Effective forces between interfaces in type-I superconductors

Abstract

Semi-infinite type-I superconductors with surface enhancement at the wall show interface delocalization transitions analogous to wetting transitions in classical liquids. Within Ginzburg-Landau theory the effective forces between the wall and the SC/N-interface decay exponentially ("short-range forces"). Going beyond GL-theory we show that in general planar interfaces of a type-I superconductor with vacuum, normal conductors or other superconductors interact via long-ranged (algebraic) dispersion forces. Invoking BCS-results for the dielectric function of a superconductor an algebraic correction to the effective interface potential of the unusual form V ( ) ∼ −5 is found, where is the thickness of the surface superconducting sheath. This in contrast to classical fluids, where the retarded contribution is V ( ) ∼ −3 . The effective force can be either attractive or repulsive depending on the superconductor used for surface enhancement. Consequences for the interface displacement transition scenario are outlined.

Variations of Casimir energy from a superconducting transition

“…Now it is clear that non-local effects are important, in general, in superconductors, by virtue of the very small skin depth (of the order of the penetration depth λ, typically 500 Å or so) also in the frequency region characteristic of the normal skin effect in normal metals (for an interesting discussion of non-local effects in the computation of dispersion forces in superconductors, see Ref. [18]). Moreover, for small separations L, as well as for small film thicknesses D < 25 − 30 nm and/or at cryogenic temperatures non-local effects become important also in the normal state [19], and indeed it has been advocated that space dispersion should be taken into account, for example, to evaluate the influence of thin metal coatings, that are used to protect the plates in most of the current experiments on the Casimir effect (see [3] and last of Refs.…”

Equilibrium intermediate-state patterns in a type-I superconducting slab in an arbitrarily oriented applied magnetic field

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. For further background we refer the reader to several books and reviews.…”

“…Studies of the intermediate-state structure in type-I superconductors have a long history beginning with the pioneering work of Landau 1,2 and continuing to the present; see, for example, Refs. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. For further background we refer the reader to several books and reviews.…”

Towards Measuring Variations of Casimir Energy by a Superconducting Cavity

“…It is clear that non-local effects are important, in general, in superconductors and, for the small separations that we consider (L = 10 nm), also in normal metals (for an interesting discussion of non-local effects in the computation of dispersion forces in superconductors, see Ref. [10]). However, spatial dispersion is unimportant for the purpose of computing the difference between the Casimir energies in the two states of the film.…”