Hole Binding around Ni Impurity in Cuprates

We examine the influence of Ni impurity in cuprates on the distribution of hole carriers by performing numerically exact diagonalization calculations for a model consisting of Cu3d, Ni3d, and O2p orbitals. Using realistic parameters for the system, we find that a hole is predominantly bound to O2p orbitals around the Ni impurity forming the Zhang-Rice doublet. This imposes strong restrictions on modeling Ni-substituted cuprates. We propose a resonant inelastic x-ray scattering experiment for Ni K-edge to confirm hole binding around the Ni impurity.