Energy gap in layered superconductors

The anisotropy of the gap in layered compounds is studied in the framework of the BCS model, taking into account the interlayer and different intralayer couplings in the system. The compounds with alternating normal (N) and superconducting (S) layers are studied in detail, the N layers being assumed to have zero pairing intralayer interaction. In S-N systems with Josephson coupling of layers, there are two quite different gaps and also different temperature scales of the superconducting properties of the S and N layers. The results are used to discuss the behavior of high-${\mathit{T}}_{\mathit{c}}$ superconductors and possible artificial superlattices based on these compounds.