Prediction of s± -Wave Superconductivity Enhanced by Electronic Doping in Trilayer Nickelates La4</mml:…

Motivated by the recently reported signatures of superconductivity in trilayer La₄Ni₃O₁₀ under pressure, we comprehensively study this system using ab initio and random-phase approximation techniques. Without electronic interactions, the Ni d_{3z²-r²} orbitals show a bonding-antibonding and nonbonding splitting behavior via the O pz orbitals inducing a "trimer" lattice in La₄Ni₃O₁₀, analogous to the dimers of La₃Ni₂O₇. The Fermi surface consists of three electron sheets with mixed eg orbitals, and a hole and an electron pocket made up of the d_{3z²-r²} orbital, suggesting a Ni two-orbital minimum model. In addition, we find that superconducting pairing is induced in the s±-wave channel due to partial nesting between the M=(π,π) centered pockets and portions of the Fermi surface centered at the Γ=(0,0) point. With changing electronic density n, the s± instability remains leading and its pairing strength shows a domelike behavior with a maximum around n=4.2 (∼6.7% electron doping). The superconducting instability disappears at the same electronic density as that in the new 1313 stacking La₃Ni₂O₇, correlated with the vanishing of the hole pocket that arises from the trilayer sublattice, suggesting that the high-Tc superconductivity of La₃Ni₂O₇ does not originate from a trilayer and monolayer structure. Furthermore, we confirm the experimentally proposed spin state in La₄Ni₃O₁₀ with an in-plane (π, π) order and antiferromagnetic coupling between the top and bottom Ni layers, and spin zero in the middle layer.