Interlayer pairing mechanism for bilayer nickelate superconductors
Abstract
The discovery of superconductivity in Ruddlesden-Popper bilayer nickelates under both high pressure and ambient conditions has opened a new paradigm for exploring unconventional superconductivity. This review provides a brief survey of theoretical progress on bilayer nickelate superconductors. Drawing from the key experimental observations, we summarize essential physical ingredients including the hybridized Ni-3dx2−y2 and 3dz2 electronic structure, orbital-dependent electronic correlation, Hund's coupling, and strong interlayer magnetic coupling. The fundamental theoretical models including the bilayer two-orbital Hubbard model and its minimal t-J variants are introduced. Starting from the atomic-limit interlayer valence bond picture of the half-filled dz2 orbital, we elaborate on strong correlation interlayer pairing mechanisms based on different limiting considerations. Specific emphasis is placed on the hybridization mechanism, where the dz2 local singlet pairs provide the pairing energy and their hybridization with itinerant dx2−y2 promotes superconducting phase coherence. We further analyze the pairing symmetry, the dependence of Tc on various internal and external parameters, the nontrivial normal state properties including the Fermi liquid, non-Fermi liquid, weakly insulating and pseudogap behaviors. Effects of pressure tuning, oxygen content, and Kondo scattering induced by oxygen vacancies are also discussed. Finally, weak correlation theories based on spin fluctuations associated with Fermi surface nesting are briefly covered.
Related
- Selective suppression of electronic orders via interlayer coupling in superconducting bilayer nickelate thin films
- Orbital-Selective Coexistence of Interlayer Spin-Singlet Formation and SDW Order with Anomalous Spin Reconfiguration in Bilayer Nickelate La3Ni2O7 Revealed by 17O-NMR
- Spectroscopic evidence of competing diagonal spin interactions and spin disproportionation in the bilayer nickelate La 3 Ni 2 O 7
- Observation of superconductivity-induced leading-edge gap in a bilayer nickelate
- Direct imaging of the Ni eg hole orbitals in the bilayer nickelate La2SmNi2O7
BibTeX
@misc{wang2026interlayer,
title = {{Interlayer pairing mechanism for bilayer nickelate superconductors}},
author = {Jiangfan Wang and Yi-feng Yang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2606.15298},
eprint = {2606.15298},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.15298},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Interlayer pairing mechanism for bilayer nickelate superconductors
AU - Jiangfan Wang
AU - Yi-feng Yang
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2606.15298
UR - https://arxiv.org/abs/2606.15298
AB - The discovery of superconductivity in Ruddlesden-Popper bilayer nickelates under both high pressure and ambient conditions has opened a new paradigm for exploring unconventional superconductivity. This review provides a brief survey of theoretical progress on bilayer nickelate superconductors. Drawing from the key experimental observations, we summarize essential physical ingredients including the hybridized Ni-3d_x^2−y^2 and 3d_z^2 electronic structure, orbital-dependent electronic correlation, Hund's coupling, and strong interlayer magnetic coupling. The fundamental theoretical models including the bilayer two-orbital Hubbard model and its minimal t-J variants are introduced. Starting from the atomic-limit interlayer valence bond picture of the half-filled d_z^2 orbital, we elaborate on strong correlation interlayer pairing mechanisms based on different limiting considerations. Specific emphasis is placed on the hybridization mechanism, where the d_z^2 local singlet pairs provide the pairing energy and their hybridization with itinerant d_x^2−y^2 promotes superconducting phase coherence. We further analyze the pairing symmetry, the dependence of T_c on various internal and external parameters, the nontrivial normal state properties including the Fermi liquid, non-Fermi liquid, weakly insulating and pseudogap behaviors. Effects of pressure tuning, oxygen content, and Kondo scattering induced by oxygen vacancies are also discussed. Finally, weak correlation theories based on spin fluctuations associated with Fermi surface nesting are briefly covered.
ER -