Daily Overview: Today’s highlight focuses on an in-depth understanding of the electronic structure of hybrid Ruddlesden–Popper nickelates. [1] Using the fluctuation exchange approximation, the superconducting properties of a two-orbital model in La₃Ni₂O₇ thin films under ambient pressure are systematically analyzed. It reveals how hole-doping-induced Fermi surface nesting (between δ and γ pockets, as well as between α and β pockets) synergistically enhances s±-wave pairing, indicating that this nesting-driven spin fluctuation mechanism provides a feasible route to enhance ambient-pressure superconductivity in this system. arXiv submission processing window: 2026-03-04 00:00 to 2026-03-04 00:00 UTC.

1. Possible Enhancement of Superconductivity in Ambient-Pressure La$_3$Ni$_2$O$_7$ Thin Film

Summary: This study systematically analyzes the superconducting properties of a two-site, two-orbital model (including d orbitals) in the weak correlation regime of La₃Ni₂O₇ thin-film superconductors under ambient pressure, using the fluctuation exchange (FLEX) approximation, with a focus on its dependence on hole doping. Through a detailed investigation of the Fermi surface topology, it is found that when the δ pocket, composed of the d_{z²} antibonding orbital, appears near the Γ point, the nesting between the δ and γ pockets, together with the nesting between the α and β pockets, jointly promotes mutual enhancement of s±-wave pairing at the corresponding wave vectors. The study further proposes that this nesting-driven spin-fluctuation-induced pairing enhancement mechanism provides a plausible explanation for the improvement of ambient-pressure superconductivity in this system.