Surface Effect on Spatial Length-Scales in a Two-Gap Superconductor

The healing of two-band superconductivity near its interface is studied. It is demonstrated that the restoration of superconductivity gaps in the immediate vicinity of the interface is governed by two length scales: the first one diverges at critical temperature T _c , while the second one diverges at T _c+<T _c . By moving away from the boundary, the temperature dependencies of characteristic lengths change so that singularity at T _c+ becomes removed in the bulk by arbitrary weak interband coupling. The asymptotes for the spatial behavior of gaps have been found analytically near the surface and approaching the bulk state.