Oxygen ordering in the basal plane of YBa2Cu3Oz

Abstract

The ground-state configurations of a lattice-gas model introduced by de Fontaine, Wille, and Moss for the distribution of empty and occupied oxygen sites in the Cu-O basal plane of the high-temperature superconductor YBa2Cu3Oz are determined. It is shown rigorously that the configurations proposed earlier by Wille and de Fontaine basically exhaust the set of possible stable ground-state structures. States of partial order are excluded, except for special values of the interaction constants.