Electronic structure and two-orbital model of the quadlayer La₅Ni₄O₁₃

Summary

Using density functional theory (DFT) and random phase approximation (RPA) calculations, we systematically investigated the electronic structures of the four-layer Ruddlesden–Popper nickelate La₅Ni₄O₁₃ under ambient pressure, 5% isotropic compressive strain, and 4% c-axis uniaxial strain, and constructed a four-layer two-orbital model based on Wannier downfolding. DFT shows that isotropic strain broadens the Ni-e_g bands and induces charge transfer from O-p to Ni-d, whereas c-axis uniaxial strain selectively shifts the d_z2-derived bonding1 band upward while leaving the d_x2-y2 dispersion almost unchanged. The two-orbital model reproduces the low-energy Ni-e_g bands. Under ambient pressure and 5% isotropic strain, the Fermi surface consists of two electron pockets (α, δ) and three hole pockets (β, β′, β″); under uniaxial strain, a γ hole pocket with d_z2 orbital character emerges. RPA calculations show that the dominant spin response changes from q≈(2π/3,2π/3) at ambient pressure to q≈(π,π) under both strains, and is enhanced under c-axis compression. The authors therefore suggest that c-axis compression may provide four-layer nickelates with a favorable superconducting pathway similar to those of bilayer and trilayer nickelates.

Materials

• La₅Ni₄O₁₃

Methods

• DFT
• RPA
• Wannier downfolding
• VASP
• PAW
• PBE
• GGA
• WANNIER90
• quadlayer two-orbital tight-binding model

Keywords

• ruddlesden popper nickelates
• pressure induced superconductivity
• ni e_g bands
• charge transfer
• fermi surface
• electron pockets
• hole pockets
• lifshitz transition
• spin susceptibility
• spin fluctuations
• interlayer coupling
• uniaxial strain
• isotropic strain

Highlights

• Systematically compares ambient pressure, 5% isotropic compressive strain, and 4% c-axis uniaxial strain in the quadlayer Ruddlesden-Popper nickelate La₅Ni₄O₁₃.
• Constructs a quadlayer two-orbital model via Wannier downfolding that captures the strain evolution of the Fermi surface.
• Identifies a strain-induced Lifshitz transition under c-axis uniaxial strain, where a d_z²-derived γ hole pocket emerges, unlike under ambient or isotropic strain.
• Shows that c-axis compression enhances the spin susceptibility at (π, π), suggesting a possible superconducting pairing channel analogous to bilayer and trilayer nickelates.

Conclusions

• DFT calculations show that 5% isotropic strain broadens the Ni-e_g bands and induces charge transfer from O-p to Ni-d orbitals, whereas 4% c-axis uniaxial strain selectively shifts the d_z²-derived bonding1 band upward while leaving the d_x²-y² dispersion nearly unchanged.
• A quadlayer two-orbital model constructed by Wannier downfolding reproduces the low-energy Ni-e_g bands and shows that the d_z²-derived hole pocket remains absent under ambient pressure and isotropic strain but emerges around the M point under 4% c-axis uniaxial strain, signaling a strain-induced Lifshitz transition.
• RPA calculations reveal that the leading spin response shifts from q approximately (2π/3, 2π/3) at ambient pressure to q approximately (π, π) under both strain conditions and is enhanced under c-axis compression.
• The results suggest that c-axis compression may provide a favorable route to superconductivity in quadlayer La₅Ni₄O₁₃ analogous to that in bilayer and trilayer nickelates, and that uniaxial compression is more efficient than hydrostatic pressure for generating the d_z²-derived hole pocket.

Main claims

Not available in this batch.

Workflow

Not available in this batch.