T. Arima, Y. Tokura, et al.
Physica C: Superconductivity and its applications
The difference in Madelung site potential, VM, between a hole on a copper site and one on an oxygen site can control the holes site preference and ability to delocalize. Among a variety of copper oxide structures, eVM is shown to vary by 3 eV and to clearly separate two classes of compounds: Those with eVM>47 eV are metallic with high Tc and delocalized holes, whereas those with lower "VM are semiconducting because their holes are self-trapped on oxygen. © 1989 The American Physical Society.
T. Arima, Y. Tokura, et al.
Physica C: Superconductivity and its applications
Y. Tokura, J.B. Torrance, et al.
JACS
A. Girlando, C. Pecile, et al.
Solid State Communications
J.B. Torrance, B.A. Scott, et al.
Physical Review B