Pressure induced redistribution of oxygen hole states in La₄Ni₃O₁₀

Summary

This paper employs density functional theory calculations combined with multi-orbital, multi-atomic cluster exact diagonalization including local exchange and Coulomb interactions to study the local low-energy electronic states of the trilayer nickel oxide La₄Ni₃O₁₀ using a minimal Ni₃O₁₄ cluster. The study finds that under ambient pressure, all three Ni ions are nominally +2 valent, with one of the two extra holes localized in the central NiO₂ layer, forming a Zhang-Rice singlet with the dx²-y² orbital; the other hole predominantly occupies the antibonding combination of interlayer O p_z orbitals and hybridizes with an out-of-plane tri-spin polaron formed by the dz² orbitals of the three NiO₂ layers. Consequently, the in-plane spin orientation is alternately carried by the outer dx²-y² orbitals, with antiferromagnetic interlayer correlations, while the central layer is insulating with negligible magnetic moment. Under high pressure, the two extra holes concentrate on one outer layer and the inner layer, respectively, forming either a Zhang-Rice singlet or an in-plane tri-spin polaron on the dx²-y² orbitals. The possible charge and spin ordered states suggested by the cluster results highlight the similarity between the bilayer La₃Ni₂O₇ and the trilayer La₄Ni₃O₁₀.

Materials

• La₄Ni₃O₁₀

Methods

• DFT
• Multi-orbital cluster exact diagonalization
• Wannier projections
• Ni₃O₁₄ cluster model

Keywords

• zhang rice singlet
• three spin polaron
• oxygen hole states
• spin density wave
• charge density wave
• intertwined order

Highlights

• The study reveals pressure-induced redistribution of oxygen hole states in La₄Ni₃O₁₀.
• It provides insights into the interplay between structure and electronic correlations in trilayer nickelates.

Conclusions

• At ambient pressure, one extra hole localizes in the central NiO₂ layer forming a Zhang-Rice singlet with dx2-y2 orbital, while the other hole occupies the antibonding combination of interlayer O pz orbitals hybridizing with a three-spin polaron.
• At high pressure, the two extra holes concentrate on outer and inner layers separately forming Zhang-Rice singlets or in-plane three-spin polarons.
• The central layer becomes insulating with negligible magnetic moment.
• Possible charge and spin ordered states highlight similarities between bilayer La₃Ni₂O₇ and trilayer La₄Ni₃O₁₀.

Main claims

• At ambient pressure, one extra hole localizes in the central NiO₂ layer forming a Zhang-Rice singlet with dx2-y2 orbital.
  • Evidence: Abstract,Full text: At ambient pressure, one of the two extra holes is localized in the central NiO₂ layer forming a Zhang-Rice singlet with dx2-y2 orbital.
• At high pressure, the two extra holes concentrate on one outer layer and the inner layer, forming ZRS or in-plane 3SP.
  • Evidence: Abstract,Full text: At high pressure, the two extra holes are concentrated on one of two outer layers and the inner layer separately forming the ZRS with dx2-y2 orbitals or in-plane 3SP.
• The pressure-induced redistribution of oxygen hole states results in different magnetic and electronic properties.
  • Evidence: Abstract,Full text: At ambient pressure, in-plane spin orientation alternation is carried by outer dx2-y2 orbitals with interlayer AFM correlation; central layer is insulating.

Workflow

• DFT_calculation
  • Materials: La₄Ni₃O₁₀
  • Methods: VASP; Wien2K; maximally localized Wannier functions
• cluster_ED_calculation
  • Methods: exact diagonalization of Ni₃O₁₄ cluster; multi-orbital Hamiltonian
  • Observations: dominant configurations and weights
• state_analysis
  • Methods: spin state analysis; weight distribution
  • Observations: pressure-induced redistribution of oxygen hole states
• interpretation — At ambient pressure, one hole forms a Zhang-Rice singlet in central layer; at high pressure, holes redistribute to outer layers.