Point-contact spectroscopy of Al- and C-doped MgB2: Superconducting energy gaps and scattering studies

TitlePoint-contact spectroscopy of Al- and C-doped MgB2: Superconducting energy gaps and scattering studies
Publication TypeJournal Article
Year of Publication2007
AuthorsSzabo P, Samuely P, Pribulova Z, Angst M, Bud'ko S, Canfield PC, Marcus J
Journal TitlePhysical Review B
Volume75
Pages144507
Date PublishedApr
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberISI:000246075100085
KeywordsANISOTROPY PARAMETERS, EXCESS CURRENT, field, MAGNESIUM DIBORIDE
Abstract

The two-band and/or two-gap superconductivity in aluminum- and carbon-doped MgB2 has been addressed by the point-contact spectroscopy. Two gaps are preserved in all samples with T(c)(')s down to 22 K. The evolution of two gaps as a function of the critical temperature in the doped systems suggests the dominance of the band-filling effects, but for the increased Al doping, the enhanced interband scattering must also be considered. The extraction of the zero-energy density of states for the pi and sigma bands using a simple physical model demonstrates that significant changes in the relative weighting of the intraband scattering are created in the case of the C doping with the scattering in the pi band enhanced faster than in the sigma one. The Al doping does not change the relative weight of the scatterings within the bands.

DOI10.1103/PhysRevB.75.144507
Alternate JournalPhys. Rev. B