Transition temperature of superconductor-insulator superlattices.

We have extended the theory of layered superconductors to describe superlattices in which layers of superconducting material consisting of M unit cells are separated by insulating layers that are N unit cells thick. An intercell pairing interaction is identified which controls the variation of Te with M and N, and raises Tc from low to high temperatures. The independence is traced back to a finite-size effect corresponding to crossover from nearly two- to three-dimensional behaviour. © 1991 IOP Publishing Ltd.