Resolution of the negative U problem in early transition metals: a reinterpretation of the LVV auger spectra

Abstract

The early transition elements (Sc-Mn) exhibit L₂₃-M₄₅M₄₅ Auger spectra shifted to higher kinetic energy compared to the self-convoluted DOS. In the past, this was interpreted as a negative U in these materials. We show that this anomalous behaviour can be explained without invoking negative U, if the presence of a screening electron in the initial state of the Auger process is taken into account. In that case, the Auger spectrum not only has two-hole like final states, but also one-hole like final states that were not accounted for earlier. This provides a new and consistent description of the Auger process.