1
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Foltyn M, Norowski K, Savin A, Zgirski M. Quantum thermodynamics with a single superconducting vortex. SCIENCE ADVANCES 2024; 10:eado4032. [PMID: 39083614 PMCID: PMC11290525 DOI: 10.1126/sciadv.ado4032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 06/26/2024] [Indexed: 08/02/2024]
Abstract
We demonstrate complete control over dynamics of a single superconducting vortex in a nanostructure, which we coin the Single Vortex Box. Our device allows us to trap the vortex in a field-cooled aluminum nanosquare and expel it on demand with a nanosecond pulse of electrical current. Using the time-resolving nanothermometry we measure [Formula: see text] joules as the amount of the dissipated heat in the elementary process of the single-vortex expulsion. Our experiment enlightens the thermodynamics of the absorption process in the superconducting nanowire single-photon detectors, in which vortices are perceived to be essential for a formation of a detectable hotspot. The demonstrated opportunity to manipulate a single superconducting vortex reliably in a confined geometry comprises a proof of concept of a nanoscale nonvolatile memory cell with subnanosecond write and read operations, which offers compatibility with quantum processors based either on superconducting qubits or on rapid single-flux quantum circuits.
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Affiliation(s)
- Marek Foltyn
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, Warsaw PL 02668, Poland
| | - Konrad Norowski
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, Warsaw PL 02668, Poland
| | - Alexander Savin
- QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto FI-00076, Finland
| | - Maciej Zgirski
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, Warsaw PL 02668, Poland
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2
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Golod T, Morlet-Decarnin L, Krasnov VM. Word and bit line operation of a 1 × 1 μm 2 superconducting vortex-based memory. Nat Commun 2023; 14:4926. [PMID: 37582835 PMCID: PMC10427686 DOI: 10.1038/s41467-023-40654-7] [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: 02/10/2023] [Accepted: 08/01/2023] [Indexed: 08/17/2023] Open
Abstract
The lack of dense random access memory is one of the main bottlenecks for the creation of a digital superconducting computer. In this work we study experimentally vortex-based superconducting memory cells. Three main results are obtained. First, we test scalability and demonstrate that the cells can be straightforwardly miniaturized to submicron sizes. Second, we emphasize the importance of conscious geometrical engineering. In the studied devices we introduce an asymmetric easy track for vortex motion and show that it enables a controllable manipulation of vortex states. Finally, we perform a detailed analysis of word and bit line operation of a 1 × 1 μm2 cell. High-endurance, non-volatile operation at zero magnetic field is reported. Remarkably, we observe that the combined word and bit line threshold current is significantly reduced compared to the bare word-line operation. This could greatly improve the selectivity of individual cell addressing in a multi-cell RAM. The achieved one square micron area is an important milestone and a significant step forward towards creation of a dense cryogenic memory.
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Affiliation(s)
- Taras Golod
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691, Stockholm, Sweden
| | - Lise Morlet-Decarnin
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691, Stockholm, Sweden
| | - Vladimir M Krasnov
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691, Stockholm, Sweden.
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3
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Thakur S, Tamarat P, Rochet A, Birk J, Veshchunov IS, Bezard M, Buzdin AI, Trebbia JB, Lounis B. High-resolution optical imaging of single magnetic flux quanta with a solid immersion lens. OPTICS EXPRESS 2023; 31:24194-24202. [PMID: 37475252 DOI: 10.1364/oe.494474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 05/25/2023] [Indexed: 07/22/2023]
Abstract
Magneto-optical imaging of quantized magnetic flux tubes in superconductors - Abrikosov vortices - is based on Faraday rotation of light polarization within a magneto-optical indicator placed on top of the superconductor. Due to severe aberrations induced by the thick indicator substrate, the spatial resolution of vortices is usually well beyond the optical diffraction limit. Using a high refractive index solid immersion lens placed onto the indicator garnet substrate, we demonstrate wide field optical imaging of single flux quanta in a Niobium film with a resolution better than 600 nm and sub-second acquisition periods, paving the way to high-precision and fast vortex manipulation. Vectorial field simulations are also performed to reproduce and optimize the experimental features of vortex images.
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4
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Iguchi Y, Shi RA, Kihou K, Lee CH, Barkman M, Benfenati AL, Grinenko V, Babaev E, Moler KA. Superconducting vortices carrying a temperature-dependent fraction of the flux quantum. Science 2023:eabp9979. [PMID: 37262195 DOI: 10.1126/science.abp9979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/15/2023] [Indexed: 06/03/2023]
Abstract
Magnetic field penetrates type-II bulk superconductors by forming quantum vortices that enclose a magnetic flux equal to the magnetic flux quantum. The flux quantum is a universal quantity that depends only on fundamental constants. Here we investigate isolated vortices in the hole-overdoped Ba1-xKxFe2As2 (x = 0.77) by using scanning superconducting quantum interference device (SQUID) magnetometry. In many locations, we observed vortices that carried only part of a flux quantum, with a magnitude that varied continuously with temperature. We interpret these features as quantum vortices with non-universally quantized (fractional) magnetic flux whose magnitude is determined by the temperature-dependent parameters of a multiband superconductor. The demonstrated mobility and manipulability of the fractional vortices may enable applications in fluxonics-based computing.
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Affiliation(s)
- Yusuke Iguchi
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Ruby A Shi
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Kunihiro Kihou
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Chul-Ho Lee
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Mats Barkman
- Department of Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Andrea L Benfenati
- Department of Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Vadim Grinenko
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 201210, China
| | - Egor Babaev
- Department of Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Kathryn A Moler
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Physics, Stanford University, Stanford, CA 94305, USA
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
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5
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Keren I, Gutfreund A, Noah A, Fridman N, Di Bernardo A, Steinberg H, Anahory Y. Chip-Integrated Vortex Manipulation. NANO LETTERS 2023; 23:4669-4674. [PMID: 36917692 DOI: 10.1021/acs.nanolett.3c00324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The positions of Abrikosov vortices have long been considered as means to encode classical information. Although it is possible to move individual vortices using local probes, the challenge of scalable on-chip vortex-control remains outstanding, especially when considering the demands of controlling multiple vortices. Realization of vortex logic requires means to shuttle vortices reliably between engineered pinning potentials, while concomitantly keeping all other vortices fixed. We demonstrate such capabilities using Nb loops patterned below a NbSe2 layer. SQUID-on-Tip (SOT) microscopy reveals that the loops localize vortices in designated sites to a precision better than 100 nm; they realize "push" and "pull" operations of vortices as far as 3 μm. Successive application of such operations shuttles a vortex between adjacent loops. Our results may be used as means to integrate vortices in future quantum circuitry. Strikingly, we demonstrate a winding operation, paving the way for future topological quantum computing and simulations.
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Affiliation(s)
- Itai Keren
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
| | - Alon Gutfreund
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
| | - Avia Noah
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
| | - Nofar Fridman
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
| | - Angelo Di Bernardo
- Department of Physics, University of Konstanz, Universitätstrasse 10, 78457 Konstanz, Germany
| | - Hadar Steinberg
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yonathan Anahory
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
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6
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Sigloch F, Sangiao S, Orús P, de Teresa JM. Direct-write of tungsten-carbide nanoSQUIDs based on focused ion beam induced deposition. NANOSCALE ADVANCES 2022; 4:4628-4634. [PMID: 36341293 PMCID: PMC9595190 DOI: 10.1039/d2na00602b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
NanoSQUIDs are quantum sensors that excel in detecting a small change in magnetic flux with high sensitivity and high spatial resolution. Here, we employ resist-free direct-write Ga+ Focused Ion Beam Induced Deposition (FIBID) techniques to grow W-C nanoSQUIDs, and we investigate their electrical response to changes in the magnetic flux. Remarkably, FIBID allows the fast (3 min) growth of 700 nm × 300 nm nanoSQUIDs based on narrow nanobridges (50 nm wide) that act as Josephson junctions. Albeit the SQUIDs exhibit a comparatively low modulation depth and obtain a high inductance, the observed transfer coefficient (output voltage to magnetic flux change) is comparable to other SQUIDs (up to 1300 μV/Φ 0), which correlates with the high resistivity of W-C in the normal state. We discuss here the potential of this approach to reduce the active area of the nanoSQUIDs to gain spatial resolution as well as their integration on cantilevers for scanning-SQUID applications.
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Affiliation(s)
- Fabian Sigloch
- Instituto de Nanociencia y Materiales de Aragon (INMA), Universidad de Zaragoza-CSIC 50009 Zaragoza Spain
| | - Soraya Sangiao
- Instituto de Nanociencia y Materiales de Aragon (INMA), Universidad de Zaragoza-CSIC 50009 Zaragoza Spain
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza 50018 Spain
| | - Pablo Orús
- Instituto de Nanociencia y Materiales de Aragon (INMA), Universidad de Zaragoza-CSIC 50009 Zaragoza Spain
| | - José M de Teresa
- Instituto de Nanociencia y Materiales de Aragon (INMA), Universidad de Zaragoza-CSIC 50009 Zaragoza Spain
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza 50018 Spain
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7
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Bobkova IV, Bobkov AM, Silaev MA. Magnetoelectric effects in Josephson junctions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:353001. [PMID: 35709718 DOI: 10.1088/1361-648x/ac7994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
The review is devoted to the fundamental aspects and characteristic features of the magnetoelectric effects, reported in the literature on Josephson junctions (JJs). The main focus of the review is on the manifestations of the direct and inverse magnetoelectric effects in various types of Josephson systems. They provide a coupling of the magnetization in superconductor/ferromagnet/superconductor JJs to the Josephson current. The direct magnetoelectric effect is a driving force of spin torques acting on the ferromagnet inside the JJ. Therefore it is of key importance for the electrical control of the magnetization. The inverse magnetoelectric effect accounts for the back action of the magnetization dynamics on the Josephson subsystem, in particular, making the JJ to be in the resistive state in the presence of the magnetization dynamics of any origin. The perspectives of the coupling of the magnetization in JJs with ferromagnetic interlayers to the Josephson current via the magnetoelectric effects are discussed.
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Affiliation(s)
- I V Bobkova
- Institute of Solid State Physics, Chernogolovka, Moscow Region 142432, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
- National Research University Higher School of Economics, Moscow 101000, Russia
| | - A M Bobkov
- Institute of Solid State Physics, Chernogolovka, Moscow Region 142432, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
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8
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Golod T, Krasnov VM. Demonstration of a superconducting diode-with-memory, operational at zero magnetic field with switchable nonreciprocity. Nat Commun 2022; 13:3658. [PMID: 35760801 PMCID: PMC9237109 DOI: 10.1038/s41467-022-31256-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 06/10/2022] [Indexed: 11/09/2022] Open
Abstract
Diode is one of the basic electronic components. It has a nonreciprocal current response, associated with a broken space/time reversal symmetry. Here we demonstrate prototypes of superconducting diodes operational at zero magnetic field. They are based on conventional niobium planar Josephson junctions, in which space/time symmetry is broken by a combination of self-field effect from nonuniform bias and stray fields from a trapped Abrikosov vortex. We demonstrate that nonreciprocity of critical current in such diodes can reach an order of magnitude and rectification efficiency can exceed 70%. Furthermore, we can easily change the diode polarity and switch nonreciprocity on/off by changing the bias configuration and by trapping/removing of a vortex. This facilitates a memory functionality. We argue that such a diode-with-memory can be used for a future generation of in-memory superconducting computers.
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Affiliation(s)
- Taras Golod
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691, Stockholm, Sweden
| | - Vladimir M Krasnov
- Department of Physics, Stockholm University, AlbaNova University Center, SE-10691, Stockholm, Sweden.
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9
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Orús P, Sigloch F, Sangiao S, De Teresa JM. Superconducting Materials and Devices Grown by Focused Ion and Electron Beam Induced Deposition. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:1367. [PMID: 35458074 PMCID: PMC9029853 DOI: 10.3390/nano12081367] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 01/27/2023]
Abstract
Since its discovery in 1911, superconductivity has represented an equally inciting and fascinating field of study in several areas of physics and materials science, ranging from its most fundamental theoretical understanding, to its practical application in different areas of engineering. The fabrication of superconducting materials can be downsized to the nanoscale by means of Focused Ion/Electron Beam Induced Deposition: nanopatterning techniques that make use of a focused beam of ions or electrons to decompose a gaseous precursor in a single step. Overcoming the need to use a resist, these approaches allow for targeted, highly-flexible nanopatterning of nanostructures with lateral resolution in the range of 10 nm to 30 nm. In this review, the fundamentals of these nanofabrication techniques are presented, followed by a literature revision on the published work that makes use of them to grow superconducting materials, the most remarkable of which are based on tungsten, niobium, molybdenum, carbon, and lead. Several examples of the application of these materials to functional devices are presented, related to the superconducting proximity effect, vortex dynamics, electric-field effect, and to the nanofabrication of Josephson junctions and nanoSQUIDs. Owing to the patterning flexibility they offer, both of these techniques represent a powerful and convenient approach towards both fundamental and applied research in superconductivity.
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Affiliation(s)
- Pablo Orús
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Fabian Sigloch
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Soraya Sangiao
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), University of Zaragoza, 50018 Zaragoza, Spain
| | - José María De Teresa
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), University of Zaragoza, 50018 Zaragoza, Spain
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10
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Mintairov AM, Lebedev DV, Vlasov AS, Blundell SA. Majorana Anyon Composites in Magneto-Photoluminescence Spectra of Natural Quantum Hall Puddles. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:1016. [PMID: 35335829 PMCID: PMC8956118 DOI: 10.3390/nano12061016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/10/2022] [Accepted: 03/17/2022] [Indexed: 11/23/2022]
Abstract
In magneto-photoluminescence (magneto-PL) spectra of quasi two-dimensional islands (quantum dots) having seven electrons and Wigner−Seitz radius rs~1.5, we revealed a suppression of magnetic field (B) dispersion, paramagnetic shifts, and jumps of the energy of the emission components for filling factors ν > 1 (B < 10 T). Additionally, we observed B-hysteresis of the jumps and a dependence of all these anomalous features on rs. Using a theoretical description of the magneto-PL spectra and an analysis of the electronic structure of these dots based on the single-particle Fock−Darwin spectrum and many-particle configuration-interaction calculations, we show that these observations can be described by the rs-dependent formation of the anyon (magneto-electron) composites (ACs) involving single-particle states having non-zero angular momentum and that the anyon states observed involve Majorana modes (MMs), including zero-B modes having an equal number of vortexes and anti-vortexes, which can be considered as Majorana anyons. We show that the paramagnetic shift corresponds to a destruction of the equilibrium self-formed ν~5/2 AC by the external magnetic field and that the jumps and their hysteresis can be described in terms of Majorana qubit states controlled by B and rs. Our results show a critical role of quantum confinement in the formation of magneto-electrons and implies the liquid-crystal nature of fractional quantum Hall effect states, the Majorana anyon origin of the states having even ν, i.e., composite fermions, which provide new opportunities for topological quantum computing.
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Affiliation(s)
- Alexander M. Mintairov
- Ioffe Institute, 194021 Saint Petersburg, Russia; (D.V.L.); (A.S.V.)
- Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | | | - Alexey S. Vlasov
- Ioffe Institute, 194021 Saint Petersburg, Russia; (D.V.L.); (A.S.V.)
| | - Steven A. Blundell
- SyMMES, IRIG, CNRS, CEA, University Grenoble Alpes, F-38000 Grenoble, France;
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11
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Superconducting Properties and Electron Scattering Mechanisms in a Nb Film with a Single Weak-Link Excavated by Focused Ion Beam. MATERIALS 2021; 14:ma14237274. [PMID: 34885429 PMCID: PMC8658209 DOI: 10.3390/ma14237274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 11/18/2021] [Accepted: 11/20/2021] [Indexed: 11/16/2022]
Abstract
Granularity is one of the main features restricting the maximum current which a superconductor can carry without losses, persisting as an important research topic when applications are concerned. To directly observe its effects on a typical thin superconducting specimen, we have modeled the simplest possible granular system by fabricating a single artificial weak-link in the center of a high-quality Nb film using the focused ion beam technique. Then, its microstructural, magnetic, and electric properties in both normal and superconducting states were studied. AC susceptibility, DC magnetization, and magneto-transport measurements reveal well-known granularity signatures and how they negatively affect superconductivity. Moreover, we also investigate the normal state electron scattering mechanisms in the Boltzmann theory framework. The results clearly demonstrate the effect of the milling technique, giving rise to an additional quadratic-in-temperature contribution to the usual cubic-in-temperature sd band scattering for the Nb film. Finally, by analyzing samples with varying density of incorporated defects, the emergence of the additional contribution is correlated to a decrease in their critical temperature, in agreement with recent theoretical results.
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12
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Tesař R, Šindler M, Kadlec C, Lipavský P, Skrbek L, Koláček J. Mass of Abrikosov vortex in high-temperature superconductor YBa[Formula: see text]Cu[Formula: see text]O[Formula: see text]. Sci Rep 2021; 11:21708. [PMID: 34741065 PMCID: PMC8571276 DOI: 10.1038/s41598-021-00846-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 10/19/2021] [Indexed: 11/16/2022] Open
Abstract
For more than four decades, mass of Abrikosov vortices defied experimental observations. We demonstrate a method of its detection in high-temperature superconductors. Similarly to electrons, fluxons circulate in the direction given by the magnetic field, causing circular dichroism. We report the magneto-transmittance of a nearly optimally doped thin YBa[Formula: see text]Cu[Formula: see text]O[Formula: see text] film, measured using circularly polarized submillimeter waves. The circular dichroism emerges in the superconducting state and increases with dropping temperature. Our results confirm the dominant role of quasiparticle states in the vortex core and yield the diagonal fluxon mass of [Formula: see text] electron masses per centimeter at 45 K and zero-frequency limit, and even larger off-diagonal mass of [Formula: see text]/cm.
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Affiliation(s)
- Roman Tesař
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - Michal Šindler
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - Christelle Kadlec
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - Pavel Lipavský
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Ladislav Skrbek
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Jan Koláček
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
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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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Golod T, Hovhannisyan RA, Kapran OM, Dremov VV, Stolyarov VS, Krasnov VM. Reconfigurable Josephson Phase Shifter. NANO LETTERS 2021; 21:5240-5246. [PMID: 34114467 PMCID: PMC8289326 DOI: 10.1021/acs.nanolett.1c01366] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/08/2021] [Indexed: 06/01/2023]
Abstract
Phase shifter is one of the key elements of quantum electronics. In order to facilitate operation and avoid decoherence, it has to be reconfigurable, persistent, and nondissipative. In this work, we demonstrate prototypes of such devices in which a Josephson phase shift is generated by coreless superconducting vortices. The smallness of the vortex allows a broad-range tunability by nanoscale manipulation of vortices in a micron-size array of vortex traps. We show that a phase shift in a device containing just a few vortex traps can be reconfigured between a large number of quantized states in a broad [-3π, +3π] range.
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Affiliation(s)
- Taras Golod
- Department
of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden
| | - Razmik A. Hovhannisyan
- Department
of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden
- Moscow
Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Olena M. Kapran
- Department
of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden
| | | | | | - Vladimir M. Krasnov
- Department
of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden
- Moscow
Institute of Physics and Technology, 141700 Dolgoprudny, Russia
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15
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Orús P, Córdoba R, Hlawacek G, De Teresa JM. Superconducting properties of in-plane W-C nanowires grown by He + focused ion beam induced deposition. NANOTECHNOLOGY 2021; 32:085301. [PMID: 33171446 DOI: 10.1088/1361-6528/abc91c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Focused ion beam induced deposition (FIBID) is a nanopatterning technique that uses a focused beam of charged ions to decompose a gaseous precursor. So far, the flexible patterning capabilities of FIBID have been widely exploited in the fabrication of superconducting nanostructures, using the W(CO)6 precursor mostly in combination with a focused beam of Ga+ ions. Here, the fabrication and characterization of superconducting in-plane tungsten-carbon (W-C) nanostructures by He+ FIBID of the W(CO)6 precursor is reported. A patterning resolution of 10 nm has been achieved, which is virtually unattainable for Ga+ FIBID. When the nanowires are patterned with widths of 20 nm and above, the deposited material is superconducting below 3.5-4 K. In addition, nanowires with widths of 60 and 90 nm have been found to sustain long-range controlled nonlocal superconducting vortex transfer along 3 μm. Overall, these findings strengthen the capabilities of He+ FIBID of W-C in the growth and patterning of in-plane superconducting nanodevices.
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Affiliation(s)
- Pablo Orús
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), University of Zaragoza, 50018 Zaragoza, Spain
| | - Rosa Córdoba
- Instituto de Ciencia Molecular, Universitat de València, Paterna, 46980 València, Spain
| | - Gregor Hlawacek
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - José María De Teresa
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), University of Zaragoza, 50018 Zaragoza, Spain
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16
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Rochet A, Vadimov V, Magrini W, Thakur S, Trebbia JB, Melnikov A, Buzdin A, Tamarat P, Lounis B. On-Demand Optical Generation of Single Flux Quanta. NANO LETTERS 2020; 20:6488-6493. [PMID: 32787167 DOI: 10.1021/acs.nanolett.0c02166] [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
Superconductors can host quantized magnetic flux tubes surrounded by supercurrents, called Abrikosov vortices. Vortex penetration into a superconducting film is usually limited to its edges and triggered by external magnetic fields or local electrical currents. With a view to novel research directions in quantum computation, the possibility to generate and control single flux quanta in situ is thus challenging. We introduce a far-field optical method to sculpt the magnetic flux or generate permanent single vortices at any desired position in a superconductor. It is based on a fast quench following the absorption of a tightly focused laser pulse that locally heats the superconductor above its critical temperature. We achieve ex-nihilo creation of a single vortex pinned at the center of the hotspot, while its counterpart opposite flux is trapped tens of micrometers away at its boundaries. Our method paves the way to optical operation of Josephson transport with single flux quanta.
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Affiliation(s)
- Antonine Rochet
- Université de Bordeaux, LP2N, F-33405 Talence, France
- Institut d'Optique & CNRS, LP2N, F-33405 Talence, France
| | - Vasiliy Vadimov
- Institute for Physics of Microstructures, Russian Academy of Sciences, 603095 Nizhny Novgorod, GSP-105, Russia
| | - William Magrini
- Université de Bordeaux, LP2N, F-33405 Talence, France
- Institut d'Optique & CNRS, LP2N, F-33405 Talence, France
| | - Siddharatha Thakur
- Université de Bordeaux, LP2N, F-33405 Talence, France
- Institut d'Optique & CNRS, LP2N, F-33405 Talence, France
| | - Jean-Baptiste Trebbia
- Université de Bordeaux, LP2N, F-33405 Talence, France
- Institut d'Optique & CNRS, LP2N, F-33405 Talence, France
| | - Alexander Melnikov
- Institute for Physics of Microstructures, Russian Academy of Sciences, 603095 Nizhny Novgorod, GSP-105, Russia
- Sirius University of Science and Technology, 1 Olympic Ave, 354340 Sochi, Russia
| | - Alexander Buzdin
- University of Bordeaux, LOMA UMR-CNRS 5798, F-33405 Talence, France
| | - Philippe Tamarat
- Université de Bordeaux, LP2N, F-33405 Talence, France
- Institut d'Optique & CNRS, LP2N, F-33405 Talence, France
| | - Brahim Lounis
- Université de Bordeaux, LP2N, F-33405 Talence, France
- Institut d'Optique & CNRS, LP2N, F-33405 Talence, France
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17
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Fernández-Pacheco A, Skoric L, De Teresa JM, Pablo-Navarro J, Huth M, Dobrovolskiy OV. Writing 3D Nanomagnets Using Focused Electron Beams. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E3774. [PMID: 32859076 PMCID: PMC7503546 DOI: 10.3390/ma13173774] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/10/2020] [Accepted: 08/20/2020] [Indexed: 12/18/2022]
Abstract
Focused electron beam induced deposition (FEBID) is a direct-write nanofabrication technique able to pattern three-dimensional magnetic nanostructures at resolutions comparable to the characteristic magnetic length scales. FEBID is thus a powerful tool for 3D nanomagnetism which enables unique fundamental studies involving complex 3D geometries, as well as nano-prototyping and specialized applications compatible with low throughputs. In this focused review, we discuss recent developments of this technique for applications in 3D nanomagnetism, namely the substantial progress on FEBID computational methods, and new routes followed to tune the magnetic properties of ferromagnetic FEBID materials. We also review a selection of recent works involving FEBID 3D nanostructures in areas such as scanning probe microscopy sensing, magnetic frustration phenomena, curvilinear magnetism, magnonics and fluxonics, offering a wide perspective of the important role FEBID is likely to have in the coming years in the study of new phenomena involving 3D magnetic nanostructures.
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Affiliation(s)
- Amalio Fernández-Pacheco
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK;
| | - Luka Skoric
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK;
| | - José María De Teresa
- Instituto de Nanociencia y Materiales de Aragón (INMA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA) and Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain;
| | - Javier Pablo-Navarro
- Laboratorio de Microscopías Avanzadas (LMA) and Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain;
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Michael Huth
- Institute of Physics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
| | - Oleksandr V. Dobrovolskiy
- Institute of Physics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
- Faculty of Physics, University of Vienna, 1090 Vienna, Austria
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18
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Córdoba R, Orús P, Jelić ŽL, Sesé J, Ibarra MR, Guillamón I, Vieira S, Palacios JJ, Suderow H, Milosević MV, De Teresa JM. Long-range vortex transfer in superconducting nanowires. Sci Rep 2019; 9:12386. [PMID: 31455848 PMCID: PMC6712003 DOI: 10.1038/s41598-019-48887-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/01/2019] [Indexed: 11/24/2022] Open
Abstract
Under high-enough values of perpendicularly-applied magnetic field and current, a type-II superconductor presents a finite resistance caused by the vortex motion driven by the Lorentz force. To recover the dissipation-free conduction state, strategies for minimizing vortex motion have been intensely studied in the last decades. However, the non-local vortex motion, arising in areas depleted of current, has been scarcely investigated despite its potential application for logic devices. Here, we propose a route to transfer vortices carried by non-local motion through long distances (up to 10 micrometers) in 50 nm-wide superconducting WC nanowires grown by Ga+ Focused Ion Beam Induced Deposition. A giant non-local electrical resistance of 36 Ω has been measured at 2 K in 3 μm-long nanowires, which is 40 times higher than signals reported for wider wires of other superconductors. This giant effect is accounted for by the existence of a strong edge confinement potential that hampers transversal vortex displacements, allowing the long-range coherent displacement of a single vortex row along the superconducting channel. Experimental results are in good agreement with numerical simulations of vortex dynamics based on the time-dependent Ginzburg-Landau equations. Our results pave the way for future developments on information technologies built upon single vortex manipulation in nano-superconductors.
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Affiliation(s)
- Rosa Córdoba
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, E-50009, Zaragoza, Spain. .,Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009, Zaragoza, Spain. .,Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, Paterna, 46980, Spain.
| | - Pablo Orús
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, E-50009, Zaragoza, Spain.,Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009, Zaragoza, Spain
| | - Željko L Jelić
- University of Antwerp, Department Physics, Groenenborgerlaan 171, B-2020, Antwerp, Belgium
| | - Javier Sesé
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, E-50009, Zaragoza, Spain.,Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009, Zaragoza, Spain.,Laboratorio de Microscopías Avanzadas (LMA)-Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, E-50018, Zaragoza, Spain
| | - Manuel Ricardo Ibarra
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, E-50009, Zaragoza, Spain.,Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009, Zaragoza, Spain.,Laboratorio de Microscopías Avanzadas (LMA)-Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, E-50018, Zaragoza, Spain
| | - Isabel Guillamón
- Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Sebastián Vieira
- Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Juan José Palacios
- Departamento de Física de la Materia Condensada, Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Hermann Suderow
- Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Milorad V Milosević
- University of Antwerp, Department Physics, Groenenborgerlaan 171, B-2020, Antwerp, Belgium
| | - José María De Teresa
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, E-50009, Zaragoza, Spain. .,Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009, Zaragoza, Spain. .,Laboratorio de Microscopías Avanzadas (LMA)-Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, E-50018, Zaragoza, Spain.
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19
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Klenov N, Khaydukov Y, Bakurskiy S, Morari R, Soloviev I, Boian V, Keller T, Kupriyanov M, Sidorenko A, Keimer B. Periodic Co/Nb pseudo spin valve for cryogenic memory. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:833-839. [PMID: 31019870 PMCID: PMC6466729 DOI: 10.3762/bjnano.10.83] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
We present a study of magnetic structures with controllable effective exchange energy for Josephson switches and memory applications. As a basis for a weak link we propose to use a periodic structure composed of ferromagnetic (F) layers spaced by thin superconductors (s). Our calculations based on the Usadel equations show that switching from parallel (P) to antiparallel (AP) alignment of neighboring F layers can lead to a significant enhancement of the critical current through the junction. To control the magnetic alignment we propose to use a periodic system whose unit cell is a pseudo spin valve of structure F1/s/F2/s where F1 and F2 are two magnetic layers having different coercive fields. In order to check the feasibility of controllable switching between AP and P states through the whole periodic structure, we prepared a superlattice [Co(1.5 nm)/Nb(8 nm)/Co(2.5 nm)/Nb(8 nm)]6 between two superconducting layers of Nb(25 nm). Neutron scattering and magnetometry data showed that parallel and antiparallel alignment can be controlled with a magnetic field of only several tens of Oersted.
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Affiliation(s)
- Nikolay Klenov
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
- All-Russian Research Institute of Automatics n.a. N.L. Dukhov (VNIIA), 127055, Moscow, Russia
| | - Yury Khaydukov
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Max Planck Society Outstation at the Heinz Maier-Leibnitz Zentrum (MLZ), D-85748 Garching, Germany
| | - Sergey Bakurskiy
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
| | - Roman Morari
- Institute of Electronic Engineering and Nanotechnologies ASM, MD2028 Kishinev, Moldova
| | - Igor Soloviev
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
| | - Vladimir Boian
- Institute of Electronic Engineering and Nanotechnologies ASM, MD2028 Kishinev, Moldova
| | - Thomas Keller
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Max Planck Society Outstation at the Heinz Maier-Leibnitz Zentrum (MLZ), D-85748 Garching, Germany
| | - Mikhail Kupriyanov
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
- Solid State Physics Department, KFU, 420008 Kazan, Russia
| | - Anatoli Sidorenko
- Institute of Electronic Engineering and Nanotechnologies ASM, MD2028 Kishinev, Moldova
| | - Bernhard Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
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20
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Díaz-Méndez R, Pupillo G, Mezzacapo F, Wallin M, Lidmar J, Babaev E. Phase-change switching in 2D via soft interactions. SOFT MATTER 2019; 15:355-358. [PMID: 30556570 DOI: 10.1039/c8sm01738g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present a new type of phase-change behavior relevant for information storage applications, that can be observed in 2D systems with cluster-forming ability. The temperature-based control of the ordering in 2D particle systems depends on the existence of a crystal-to-glass transition. We perform molecular dynamics simulations of models with soft interactions, demonstrating that the crystalline and amorphous structures can be easily tuned by heat pulses. The physical mechanism responsible for this behavior is a self-assembled polydispersity, that depends on the cluster-forming ability of the interactions. Therefore, the range of real materials that can perform such a transition is very wide in nature, ranging from colloidal suspensions to vortex matter. The state of the art in soft matter experimental setups, controlling interactions, polydispersity and dimensionality, makes it a very fertile ground for practical applications.
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Affiliation(s)
- Rogelio Díaz-Méndez
- Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
| | - Guido Pupillo
- icFRC, ISIS (UMR 7006), IPCMS (UMR 7504), Université de Strasbourg and CNRS, 67000 Strasbourg, France
| | - Fabio Mezzacapo
- Laboratoire de Physique, CNRS UMR 5672, ENS de Lyon, F-69364 Lyon Cedex 07, France
| | - Mats Wallin
- Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
| | - Jack Lidmar
- Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
| | - Egor Babaev
- Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
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21
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Borodianskyi EA, Krasnov VM. Josephson emission with frequency span 1-11 THz from small Bi 2Sr 2CaCu 2O 8+δ mesa structures. Nat Commun 2017; 8:1742. [PMID: 29170380 PMCID: PMC5701082 DOI: 10.1038/s41467-017-01888-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/22/2017] [Indexed: 11/09/2022] Open
Abstract
Mesa structures made of Bi2Sr2CaCu2O8+δ high-temperature superconductor represent stacks of atomic scale intrinsic Josephson junctions. They can be used for generation of high-frequency electromagnetic waves. Here we analyze Josephson emission from small-but-high mesas (with a small area, but containing many stacked junctions). We have found strong evidence for tunable terahertz emission with a good efficacy in a record high-frequency span 1-11 THz, approaching the theoretical upper limit for this superconductor. Emission maxima correspond to in-phase cavity modes in the mesas, indicating coherent superradiant nature of the emission. We conclude that terahertz emission requires a threshold number of junctions N ~ 100. The threshold behavior is not present in the classical description of stacked Josephson junctions and suggests importance of laser-like cascade amplification of the photon number in the cavity.
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Affiliation(s)
- E A Borodianskyi
- Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91, Stockholm, Sweden
| | - V M Krasnov
- Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91, Stockholm, Sweden.
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22
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Bekaert J, Bignardi L, Aperis A, van Abswoude P, Mattevi C, Gorovikov S, Petaccia L, Goldoni A, Partoens B, Oppeneer PM, Peeters FM, Milošević MV, Rudolf P, Cepek C. Free surfaces recast superconductivity in few-monolayer MgB 2: Combined first-principles and ARPES demonstration. Sci Rep 2017; 7:14458. [PMID: 29089566 PMCID: PMC5663715 DOI: 10.1038/s41598-017-13913-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 10/02/2017] [Indexed: 11/08/2022] Open
Abstract
Two-dimensional materials are known to harbour properties very different from those of their bulk counterparts. Recent years have seen the rise of atomically thin superconductors, with a caveat that superconductivity is strongly depleted unless enhanced by specific substrates, intercalants or adatoms. Surprisingly, the role in superconductivity of electronic states originating from simple free surfaces of two-dimensional materials has remained elusive to date. Here, based on first-principles calculations, anisotropic Eliashberg theory, and angle-resolved photoemission spectroscopy (ARPES), we show that surface states in few-monolayer MgB2 make a major contribution to the superconducting gap spectrum and density of states, clearly distinct from the widely known, bulk-like σ- and π-gaps. As a proof of principle, we predict and measure the gap opening on the magnesium-based surface band up to a critical temperature as high as ~30 K for merely six monolayers thick MgB2. These findings establish free surfaces as an unavoidable ingredient in understanding and further tailoring of superconductivity in atomically thin materials.
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Affiliation(s)
- J Bekaert
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium.
| | - L Bignardi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands
- Elettra Sincrotrone Trieste, Strada Statale 14 km.163.5, I-34149, Trieste, Italy
| | - A Aperis
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20, Uppsala, Sweden
| | - P van Abswoude
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands
| | - C Mattevi
- IOM-CNR, Laboratorio TASC, Strada Statale 14 km.163.5, I-34149, Trieste, Italy
- Department of Materials, Imperial College London, Exhibition road, SW7 2AZ, London, United Kingdom
| | - S Gorovikov
- Elettra Sincrotrone Trieste, Strada Statale 14 km.163.5, I-34149, Trieste, Italy
- Canadian Light Source Inc., 44 Innovation Blvd, Saskatoon, SK S7N 2V3, Canada
| | - L Petaccia
- Elettra Sincrotrone Trieste, Strada Statale 14 km.163.5, I-34149, Trieste, Italy
| | - A Goldoni
- Elettra Sincrotrone Trieste, Strada Statale 14 km.163.5, I-34149, Trieste, Italy
| | - B Partoens
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium
| | - P M Oppeneer
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20, Uppsala, Sweden
| | - F M Peeters
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium
| | - M V Milošević
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium.
| | - P Rudolf
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands.
| | - C Cepek
- IOM-CNR, Laboratorio TASC, Strada Statale 14 km.163.5, I-34149, Trieste, Italy
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23
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Ge JY, Gladilin VN, Tempere J, Devreese J, Moshchalkov VV. Controlled Generation of Quantized Vortex-Antivortex Pairs in a Superconducting Condensate. NANO LETTERS 2017; 17:5003-5007. [PMID: 28693319 DOI: 10.1021/acs.nanolett.7b02180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Quantized vortices, as topological defects, play an important role in both physics and technological applications of superconductors. Normally, the nucleation of vortices requires the presence of a high magnetic field or current density, which allow the vortices to enter from the sample boundaries. At the same time, the controllable generation of individual vortices inside a superconductor is still challenging. Here, we report the controllable creation of single quantum vortices and antivortices at any desirable position inside a superconductor. We exploit the local heating effect of a scanning tunneling microscope (STM) tip: superconductivity is locally suppressed by the tip and vortex-antivortex pairs are generated when supercurrent flows around the hot spot. The experimental results are well-explained by theoretical simulations within the Ginzburg-Landau approach.
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Affiliation(s)
- Jun-Yi Ge
- INPAC-Institute for Nanoscale Physics and Chemistry, KU Leuven , Celestijnenlaan 200D, B-3001 Leuven, Belgium
| | - Vladimir N Gladilin
- INPAC-Institute for Nanoscale Physics and Chemistry, KU Leuven , Celestijnenlaan 200D, B-3001 Leuven, Belgium
- TQC-Theory of Quantum and Complex Systems, Universiteit Antwerpen , Universiteitsplein 1, B-2610 Antwerpen, Belgium
| | - Jacques Tempere
- TQC-Theory of Quantum and Complex Systems, Universiteit Antwerpen , Universiteitsplein 1, B-2610 Antwerpen, Belgium
| | - Jozef Devreese
- TQC-Theory of Quantum and Complex Systems, Universiteit Antwerpen , Universiteitsplein 1, B-2610 Antwerpen, Belgium
| | - Victor V Moshchalkov
- INPAC-Institute for Nanoscale Physics and Chemistry, KU Leuven , Celestijnenlaan 200D, B-3001 Leuven, Belgium
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24
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Imaging of super-fast dynamics and flow instabilities of superconducting vortices. Nat Commun 2017; 8:85. [PMID: 28729642 PMCID: PMC5519736 DOI: 10.1038/s41467-017-00089-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 06/01/2017] [Indexed: 11/08/2022] Open
Abstract
Quantized magnetic vortices driven by electric current determine key electromagnetic properties of superconductors. While the dynamic behavior of slow vortices has been thoroughly investigated, the physics of ultrafast vortices under strong currents remains largely unexplored. Here, we use a nanoscale scanning superconducting quantum interference device to image vortices penetrating into a superconducting Pb film at rates of tens of GHz and moving with velocities of up to tens of km/s, which are not only much larger than the speed of sound but also exceed the pair-breaking speed limit of superconducting condensate. These experiments reveal formation of mesoscopic vortex channels which undergo cascades of bifurcations as the current and magnetic field increase. Our numerical simulations predict metamorphosis of fast Abrikosov vortices into mixed Abrikosov-Josephson vortices at even higher velocities. This work offers an insight into the fundamental physics of dynamic vortex states of superconductors at high current densities, crucial for many applications.Ultrafast vortex dynamics driven by strong currents define eletromagnetic properties of superconductors, but it remains unexplored. Here, Embon et al. use a unique scanning microscopy technique to image steady-state penetration of super-fast vortices into a superconducting Pb film at rates of tens of GHz and velocities up to tens of km/s.
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Soloviev II, Klenov NV, Bakurskiy SV, Kupriyanov MY, Gudkov AL, Sidorenko AS. Beyond Moore's technologies: operation principles of a superconductor alternative. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:2689-2710. [PMID: 29354341 PMCID: PMC5753050 DOI: 10.3762/bjnano.8.269] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 11/19/2017] [Indexed: 05/23/2023]
Abstract
The predictions of Moore's law are considered by experts to be valid until 2020 giving rise to "post-Moore's" technologies afterwards. Energy efficiency is one of the major challenges in high-performance computing that should be answered. Superconductor digital technology is a promising post-Moore's alternative for the development of supercomputers. In this paper, we consider operation principles of an energy-efficient superconductor logic and memory circuits with a short retrospective review of their evolution. We analyze their shortcomings in respect to computer circuits design. Possible ways of further research are outlined.
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Affiliation(s)
- Igor I Soloviev
- Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, 119991, Moscow, Russia
- Moscow Technological University (MIREA), 119454, Moscow, Russia
| | - Nikolay V Klenov
- Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, 119991, Moscow, Russia
- Moscow Technological University (MIREA), 119454, Moscow, Russia
- All-Russian Research Institute of Automatics n.a. N.L. Dukhov (VNIIA), 127055, Moscow, Russia
| | - Sergey V Bakurskiy
- Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, 119991, Moscow, Russia
| | - Mikhail Yu Kupriyanov
- Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, 119991, Moscow, Russia
- Solid State Physics Department, Kazan Federal University, 420008, Kazan, Russia
| | - Alexander L Gudkov
- Lukin Scientific Research Institute of Physical Problems, 124460, Zelenograd, Moscow, Russia
| | - Anatoli S Sidorenko
- Solid State Physics Department, Kazan Federal University, 420008, Kazan, Russia
- Ghitu Institute of Electronic Engineering and Nanotechnologies ASM, Chisinau, Moldova
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Nanoscale assembly of superconducting vortices with scanning tunnelling microscope tip. Nat Commun 2016; 7:13880. [PMID: 27934960 PMCID: PMC5155158 DOI: 10.1038/ncomms13880] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/08/2016] [Indexed: 11/09/2022] Open
Abstract
Vortices play a crucial role in determining the properties of superconductors as well as their applications. Therefore, characterization and manipulation of vortices, especially at the single-vortex level, is of great importance. Among many techniques to study single vortices, scanning tunnelling microscopy (STM) stands out as a powerful tool, due to its ability to detect the local electronic states and high spatial resolution. However, local control of superconductivity as well as the manipulation of individual vortices with the STM tip is still lacking. Here we report a new function of the STM, namely to control the local pinning in a superconductor through the heating effect. Such effect allows us to quench the superconducting state at nanoscale, and leads to the growth of vortex clusters whose size can be controlled by the bias voltage. We also demonstrate the use of an STM tip to assemble single-quantum vortices into desired nanoscale configurations.
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Abstract
In an electronic triode, the electron current emanating from the cathode is regulated by the electric potential on a grid between the cathode and the anode. Here we demonstrate a triode for single quantum magnetic field carriers, where the flow of individual magnetic vortices in a superconducting film is regulated by the magnetic potential of striae of soft magnetic strips deposited on the film surface. By rotating an applied in-plane field, the magnetic strip potential can be varied due to changes in the magnetic charges at the strip edges, allowing accelerated or retarded motion of magnetic vortices inside the superconductor. Scaling down our design and reducing the gap width between the magnetic stripes will enable controlled manipulation of individual vortices and creation of single flux quantum circuitry for novel high-speed low-power superconducting electronics.
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Velocimetry of superconducting vortices based on stroboscopic resonances. Sci Rep 2016; 6:35687. [PMID: 27774995 PMCID: PMC5075923 DOI: 10.1038/srep35687] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/03/2016] [Indexed: 11/25/2022] Open
Abstract
An experimental determination of the mean vortex velocity in superconductors mostly relies on the measurement of flux-flow resistance with magnetic field, temperature, or driving current. In the present work we introduce a method combining conventional transport measurements and a frequency-tuned flashing pinning potential to obtain reliable estimates of the vortex velocity. The proposed device is characterized using the time-dependent Ginzburg-Landau formalism, where the velocimetry method exploits the resonances in mean vortex dissipation when temporal commensuration occurs between the vortex crossings and the flashing potential. We discuss the sensitivity of the proposed technique on applied current, temperature and heat diffusion, as well as the vortex core deformations during fast motion.
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