Spin and charge ordering in self-doped Mott insulators

Abstract

We have investigated possible spin and charge ordered states in $3d$ transition-metal oxides with small or negative charge-transfer energy, which can be regarded as self-doped Mott insulators, using Hartree-Fock calculations on $d\ensuremath{-}p$-type lattice models. It was found that an antiferromagnetic state with charge ordering in oxygen $2p$ orbitals is favored for relatively large charge-transfer energy and may be relevant for ${\mathrm{PrNiO}}_{3}$ and ${\mathrm{NdNiO}}_{3}.$ On the other hand, an antiferromagnetic state with charge ordering in transition-metal $3d$ orbitals tends to be stable for highly negative charge-transfer energy and can be stabilized by the breathing-type lattice distortion; this is probably realized in ${\mathrm{YNiO}}_{3}.$