Electronic Structure and Superconductivity of High T sub c Cu-Oxides (01 January 1988)

The discovery of high T sub c superconductivity prompted an enormous theoretical activity in trying to understand the underlying physics. The situation is, however, still rather unsettled. Here we take a critical look at the basic electronic structure of the Cu-oxide compounds, from which models for superconductivity will have to be derived. 

As originally observed in the (214) La sub 2 CuO sub 4 compound, later somewhat questioned for the (123) YBa sub 2 Cu sub 3 O sub 7 compound, but now more convincingly confirmed for the (12 sup 3) CaBi sub 2 Sr sub 2 Cu sub 2 O sub 8 compound, the for superconductivity essential structural elements seem to consist of 2D square Cu-O networks with varying carrier concentrations. Differences in structural environment (crystal fields, etc.) are possibly also of relevance.