Influence of parametersUandJin the LSDA+Umethod on electronic structure of the perovskitesLaMO3(M=Cr,Mn,Fe,Co,Ni)

The electronic structures of the perovskite oxides $\mathrm{La}M{\mathrm{O}}_3(M=\mathrm{C}\mathrm{r},\mathrm{}\mathrm{M}\mathrm{n},\mathrm{}\mathrm{F}\mathrm{e},\mathrm{}\mathrm{C}\mathrm{o},\mathrm{}\mathrm{and}\mathrm{}\mathrm{Ni})$ have been studied in the local-spin density approximation $\mathrm{LSDA}+U$ method with the on-site Coulomb interaction parameter U varying from 0.0 to 10.5 eV, and exchange parameter J, from 0.35 to 0.95 eV. It is found that the splitting of the occupiedspin-up bands and the corresponding unoccupied spin-down bands increases almost linearly with the increase of U, while the positions of the completely empty orbitals (both spin-up and -down bands are unoccupied) are not sensitive to the value of U. These features cause the gaps of the compounds to increase first with U, and then they can increase $\left({\mathrm{LaFeO}}_3\right),$ decrease $({\mathrm{LaCrO}}_3$ and ${\mathrm{LaMnO}}_3)$ or even drop to zero $\left({\mathrm{LaCoO}}_3\right).\mathrm{}$ The local magnetic moments increase linearly with increasing U. After considering the on-site Coulomb interaction, the binding energies for the perovskites are lowered, and decrease with the increase of U. The exchange parameter J also influences the electronic properties, though not as strongly as that of the U. A group of values of U and J parameters, which can give results closer to that given by experiments, have been found.