Evidence of an atomistic universal structural entity for high-temperature superconductivity

Evidence is presented that the spatial regions responsible for superconductivity in NdBa2Cu3O7, Nd2-zCezCuO4, and Nd2-zCezSr2Cu2NbO10 are different in the three materials, based on the locations of the superconducting condensates as extracted from: pair-breaking data, the locations of the charge reservoirs, the effects of Ce doping, crystal-field splitting, and the different charges on the Nd2-zCezCuO4 in "free" bulk Nd2-zCezCuO4 and in "superlattice" Nd2-zCezCuO4/SrO/NbO2/SrO/CuO2/. Analyses show that the universal entity responsible for superconductivity is not a spatially extended or planar structure, but is atomistic charge-reservoir oxygen. This suggests that Ba1-aKaPb1-bBibCu3 should be reclassified as a high-temperature oxide superconductor, with Tc approximate to 32 K for b-->1. Predictions of the critical temperatures of Nd2-zCezSr2Cu2NbO10 and Nd2-zCezSr2Cu2TaO10, based on this picture, are successful. (C) 1998 American Institute of Physics. [S0021-8979(98)05003-8].