Different length-scales for order parameters in two-gap superconductors:   the extended Ginzburg-Landau theory
  Using the Ginzburg-Landau theory extended to the next-to-leading order we determine numerically the healing lengths of the two order parameters at the two-gap superconductor/normal metal interface. We demonstrate on several examples that those can be significantly different even in the strict domain of applicability of the Ginzburg-Landau theory. This justifies the use of this theory to describe relevant physics of two-gap superconductors, distinguishing them from their single-gap counterparts. The calculational degree of complexity increases only slightly with respect to the conventional Ginzburg-Landau expansion, thus the extended Ginzburg-Landau model remains numerically far less demanding compared to the full microscopic approaches. 
L. Komendov\'a, M. V. Milo\v{s}evi\'c, A. A. Shanenko, and F. M.   Peeters
cond-mat.supr-con