Superconducting properties and materials articles within Nature Communications

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  • Article |

    It is known that the spin-excitation spectrum of the undoped parents of iron-pnictide superconductors contains a pronounced magnon peak, but it is unclear whether this survives doping into the superconducting state. Schmitt et al.report resonant inelastic X-ray scattering spectra that suggest it does.

    • Ke-Jin Zhou
    • , Yao-Bo Huang
    •  & Thorsten Schmitt
  • Article |

    The motion of magnetic vortices induced in type-II superconductors by a magnetic field degrades their ability to conduct electricity with zero resistance. Córdoba et al.demonstrate a means to immobilize these vortices, reversing their deleterious effect as the applied magnetic field is increased.

    • R. Córdoba
    • , T. I. Baturina
    •  & V. M. Vinokur
  • Article |

    One of the advantages that it is hoped quantum computers will have over classical computers is their ability to accurately simulate quantum phenomena. Silveri et al.take a step towards this goal by simulating so-called motional averaging in an artificial atom realized by a superconducting quantum bit.

    • Jian Li
    • , M.P. Silveri
    •  & G.S. Paraoanu
  • Article |

    Understanding high temperature superconductivity in the cuprates is one of the hardest problems in physics to date. Wang et al.use state-of-the-art scanning tunnelling spectroscopy to visualize the atomic-scale electronic structure of the Mott insulator phase from which this elusive state emerges.

    • Cun Ye
    • , Peng Cai
    •  & Yayu Wang
  • Article |

    Iron-based superconductors have the potential to carry higher currents and withstand higher magnetic fields than present-day superconducting cables. Using an approach developed for cuprates, Si et al. improve the high-field performance of iron-based superconductors well beyond that of conventional superconductors.

    • Weidong Si
    • , Su Jung Han
    •  & Qiang Li
  • Article |

    Non-Abelian anyons are exotic quasiparticles envisioned to be promising candidates for solid-state quantum computation. Clarkeet al. propose a device fabricated from fractional quantum Hall states and superconductors that supports a new type of non-Abelian defect that binds parafermionic zero modes.

    • David J. Clarke
    • , Jason Alicea
    •  & Kirill Shtengel
  • Article |

    The Cooper pairs that losslessly conduct current in a superconductor can be split into two spatially separated but quantum mechanically entangled electrons. In this paper, non-local cross-correlation measurements of pairs split within a superconducting wire indicate the efficiency of this process can approach 100%.

    • Anindya Das
    • , Yuval Ronen
    •  & Hadas Shtrikman
  • Article
    | Open Access

    Topological insulators are a unique class of materials characterized by exotic metallic states at their surface, while remaining insulated in the bulk. Sacépéet al. show how to manipulate normal and superconducting electronic transport at the surface of the topological insulator Bi2Se3, by tuning a gate-voltage to vary the electronic density.

    • Benjamin Sacépé
    • , Jeroen B. Oostinga
    •  & Alberto F. Morpurgo
  • Article |

    Charge density waves in the structure and electron density of layered materials are closely linked to superconductivity. Using scanning tunnelling techniques, Rahnejatet al. demonstrate the occurrence of such waves in the doped graphene sheets of the superconductor CaC6.

    • K.C. Rahnejat
    • , C.A. Howard
    •  & M. Ellerby
  • Article |

    Intercalating alkali metals into picene—a hydrocarbon with five linearly fused benzene rings—results in superconducting materials. Now, alkali-metal-doped phenanthrene, which consists of three fused benzene rings, is also found to be superconducting, opening up a broader class of organic superconductors.

    • X.F. Wang
    • , R.H. Liu
    •  & X.H. Chen
  • Article |

    It is unclear whether the Fermi surface in the normal state of underdoped cuprates is ambipolar or solely nodal. Here, measuring the second harmonic oscillations in underdoped YBa2Cu3O6+xreveals the origin as an oscillatory chemical potential, based on which a Fermi surface consisting of a nodal pocket is identified.

    • Suchitra E. Sebastian
    • , N. Harrison
    •  & G.G. Lonzarich
  • Article
    | Open Access

    An electron pocket exists in the Fermi-surface of the high temperature superconductor YBa2Cu3Oy, but its origin is unknown. Here, YBa2Cu3Oy and La1.8−xEu0.2SrxCuO4 are both shown to exhibit Fermi-surface reconstruction, and in the latter, this is due to stripe order, suggesting that the same mechanism exists in YBa2Cu3Oy.

    • F. Laliberté
    • , J. Chang
    •  & Louis Taillefer
  • Article |

    Composites of carbon nanotubes and superconductors provide technologically important new, or improved, functionalities. Here, with a chemical solution approach, well-aligned carbon nanotube forests embedded in a superconducting NbC matrix are shown to effectively enhance the superconducting properties of NbC.

    • G.F. Zou
    • , H.M. Luo
    •  & Q.X. Jia
  • Article
    | Open Access

    High critical temperature superconductors could be used to produce ideal electric power lines, but the misalignment of crystalline grain boundaries reduces current density. Here, pnictide superconductors are found to be more tolerant to misaligned grain boundaries than cuprates.

    • Takayoshi Katase
    • , Yoshihiro Ishimaru
    •  & Hideo Hosono
  • Article
    | Open Access

    In some iron-based materials, unconventional superconductivity can emerge near a quantum phase transition where long-range magnetic order vanishes. Giovannettiet al.show that the magnetic quantum phase transition in an iron pnictide superconductor is very close to the quantum tricritical point.

    • Gianluca Giovannetti
    • , Carmine Ortix
    •  & José Lorenzana
  • Article
    | Open Access

    Understanding how the high-energy physics of Mott-like excitations affects condensate formation is a key challenge in high-temperature superconductivity. Giannettiet al. clarify the relationship of many-body CuO2excitations and the onset of superconductivity using a new optical pump supercontinuum-probe technique.

    • Claudio Giannetti
    • , Federico Cilento
    •  & Fulvio Parmigiani
  • Article
    | Open Access

    In the pseudogap state of cuprates, although diamagnetic signals have been detected, a Meissner effect has never been observed. Morenzoni and colleagues probe the local diamagnetic response in the normal state of an underdoped layer showing that a 'barrier' layer exhibits a Meissner effect.

    • Elvezio Morenzoni
    • , Bastian M. Wojek
    •  & Ivan Božović
  • Article
    | Open Access

    Electronic excitations with energies near the superconducting energy gap are strongly affected by superconducting transitions. The authors show, with a comprehensive optical investigation, that excitations with energies up to two orders of magnitude greater are also affected by the transition.

    • A. Charnukha
    • , P. Popovich
    •  & A. V. Boris
  • Article |

    In high-temperature superconductors, a very low density of states, the pseudogap, exists even above the critical temperature. Here, the authors show that this is also the case for a conventional superconductor, titanium nitride thin films, and that this pseudogap is induced by superconducting fluctuations.

    • Benjamin Sacépé
    • , Claude Chapelier
    •  & Marc Sanquer
  • Article |

    The integration of oxide nanoelectronics with silicon platforms is a necessary step for the fabrication of ultrahigh-density devices. Here, the authors grow a LaAlO3/SrTiO3interface directly on silicon, and show the reversible creation of a two-dimensional electron gas confined within nanowires located on the surface.

    • J.W. Park
    • , D.F. Bogorin
    •  & C.B. Eom
  • Article |

    The magnetic flux lines in a superconductor present intricate patterns, whose origins are seldom understood. Here the authors link them to geometrical effects by means of the 'hairy ball' theorem, which states that for a vector field on a sphere there will always be at least one singularity.

    • Mark Laver
    •  & Edward. M. Forgan