Hierarchical structure of primary and hybridization-induced superconducting correlations in bilayer nickelates
Abstract
The discovery of high-pressure superconductivity in the bilayer nickelate La ₃ Ni ₂ O ₇ , with a transition temperature approaching 80 K, has stimulated intense debate regarding its microscopic origin. Although an s ± gap symmetry has been widely proposed, the electronic degrees of freedom responsible for pairing remain unsettled. Here we investigate a bilayer two-orbital Hubbard model using the variational Monte Carlo method and reveal a hierarchical pairing structure in bilayer nickelates. The primary pairing tendency originates from the bonding–antibonding splitting of the Ni 3dz2 3 d z 2 orbitals, while orbital hybridization redistributes superconducting correlations to the dx2−y2 d x 2 − y 2 channel despite its weak intrinsic pairing tendency. This distinction between the origin of pairing and the resulting superconducting correlations explains why the two orbital channels exhibit comparable long-range correlations. The resulting s ± state is robust against changes in Fermi-surface topology. These results reconcile apparently competing theoretical scenarios and provide a comprehensive understanding, highlighting the distinctive role of orbital hybridization in multilayer correlated superconductors.
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BibTeX
@article{watanabe2026hierarchical,
title = {{Hierarchical structure of primary and hybridization-induced superconducting correlations in bilayer nickelates}},
author = {Hiroshi Watanabe and Hirofumi Sakakibara and Kazuhiko Kuroki},
journal = {Communications Physics},
year = {2026},
month = oct,
doi = {10.1038/s42005-026-02928-6},
url = {https://www.nature.com/articles/s42005-026-02928-6},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Hierarchical structure of primary and hybridization-induced superconducting correlations in bilayer nickelates
AU - Hiroshi Watanabe
AU - Hirofumi Sakakibara
AU - Kazuhiko Kuroki
PY - 2026
DA - 2026/10/28
JO - Communications Physics
DO - 10.1038/s42005-026-02928-6
UR - https://www.nature.com/articles/s42005-026-02928-6
AB - The discovery of high-pressure superconductivity in the bilayer nickelate La ₃ Ni ₂ O ₇ , with a transition temperature approaching 80 K, has stimulated intense debate regarding its microscopic origin. Although an s ± gap symmetry has been widely proposed, the electronic degrees of freedom responsible for pairing remain unsettled. Here we investigate a bilayer two-orbital Hubbard model using the variational Monte Carlo method and reveal a hierarchical pairing structure in bilayer nickelates. The primary pairing tendency originates from the bonding–antibonding splitting of the Ni 3d_z^2 3 d z 2 orbitals, while orbital hybridization redistributes superconducting correlations to the d_x^2−y^2 d x 2 − y 2 channel despite its weak intrinsic pairing tendency. This distinction between the origin of pairing and the resulting superconducting correlations explains why the two orbital channels exhibit comparable long-range correlations. The resulting s ± state is robust against changes in Fermi-surface topology. These results reconcile apparently competing theoretical scenarios and provide a comprehensive understanding, highlighting the distinctive role of orbital hybridization in multilayer correlated superconductors.
SN - 2399-3650
ER -