Non-local electrodynamics effect on surface superconductivity
Instituut voor Theoretische Fysica, Katholieke Universiteit Leuven - Celestijnenlaan 200 D, BE-3001 Leuven, Belgium, EU
Accepted: 5 April 2011
Effects of non-local electrodynamics on surface superconductivity in type-I superconductors in zero magnetic field are predicted, employing the Ginzburg-Landau (GL) theory as the local approximation. A perturbation expansion in the ratio ξ0/ξ(T) is set up, where ξ0 is the Pippard (or BCS) coherence length and ξ the temperature-dependent GL coherence length of superconductivity. For materials with surface enhancement of superconductivity, characterized by a negative GL surface extrapolation length b and by a surface critical temperature Tcs that exceeds the bulk Tc, an additional increase of Tcs is predicted. Calculations to first order in ξ0/ξ(T) show that about 13% of the recently measured difference Tcs−Tc≈0.05 K in a surface-enhanced Sn film, is attributable to a non-local electrodynamics effect.
PACS: 68.35.Rh – Phase transitions and critical phenomena / 74.25.Bt – Thermodynamic properties / 64.60.F- – Equilibrium properties near critical points, critical exponents
© EPLA, 2011