COMPUTATION OF ANTIFERROMAGNETIC PROPERTIES OF ORTHORHOMBIC CACUO2

The electronic structure of CaCuO2 in the experimentally observed orthorhombic structure has been computed with the spin polarized, full potential pseudofunction energy band method. The bands are found to be insulating and very narrow near the Fermi energy resulting in a large magnetic moment of 0.58 mu(B) on the Cu atoms. The fundamental difference in the bands between this phase which contains Cu-O chains and the layered Bi or Tl cuprates is that the broad antibonding bands associated with the Cu-O bonds are located above the Fermi energy in the orthorhombic phase. Introduction of Sr for Ca causes the magnetic moments to change and the bands to overlap slightly to give semimetallic behavior.