INTERFACE DELOCALIZATION TRANSITION IN TYPE-I SUPERCONDUCTORS

Within the Ginzburg-Landau theory, which is known to be quantitatively correct for classical superconductors, it is shown that a type-I superconductor with enhanced order parameter \psi\(2) at the surface displays an interface delocalization or ''wetting'' transition. Surprisingly, the order of the transition is controlled by a bulk material constant, the Ginzburg-Landau parameter kappa. First-order wetting is predicted for 0 less than or equal to kappa < 0.374 and critical wetting for 0.374 < kappa < 1/root 2. Superconductors are likely to be an ideal test case for experimental observation of critical wetting.