Open questions in the theory of multigap superconductivity in MgB2
Abstract
The two-gap model for superconductivity in MgB2 has been very successful in explaining a large variety of experiments. It appears to be generally accepted by now. However, there are open questions in this model: (1) MgB2 having 4 sheets of the Fermi surface, can future experiments reveal more than 2 gaps? (2) Should multiband effects be taken into account in Coulomb repulsion terms, and if yes, do they have a serious effect on superconducting properties? (3) Are observed normal transport properties fully explainable in the framework of our current understanding of the electronic structure and electron-phonon coupling in MgB_2? (4) Why nobody has yet succeeded to demonstrate merging of the two gaps in case of strong impurity scattering? Our answers to these question are (1) no, (2) yes and yes, (3) not all, and for the 4th question we can offer some arguments, but admit that we do not have a complete answer. We conclude that despite an impressive progress, the superconductivity in MgB2 is not yet fully understood.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2003
- Bibcode:
- 2003APS..MARX20010M