Electronic excitation spectra from ab-initio band structure results for LaMO₃ (M = Cr-Ni)

We present calculated electron excitation spectra for the LaMO_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.