Electronic structure ofLaMnO3in theab initiocrystal Hartree-Fock approximation

We find that an ab initio electronic structure calculation in the Hartree-Fock approximation (HFA) leads to the experimentally observed magnetic and orbital orderings in ${\mathrm{LaMnO}}_3,$ as well as its insulating character. While such agreement was also found in density-functional theories (DFT’s), there are large differences in other physical predictions. The HFA results are discussed vis a vis two different DFT’s and an embedded cluster theory, as well as x-ray photoemission and inelastic neutron scattering experiments.