slip nucleation provides a robust topological protection against stochastic phase-slips and magnetic-flux noise. These properties make the Josephson phase-slip memory a promising solution for advanced superconducting classical logic architectures or flux qubits. Superconducting computing promises enhanced computational power, but scalable and fast superconducting memories are still not implemented. Here, the authors demonstrate a superconducting memory cell based on hysteretic phase-slip transition, without degradation up to ~1 K over several days.
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14
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Kruk SS, Gao W, Choi DY, Zentgraf T, Zhang S, Kivshar Y. Nonlinear Imaging of Nanoscale Topological Corner States. NANO LETTERS 2021; 21:4592-4597. [PMID: 34008406 DOI: 10.1021/acs.nanolett.1c00449] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Topological states of light represent counterintuitive optical modes localized at boundaries of finite-size optical structures that originate from the properties of the bulk. Being defined by bulk properties, such boundary states are insensitive to certain types of perturbations, thus naturally enhancing robustness of photonic circuitries. Conventionally, the N-dimensional bulk modes correspond to (N - 1)-dimensional boundary states. The higher-order bulk-boundary correspondence relates N-dimensional bulk to boundary states with dimensionality reduced by more than 1. A special interest lies in miniaturization of such higher-order topological states to the nanoscale. Here, we realize nanoscale topological corner states in metasurfaces with C6-symmetric honeycomb lattices. We directly observe nanoscale topology-empowered edge and corner localizations of light and enhancement of light-matter interactions via a nonlinear imaging technique. Control of light at the nanoscale empowered by topology may facilitate miniaturization and on-chip integration of classical and quantum photonic devices.
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Affiliation(s)
- Sergey S Kruk
- Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra, Australian Capital Territory 2601, Australia
- Department of Physics, Paderborn University, 33098 Paderborn, Germany
| | - Wenlong Gao
- Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra, Australian Capital Territory 2601, Australia
- Department of Physics, Paderborn University, 33098 Paderborn, Germany
| | - Duk-Yong Choi
- Laser Physics Center, Research School of Physics, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Thomas Zentgraf
- Department of Physics, Paderborn University, 33098 Paderborn, Germany
| | - Shuang Zhang
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT United Kingdom
- Department of Physics and Department of Electrical & Electronic Engineering, University of Hong Kong, Hong Kong, China
| | - Yuri Kivshar
- Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra, Australian Capital Territory 2601, Australia
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15
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Larson TFQ, Zhao L, Arnault EG, Wei MT, Seredinski A, Li H, Watanabe K, Taniguchi T, Amet F, Finkelstein G. Zero Crossing Steps and Anomalous Shapiro Maps in Graphene Josephson Junctions. NANO LETTERS 2020; 20:6998-7003. [PMID: 32902995 DOI: 10.1021/acs.nanolett.0c01598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The AC Josephson effect manifests itself in the form of "Shapiro steps" of quantized voltage in Josephson junctions subject to radiofrequency (RF) radiation. This effect presents an early example of a driven-dissipative quantum phenomenon and is presently utilized in primary voltage standards. Shapiro steps have also become one of the standard tools to probe junctions made in a variety of novel materials. Here we study Shapiro steps in a widely tunable graphene-based Josephson junction in which the high-frequency dynamics is determined by the on-chip environment. We investigate the variety of patterns that can be obtained in this well-understood system depending on the carrier density, temperature, RF frequency, and magnetic field. Although the patterns of Shapiro steps can change drastically when just one parameter is varied, the overall trends can be understood and the behaviors straightforwardly simulated, showing some key differences from the conventional RCSJ model. The resulting understanding may help interpret similar measurements in more complex materials.
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Affiliation(s)
- Trevyn F Q Larson
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Lingfei Zhao
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Ethan G Arnault
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Ming-Tso Wei
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Andrew Seredinski
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Henming Li
- Department of Physics and Astronomy, Appalachian State University, Boone, North Carolina 28607, United States
| | - Kenji Watanabe
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - François Amet
- Department of Physics and Astronomy, Appalachian State University, Boone, North Carolina 28607, United States
| | - Gleb Finkelstein
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
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16
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Klees RL, Rastelli G, Cuevas JC, Belzig W. Microwave Spectroscopy Reveals the Quantum Geometric Tensor of Topological Josephson Matter. PHYSICAL REVIEW LETTERS 2020; 124:197002. [PMID: 32469576 DOI: 10.1103/physrevlett.124.197002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/13/2019] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Quantization effects due to topological invariants such as Chern numbers have become very relevant in many systems, yet key quantities such as the quantum geometric tensor providing local information about quantum states remain experimentally difficult to access. Recently, it has been shown that multiterminal Josephson junctions constitute an ideal platform to synthesize topological systems in a controlled manner. We theoretically study properties of Andreev states in topological Josephson matter and demonstrate that the quantum geometric tensor of Andreev states can be extracted by synthetically polarized microwaves. The oscillator strength of the absorption rates provides direct evidence of topological quantum properties of the Andreev states.
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Affiliation(s)
- R L Klees
- Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
| | - G Rastelli
- Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
- Zukunftskolleg, Universität Konstanz, D-78457 Konstanz, Germany
| | - J C Cuevas
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - W Belzig
- Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
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17
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Ménard GC, Anselmetti GLR, Martinez EA, Puglia D, Malinowski FK, Lee JS, Choi S, Pendharkar M, Palmstrøm CJ, Flensberg K, Marcus CM, Casparis L, Higginbotham AP. Conductance-Matrix Symmetries of a Three-Terminal Hybrid Device. PHYSICAL REVIEW LETTERS 2020; 124:036802. [PMID: 32031865 DOI: 10.1103/physrevlett.124.036802] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Indexed: 06/10/2023]
Abstract
We present conductance-matrix measurements of a three-terminal superconductor-semiconductor hybrid device consisting of two normal leads and one superconducting lead. Using a symmetry decomposition of the conductance, we find that antisymmetric components of pairs of local and nonlocal conductances qualitatively match at energies below the superconducting gap, and we compare this finding with symmetry relations based on a noninteracting scattering matrix approach. Further, the local charge character of Andreev bound states is extracted from the symmetry-decomposed conductance data and is found to be similar at both ends of the device and tunable with gate voltage. Finally, we measure the conductance matrix as a function of magnetic field and identify correlated splittings in low-energy features, demonstrating how conductance-matrix measurements can complement traditional single-probe measurements in the search for Majorana zero modes.
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Affiliation(s)
- G C Ménard
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Microsoft Quantum-Copenhagen, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - G L R Anselmetti
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Microsoft Quantum-Copenhagen, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - E A Martinez
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Microsoft Quantum-Copenhagen, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - D Puglia
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Microsoft Quantum-Copenhagen, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - F K Malinowski
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Microsoft Quantum-Copenhagen, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - J S Lee
- California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
| | - S Choi
- Department of Electrical Engineering, University of California, Santa Barbara, California 93106, USA
| | - M Pendharkar
- Department of Electrical Engineering, University of California, Santa Barbara, California 93106, USA
| | - C J Palmstrøm
- California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
- Department of Electrical Engineering, University of California, Santa Barbara, California 93106, USA
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - K Flensberg
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - C M Marcus
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Microsoft Quantum-Copenhagen, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - L Casparis
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Microsoft Quantum-Copenhagen, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - A P Higginbotham
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Microsoft Quantum-Copenhagen, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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18
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Draelos AW, Wei MT, Seredinski A, Li H, Mehta Y, Watanabe K, Taniguchi T, Borzenets IV, Amet F, Finkelstein G. Supercurrent Flow in Multiterminal Graphene Josephson Junctions. NANO LETTERS 2019; 19:1039-1043. [PMID: 30620606 DOI: 10.1021/acs.nanolett.8b04330] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigate the electronic properties of ballistic planar Josephson junctions with multiple superconducting terminals. Our devices consist of monolayer graphene encapsulated in boron nitride with molybdenum-rhenium contacts. Resistance measurements yield multiple resonant features, which are attributed to supercurrent flow among adjacent and nonadjacent Josephson junctions. In particular, we find that superconducting and dissipative currents coexist within the same region of graphene. We show that the presence of dissipative currents primarily results in electron heating and estimate the associated temperature rise. We find that the electrons in encapsulated graphene are efficiently cooled through the electron-phonon coupling.
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Affiliation(s)
- Anne W Draelos
- Department of Physics , Duke University , Durham , North Carolina 27708 , United States
| | - Ming-Tso Wei
- Department of Physics , Duke University , Durham , North Carolina 27708 , United States
| | - Andrew Seredinski
- Department of Physics , Duke University , Durham , North Carolina 27708 , United States
| | - Hengming Li
- Department of Physics and Astronomy , Appalachian State University , Boone , North Carolina 28607 , United States
| | - Yash Mehta
- Department of Physics and Astronomy , Appalachian State University , Boone , North Carolina 28607 , United States
| | - Kenji Watanabe
- Advanced Materials Laboratory , NIMS , Tsukuba 305-0044 , Japan
| | | | - Ivan V Borzenets
- Department of Physics , City University of Hong Kong , Kowloon , Hong Kong SAR
| | - François Amet
- Department of Physics and Astronomy , Appalachian State University , Boone , North Carolina 28607 , United States
| | - Gleb Finkelstein
- Department of Physics , Duke University , Durham , North Carolina 27708 , United States
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19
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De Simoni G, Paolucci F, Solinas P, Strambini E, Giazotto F. Metallic supercurrent field-effect transistor. NATURE NANOTECHNOLOGY 2018; 13:802-805. [PMID: 29967460 DOI: 10.1038/s41565-018-0190-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
In their original formulation of superconductivity, the London brothers predicted1 the exponential suppression of an electrostatic field inside a superconductor over the so-called London penetration depth2-4, λL. Despite a few experiments indicating hints of perturbation induced by electrostatic fields5-7, no clue has been provided so far on the possibility to manipulate metallic superconductors via the field effect. Here, we report field-effect control of the supercurrent in all-metallic transistors made of different Bardeen-Cooper-Schrieffer superconducting thin films. At low temperature, our field-effect transistors show a monotonic decay of the critical current under increasing electrostatic field up to total quenching for gate voltage values as large as ±40 V in titanium-based devices. This bipolar field effect persists up to ~85% of the critical temperature (~0.41 K), and in the presence of sizable magnetic fields. A similar behaviour is observed in aluminium thin-film field-effect transistors. A phenomenological theory accounts for our observations, and points towards the interpretation in terms of an electric-field-induced perturbation propagating inside the superconducting film. In our understanding, this affects the pairing potential and quenches the supercurrent. These results could represent a groundbreaking asset for the realization of all-metallic superconducting field-effect electronics and leading-edge quantum information architectures8,9.
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Affiliation(s)
- Giorgio De Simoni
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Federico Paolucci
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | | | - Elia Strambini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Francesco Giazotto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy.
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20
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Nonlocal supercurrent of quartets in a three-terminal Josephson junction. Proc Natl Acad Sci U S A 2018; 115:6991-6994. [PMID: 29915041 DOI: 10.1073/pnas.1800044115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A novel nonlocal supercurrent, carried by quartets, each consisting of four electrons, is expected to appear in a voltage-biased three-terminal Josephson junction. This supercurrent results from a nonlocal Andreev bound state (ABS), formed among three superconducting terminals. While in a two-terminal Josephson junction the usual ABS, and thus the dc Josephson current, exists only in equilibrium, the ABS, which gives rise to the quartet supercurrent, persists in the nonlinear regime. In this work, we report such resonance in a highly coherent three-terminal Josephson junction made in an InAs nanowire in proximity to an aluminum superconductor. In addition to nonlocal conductance measurements, cross-correlation measurements of current fluctuations provided a distinctive signature of the quartet supercurrent. Multiple device geometries had been tested, allowing us to rule out competing mechanisms and to establish the underlying microscopic origin of this coherent nondissipative current.
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21
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Phase-driven charge manipulation in Hybrid Single-Electron Transistor. Sci Rep 2017; 7:13492. [PMID: 29044174 PMCID: PMC5647419 DOI: 10.1038/s41598-017-13894-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 10/02/2017] [Indexed: 12/03/2022] Open
Abstract
Phase-tunable hybrid devices, built upon nanostructures combining normal metal and superconductors, have been the subject of intense studies due to their numerous combinations of different charge and heat transport configurations. They exhibit solid applications in quantum metrology and coherent caloritronics. Here we propose and realize a new kind of hybrid device with potential application in single charge manipulation and quantized current generation. We show that by tuning superconductivity on two proximized nanowires, coupled via a Coulombic normal-metal island, we are able to control its charge state configuration. This device supports a one-control-parameter cycle being actuated by the sole magnetic flux. In a voltage biased regime, the phase-tunable superconducting gaps can act as energy barriers for charge quanta leading to an additional degree of freedom in single electronics. The resulting configuration is fully electrostatic and the current across the device is governed by the quasiparticle populations in the source and drain leads. Notably, the proposed device can be realized using standard nanotechniques opening the possibility to a straightforward coupling with the nowadays well developed superconducting electronics.
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22
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Meyer JS, Houzet M. Nontrivial Chern Numbers in Three-Terminal Josephson Junctions. PHYSICAL REVIEW LETTERS 2017; 119:136807. [PMID: 29341692 DOI: 10.1103/physrevlett.119.136807] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Indexed: 06/07/2023]
Abstract
Recently, it has been predicted that the Andreev bound state spectrum of four-terminal Josephson junctions may possess zero-energy Weyl singularities. Using one superconducting phase as a control parameter, these singularities are associated with topological transitions between time-reversal symmetry broken phases with different Chern numbers. Here we show that such topological transitions may also be tuned with a magnetic flux through the junction area in a three-terminal geometry.
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Affiliation(s)
- Julia S Meyer
- Univ. Grenoble Alpes, CEA, INAC-Pheliqs, 38000 Grenoble, France
| | - Manuel Houzet
- Univ. Grenoble Alpes, CEA, INAC-Pheliqs, 38000 Grenoble, France
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23
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Zazunov A, Buccheri F, Sodano P, Egger R. 6π Josephson Effect in Majorana Box Devices. PHYSICAL REVIEW LETTERS 2017; 118:057001. [PMID: 28211714 DOI: 10.1103/physrevlett.118.057001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Indexed: 06/06/2023]
Abstract
We study Majorana devices featuring a competition between superconductivity and multichannel Kondo physics. Our proposal extends previous work on single-channel Kondo systems to a topologically nontrivial setting of a non-Fermi liquid type, where topological superconductor wires (with gap Δ) represent leads tunnel coupled to a Coulomb-blockaded Majorana box. On the box, a spin degree of freedom with Kondo temperature T_{K} is nonlocally defined in terms of Majorana states. For Δ≫T_{K}, the destruction of Kondo screening by superconductivity implies a 4π-periodic Josephson current-phase relation. Using a strong-coupling analysis in the opposite regime Δ≪T_{K}, we find a 6π-periodic Josephson relation for three leads, with critical current I_{c}≈eΔ^{2}/ℏT_{K}, corresponding to the transfer of fractionalized charges e^{*}=2e/3.
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Affiliation(s)
- A Zazunov
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - F Buccheri
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - P Sodano
- International Institute of Physics, Universidade Federal do Rio Grande do Norte, 59012-970 Natal, Brazil
- INFN, Sezione di Perugia, Via Alessandro Pascoli, I-06123 Perugia, Italy
| | - R Egger
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
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24
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Amundsen M, Ouassou JA, Linder J. Analytically determined topological phase diagram of the proximity-induced gap in diffusive n-terminal Josephson junctions. Sci Rep 2017; 7:40578. [PMID: 28094289 PMCID: PMC5240117 DOI: 10.1038/srep40578] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/07/2016] [Indexed: 12/03/2022] Open
Abstract
Multiterminal Josephson junctions have recently been proposed as a route to artificially mimic topological matter with the distinct advantage that its properties can be controlled via the superconducting phase difference, giving rise to Weyl points in 4-terminal geometries. A key goal is to accurately determine when the system makes a transition from a gapped to non-gapped state as a function of the phase differences in the system, the latter effectively playing the role of quasiparticle momenta in conventional topological matter. We here determine the proximity gap phase diagram of diffusive n-terminal Josephson junctions (), both numerically and analytically, by identifying a class of solutions to the Usadel equation at zero energy in the full proximity effect regime. We present an analytical equation which provides the phase diagram for an arbitrary number of terminals n. After briefly demonstrating the validity of the analytical approach in the previously studied 2- and 3-terminal cases, we focus on the 4-terminal case and map out the regimes where the electronic excitations in the system are gapped and non-gapped, respectively, demonstrating also in this case full agreement between the analytical and numerical approach.
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Affiliation(s)
- Morten Amundsen
- Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Jabir Ali Ouassou
- Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Jacob Linder
- Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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