Introduction of oxyanions into copper oxides : a route for the generation of new high Tc superconductors

Superconductivity in the cuprates originates from the [CuO2]∞ layers that are built up from corner-sharing CuO4 square planar groups. This bidimensionality, absolutely necessary for the appearance of superconductivity makes that the infinite layer (IL) structure Ca0.85Sr0.15CuO2 [1] should be the most simple superconductor, built up from the stacking of [CuO2]∞ and [Ca]∞ layers. In fact, prepared at normal pressure, this phase does not superconduct, due to the absence of the mixed valence Cu(II)-Cu(III). Nevertheless, it can be considered as the parent structure for the generation of new superconductors. (orig.)