Structure of four families of layered copper-oxide high T/sub c/ superconductors

Four major families of copper-oxide based high T/sub c/ superconductors have been identified by a number of research groups. It is now well established that the superconductivity is associated with the layers of copper-oxide and that some of the remaining structural building blocks in each primitive cell act as electron acceptors which induce the holes in the copper-oxide layers necessary for superconductivity. 9 refs., 4 figs