Core-level photoemission spectra of low-dimensional copper-oxide systems

Intersite screening effects on the Cu 2p X-ray photoemission spectrum (XPS) are discussed for low-dimensional Cu-O systems on the basis of Lanczos calculations for multiple-Cu-site clusters. The effects are compared between edge-sharing and corner-sharing one-dimensional systems and between one- and two-dimensional systems. The line shape of the calculated Cu 2p XPS differs considerably for these systems, reflecting the different charge distributions in the photoemission final states. These results are compared with the experimental spectra of Bi₂CuO₄, Sr₂CuO₃, CuGeO₃, La₂CuO₄ and Sr₂CuO₂Cl₂.