Koshelev A E, Golubov A A
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Phys Rev Lett. 2004 Mar 12;92(10):107008. doi: 10.1103/PhysRevLett.92.107008.
It is well established that the superconductivity in the recently discovered superconducting compound MgB2 resides in the quasi-two-dimensional band (sigma band) and three-dimensional band (pi 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 pi band, we derive the simplest equations, which describe properties of such superconductors near Tc, and explore some consequences of these equations.
众所周知，最近发现的超导化合物MgB₂中的超导性存在于准二维能带（σ能带）和三维能带（π能带）中。我们证明，由于这种能带结构，各向异性的金兹堡-朗道理论实际上没有适用范围，因为在c方向上的梯度展开会失效。在脏π能带的情况下，我们推导了描述此类超导体在Tc附近性质的最简单方程，并探讨了这些方程的一些结果。
