The effects of nonmagnetic impurity atoms on the electronic states of CuO2 planes

We study the effects of nonmagnetic impurities on the electronic states of CuO2 planes in copper oxides. We calculate the local density of states at the copper sites and the oxygen sites, around the impurities. The local density of states in the CuO2 plane with the impurities increases or decreases, depending on the energy ω, as compared with those without the impurities. The spatial distribution of the local density of states has an anisotropic shape in the vicinity of the Fermi energy ω∼ωF. At ϵp (p-level) <ω<ϵd (d-level), there is a difference in the spatial distribution of the local density of states between the d- and p-electrons, while at other energies, those of the d- and p-electrons are practically the same.