Calculations were made of the change in the superconducting transition temperature, caused by interband nonmagnetic impurity scattering, by using the Eliashberg theory for the 2-band model of this compound. A much slower rate of TC suppression was obtained compared to the prediction based on the BCS treatment of the two-band model which ignores renormalization and damping associated with the electron–phonon interaction. Hence, the interband impurity scattering rates deduced from experiments on MgB2 using the formula which resulted from the BCS approach to the 2-band model were underestimated. The BCS treatment of the 2-band model was generalized so as to include renormalization effects of the electron–phonon interaction. Excellent agreement with full strong coupling calculations was found.

On the Rate of TC Suppression by Interband Impurity Scattering in MgB2. B.Mitrovic: Journal of Physics - Condensed Matter, 2004, 16, 9013-22