Strong Coupling Superconductivity in Iron-Chalcogenide FeTe$_{0.55}$Se$_{0.45}$

W. K. Park; C. R. Hunt; H. Z. Arham; Z. J. Xu; J. S. Wen; Z. W. Lin; Q. Li; G. D. Gu; L. H. Greene

Strong Coupling Superconductivity in Iron-Chalcogenide FeTe$_{0.55}$Se$_{0.45}$

Superconductivity 2010-05-04 v1 Strongly Correlated Electrons

Authors: W. K. Park , C. R. Hunt , H. Z. Arham , Z. J. Xu , J. S. Wen , Z. W. Lin , Q. Li , G. D. Gu , L. H. Greene

Abstract

The superconducting order parameter in the iron-chalcogenide superconductor FeTe $_{0.55}$ Se $_{0.45}$ ( $T_\textrm{c}$ = 14.2 K) is investigated by point-contact Andreev reflection spectroscopy. The energy gap magnitude (3.8 meV at 1.70 K) and temperature dependence as extracted from the Andreev conductance spectra reveal strong-coupling superconductivity and is consistent with $s$ -wave order parameter symmetry. No clear evidence for multiple order parameters or interference from multiple bands is observed. A conductance enhancement persists above $T_\textrm{c}$ to $\sim 18-20$ K and possible origins, including novel quasiparticle scattering due to strong antiferromagnetic spin fluctuations, are discussed.

Keywords

iron-chalcogenide superconductor point-contact andreev reflection strong-coupling superconductivity s-wave order parameter antiferromagnetic spin fluctuations

Cite

@article{arxiv.1005.0190,
  title  = {Strong Coupling Superconductivity in Iron-Chalcogenide FeTe$_{0.55}$Se$_{0.45}$},
  author = {W. K. Park and C. R. Hunt and H. Z. Arham and Z. J. Xu and J. S. Wen and Z. W. Lin and Q. Li and G. D. Gu and L. H. Greene},
  journal= {arXiv preprint arXiv:1005.0190},
  year   = {2010}
}

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5 pages, 3 figures

Strong Coupling Superconductivity in Iron-Chalcogenide FeTe$_{0.55}$Se$_{0.45}$

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