On the chemistry of superconductivity

High-temperature superconductivity is observed in ceramics with complex crystal structures. In each case, perovskite-like layers (CuO2) are found next to cation-monoxide layers (LaO or CuO). We suggest that Bloch wave functions in these two layers are hybridized. The interaction of the bottom of an energy band in the monoxide layer with the top of the perovskite band gives rise to states with a low group velocity within these layers. Superconductivity is explained by the strong interaction of these electrons with loosely-bound oxygen ions which leads to pairing and ordering of the electrons. Experimental verification of this model may be obtained by observing the variation of the current due to the dependence of the group velocity on the location of oxygen ions.