Spin, charge, and orbital ordering in 3d transition-metal oxides studied by model Hartree-Fock calculation

We have spin, charge, and orbital ordered states in the perovskite-type lattice models for La2-xSrxCuO4, La2-xSrxNiO4, and Pr1-xCaxMnO3 by means of unrestricted Hartree-Fock calculations. Present calculations show that, although the vertical charge stripes along the (1,0) direction of the Cu-O square lattice are favored in the cuprates with the charge-transfer energy Delta of similar to2 eV, the diagonal stripes along the (1,1) direction are stable in the nickelates with Delta of similar to4 eV. For the manganites with Delta of similar to4 eV, it has been found that the (1,1,0)-type charge-ordered state with the orbital ordering at the Mn3+ sites are stabilized by the Jahn-Teller distortion at the Mn3+ sites.