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Abstract:
We have studied the core level photoemission spectra of the
two-dimensional cuprates Sr2CuO2Cl2, Sr2CuO2Br2, Ca2CuO2Cl2,
Bi2Sr2CaCu2O8+delta, and Nd2CuO4, with particular focus on the
screening response to core-hole creation in the Cu-2p(3/2)
level. The influence of the apex positions on the shape of the
so-called main line is investigated, and found to be weak.
Additionally, an Anderson impurity model was used to fit the
shape of the main lines, obtaining good agreement with the data
from Nd2CuO4. For the other compounds, while the energy spread
of the two screening channels (local and nonlocal) is well
reproduced, the theory underestimates the width of the
nonlocally screened feature. The shapes of the main lines are
discussed in detail.