M. Putti et al 2007 EPL 77 57005 doi:10.1209/0295-5075/77/57005
M. Putti1, P. Brotto1, M. Monni1, E. Galleani d'Agliano1, A. Sanna2 and S. Massidda2
Show affiliationsOne of the most important predictions of the two-gap theory of superconductivity concerns the role of interband scattering (IBS) by impurities. IBS is expected to decrease the critical temperature, Tc, of MgB2 to a saturation value of about 20 K, where the two gaps merge to a single one. These predictions have been partially contradicted by experiments. In fact, Tc does not saturate in irradiated samples, but decreases linearly with residual resistivity and the merging of the gaps has been observed at a much lower Tc (11 K). In this paper we argue that, while at low level of disorder IBS is the leading mechanism that suppresses superconductivity, at higher disorder the experimental results can only be understood if the smearing of the density of states due to intraband electron lifetime effects is considered.
74.70.Ad Metals; alloys and binary compounds (including A15, MgB2, etc.)
61.80.Hg Neutron radiation effects
74.62.Dh Effects of crystal defects, doping and substitution
Issue 5 (March 2007)
Received 27 November 2006, in final form 10 January 2007
Published 20 February 2007
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