Spin and charge ordering in self-doped Mott insulators

TL;DR

This paper explores spin and charge orderings in self-doped Mott insulators, revealing different stable states depending on charge-transfer energy, with implications for specific nickelate compounds.

Contribution

It provides a theoretical analysis of spin and charge ordered states in 3d transition-metal oxides using Hartree-Fock calculations, highlighting conditions for different orderings.

Findings

Antiferromagnetic charge order in oxygen orbitals for large charge-transfer energy.

Charge order in transition-metal orbitals for highly negative charge-transfer energy.

Stability of states influenced by lattice distortions.

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-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 PrNiO$_3$ and NdNiO$_3$. On the other hand, an antiferromagnetic state with charge ordering in transition-metal 3$d$ 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 YNiO$_3$.