Photoemission Electron Spectroscopy II: Satellites by Local Excitations

Abstract

  Photoemission process leaves the target system in various final states that are lacking one electron with respect to the initial state. Except for the trivial noninteracting case, the final-state effects result in separate features in the photoemission electron spectra (PES). They are distinguished as the main feature and its satellites. Knowledge about those features for a given material is fundamentally important in understanding the electronic property of the material. We discuss the main and satellite features signaled in PES especially when the final states are reached by the local excitations, usually corresponding to the atoms, molecules, or strongly correlated electron solids like transition metal or rare earth metal compounds or several organic compounds. In particular, we focus on a few famous and prototypical PES problems of transition metal compounds (i.e., 3d-valence insulators, or sometimes narrow band 3d metals) and their understanding.