Multiple-gap features from break-junction tunneling in the superconducting MgB2

Tomoaki Takasaki, Toshikazu Ekino, Takahiro Muranaka, Takayuki Ichikawa, Hironobu Fujii, Jun Akimitsu

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Tunneling spectroscopy measurements on polycrystalline MgB2 have been carried out with a break-junction technique. The observed spectra exhibit the multiple-gap feature, which can be expressed by the correlated two-gap model. From the conductance fittings at 4.2 K, the gap parameters can be classified into ΔS = 2:2 ± 0:3 meV, ΔM = 6:0 ± 1:5 meV, and ΔL = ≅ 10 meV. All these gaps exist up to the same critical temperature Tc. The ΔM undergoes various ways of temperature dependence, which can be attributed to the proximity-induced gap. We have also observed the conductances showing the features of normal conducting and/or low-Tc phases. Our tunneling data can be explained by the proximity effect combined with the bulk multiple-gap features.

Original languageEnglish
Pages (from-to)1902-1913
Number of pages12
Journaljournal of the physical society of japan
Issue number7
Publication statusPublished - Jul 1 2004
Externally publishedYes


  • Break junction
  • MgB
  • Multiplegap structure
  • Superconductivity
  • The correlated two-gap model
  • Tunneling spectroscopy

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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