A second superconducting energy gap of Nb_3Sn observed by breakjunction point-contact spectroscopy

Abstract

We report on investigations of the superconducting energy gap of the A15 superconductor Nb_3Sn by point-contact spectroscopy of breakjunctions. The voltage-dependent differential conductance dI/dV reveals features of a second energy gap besides the energy gap known from previous tunnel measurements with maxima at Δ_1=3.92 +/- 0.16 meV and Δ_2=0.85 +/- 0.17 meV as derived from a histogram summarizing the data of more than 60 contacts. These findings are the first spectroscopic evidence that Nb_3Sn belongs to the class of two-band superconductors and they are in line with low-temperature specific-heat measurements on Nb_3Sn.

References in corpus (5)

• Phenomenological two-gap model for the specific heat of MgB_2
• A Review of the Properties of Nb3Sn and Their Variation with A15 Composition, Morphology and Strain State
• Specific heat of Nb_3Sn: The case for a second energy gap
• Superconducting energy gap distribution of MgB${}_2$ investigated by point-contact spectroscopy
• Advances in point-contact spectroscopy: two-band superconductor MgB2 (A review)

Cited by in corpus (2)

• A review of two-band superconductivity: materials and effects on the thermodynamic and reversible mixed-state properties
• Impact of disorder on the superconducting transition temperature near a Lifshitz transition