Competition between screening channels in core-level x-ray photoemission as a probe of changes in the ground-state properties of transition-metal compounds

Core-level x-ray photoemission spectra (XPS) for copper, manganese, and ruthenium compounds are calculated. A strong dependence of the spectral line shape on electron and/or hole doping, magnetic and orbital ordering is observed. The changes can be explained in terms of the competition between local and nonlocal screening effects. In contrast to earlier claims, we find that the changes do not result from additional quasiparticle states at the Fermi level but from a strong coupling of the different screening channels to changes in the ground state. The strong sensitivity of core-level XPS on the surrounding transition-metal atoms enables the study of temperature- and doping-induced changes in orbital occupation and ordering.