First-principles calculations were made of various patterns of O/vacancy ordering in the Cu-O chains. The effective interactions of the O atoms on the basal plane were determined from the total energy values by using the cluster expansion technique. The effect of ordering on the density of states at the Fermi level was also considered.

First-Principles Study of Oxygen Ordering in Cu3Ba2YO7. C.Ambrosch-Draxi, P.A.Korzhavyi, B.Johansson: Physica C, 2000, 341-348[3], 1997-8