corner
corner
APS » Journals » Phys. Rev. B » Volume 71 » Issue 6
< Previous Article | Next Article >

Phys. Rev. B 71, 060503(R) (2005) [4 pages]

Evidence for single-gap superconductivity in Mg(B1−xCx)2 single crystals with x=0.132 from point-contact spectroscopy

Download: PDF (280 kB) Buy this article Export: BibTeX or EndNote (RIS)

R. S. Gonnelli1,2, D. Daghero1,2, A. Calzolari1, G. A. Ummarino1,2, Valeria Dellarocca1, V. A. Stepanov3, S. M. Kazakov4, N. Zhigadlo4, and J. Karpinski4
1Dipartimento di Fisica and INFM, Politecnico di Torino, 10129 Torino, Italy
2INFM - LAMIA, Corso Perrone 24, 16152 Genova, Italy
3P.N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia
4Solid State Physics Laboratory, ETH, CH-8093 Zurich, Switzerland

Received 10 July 2004; revised 3 December 2004; published 14 February 2005

We report the results of the first directional point-contact measurements in Mg(B1−xCx)2 single crystals with 0.047⩽x⩽0.132. The two-gap superconductivity typical of MgB2 persists up to x=0.105. In this region, the values of the gaps Δσ and Δπ were determined by fitting the Andreev-reflection conductance curves with a two-band Blonder-Tinkham-Klapwijk (BTK) model, and confirmed by the single-band BTK fit of the σ- and π-band conductances, separated by means of a magnetic field. At x=0.132, when Tc=19 K, we clearly observed the merging of the two gaps into one of amplitude Δ≃3 meV.

© 2005 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.71.060503
DOI:
10.1103/PhysRevB.71.060503
PACS:
74.50.+r, 74.45.+c, 74.70.Ad
 
< Previous Article | Next Article >