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Retention of Two-Band Superconductivity in Highly Carbon-Doped MgB2

H. Schmidt·K. E. Gray·D. G. Hinks·J. F. Zasadzinski·M. Avdeev·J. D. Jorgensen·J. C. Burley
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Abstract

Tunneling data on MgB_{1.8}C_{0.2} show a reduction in the energy gap of the pi-bands by a factor of two from undoped MgB2 that is consistent with the Tc reduction, but inconsistent with the expectations of the dirty limit. Dirty-limit theory for undoped MgB2 predicts a single gap about three times larger than measured and a reduced Tc comparable to that measured. Our heavily-doped samples exhibit a uniform dispersion of C suggestive of significantly enhanced scattering, and we conclude that the retention of two-band superconductivity in these samples is caused by a selective suppression of interband scattering.

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H. Schmidt, K. E. Gray, D. G. Hinks, J. F. Zasadzinski, M. Avdeev, J. D. Jorgensen, J. C. Burley. 2003-07-18. Retention of Two-Band Superconductivity in Highly Carbon-Doped MgB2. https://doi.org/10.1103/physrevb.68.060508

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