Superconductivity in cuprate artificial structures

Superlattices based on standard high temperature superconductors (HTS) such as YBa2Cu3O7?x and Bi2Sr2CunCan?1Ox have been extensively used to investigate many fundamental issues in HTS physics such as dimensionality, vortex dynamics, proximity effects, epitaxial strain effects, interplay between superconductivity and magnetism. Recently, a different approach based on thin layers of the (Ca, Sr, Ba)CuO2 compounds (infinite layers compounds) has been applied to the synthesis of superconducting cuprate heterostructures. Ideal infinite layer (IL) compounds alone are not superconducting; however, in IL-based heterostructures, the occurrence of charge transfer among layers containing different alkaline earth ions can give rise to superconductivity. Structural features of these heterostructures can be engineered in a wide range and, consequently, their superconducting properties are studied. The highlights of these investigations are reviewed here.