The electronic structure of CaCuO2 and SrCuO2

We have calculated and compared the electronic structures of both the 1D CuO-chain compound SrCuO2 and the 2D CuO2-plane material CaCuO2, on the basis of the local-spin-density approximation (LSDA) and the on-site Coulomb interaction correction (LSDA + U). The LSDA calculation gives a nonmagnetic and metallic solution as usual for CaCuO2, while it yields an antiferromagnetic (AFM) and insulating one for SrCuO2 due to the decreasing pd hybridization and the subsequent spin polarization with lowering dimensionality. Strongly in favour of orbital and spin polarizations of the Cu 3d states, the U interaction dominates in forming the charge transfer insulating character of both of the AFM cuprates. Some of the differences between the electronic structures can be qualitatively accounted for by the variance of dimensionality.