Daily Overview: Recent highlight studies focus on topological superconducting mechanisms induced by layer asymmetry in substrate-supported bilayer nickelate (La₃Ni₂O₇) thin films. First-principles-based two-orbital model investigations indicate that, under the premise of dominant interlayer pairing, the interplay between substrate-induced layer-asymmetric potentials and layer-staggered Rashba spin-orbit coupling drives the system into a DIII-class time-reversal-invariant topological superconducting phase protected by diagonal mirror symmetry. This nontrivial topological character originates from the reversal of the pairing sign on the spin-split bonding Fermi surface, manifesting specifically as a nonzero diagonal mirror winding number and Majorana Kramers pairs at the [11] edge, while orbital hybridization effects give rise to bulk Dirac nodes and zero-energy flat bands deviating from the diagonal direction. These theoretical predictions establish the potential of bilayer nickelates as a topological superconducting platform, where tunable topological transitions and boundary modes offer new avenues for probing unconventional pairing mechanisms. arXiv submission processing window: 2026-10-05 00:00 to 2026-10-05 00:00 UTC.

1. Layer-Asymmetry-Induced Topological Superconductivity in High-T$_c$ Bilayer Nickelates

Summary: Based on a first-principles-derived two-orbital model, this study investigates the mechanism of topological superconductivity in substrate-supported bilayer nickelate thin films (La₃Ni₂O₇). Under the assumption of dominant interlayer pairing, the substrate-induced layer-asymmetric potential and layer-staggered Rashba spin-orbit coupling drive the system into a time-reversal-invariant topological superconducting phase of class DIII, which is protected by diagonal mirror symmetry. This nontrivial topology originates from the reversal of the pairing sign on the spin-split bonding Fermi surface, manifesting as a nonzero diagonal mirror winding number and Majorana Kramers pairs at the [11] edge. Furthermore, orbital hybridization gives rise to bulk Dirac nodes and zero-energy flat bands that deviate from the diagonal direction. The research establishes the potential of bilayer nickelates as a platform for topological superconductivity, where tunable topological transitions and boundary modes provide a new avenue for probing unconventional pairing.