Impurity energy levels and stability of Cr and Mn ions in cubicBaTiO3

The self-consistent-field multiple-scattering Xα method has been used to calculate the electronic structures of substitutional chromium and manganese ions (valence states investigated: from +2 to +6) in cubic ${\mathrm{BaTiO}}_3$. The energy levels of the 3d states are provided, compared to the valence-band edge, for high- and low-spin configurations, while the ground state of each ion is determined through the transition-state procedure. This, combined with previous results, allows one to predict that in this crystal the stability of Cr and Mn extends over four and three valence states respectively, and that the former especially could exist under hexavalent form.