8,605 research outputs found

    Reply to [arXiv:1201.5347] "Comment on 'Vortex-assisted photon counts and their magnetic field dependence in single-photon superconducting detectors'"

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    We argue that cutoff in the London model cannot be settled without use of the microscopic theory

    Charge current in ferromagnet - triplet superconductor junctions

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    We calculate the tunneling conductance spectra of a ferromagnetic metal / insulator / triplet superconductor from the reflection amplitudes using the Blonder-Tinkham-Klapwijk (BTK) formula. For the triplet superconductor, we assume one special pp-wave order parameter, having line nodes, and two two dimensional ff-wave order parameters with line nodes, breaking the time reversal symmetry. Also we examine nodeless pairing potentials. The evolution of the spectra with the exchange potential depends solely on the topology of the gap. The weak Andreev reflection within the ferromagnet results in the suppression of the tunneling conductance and eliminates the resonances due to the anisotropy of the pairing potential. The tunneling spectra splits asymmetrically with respect to E=0E=0 under the influence of an external magnetic field. The results can be used to distinguish between the possible candidate pairing states of the superconductor Sr2_2RuO4_4.Comment: 15 pages with 8 figure

    Emergence of intrinsic superconductivity below 1.178 K in the topologically non-trivial semimetal state of CaSn3

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    Topological materials which are also superconducting are of great current interest, since they may exhibit a non-trivial topologically-mediated superconducting phase. Although there have been many reports of pressure-tuned or chemical-doping-induced superconductivity in a variety of topological materials, there have been few examples of intrinsic, ambient pressure superconductivity in a topological system having a stoichiometric composition. Here, we report that the pure intermetallic CaSn3 not only exhibits topological fermion properties but also has a superconducting phase at 1.178 K under ambient pressure. The topological fermion properties, including the nearly zero quasi-particle mass and the non-trivial Berry phase accumulated in cyclotron motions, were revealed from the de Haas-van Alphen (dHvA) quantum oscillation studies of this material. Although CaSn3 was previously reported to be superconducting at 4.2K, our studies show that the superconductivity at 4.2K is extrinsic and caused by Sn on the degraded surface, whereas its intrinsic bulk superconducting transition occurs at 1.178 K. These findings make CaSn3 a promising candidate for exploring new exotic states arising from the interplay between non-trivial band topology and superconductivity, e.g. topological superconductivityComment: 20 pages,4 figure

    Tunneling conductance in normal metal - triplet superconductor junction

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    We calculate the tunneling conductance spectra of a normal metal / insulator / triplet superconductor from the reflection amplitudes using the Blonder-Tinkham-Klapwijk (BTK) formula. For the triplet superconductor we assume one special p-wave order parameter having line nodes and two two dimensional ff-wave order parameters with line nodes breaking the time-reversal symmetry. Also we examine nodeless pairing potentials. The tunneling peaks are due to the formation of bound states for each surface orientation at discrete quasiparticles trajectory angles. The tunneling spectra can be used to distinguish the possible candidate pairing states of the superconductor Sr2_2RuO4_4.Comment: 4 pages with 3 figures, presented at the second Euroconference on Vortex Matter in Superconductors, 15-25 September 2001, Crete, Greec

    Magnetic quantum critical point and superconductivity in UPt3 doped with Pd

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    Transverse-field muon spin relaxation measurements have been carried out on the heavy-fermion superconductor UPt3 doped with small amounts of Pd. We find that the critical Pd concentration for the emergence of the large-moment antiferromagnetic phase is ~0.6 at.%Pd. At the same Pd content, superconductivity is completely suppressed. The existence of a magnetic quantum critical point in the phase diagram, which coincides with the critical point for superconductivity, provides evidence for ferromagnetic spin-fluctuation mediated odd-parity superconductivity, which competes with antiferromagnetic order.Comment: 4 pages (includes 3 figures); postscript fil

    Magnetic quantum critical point and superconductivity in UPt3 doped with Pd

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    Transverse-field muon spin relaxation measurements have been carried out on the heavy-fermion superconductor UPt3 doped with small amounts of Pd. We find that the critical Pd concentration for the emergence of the large-moment antiferromagnetic phase is ~0.6 at.%Pd. At the same Pd content, superconductivity is completely suppressed. The existence of a magnetic quantum critical point in the phase diagram, which coincides with the critical point for superconductivity, provides evidence for ferromagnetic spin-fluctuation mediated odd-parity superconductivity, which competes with antiferromagnetic order.Comment: 4 pages (includes 3 figures); postscript fil
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