Point-contact Andreev-reflection spectroscopy in Fe(Te,Se) films: Multiband superconductivity and electron-boson coupling

D. Daghero, P. Pecchio, G. A. Ummarino, F. Nabeshima, Y. Imai, A. Maeda, I. Tsukada, S. Komiya, R. S. Gonnelli

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


We report on a study of the superconducting order parameter in Fe(Te1?xSex) thin films (with different Se contents: x = 0.3, 0.4, 0.5) by means of point-contact Andreev-reflection spectroscopy (PCARS). The PCARS spectra show reproducible evidence of multiple structures, namely two clear conductance maxima associated to a superconducting gap of amplitude δE ≃ 2.75kBTc and additional shoulders at higher energy that, as we show, are the signature of the strong interaction of charge carriers with a bosonic mode whose characteristic energy coincides with the spin-resonance energy. The details of some PCARS spectra at low energy suggest the presence of a smaller and not easily discernible gap of amplitude δH simel 1.75kBTc. The existence of this gap and its amplitude are confirmed by PCARS measurements in ? Fe(Te1-xSex) single crystals. The values of the two gaps δE and δH, once plotted as a function of the local critical temperature TcA , turn out to be in perfect agreement with the results obtained by various experimental techniques reported in literature.

Original languageEnglish
Article number124014
JournalSuperconductor Science and Technology
Issue number12
Publication statusPublished - 2014 Dec 1
Externally publishedYes


  • Andreev reflection spectroscopy
  • chalcogenide superconductors
  • superconducting films

ASJC Scopus subject areas

  • Ceramics and Composites
  • Condensed Matter Physics
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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