Theory of oxygen 1s resonant X-ray emission spectroscopy in copper-based oxides

Many-body effects on the oxygen 1s resonant X-ray emission spectrum (O 1s RXES) in copper-based oxides, such as Sr₂CuO₃ and La₂CuO₄, are discussed on the basis of cluster-model calculations. The Zhang-Rice singlet excitation, which is a typical many-body state in Cu-based oxide systems, can be detected at low temperatures where the antiferromagnetic correlation between the neighboring Cu spins is strong. Thus the present study emphasizes that the O 1s RXES can be a good tool to obtain information on the Cu 3d states. In particular the polarization-dependent RXES gives the symmetry-decomposed information.