Low-energy description of the metal-insulator transition in the rare-earth nickelates
Low-energy description of the metal-insulator transition in the rare-earth nickelates
We propose a simple theoretical description of the metal-insulator transition of rare-earth nickelates. The theory involves only two orbitals per nickel site, corresponding to the low-energy antibonding ${e}_{g}$ states. In the monoclinic insulating state, bond-length disproportionation splits the manifold of ${e}_{g}$ bands, corresponding to a modulation of the effective on-site …