Momentum dependence of the superconducting gap in Ba1-xKxFe2As2

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • D. V. Evtushinsky - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • D. S. Inosov - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • V. B. Zabolotnyy - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • A. Koitzsch - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • M. Knupfer - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • B. Buechner - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • M. S. Viazovska - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • G. L. Sun - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • V. Hinkov - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • A. V. Boris - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • C. T. Lin - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • B. Keimer - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • A. Varykhalov - , Helmholtz Centre Berlin for Materials and Energy (Author)
  • A. A. Kordyuk - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • S. V. Borisenko - , Leibniz Institute for Solid State and Materials Research Dresden (Author)

Abstract

The precise momentum dependence of the superconducting gap in the iron-arsenide superconductor Ba1-xKxFe2As2 (BKFA) with T-c=32 K was determined from angle-resolved photoemission spectroscopy (ARPES) via fitting the distribution of the quasiparticle density to a model. The model incorporates finite lifetime and experimental resolution effects, as well as accounts for peculiarities of BKFA electronic structure. We have found that the value of the superconducting gap is practically the same for the inner Gamma barrel, X pocket, and "blade" pocket, and equals 9 meV, while the gap on the outer Gamma barrel is estimated to be less than 4 meV, resulting in 2 Delta/k(B)T(c)=6.8 for the large gap and 2 Delta/k(B)T(c)< 3 for the small gap. A large (77 +/- 3 %) nonsuperconducting component in the photoemission signal is observed below T-c. Details of gap extraction from ARPES data are discussed in Appendixes A x B.

Details

Original languageEnglish
Article number054517
Number of pages13
JournalPhysical Review B
Volume79
Issue number5
Publication statusPublished - Feb 2009
Peer-reviewedYes
Externally publishedYes

External IDs

Scopus 61849115238

Keywords

Keywords

  • barium compounds, high-temperature superconductors, iron compounds, photoelectron spectra, potassium compounds, quasiparticles, superconducting energy gap

Library keywords