Electronic structure, quasiparticle renormalizations, and magnetic correlations in the alternating single-layer bilayer nickelate La₅Ni₃O₁₁

Summary

This study systematically investigates the electronic structure and magnetic correlations in the normal state of the alternating monolayer-bilayer Ruddlesden-Popper nickelate La₅Ni₃O₁₁ (1212-LNO) using the DFT+DMFT method. The results reveal significant differences between structurally distinct monolayer and bilayer Ni ions: the e_g states of bilayer Ni ions form strongly renormalized quasiparticle bands, with effective mass enhancement factors of approximately 3.5 and 4.2 for the Ni x²-y² and 3z²-r² orbitals, respectively; while the e_g states of monolayer Ni ions exhibit an orbital-selective Mott insulating state, where the Ni 3z²-r² orbital possesses a narrow gap and the x²-y² orbital displays metallic but strongly incoherent (non-Fermi liquid) behavior. Magnetic correlation analysis indicates that intertwined spin and charge density wave stripes may form in the bilayer NiO₆ planes, with the primary instability corresponding to an “up-down-0” spin pattern at wave vector Q=(1/3,1/3) competing with a “up-up-down-down” double-stripe state at (1/4,1/4). The 3d electrons of monolayer Ni tend to form Néel-type magnetic order. Under pressure, 1212-LNO undergoes an orbital-selective Mott insulator-metal transition accompanied by the metallization of the monolayer Ni e_g states, which exhibit strongly incoherent non-Fermi liquid behavior near the Fermi level. Overall, correlation effects significantly restructure the magnetic correlations from DFT-predicted monolayer-dominated to bilayer-dominated behavior, emphasizing the critical roles of interlayer confinement and orbital-dependent correlations.

Materials

• La₅Ni₃O₁₁ (1212-LNO)

Methods

• DFT+DMFT

Keywords

• orbital selective mott transition
• magnetic correlations
• spin stripes
• non fermi liquid
• confinement effects

Highlights

• Correlation effects cause a crossover from monolayer-dominated (in DFT) to bilayer-dominated magnetic correlations.
• Emergent flat-band behavior of bilayer Ni states near the Fermi level.

Conclusions

• Bilayer Ni ions form strongly renormalized quasiparticle bands with mass enhancement factors ≈3.5 and 4.2 for dx2-y2 and d3z2-r2 orbitals, while monolayer Ni ions show an orbital-selective Mott insulating state.
• Magnetic correlations are dominated by bilayer Ni states with stripe instabilities at wave vectors (1/3,1/3) and (1/4,1/4).
• Under pressure, an orbital-selective Mott insulator-metal transition occurs, with monolayer Ni exhibiting non-Fermi-liquid behavior.

Main claims

• The e_g states of bilayer Ni ions form strongly renormalized quasiparticle bands with mass enhancement factors of approximately 3.5 and 4.2 for the Ni dx2-y2 and d_z2 orbitals, respectively.
  • Evidence: the e_g states of bilayer Ni ions form strongly renormalized quasiparticle bands, with effective mass enhancement factors of approximately 3.5 and 4.2 for the Ni x²-y² and 3z²-r² orbitals
• The e_g states of monolayer Ni ions exhibit an orbital-selective Mott insulating state, where the Ni 3d_z2 orbital has a narrow gap and the 3dx2-y2 orbital displays metallic but strongly incoherent (non-Fermi-liquid) behavior.
  • Evidence: the e_g states of monolayer Ni ions exhibit an orbital-selective Mott insulating state, where the Ni 3z²-r² orbital possesses a narrow gap and the x²-y² orbital displays metallic but strongly incoherent (non-Fermi liquid) behavior.
• Magnetic correlation analysis indicates intertwined spin and charge density wave stripes in the bilayer NiO₆ planes, with the primary instability corresponding to an 'up-down-0' spin pattern at Q=(1/3,1/3) competing with a 'up-up-down-down' double-stripe state at (1/4,1/4).
  • Evidence: Magnetic correlation analysis indicates that intertwined spin and charge density wave stripes may form in the bilayer NiO₆ planes, with the primary instability corresponding to an “up-down-0” spin pattern at wave vector Q=(1/3,1/3) competing with a “up-up-down-down” double-stripe state at (1/4,1/4).

Workflow

• DFT+DMFT calculation for electronic structure — Electronic states show layer- and orbital-dependent correlations.
  • Materials: La₅Ni₃O₁₁ (1212-LNO)
  • Methods: DFT+DMFT with continuous-time quantum Monte Carlo
  • Observations: qualitative differences between monolayer and bilayer Ni ions; bilayer Ni: strongly renormalized quasiparticle bands with mass enhancement factors 3.5 (dx2-y2) and 4.2 (d_z2); monolayer Ni: orbital-selective Mott insulating state, d_z2 has narrow gap, dx2-y2 metallic but incoherent (non-Fermi-liquid)
• analysis of magnetic correlations — Magnetic correlations are dominated by bilayer NiO₆ block with intertwined spin and charge density wave stripes.
  • Materials: 1212-LNO
  • Methods: static magnetic susceptibility from DMFT Green's function
  • Observations: leading instability: bilayer NiO₆ block with wave vector (1/3,1/3) corresponding to 'up-down-0' spin pattern; competing instability: (1/4,1/4) corresponding to 'up-up-down-down' double-stripe state; monolayer Ni: Néel-type order
• pressure study — Under pressure, 1212-LNO undergoes an orbital-selective Mott insulator-metal transition in the monolayer, but bilayer magnetic correlations dominate.
  • Materials: 1212-LNO at 30 GPa
  • Methods: DFT+DMFT
  • Observations: Mott insulator-metal transition in monolayer Ni; monolayer Ni states show non-Fermi-liquid behavior with strongly incoherent spectral weight; bilayer Ni quasiparticle renormalizations reduced; magnetic correlations similar to ambient pressure