## Abstract

We have studied transition-metal 3d-oxygen 2p lattice models, where full degeneracy of transition-metal 3d and oxygen 2p orbitals and on-site Coulomb and exchange interactions between 3d electrons are taken into account, by means of a spin- and orbital-unrestricted Hartree-Fock (HF) approximation. The electronic-structure parameters deduced from the cluster-model analyses of the photoemission spectra are used as input. We have applied this method to perovskite-type 3d transition-metal oxides, which exhibit various electrical and magnetic properties. It is shown that the HF results can explain the ground-state properties of insulating oxides. The relationship between spin- and orbital-ordered solutions and the Jahn-Teller-type and (Formula presented)-type distortions in R(Formula presented), R(Formula presented), R(Formula presented), and R(Formula presented) (R is a rare earth atom or Y) is extensively studied. Single-particle excitation spectra calculated using Koopmans’ theorem give us an approximate but relevant picture on the electronic structure of the perovskite-type 3d transition-metal oxides. As a drawback, the HF calculations tend to overestimate the magnitude of the band gap compared with the experimental results and to predict some paramagnetic metals as antiferromagnetic insulators.

Original language | English |
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Pages (from-to) | 5368-5380 |

Number of pages | 13 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 54 |

Issue number | 8 |

DOIs | |

Publication status | Published - 1996 Jan 1 |

Externally published | Yes |

## ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics