Why Magnesium Diboride Is Not Described by Anisotropic Ginzburg-Landau Theory
Abstract
It is well established that the superconductivity in the recently discovered superconducting compound MgB2 resides in the quasi-two-dimensional band (σ band) and three-dimensional band (π band). We demonstrate that, due to such band structure, the anisotropic Ginzburg-Landau theory practically does not have a region of applicability, because gradient expansion in the c direction breaks down. In the case of a dirty π band, we derive the simplest equations, which describe properties of such superconductors near Tc, and explore some consequences of these equations.
- Publication:
-
Physical Review Letters
- Pub Date:
- March 2004
- DOI:
- 10.1103/PhysRevLett.92.107008
- arXiv:
- arXiv:cond-mat/0401339
- Bibcode:
- 2004PhRvL..92j7008K
- Keywords:
-
- 74.20.De;
- 74.70.Ad;
- Phenomenological theories;
- Metals;
- alloys and binary compounds;
- Condensed Matter - Superconductivity
- E-Print:
- 4 pages, 2 fugures, Subm. Phys. Rev. Lett