Orbital polarization and charge transfer in layered nickelates

April 12, 2023

In a study published in Physical Review B, researchers report calculations of resonant inelastic X-ray scattering spectra used to determine the unique features of reduced valence layered nickelates.

RIXS spectra for R₄Ni₃O₈ in the incident energy – energy loss plane. The top plots are the calculations, the bottom plots the data, the left plots s polarized, the right plots p polarized. The vertical feature near zero incident energy and a loss energy above 4 eV is from charge transfer between Ni 3d and O 2p. The polarization change of the diagonal line as a function of energy is from nickel 3d hybridized with R 5d.

Scientific Achievement

By developing a new formalism for resonant inelastic x-ray scattering (RIXS) spectra, we are able to interpret unique features of reduced valence layered nickelates.

Significance and Impact

Cuprates and reduced valence nickelates are both superconducting. The question is whether they are related or not. Our work suggests that they indeed are.

Research Details

Our RIXS formalism is based on orbitally resolved density of states from density functional theory (DFT) and dynamical mean field theory (DMFT) calculations.
Calculations were done for RNiO₂, R₄Ni₃O₈, R₄Ni₃O₁₀, and CaCuO₂ (R a rare earth) and then compared to RIXS data.

DOI: 10.1103/PhysRevB.107.16512

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