Ground-state valency and spin configuration of the Ni-ions in nickelates

Abstract

The ab initio self-interaction-corrected local-spin-density approximation is used to study the electronic structure of both stoichiometric and non-stoichiometric nickelates. From total energy considerations it emerges that, in their ground-state, both LiNiO2 and NaNiO2 are insulators, with the Ni ion in the Ni3+ low spin state (6t2g 1eg) configuration. It is established that a substitution of a number of Li/Na atoms by divalent impurities drives an equivalent number of Ni ions in the NiO2 layers from the JT-active trivalent low-spin state to the JT-inactive divalent state. We describe how the observed considerable di_erences between LiNiO2 and NaNiO2 can be explained through the creation of Ni2+ impurities in LiNiO2. The indications are that the random distribution of the Ni2+ impurities might be responsible for the destruction of the long-range orbital ordering in LiNiO2.

arXiv comment3 figures, 1 table

References in corpus (5)

• Orbital ordering in frustrated Jahn-Teller systems
• Orbital frustration at the origin of the magnetic behavior in LiNiO2
• Interlayer Magnetic Frustration in Quasi-stoichiometric Li1-xNi1+xO2
• Ordering and Spin Waves in NaNiO2 : A Stacked Quantum Ferromagnet
• Ferrodistorsive orbital ordering in the layered nickelate NaNiO_2: A density-functional study

Cited by in corpus (4)

• LiNiO${}_2$ as a high-entropy charge- and bond-disproportionated glass
• Paraorbital ground state of trivalent Ni ion in LiNiO${}_2$ from DFT+DMFT calculations
• Effect of magnesium doping on the orbital and magnetic order in LiNiO2
• Metal-insulator transition in half-filling two-orbital Hubbard model on triangular lattice