ANOMALOUS CHARGE-TRANSFER IN LA2-BETA-SR-BETA-CUO4 AND IN ND2-ZCEZCUO4

The hypothesis of charge-transfer to the cuprate-planes, which lies at the foundation for most theories on high-temperature superconductivit y, is re-examined in light of recent neutron-diffraction data for La2- betaSrbetaCuO4 and Nd2-zCezCuO4. The data indicate that the cuprate-pl anes do not acquire holes as the materials become superconducting, and that the superconducting p-type regions of the unit cells are in the noncuprate-plane charge-reservoir layers instead. (C) 1995 American In stitute of Physics.