1,189 results on '"Superconductivity -- Research"'
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2. Sudden death of quantum fluctuations defies current theories of superconductivity
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Superconductivity -- Research ,Quantum theory -- Research ,Superconductors -- Properties ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry ,Princeton University -- Research - Abstract
Princeton NJ (SPX) Jan 12, 2024 Princeton physicists have discovered an abrupt change in quantum behavior while experimenting with a three-atom-thin insulator that can be easily switched into a superconductor. [...]
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- 2024
3. Superconductivity in rhombohedral trilayer graphene
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Zhou, Haoxin, Xie, Tian, Taniguchi, Takashi, Watanabe, Kenji, and Young, Andrea F.
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Superconductivity -- Research ,Graphene -- Electric properties ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
To access superconductivity via the electric field effect in a clean, two-dimensional device is a central goal of nanoelectronics. Recently, superconductivity has been realized in graphene moiré heterostructures.sup.1-4; however, many of these structures are not mechanically stable, and experiments show signatures of strong disorder. Here we report the observation of superconductivity--manifesting as low or vanishing resistivity at sub-kelvin temperatures--in crystalline rhombohedral trilayer graphene.sup.5,6, a structurally metastable carbon allotrope. Superconductivity occurs in two distinct gate-tuned regions (SC1 and SC2), and is deep in the clean limit defined by the ratio of mean free path and superconducting coherence length. Mapping of the normal state Fermi surfaces by quantum oscillations reveals that both superconductors emerge from an annular Fermi sea, and are proximal to an isospin-symmetry-breaking transition where the Fermi surface degeneracy changes.sup.7. SC1 emerges from a paramagnetic normal state, whereas SC2 emerges from a spin-polarized, valley-unpolarized half-metal.sup.17 and violates the Pauli limit for in-plane magnetic fields by at least one order of magnitude.sup.8,9. We discuss our results in view of several mechanisms, including conventional phonon-mediated pairing.sup.10,11, pairing due to fluctuations of the proximal isospin order.sup.12, and intrinsic instabilities of the annular Fermi liquid.sup.13,14. Our observation of superconductivity in a clean and structurally simple two-dimensional metal provides a model system to test competing theoretical models of superconductivity without the complication of modelling disorder, while enabling new classes of field-effect controlled electronic devices based on correlated electron phenomena and ballistic electron transport. Superconductivity is observed in rhombohedral trilayer graphene in the absence of a moiré superlattice, with two distinct superconducting states both occurring at a symmetry-breaking transition where the Fermi surface degeneracy changes., Author(s): Haoxin Zhou [sup.1] , Tian Xie [sup.1] , Takashi Taniguchi [sup.2] , Kenji Watanabe [sup.3] , Andrea F. Young [sup.1] Author Affiliations: (1) Department of Physics, University of California, [...]
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- 2021
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4. A soaring career
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Johnson, Alexandra
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- 2023
5. Incoherent transport across the strange-metal regime of overdoped cuprates
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Ayres, J., Berben, M., Culo, M., Hsu, Y.-T., van Heumen, E., Huang, Y., and Zaanen, J.
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Copper oxide superconductors -- Magnetic properties ,Superconductivity -- Research ,Electron transport -- Research ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Strange metals possess highly unconventional electrical properties, such as a linear-in-temperature resistivity.sup.1-6, an inverse Hall angle that varies as temperature squared.sup.7-9 and a linear-in-field magnetoresistance.sup.10-13. Identifying the origin of these collective anomalies has proved fundamentally challenging, even in materials such as the hole-doped cuprates that possess a simple bandstructure. The prevailing consensus is that strange metallicity in the cuprates is tied to a quantum critical point at a doping p* inside the superconducting dome.sup.14,15. Here we study the high-field in-plane magnetoresistance of two superconducting cuprate families at doping levels beyond p*. At all dopings, the magnetoresistance exhibits quadrature scaling and becomes linear at high values of the ratio of the field and the temperature, indicating that the strange-metal regime extends well beyond p*. Moreover, the magnitude of the magnetoresistance is found to be much larger than predicted by conventional theory and is insensitive to both impurity scattering and magnetic field orientation. These observations, coupled with analysis of the zero-field and Hall resistivities, suggest that despite having a single band, the cuprate strange-metal region hosts two charge sectors, one containing coherent quasiparticles, the other scale-invariant 'Planckian' dissipators. Measurements of high-field magnetotransport in overdoped cuprates indicate that the strange-metal regime exists beyond the critical doping, and that it has both coherent and incoherent contributions., Author(s): J. Ayres [sup.1] [sup.2] [sup.3] , M. Berben [sup.2] [sup.3] , M. Culo [sup.2] [sup.3] [sup.10] , Y.-T. Hsu [sup.2] [sup.3] , E. van Heumen [sup.4] [sup.5] , Y. [...]
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- 2021
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6. Pauli-limit violation and re-entrant superconductivity in moire graphene
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Cao, Yuan, Park, Jeong Min, Watanabe, Kenji, Taniguchi, Takashi, and Jarillo-Herrero, Pablo
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Materials research ,Superconductivity -- Research ,Graphene -- Electric properties ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Moiré quantum matter has emerged as a materials platform in which correlated and topological phases can be explored with unprecedented control. Among them, magic-angle systems constructed from two or three layers of graphene have shown robust superconducting phases with unconventional characteristics.sup.1-5. However, direct evidence of unconventional pairing remains to be experimentally demonstrated. Here we show that magic-angle twisted trilayer graphene exhibits superconductivity up to in-plane magnetic fields in excess of 10 T, which represents a large (2-3 times) violation of the Pauli limit for conventional spin-singlet superconductors.sup.6,7. This is an unexpected observation for a system that is not predicted to have strong spin-orbit coupling. The Pauli-limit violation is observed over the entire superconducting phase, which indicates that it is not related to a possible pseudogap phase with large superconducting amplitude pairing. Notably, we observe re-entrant superconductivity at large magnetic fields, which is present over a narrower range of carrier densities and displacement fields. These findings suggest that the superconductivity in magic-angle twisted trilayer graphene is likely to be driven by a mechanism that results in non-spin-singlet Cooper pairs, and that the external magnetic field can cause transitions between phases with potentially different order parameters. Our results demonstrate the richness of moiré superconductivity and could lead to the design of next-generation exotic quantum matter. A large violation of the Pauli limit and re-entrant superconductivity in a magnetic field is reported for magic-angle twisted trilayer graphene, suggesting that the spin configuration of the superconducting state of this material is unlikely to consist of spin singlets., Author(s): Yuan Cao [sup.1] , Jeong Min Park [sup.1] , Kenji Watanabe [sup.2] , Takashi Taniguchi [sup.3] , Pablo Jarillo-Herrero [sup.1] Author Affiliations: (1) Department of Physics, Massachusetts Institute of [...]
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- 2021
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7. Quantum geometry found to be newest twist in superconductivity
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Superconductivity -- Research ,Quantum theory -- Research ,Superconductors -- Design and construction -- Innovations ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Dallas TX (SPX) Feb 17, 2023 Scientists at The University of Texas at Dallas and their collaborators at The Ohio State University have identified a new mechanism that gives rise [...]
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- 2023
8. Researchers gain deeper understanding of mechanism behind superconductors
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Magnetic resonance -- Research ,Superconductivity -- Research ,Superconductors -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Leipzig, Germany (SPX) Jan 18, 2023 This confirmed their own findings from 2016, when Haase and his team developed an experimental method based on magnetic resonance that can measure changes [...]
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- 2023
9. Untwisted trilayer graphene hosts superconductivity and magnetism
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Taychatanapat, Thiti
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Superconductivity -- Research ,Graphene -- Electric properties -- Magnetic properties ,Magnetism -- Research ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Superconductivity and magnetism have been observed in layered graphene in which the sheets are twisted with respect to each other. But a simpler, more stable graphene system also exhibits these phases. Trilayer graphene system without a twist shows different phases., Author(s): Thiti Taychatanapat Author Affiliations: Untwisted trilayer graphene hosts superconductivity and magnetism Electrons typically propagate without interacting in graphene, a single layer of carbon atoms arranged in a honeycomb lattice. [...]
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- 2021
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10. New insight into unconventional superconductivity
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Superconductivity -- Research ,Quantum theory -- Research ,Electron transport -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Villigen, Switzerland (SPX) Feb 10, 2022 The kagome pattern, a network of corner-sharing triangles, is well known amongst traditional Japanese basket weavers - and condensed matter physicists. The unusual geometry [...]
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- 2022
11. Superconductivity on the edge
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Superconductivity -- Research ,Quantum theory -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Washington DC (SPX) Feb 04, 2022 Scientists recently discovered novel quantum materials whose charge carriers exhibit 'topological' features. Charge carriers are particles that transport electrical charges through a material. Topology [...]
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- 2022
12. Semiconductors reach the quantum world
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Semiconductors -- Research ,Quantum theory -- Research ,Superconductivity -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Villigen, Switzerland (SPX) Jan 01, 2022 Quantum effects in superconductors could give semiconductor technology a new twist. Researchers at the Paul Scherrer Institute PSI and Cornell University in New York [...]
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- 2022
13. Unconventional superconductivity in magic-angle graphene superlattices
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Cao, Yuan, Fatemi, Valla, Fang, Shiang, Watanabe, Kenji, Taniguchi, Takashi, Kaxiras, Efthimios, and Jarillo-Herrero, Pablo
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Graphene -- Electric properties ,Physics research ,Superconductivity -- Research ,Superlattices -- Electric properties ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
The behaviour of strongly correlated materials, and in particular unconventional superconductors, has been studied extensively for decades, but is still not well understood. This lack of theoretical understanding has motivated the development of experimental techniques for studying such behaviour, such as using ultracold atom lattices to simulate quantum materials. Here we report the realization of intrinsic unconventional superconductivitywhich cannot be explained by weak electronphonon interactionsin a two-dimensional superlattice created by stacking two sheets of graphene that are twisted relative to each other by a small angle. For twist angles of about 1.1the first magic anglethe electronic band structure of this twisted bilayer graphene exhibits flat bands near zero Fermi energy, resulting in correlated insulating states at half-filling. Upon electrostatic doping of the material away from these correlated insulating states, we observe tunable zero-resistance states with a critical temperature of up to 1.7 kelvin. The temperaturecarrier-density phase diagram of twisted bilayer graphene is similar to that of copper oxides (or cuprates), and includes dome-shaped regions that correspond to superconductivity. Moreover, quantum oscillations in the longitudinal resistance of the material indicate the presence of small Fermi surfaces near the correlated insulating states, in analogy with underdoped cuprates. The relatively high superconducting critical temperature of twisted bilayer graphene, given such a small Fermi surface (which corresponds to a carrier density of about 10[sup.11] per square centimetre), puts it among the superconductors with the strongest pairing strength between electrons. Twisted bilayer graphene is a precisely tunable, purely carbon-based, two-dimensional superconductor. It is therefore an ideal material for investigations of strongly correlated phenomena, which could lead to insights into the physics of high-critical-temperature superconductors and quantum spin liquids., Author(s): Yuan Cao (corresponding author) [1]; Valla Fatemi [1]; Shiang Fang [2]; Kenji Watanabe [3]; Takashi Taniguchi [3]; Efthimios Kaxiras [2, 4]; Pablo Jarillo-Herrero (corresponding author) [1] Strong interactions among [...]
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- 2018
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14. Record-breaking superconductivity: Scandium can turn into a superconductor at a higher temperature than any other element
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Padavic-Callaghan, Karmela
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Scandium -- Electric properties -- Thermal properties ,Materials research ,Superconductivity -- Research ,Business ,Science and technology - Abstract
THE metal scandium can be made into a superconductor without having to be mixed with other substances, and this occurs at higher temperatures than for any other element. The process [...]
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- 2023
15. Resolving the puzzles of graphene superconductivity
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Materials research ,Superconductivity -- Research ,Graphene -- Electric properties ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Klosterneuburg, Austria (SPX) Dec 10, 2021 A single layer of carbon atoms arranged in a honeycomb lattice makes up the promising nanomaterial called graphene. Research on a setup of three [...]
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- 2021
16. Electron family creates previously unknown state of matter
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Superconductivity -- Research ,Quantum theory -- Research ,Electrons -- Research ,Matter -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Dresden, Germany (SPX) Nov 08, 2021 Dissipationless electric energy transport-also known as superconductivity-is seen as a beacon of hope for the energy industry. Since its discovery more than 100 years [...]
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- 2021
17. A new dimension in magnetism and superconductivity launched
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Materials research ,Superconductivity -- Research ,Magnetism -- Research ,Spintronics -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Vienna, Austria (SPX) Nov 04, 2021 Traditionally, the primary fideld, where curvature is playing a pivotal role, is the theory of general relativity. In recent years, however, the impact of [...]
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- 2021
18. Superconductor discovery called into question
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Wilkins, Alex
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Materials research ,Superconductivity -- Research ,Research validity -- Analysis ,Superconductors -- Innovations ,Business ,Science and technology - Abstract
RED matter, a material that researchers claimed showed evidence of being a room- temperature superconductor with the promise of revolutionising electronics, might not be so super after all, after another [...]
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- 2023
19. 'Red matter' superconductor could transform electronics--if it works
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Crane, Leah
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Superconductivity -- Research ,Superconductors -- Innovations -- Materials ,Business ,Science and technology - Abstract
ROOM-temperature, room-pressure superconductivity has been a central goal of materials science for more than a century, and it may have nearly been achieved. If this new superconducting material holds up, [...]
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- 2023
20. Superconductivity in a graphene system survives a strong magnetic field
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Hsu, Yi-Ting
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Materials research ,Superconductivity -- Research ,Graphene -- Electric properties -- Magnetic properties ,Magnetic fields -- Research ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
A material system known as magic-angle twisted trilayer graphene exhibits superconductivity. The observation that this superconductivity persists under a strong magnetic field could lead to advances in quantum computation. Evidence of spin-triplet superconductivity in a quasi-2D system., Author(s): Yi-Ting Hsu Author Affiliations: Superconductivity in a graphene system survives a strong magnetic field Quantum phases of matter known as superconductors transmit electrical current with zero resistance. Microscopically, this [...]
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- 2021
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21. Physicists create tunable superconductivity in twisted graphene 'nanosandwich'
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Superconductivity -- Research ,Graphene -- Electric properties -- Structure ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry ,Massachusetts Institute of Technology -- Reports - Abstract
Boston MA (SPX) Feb 02, 2021 When two sheets of graphene are stacked atop each other at just the right angle, the layered structure morphs into an unconventional superconductor, allowing [...]
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- 2021
22. New kind of superconductivity discovered
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Bose-Einstein condensation -- Research ,Superconductivity -- Research ,Superconductors -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Tokyo, Japan (SPX) Nov 09, 2020 Superconductivity is a phenomenon where an electric circuit loses its resistance and becomes extremely efficient under certain conditions. There are different ways in which [...]
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- 2020
23. UNLV and University of Rochester physicists observe room-temperature superconductivity
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Superconductivity -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry ,University of Nevada, Las Vegas -- Reports ,University of Rochester -- Reports - Abstract
Las Vegas NV (SPX) Oct 15, 2020 Physicists from the University of Nevada, Las Vegas and the University of Rochester have made a breakthrough in the long sought-after quest for [...]
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- 2020
24. Diamonds are a quantum scientist's best friend
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Diamond crystals -- Structure -- Electric properties ,Materials research ,Superconductivity -- Research ,Diamonds -- Structure -- Electric properties ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Johannesburg, South Africa (SPX) Oct 08, 2020 Diamonds have a firm foothold in our lexicon. Their many properties often serve as superlatives for quality, clarity and hardiness. Aside from the [...]
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- 2020
25. New Princeton study takes superconductivity to the edge
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Superconductivity -- Research ,Superconductors -- Research ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Byline: Staff Writers Princeton NJ (SPX) May 01, 2020, 2020 A discovery that long eluded physicists has been detected in a laboratory at Princeton. A team of physicists detected superconducting [...]
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- 2020
26. From quantum matter to high-temperature superconductivity in copper oxides
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Keimer, B., Kivelson, S.A., Norman, M.R., Uchida, S., and Zaanen, J.
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Cuprite -- Electric properties ,Quantum electrodynamics -- Research ,Superconductivity -- Research ,Copper oxide -- Electric properties ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
The discovery of high-temperature superconductivity in the copper oxides in 1986 triggered a huge amount of innovative scientific inquiry. In the almost three decades since, much has been learned about the novel forms of quantum matter that are exhibited in these strongly correlated electron systems. A qualitative understanding of the nature of the superconducting state itself has been achieved. However, unresolved issues include the astonishing complexity of the phase diagram, the unprecedented prominence of various forms of collective fluctuations, and the simplicity and insensitivity to material details of the 'normal' state at elevated temperatures., The discovery of high-temperature superconductivity in the copper oxide perovskite [La.sub.2-x][Ba.sub.x]Cu[O.sub.4] (ref. 1) ranks among the major scientific events of the twentieth century. The superconducting transition temperatures in the copper [...]
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- 2015
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27. Researchers from Quaid-i-Azam University Report Details of New Studies and Findings in the Area of Chemicals and Chemistry [Excess Carrier Density and the Role of Spin Density Waves In the Mechanism of High Tc Superconductivity In ...]
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Copper compounds -- Electric properties -- Chemical properties ,Chemical research ,Superconductivity -- Research ,Biological sciences ,Health - Abstract
2022 DEC 6 (NewsRx) -- By a News Reporter-Staff News Editor at Life Science Weekly -- Researchers detail new data in Chemicals and Chemistry. According to news originating from Islamabad, [...]
- Published
- 2022
28. Nonlinear lattice dynamics as a basis for enhanced superconductivity in Y[Ba.sub.2][Cu.sub.3][O.sub.6.5]
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Mankowsky, R., Subedi, A., Forst, M., Mariager, S.O., Chollet, M., Lemke, H.T., Robinson, J.S., Glownia, J.M., Minitti, M.P., Frano, A., Fechner, M., Spaldin, N.A., Loew, T., Keimer, B., Georges, A., and Cavalleri, A.
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Engineering research ,Crystals -- Structure ,Superconductivity -- Research ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Terahertz-frequency optical pulses can resonantly drive selected vibrational modes in solids and deform their crystal structures (1-3). In complex oxides, this method has been used to melt electronic order (4-6), drive insulator-to-metal transitions (7) and induce superconductivity (8). Strikingly, coherent interlayer transport strongly reminiscent of superconductivity can be transiently induced up to room temperature (300 kelvin) in Y[Ba.sub.2][Cu.sub.3][O.sub.6+x] (refs 9,10). Here we report the crystal structure of this exotic non-equilibrium state, determined by femtosecond X-ray diffraction and ab initio density functional theory calculations. We find that nonlinear lattice excitation in normal-state Y[Ba.sub.2][Cu.sub.3][O.sub.6+x] at above the transition temperature of 52 kelvin causes a simultaneous increase and decrease in the Cu-[O.sub.2] intra-bilayer and, respectively, inter-bilayer distances, accompanied by anisotropic changes in the in-plane O-Cu-O bond buckling. Density functional theory calculations indicate that these motions cause drastic changes in the electronic structure. Among these, the enhancement in the [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] character of the in-plane electronic structure is likely to favour superconductivity., The response of a crystal lattice to strong, resonant excitation of an infrared-active phonon mode can be described by separating the crystal Hamiltonian into its linear and nonlinear terms: H [...]
- Published
- 2014
29. Normal-state nodal electronic structure in underdoped high- [t.sub.c] copper oxides
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Sebastian, Suchitra E., Harrison, N., Balakirev, F.F., Altarawneh, M.M., Goddard, P.A., Liang, Ruixing, Bonn, D.A., Hardy, W.N., and Lonzarich, G.G.
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Cuprite -- Models -- Structure -- Electric properties -- Research ,Superconductivity -- Research ,Copper oxide -- Models -- Structure -- Electric properties -- Research ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
An outstanding problem in the field of high-transition-temperature (high- [T.sub.c]) superconductivity is the identification of the normal state out of which superconductivity emerges in the mysterious underdoped regime (1). The [...]
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- 2014
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30. RMF+BCS approach for drip-line isotopes of Si
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Saxena, G., Singh, D., Kaushik, M., and Singh, S. Somorendro
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Quantum field theory -- Research ,Isotopes -- Research ,Superconductivity -- Research ,Nuclear physics -- Research ,Silicon -- Properties ,Physics - Abstract
We have employed the relativistic mean field (RMF)+BCS approach, to study ground state properties of drip line isotopes of Si. In this approach the single particle continuum corresponding to the RMF is replaced by a set of discrete positive energy states for the calculations of pairing energy. Detailed analysis of separation energy, single particle spectrum, pairing energies, and densities of the nuclei predict weakly bound structure in neutron-rich Si isotopes, which is seen to be due to the large spatial extension of the wave functions for the weakly bound single particle states with low orbital angular momentum having very small centrifugal barriers. PACS Nos.: 21.10.-k, 21.10.Ft, 21.10.Dr, 21.10.Gv, 21.10.-n, 21.60.Jz. Nous avons utilise une approche de champ moyen relativiste (RMF)+BCS pour etudier les proprietes des isotopes du Si pres de la drip line. Ici, le continuum a une particule correspondant au RMF est remplace par un ensemble d'etats discrets a energie positive pour le calcul de l'energie de pairage. L'analyse detaillee de l'energie de separation, du spectre a une particule, des energies de pairage et des densites nucleaires, decrit une structure faiblement liee pour les isotopes de Si riches en neutrons. Nous l'expliquons par la grande extension spatiale des fonctions d'onde pour les etats a une particule faiblement lies, avec faible moment angulaire et de tres basses barrieres centrifuges. [Traduit par la Redaction], 1. Introduction With advancements in nuclear experimental techniques and the development of radioactive nuclear beams facilities around the world, it has been possible to study for the first time the [...]
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- 2014
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31. Interface superconductor with gap behaviour like a high-temperature superconductor
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Richter, C., Boschker, H., Dietsche, W., Fillis-Tsirakis, E., Jany, R., Loder, F., Kourkoutis, L.F., Muller, D.A., Kirtley, J.R., Schneider, C.W., and Mannhart, J.
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Superconductivity -- Research ,Superconductors -- Properties ,Spectrum analysis -- Usage ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
The physics of the superconducting state in two-dimensional (2D) electron systems is relevant to understanding the high-transition-temperature copper oxide superconductors and for the development of future superconductors based on interface electron systems (1). But it is not yet understood how fundamental superconducting parameters, such as the spectral density of states, change when these superconducting electron systems are depleted of charge carriers. Here we use tunnel spectroscopy with planar junctions to measure the behaviour of the electronic spectral density of states as a function of carrier density, clarifying this issue experimentally. We chose the conducting LaAl[O.sub.3]SrTi[O.sub.3]interface (2) as the 2D superconductor, because this electron system can be tuned continuously with an electric gate field (3). We observed an energy gap of the order of 40 microelectronvolts in the density of states, whose shape is well described by the Bardeen-Cooper-Schrieffer superconducting gap function. In contrast to the dome-shaped dependence of the critical temperature, the gap increases with charge carrier depletion in both the underdoped region and the overdoped region. These results are analogous to the pseudogap behaviour of the high-transition-temperature copper oxide superconductors and imply that the smooth continuation of the superconducting gap into pseudogap-like behaviour could be a general property of 2D superconductivity., One of the main challenges in understanding the superconductivity of copper oxide superconductors is to identify the origin and nature of the pseudogap phase in the underdoped regime (4,5). This [...]
- Published
- 2013
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32. Applying pressure is way toward generating more electricity from waste heat
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Superconductivity -- Research ,Waste heat -- Research ,Thermoelectricity -- Research ,Servers (Computers) ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Byline: Staff Writers Osaka, Japan (SPX) Jul 01, 2019, 2019 Researchers at Osaka University have been able to enhance the power factor of a promising thermoelectric material by more than [...]
- Published
- 2019
33. Superinsulators to become scientists' quark playgrounds
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United States. Department of Energy -- Research ,Quarks -- Properties -- Research ,Superconductivity -- Research ,Neutrons -- Properties ,Protons -- Properties ,Scientists ,Colliders (Nuclear physics) ,Playgrounds ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Byline: Staff WritersLemont IL (SPX) Feb 01, 2019, 2019 Scientists widely accept the existence of quarks, the fundamental particles that make up protons and neutrons. But information about them is [...]
- Published
- 2019
34. Artificial magnetic field produces exotic behavior in graphene sheets
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São Paulo, Brazil (City) -- Environmental aspects ,Graphene -- Research -- Environmental aspects ,Magnetic fields -- Research ,Superconductivity -- Research ,Physicists ,Graphite ,Displays (Marketing) ,Nobel laureates ,Aircraft ,Aerospace and defense industries ,Astronomy ,High technology industry ,Telecommunications industry - Abstract
Byline: Staff WritersSao Paulo, Brazil (SPX) Dec 03, 2018, 2018 A simple sheet of graphene has noteworthy properties due to a quantum phenomenon in its electron structure named Dirac cones [...]
- Published
- 2018
35. Exciting Andreev pairs in a superconducting atomic contact
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Bretheau, L., Girit, Ç. Ã-., Pothier, H., Esteve, D., and Urbina, C.
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Superconductivity -- Research ,Josephson effect -- Research ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
A fundamental and previously unobserved aspect of the Josephson effect is revealed through spectroscopic measurements of the excited Andreev states in superconducting atomic contacts. A new twist on the Josephson effect Brian Josephson proposed in 1962 that a dissipationless 'supercurrent' should flow between two superconductors separated by a weak link such as a tunnel junction. He was right, and the Josephson effect launched a new field of research with applications to magnetometry, medicine and astronomy. This paper describes an aspect of the Josephson effect that has previously been overlooked. Existing Josephson junction applications are based on properties of just the ground state, in which the electron pairs that carry the supercurrent localize at the weak link and form so-called Andreev doublets of ground and excited pair states. Bretheau et al. establish the existence of excited Andreev pair states through spectroscopic measurements of superconducting atomic contacts. This previously overlooked degree of freedom for tunneling electron pairs is a new quantum resource that could be exploited in novel types of superconducting qubits. The Josephson effect describes the flow of supercurrent in a weak link--such as a tunnel junction, nanowire or molecule--between two superconductors.sup.1. It is the basis for a variety of circuits and devices, with applications ranging from medicine.sup.2 to quantum information.sup.3. Experiments using Josephson circuits that behave like artificial atoms.sup.4 are now revolutionizing the way we probe and exploit the laws of quantum physics.sup.5,6. Microscopically, the supercurrent is carried by Andreev pair states, which are localized at the weak link. These states come in doublets and have energies inside the superconducting gap.sup.7,8,9,10. Existing Josephson circuits are based on properties of just the ground state of each doublet, and so far the excited states have not been directly detected. Here we establish their existence through spectroscopic measurements of superconducting atomic contacts. The spectra, which depend on the atomic configuration and on the phase difference between the superconductors, are in complete agreement with theory. Andreev doublets could be exploited to encode information in novel types of superconducting qubits.sup.11,12,13., Author(s): L. Bretheau [sup.1] , Ç. Ã-. Girit [sup.1] , H. Pothier [sup.1] , D. Esteve [sup.1] , C. Urbina [sup.1] Author Affiliations: (1) Quantronics Group, Service de Physique de [...]
- Published
- 2013
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36. The superconducting (BCS) pairing instability in the thermodynamic limit
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Marsiglio, F., Beach, K.S.D., and Gooding, R.J.
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Thermodynamics -- Research ,Approximation theory -- Research ,Mathematical physics -- Research ,Superconductivity -- Research ,Physics - Abstract
The superconducting pairing instability--as determined by a divergence of the two-particle susceptibility--is obtained in the mean field (BCS) approximation in the thermodynamic limit. The usual practice is to examine this property for a finite lattice. We illustrate that, while the conclusions remain unchanged, the technical features are very different in the thermodynamic limit and conform more closely with the usual treatment of phase transitions encountered in, for example, the mean-field paramagnetic-ferromagnetic transition. Furthermore, by going to the extreme dilute limit, one can distinguish three dimensions from one and two dimensions, in which a pairing instability occurs even for two particles. PACS Nos: 74.20.-z, 74.20.Fg L'instabilite de pairage en supraconductivite--determinee par une divergence de la susceptibilite des deux particules --est obtenue ici en approximation de champ moyen (BCS) dans la limite thermodynamique. Il est plus habituel d'examiner cette propriete dans un reseau fini. Nous illustrons que, alors que les conclusions demeurent les memes, les caracteristiques techniques sont tres differentes dans la limite thermodynamique et sont plus conformes au cadre habituel des transitions de phase rencontrees, par exemple, dans la transition en champ moyen paramagnetique-ferromagnetique. De plus, en allant a l'extreme limite de dilution, on peut y distinguer le cas a trois dimensions des cas a une et deux dimensions, dans lesquels une instabilite de pairage apparait, meme pour deux particules. [Traduit par la Redaction], 1. Introduction The Bardeen, Cooper, and Schrieffer (BCS) theory of superconductivity, following the original literature [1], is typically first presented in textbooks as a proposed variational ground state, whose energy [...]
- Published
- 2012
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37. Spin-imbalance in a one-dimensional Fermi gas
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Liao, Yean-an, Rittner, Ann Sophie C., Paprotta, Tobias, Li, Wenhui, Partridge, Guthrie B., Hulet, Randall G., Baur, Stefan K., and Mueller, Erich J.
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Particle spin -- Research ,Superconductivity -- Research ,Fermions -- Properties -- Research ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Superconductivity and magnetism generally do not coexist. Changing the relative number of up and down spin electrons disrupts the basic mechanism of superconductivity, where atoms of opposite momentum and spin form Cooper pairs. Nearly forty years ago Fulde and Ferrell (1) and Larkin and Ovchinnikov (2) (FFLO) proposed an exotic pairing mechanism in which magnetism is accommodated by the formation of pairs with finite momentum. Despite intense theoretical and experimental efforts, however, polarized superconductivity remains largely elusive (3). Unlike the three-dimensional (3D) case, theories predict that in one dimension (ID) a state with FFLO correlations occupies a major part of the phase diagram (4-12). Here we report experimental measurements of density profiles of a two-spin mixture of ultracold [sup.6]Li atoms trapped in an array of 1D tubes (a system analogous to electrons in 1D wires). At finite spin imbalance, the system phase separates with an inverted phase profile, as compared to the 3D case. In 1D, we find a partially polarized core surrounded by wings which, depending on the degree of polarization, are composed of either a completely paired or a fully polarized Fermi gas. Our work paves the way to direct observation and characterization of FFLO pairing., The FFLO states are perhaps the most interesting of a number of exotic polarized superconducting phases proposed in the past 40 years. In the original concept of Fulde and Ferrell, [...]
- Published
- 2010
- Full Text
- View/download PDF
38. Superconductivity at ~100 K in dense Si[H.sub.4][([H.sub.2]).sub.2] predicted by first principles
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Li, Yinwei, Gao, Guoying, Xie, Yu, Ma, Yanming, Cui, Tian, and Zou, Guangtian
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Superconductivity -- Research ,Silicon compounds -- Electric properties ,Silicon compounds -- Thermal properties ,Silicon compounds -- Mechanical properties ,Materials at high pressures -- Research ,Science and technology - Abstract
Motivated by the potential high-temperature superconductivity in hydrogen-rich materials, the high-pressure structures of Si[H.sub.4][([H.sub.2]).sub.2] in the pressure range 50-300 GPa were extensively explored by using a genetic algorithm. An intriguing layered orthorhombic (Ccca) structure was revealed to be energetically stable above 248 GPa with the inclusion of zero-point energy. The Ccca structure is metallic and composed of hydrogen shared Si[H.sub.8] dodecahedra layers intercalated by orientationally ordered molecular [H.sub.2]. Application of the Allen-Dynes modified McMillan equation yields remarkably high superconducting temperatures of 98-107 K at 250 GPa, among the highest values reported so far for phonon-mediated superconductors. Analysis reveals a unique superconducting mechanism that the direct interactions between [H.sub.2] and Si[H.sub.4] molecules at high pressure play the major role in the high superconductivity, while the contribution from [H.sub.2] vibrons is minor. H2-containing compounds | high-pressure | high-temperature superconductors | metallization doi/ 10.1073/pnas.1007354107
- Published
- 2010
39. Enhancement of superconductivity by pressure-driven competition in electronic order
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Chen, Xiao-Jia, Struzhkin, Viktor V., Yu, Yong, Goncharov, Alexander F., Lin, Cheng-Tian, Mao, Ho-kwang, and Hemley, Russell J.
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High temperature superconductors -- Properties -- Research ,Superconductivity -- Research - Abstract
Finding ways to achieve higher values of the transition temperature, [T.sub.c], in superconductors remains a great challenge. The super-conducting phase is often one of several competing types of electronic order, including antiferromagnetism and charge density waves (1-5). An emerging trend documented in heavy-fermion (1) and organic (2) conductors is that the maximum [T.sub.c] for superconductivity occurs under external conditions that cause the critical temperature for a competing order to go to zero. Recently, such competition has been found in multilayer copper oxide high-temperature superconductors (HTSCs (3-5)) that possess two crystallographically inequivalent Cu[O.sub.2] planes in the unit cell. However, whether the competing electronic state can be suppressed to enhance [T.sub.c] in HTSCs remains an open question. Here we show that pressure-driven phase competition leads to an unusual two-step enhancement of [T.sub.c] in optimally doped trilayer [Bi.sub.2][Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10+δ] (Bi2223). We find that [T.sub.c] first increases with pressure and then decreases after passing through a maximum. Unexpectedly, [T.sub.c] increases again when the pressure is further raised above a critical value of around 24 GPa, surpassing the first maximum. The presence of this critical pressure is a manifestation of the crossover from the competing order to superconductivity in the inner of the three Cu[O.sub.2] planes. We suggest that the increase at higher pressures occurs as a result of competition between pairing and phase ordering in different Cu[O.sub.2] planes., We used Bi2223 single crystals in the present investigation. The structure of Bi2223 consists of two insulating Bi-O and Sr-O blocking layers intercalating in the c-axis direction with two structurally [...]
- Published
- 2010
- Full Text
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40. Superconducting high-pressure phases of disilane
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Jin, Xilian, Meng, Xing, He, Zhi, Ma, Yanming, Liu, Bingbing, Cui, Tian, Zou, Guangtian, and Mao, Ho-kwang
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Silane -- Chemical properties ,Superconductivity -- Research ,Phase transformations (Statistical physics) -- Research ,High temperature chemistry -- Research ,Science and technology - Abstract
High-pressure structures of disilane ([Si.sub.2][H.sub.6]) are investigated extensively by means of first-principles density functional theory and a random structure-searching method. Three metallic structures with P-1, Pm-3m, and C2/c symmetries are found, which are more stable than those of [XY.sub.3]-type candidates under high pressure. Enthalpy calculations suggest a remarkably wide decomposition (Si and [H.sub.2]) pressure range below 135 GPa, above which three metallic structures are stable. Perturbative linear-response calculations for Pm-3m disilane at 275 GPa show a large electron-phonon coupling parameter [lambda] of 1.397 and the resulting superconducting critical temperature beyond the order of [10.sup.2] K. metallization | new phase | solid disilane doi/ 10.1073/pnas.1005242107
- Published
- 2010
41. Distortions and stabilization of simple-cubic calcium at high pressure and low temperature
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Mao, Wendy L., Wang, Lin, Ding, Yang, Yang, Wenge, Liu, Wenjun, Kim, Duck Young, Luo, Wei, Ahuja, Rajeev, Meng, Yue, Sinogeikin, Stas, Shu, Jinfu, and Mao, Ho-kwang
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Superconductivity -- Research ,Calcium -- Chemical properties ,Phase transformations (Statistical physics) -- Research ,High pressure chemistry -- Research ,Cryochemistry -- Research ,Science and technology - Abstract
Ca-III, the first superconducting calcium phase under pressure, was identified as simple-cubic (sc) by previous X-ray diffraction (XRD) experiments. In contrast, all previous theoretical calculations showed that sc had a higher enthalpy than many proposed structures and had an imaginary (unstable) phonon branch. By using our newly developed submicrometer high-pressure single-crystal XRD, cryogenic high-pressure XRD, and theoretical calculations, we demonstrate that Ca-III is neither exactly sc nor any of the lower-enthalpy phases, but sustains the sc-like, primitive unit by a rhombohedral distortion at 300 K and a monoclinic distortion below 30 K. This surprising discovery reveals a scenario that the high-pressure structure of calcium does not go to the zero-temperature global enthalpy minimum but is dictated by high-temperature anharmonicity and low-temperature metastability fine-tuned with phonon stability at the local minimum. high pressure | phase transition | superconductivity doi/ 10.1073/pnas.1005279107
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- 2010
42. Magnetism and superconductivity driven by identical 4f states in a heavy-fermion metal
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Nair, Sunil, Stockert, O., Witte, U., Nicklas, M., Schedler, R., Kiefer, K., Thompson, J.D., Bianchi, A.D., Fisk, Z., Wirth, S., and Steglich, F.
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Magnetism -- Research ,Superconductivity -- Research ,Fermions -- Properties ,Antiferromagnetism -- Research ,Science and technology - Abstract
The apparently inimical relationship between magnetism and superconductivity has come under increasing scrutiny in a wide range of material classes, where the free energy landscape conspires to bring them in close proximity to each other. Particularly enigmatic is the case when these phases microscopically interpenetrate, though the manner in which this can be accomplished remains to be fully comprehended. Here, we present combined measurements of elastic neutron scattering, magnetotransport, and heat capacity on a prototypical heavy fermion system, in which antiferromagnetism and superconductivity are observed. Monitoring the response of these states to the presence of the other, as well as to external thermal and magnetic perturbations, points to the possibility that they emerge from different parts of the Fermi surface. Therefore, a single 4f state could be both localized and itinerant, thus accounting for the coexistence of magnetism and superconductivity. strongly correlated electron systems | antiferromagnetism www.pnas.org/cgi/doi/10.1073/pnas.1004958107
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- 2010
43. General trend for pressurized superconducting hydrogen-dense materials
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Kim, Duck Young, Scheicher, Ralph H., Mao, Ho-kwang, Kang, Tae W., and Ahuja, Rajeev
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High temperature superconductors -- Properties ,Superconductivity -- Research ,Science and technology - Abstract
The long-standing prediction that hydrogen can assume a metallic state under high pressure, combined with arguments put forward more recently that this state might even be superconducting up to high temperatures, continues to spur tremendous research activities toward the experimental realization of metallic hydrogen. These efforts have however so far been impeded by the enormous challenges associated with the exceedingly large required pressure. Hydrogen-dense materials, of the M[H.sub.4] form (where M can be, e.g., Si, Ge, or Sn) or of the M[H.sub.3] form (with M being, e.g., Al, Sc, Y, or La), allow for the rather exciting opportunity to carry out a proxy study of metallic hydrogen and associated high-temperature superconductivity at pressures within the reach of current techniques. At least one experimental report indicates that a superconducting state might have been observed already in Si[H.sub.4], and several theoretical studies have predicted superconductivity in pressurized hydrogen-rich materials; however, no systematic dependence on the applied pressure has yet been identified so far. In the present work, we have used first-principles methods in an attempt to predict the superconducting critical temperature ([T.sub.c]) as a function of pressure (P) for three metal-hydride systems of the M[H.sub.3] form, namely Sc[H.sub.3], Y[H.sub.3], and La[H.sub.3]. By comparing the obtained results, we are able to point out a general trend in the [T.sub.c]-dependence on P. These gained insights presented here are likely to stimulate further theoretical studies of metallic phases of hydrogen-dense materials and should lead to new experimental investigations of their superconducting properties. ab initio calculations | high pressure | lattice dynamics | metal-hydride | superconductivity www.pnas.org/cgi/doi/10.1073/pnas.0914462107
- Published
- 2010
44. Emulation of a quantum spin with a superconducting phase qudit
- Author
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Neeley, Matthew, Ansmann, Markus, Bialczak, Radoslaw C., Hofheinz, Max, Lucero, Erik, O'Connell, Aaron D., Sank, Daniel, Wang, Haohua, Wenner, James, Cleland, Andrew N., Geller, Michael R., and Martinis, John M.
- Subjects
Superconductivity -- Research ,Quantum electronics -- Research ,Science and technology - Abstract
In quantum information processing, qudits (d-Level systems) are an extension of qubits that could speed up certain computing tasks. We demonstrate the operation of a superconducting phase qudit with a number of levels d up to d = 5 and show how to manipulate and measure the qudit state, including simultaneous control of multiple transitions. We used the qudit to emulate the dynamics of single spins with principal quantum number s = 1/2, 1, and 3/2, allowing a measurement of Berry's phase and the even parity of integer spins (and odd parity of half-integer spins) under 2[pi]-rotation. This extension of the two-Level qubit to a multilevel qudit holds promise for more-complex quantum computational architectures and for richer simulations of quantum mechanical systems.
- Published
- 2009
45. Extending universal nodal excitations optimizes superconductivity in [Bi.sub.2][Sr.sub.2]Ca[Cu.sub.2][0.sub.8+[delta]]
- Author
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Pushp, Aakash, Parker, Colin V., Pasupathy, Abhay N., Gomes, Kenjiro K., Ono, Shimpei, Wen, Jinsheng, Xu, Zhijun, Gu, Genda, and Yazdani, Ali
- Subjects
Superconductivity -- Research ,Science and technology - Abstract
Understanding the mechanism by which d wave superconductivity in the cuprates emerges and is optimized by doping the Mott insulator is one of the major outstanding problems in condensedmatter physics. Our high-resolution scanning tunneling microscopy measurements of the high--transition temperature ([T.sub.c]) superconductor [Bi.sub.2][Sr.sub.2]Ca[Cu.sub.2][0.sub.8+[delta]] show that samples with different [T.sub.c] values in the low doping regime follow a remarkably universal d wave low-energy excitation spectrum, indicating a doping-independent nodal gap. We demonstrate that [T.sub.c] instead correlates with the fraction of the Fermi surface over which the samples exhibit the universal spectrum. Optimal [T.sub.c] is achieved when all parts of the Fermi surface follow this universal, behavior. Increasing the temperature above [T.sub.c] turns the universal spectrum into an arc of gapless excitations, whereas overdoping breaks down the universal nodal behavior.
- Published
- 2009
46. Superconductivity at the two-dimensional limit
- Author
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Qin, Shengyong, Kim, Jungdae, Niu, Qian, and Shih, Chih-Kang
- Subjects
Superconductivity -- Research ,Science and technology - Abstract
Superconductivity in the extreme two-dimensional limit is studied on ultrathin lead films down to two atomic layers, where only a single channel of quantum well states exists. Scanning tunneling spectroscopy reveals that local superconducting order remains robust until two atomic layers, where the transition temperature abruptly plunges to a lower value, depending sensitively on the exact atomic structure of the film. Our result shows that Cooper pairs can still form in the last two-dimensional channel of electron states, although their binding is strongly affected by the substrate.
- Published
- 2009
47. Heavy holes as a precursor to superconductivity in antiferromagnetic [Celn.sub.3]
- Author
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Sebastian, Suchitra E., Harrison, N., Batista, C.D., Trugman, S.A., Fanelli, V., Jaime, M., Murphy, T.P., Palm, E.C., Harima, H., and Ebihara, T.
- Subjects
Superconductivity -- Research ,Antiferromagnetism -- Research ,Science and technology - Abstract
Numerous phenomenological parallels have been drawn between f- and d- electron systems in an attempt to understand their display of unconventional superconductivity. The microscopics of how electrons evolve from participation in large moment antiferromagnetism to superconductivity in these systems, however, remains a mystery. Knowing the origin of Cooper paired electrons in momentum space is a crucial prerequisite for understanding the pairing mechanism. Of special interest are pressure-induced superconductors [Celn.sub.3] and [CeRhln.sub.5] in which disparate magnetic and superconducting orders apparently coexist--arising from within the same f-electron degrees of freedom. Here, we present ambient pressure quantum oscillation measurements on [Celn.sub.3] that crucially identify the electronic structure--potentially similar to high-temperature superconductors. Heavy hole pockets of f-character are revealed in [Celn.sub.3], undergoing an unexpected effective mass divergence well before the antiferromagnetic critical field. We thus uncover the softening of a branch of quasiparticle excitations located away from the traditional spin fluctuation-dominated antiferromagnetic quantum critical point. The observed Fermi surface of dispersive f-electrons in [Celn.sub.3] could potentially explain the emergence of Cooper pairs from within a strong moment antiferromagnet. Fermi surface | heavy fermion | quantum critical point | Lifshitz transition
- Published
- 2009
48. Superconducting characteristics of 4-[Angstrom] carbon nanotube-zeolite composite
- Author
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Lortz, Rolf, Zhang, Qiucen, Shi, Wu, Ye, Jiang Ting, Qiu, Chunyin, Wang, Zhe, He, Hongtao, Sheng, Ping, Qian, Tiezheng, Tang, Zikang, Wang, Ning, Zhang, Xixiang, Wang, Jiannong, and Chan, Che Ting
- Subjects
Resistance heating -- Measurement ,Superconductivity -- Measurement ,Superconductivity -- Physiological aspects ,Superconductivity -- Research ,Zeolites -- Thermal properties ,Zeolites -- Magnetic properties ,Zeolites -- Research ,Science and technology - Abstract
We have fabricated nanocomposites consisting of 4-[Angstrom] carbon nanotubes embedded in the 0.7-nm pores of aluminophosphatefive (AFI) zeolite that display a superconducting specific heat transition at 15 K. MicroRaman spectra of the samples show strong and spatially uniform radial breathing mode (RBM) signals at 510 [cm.sup.-1] and 550 [cm.sup.-1], characteristic of the (4, 2) and (5, 0) nanotubes, respectively. The specific heat transition is suppressed at > 2 T, with a temperature dependence characteristic of finite-size effects. Comparison with theory shows the behavior to be consistent with that of a type II BCS superconductor, characterized by a coherence length of 14 [+ or -] 2 nm and a magnetic penetration length of 1.5 [+ or -] 0.7 [micro]m. Four probe and differential resistance measurements have also indicated a superconducting transition initiating at 15 K, but the magnetoresistance data indicate the superconducting network to be inhomogeneous, with a component being susceptible to magnetic fields below 3 T and other parts capable of withstanding a magnetic field of 5 T or beyond. resistance transition | specific heat | superconductivity
- Published
- 2009
49. Nearly isotropic superconductivity in (Ba,K)[Fe.sub.2][As.sub.2]
- Author
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Yuan, H.Q., Singleton, J., Balakirev, F.F., Bailey, S.A., Chen, G.F., Luo, J.L., and Wang, N.L.
- Subjects
Transition state (Chemistry) -- Evaluation -- Research ,Superconductivity -- Research ,Iron -- Properties -- Evaluation ,Arsenic -- Properties -- Evaluation ,Environmental issues ,Science and technology ,Zoology and wildlife conservation ,Evaluation ,Research ,Properties - Abstract
Superconductivity was recently observed (1-7) in iron-arsenic-based compounds with a superconducting transition temperature ([T.sub.c]) as high as 56 K, naturally raising comparisons with the high-[T.sub.c] copper oxides. The copper oxides [...]
- Published
- 2009
50. The Josephson effects
- Author
-
Petley, B.W.
- Subjects
Josephson effect -- Research ,Superconductivity -- Research ,Superfluidity -- Research ,Electromagnetism -- Research ,Magnetic fields -- Research ,Physics - Abstract
This article reviews some of the experimental work on the Josephson effects. These effects occur in both superconductivity and superfluidity. In superconductivity they are found when two superconductors are separated by a thin insulating barrier (~[10.sup.-9] m thick), or connected by a weak link of metal. A supercurrent can flow between the superconductors, and electromagnetic and magnetic fields can interact with this supercurrent. The interactions demonstrate quantum effects in a particularly striking way, have led to a better understanding of the super-conducting state, and have also found some interesting applications.
- Published
- 2009
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