Superconductivity in BiSrCaCuO Superlattices: Two-Dimensional Properties of CuO Planes

Abstract

We report resistive measurements on epitaxial superlattices consisting of alternating Bi 2 Sr 2 CaCu 2 O 8 (2212) and Bi 2 Sr 2 CuO 6 (2201) layers grown by atomic-layer-by-layer molecular beam epitaxy (MBE) using oxygen radical beams. The influence of interplane coupling between Cu-O planes was studied by varying the superlattice sequence of different c -axis half-unit cells. A single-half-unit-cell-thick 2212 layer was found to be superconducting in a 2201 matrix, independent of the conductivity and the thickness of neighboring 2201 layers. The fact that all of our superlattices showed superconductivity essentially equal to that of a 2212 single-phase film suggests that this cuprate is a two-dimensional superconductor due to its Cu-O double planes.