Electronic excitation spectra fromab initioband-structure results for LaMO3(M=Cr,Mn,Fe,Co,Ni)

We present calculated electron excitation spectra for the LaM${\mathrm{O}}_3$ series (M=Cr-Ni) obtained within ab initio band-structure calculations for the real geometric and magnetic structures. The calculated results show good agreement with the experimentally obtained spectra. This suggests that the transition-metal–transition-metal interactions via the oxygen atom play an important role in determining the spectroscopic features and indicates a smaller value of U/t than has been believed so far. The present approach undermines the importance of multiplet interactions which otherwise play an important role within various single-impurity models. © 1996 The American Physical Society.