Daily Overview: This post sorts papers by relevance to nickelate superconductors. Summaries are AI-generated and may contain errors. arXiv submission processing window: times are unavailable (UTC).

1. Pairing Mechanism in Bilayer Nickelate La$_3$Ni$_2$O$_7$ Superconductors

Summary: Research on the pairing mechanism of the bilayer nickelate La₃Ni₂O₇ high-temperature superconductor demonstrates that the unified framework based on the “genesis principle” and the “synergistic Fermi surface rule” can be naturally extended to this bilayer multi-orbital system. Through strong-correlation analysis, two dominant antiferromagnetic superexchange channels are identified: the intralayer same-orbital (d_z²) nearest-neighbor exchange J⊥ mediated by the inner apical oxygen, and the interlayer different-orbital (d_z² and d_x²-y²) nearest-neighbor exchange J_xz mediated by the in-plane oxygen. Due to the bilayer bonding-antibonding splitting and the B₁g symmetry of the d_x²-y² orbital, the two channels cooperate to produce a stable s± superconducting state, characterized by internal sign reversal between the mirror-even and mirror-odd Fermi surface pockets in momentum space. Both pairing channels maximize the superconducting gap on the β pocket with a form factor of (cosk_x − cosk_y)². This result incorporates La₃Ni₂O₇ into the unified framework of unconventional superconductivity while revealing its unique electronic environment for high-temperature superconducting pairing.