pith. machine review for the scientific record. sign in

arxiv: 2604.18385 · v2 · submitted 2026-04-20 · ❄️ cond-mat.supr-con · cond-mat.str-el

Recognition: unknown

Superconductivity in Ruddlesden-Popper nickelates: a review of recent progress, focusing on thin films

Authors on Pith no claims yet

Pith reviewed 2026-05-10 03:14 UTC · model grok-4.3

classification ❄️ cond-mat.supr-con cond-mat.str-el
keywords superconductivitynickelatesRuddlesden-Popper phasesthin filmsambient pressureLa3Ni2O7strain engineeringhigh-Tc superconductivity
0
0 comments X

The pith

Compressive strain in ultra-thin films enables ambient-pressure superconductivity in La3Ni2O7 nickelates.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper reviews recent experimental and theoretical advances on superconductivity in Ruddlesden-Popper nickelates, beginning with the high-pressure discovery of Tc around 80 K in bulk La3Ni2O7 and extending to trilayer La4Ni3O10. It emphasizes the new observation that ultra-thin La3Ni2O7 films superconduct at ambient pressure when deposited on substrates that impose compressive strain. This development removes the high-pressure constraint that previously limited experimental access, allowing a wider set of measurement techniques to probe the materials. Comparing the strained films with the pressurized bulk samples is presented as a route to clarify the pairing mechanism in these correlated systems.

Core claim

Ambient-pressure superconductivity emerges in La3Ni2O7 when grown as ultra-thin films under compressive strain from suitable substrates, paralleling the high-pressure superconductivity seen in bulk Ruddlesden-Popper nickelates.

What carries the argument

Compressive strain imposed by the substrate on the nickelate film, which modifies the lattice and electronic structure to stabilize superconductivity without external pressure.

If this is right

  • Experimental studies of nickelate superconductivity can now employ surface-sensitive probes and device fabrication methods that are incompatible with high-pressure cells.
  • Direct comparison of pressure-tuned bulk samples and strain-tuned films can isolate the role of specific lattice distortions in the superconducting mechanism.
  • The similarity between high-pressure and strain-induced superconductivity suggests that structural tuning, rather than pressure per se, is the essential control parameter.
  • Trilayer and higher-order Ruddlesden-Popper phases may also become accessible at ambient pressure through analogous thin-film strain engineering.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If strain and pressure produce equivalent electronic states, heterostructures that combine nickelate films with other functional layers could be used to test proximity effects or gate-tuned superconductivity.
  • Thickness-dependent studies of the films could reveal whether the superconductivity is truly two-dimensional or retains three-dimensional character, providing a testable distinction from the bulk pressurized case.
  • The approach may generalize to other layered correlated materials where high pressure has been required to reach a superconducting dome.

Load-bearing premise

The superconductivity measured in the films is produced by the nickelate layer itself and is not an artifact of the substrate interface or sample inhomogeneity.

What would settle it

A control experiment in which the same nickelate composition is grown without compressive strain or on a lattice-matched substrate and shows no superconductivity while all other growth and measurement conditions remain identical.

Figures

Figures reproduced from arXiv: 2604.18385 by Elbio Dagotto, Ling-Fang Lin, Thomas A. Maier, Yang Zhang.

Figure 1
Figure 1. Figure 1: FIG. 1. (a) Sketch of the oxygen reduction process used to convert NdNiO [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. (a) Temperature–pressure phase diagram of [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Resistance vs. temperature for a sample of La [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. (a) Tight-binding band structure and (b) Fermi surface of bilayer La [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. (a) Magnetic susceptibility for the two-orbital Hubbard-Hund model, using the RPA technique. Reprinted from [ [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. (a) Illustration of the [PITH_FULL_IMAGE:figures/full_fig_p009_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. Schematic crystal structures and electronic densities of 3 [PITH_FULL_IMAGE:figures/full_fig_p010_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8. Phase diagram of a small 2 [PITH_FULL_IMAGE:figures/full_fig_p010_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: FIG. 9. (a) Resistivity [PITH_FULL_IMAGE:figures/full_fig_p012_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: FIG. 10. (a) Superconductor-insulator transition in the La [PITH_FULL_IMAGE:figures/full_fig_p013_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: FIG. 11. Trend of [PITH_FULL_IMAGE:figures/full_fig_p015_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: FIG. 12. Critical temperature [PITH_FULL_IMAGE:figures/full_fig_p015_12.png] view at source ↗
Figure 13
Figure 13. Figure 13: FIG. 13. Sketch of (a) 1 unit-cell film of (La,Pr) [PITH_FULL_IMAGE:figures/full_fig_p016_13.png] view at source ↗
Figure 14
Figure 14. Figure 14: FIG. 14. ARPES results for (La,Pr,Sm) [PITH_FULL_IMAGE:figures/full_fig_p017_14.png] view at source ↗
Figure 16
Figure 16. Figure 16: FIG. 16. Superconducting pairing symmetry according to [PITH_FULL_IMAGE:figures/full_fig_p018_16.png] view at source ↗
Figure 17
Figure 17. Figure 17: FIG. 17. (a) Changes in the angle of the Ni-O-Ni bond varying the in-plane lattice constants, while relaxing the out-of-plane [PITH_FULL_IMAGE:figures/full_fig_p019_17.png] view at source ↗
Figure 18
Figure 18. Figure 18: FIG. 18. (a-d) Sketch explaining the difference between [PITH_FULL_IMAGE:figures/full_fig_p020_18.png] view at source ↗
Figure 20
Figure 20. Figure 20: FIG. 20. Phase diagram of the single-bilayer film on LSAO, [PITH_FULL_IMAGE:figures/full_fig_p022_20.png] view at source ↗
Figure 19
Figure 19. Figure 19: FIG. 19. (a) The calculated transition temperature of the [PITH_FULL_IMAGE:figures/full_fig_p022_19.png] view at source ↗
Figure 21
Figure 21. Figure 21: FIG. 21. (a) Pressure-dependent phase diagram showing the crystal structures transitions, the density-wave (denoted DW) [PITH_FULL_IMAGE:figures/full_fig_p023_21.png] view at source ↗
Figure 22
Figure 22. Figure 22: FIG. 22. Structural schematic of the (a) 1212 and (b) 1313 hybrid films on the LSAO substrate. ML and BL represent [PITH_FULL_IMAGE:figures/full_fig_p023_22.png] view at source ↗
read the original abstract

The discovery of superconductivity with Tc ~ 80 K in the nickelate Ruddlesden-Popper bilayer La3Ni2O7 at high pressure has opened a new platform for unconventional superconductivity, followed by the subsequent observation of superconductivity in trilayer La4Ni3O10, also at high pressure. Remarkably, ambient-pressure superconductivity was also observed recently in La3Ni2O7 ultra-thin films when grown on substrates that provide compressive strain. This discovery significantly extends the type of experimental techniques that can be used in nickelates, previously limited due to the high-pressure constraint. Discussing the similarities and differences among these nickel oxides will provide new insights into understanding the mechanism of high-Tc superconductivity in correlated electron systems. In this paper, we review the experimental and theoretical progress on RuddlesdenPopper nickelates, with emphasis on thin films, and discuss future perspectives and research directions.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 0 minor

Summary. The manuscript is a review of superconductivity in Ruddlesden-Popper nickelates, with emphasis on thin films. It outlines the discovery of high-pressure superconductivity (Tc ~80 K) in bilayer La3Ni2O7, subsequent observations in trilayer La4Ni3O10, and the recent report of ambient-pressure superconductivity in compressively strained ultra-thin La3Ni2O7 films. The review covers experimental and theoretical progress, similarities and differences among these systems, and future research directions to elucidate the high-Tc mechanism.

Significance. If the ambient-pressure thin-film superconductivity is intrinsic to the strained nickelate, the review is significant for highlighting how strain engineering in thin films can remove the high-pressure barrier, enabling wider use of experimental techniques and facilitating comparisons that may clarify the pairing mechanism in these correlated systems.

major comments (1)
  1. [Abstract] Abstract: The statement that ambient-pressure superconductivity was observed in La3Ni2O7 ultra-thin films grown on compressive-strain substrates is presented as a key advance extending the nickelate platform. However, the review does not address potential substrate-induced artifacts, interface reconstruction, oxygen non-stoichiometry, or strain relaxation, which are common in ultra-thin oxide films and directly bear on whether the superconductivity is intrinsic rather than artifactual.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of our review and for the constructive comment on the abstract and thin-film discussion. We address the point below and describe the revisions we will implement.

read point-by-point responses
  1. Referee: [Abstract] Abstract: The statement that ambient-pressure superconductivity was observed in La3Ni2O7 ultra-thin films grown on compressive-strain substrates is presented as a key advance extending the nickelate platform. However, the review does not address potential substrate-induced artifacts, interface reconstruction, oxygen non-stoichiometry, or strain relaxation, which are common in ultra-thin oxide films and directly bear on whether the superconductivity is intrinsic rather than artifactual.

    Authors: We agree that potential artifacts must be explicitly considered when evaluating claims of intrinsic superconductivity in ultra-thin oxide films. The abstract is intentionally concise and focuses on the reported advance, while the body of the review summarizes the experimental claims from the primary literature, including the use of compressive-strain substrates and basic structural characterization. However, we acknowledge that a more direct discussion of substrate-induced effects, interface reconstruction, oxygen non-stoichiometry, and strain relaxation is warranted to give readers a balanced perspective. In the revised manuscript we will add a dedicated paragraph within the thin-film section that reviews these common issues in oxide epitaxy, references the characterization data presented in the original reports, and notes the current experimental limitations in fully excluding artifacts. This addition will be placed immediately after the description of the ambient-pressure results and will include citations to relevant studies on strain relaxation and interface chemistry in related nickelate and cuprate systems. revision: yes

Circularity Check

0 steps flagged

No circularity: review paper reports external observations without internal derivations or self-referential predictions

full rationale

This is a review article summarizing experimental and theoretical progress on Ruddlesden-Popper nickelates from the literature, with emphasis on thin-film results. No original derivations, equations, fitted parameters, or predictions are presented in the provided text. The central claim about ambient-pressure superconductivity in compressively strained La3Ni2O7 ultra-thin films is attributed to recent external observations rather than derived within the paper. All content relies on cited external literature without self-citation chains that bear load on any claimed result, and no steps reduce by construction to the paper's own inputs. The derivation chain is absent, rendering the paper self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

As a review paper, it introduces no free parameters, axioms, or invented entities; all content summarizes previously published work.

pith-pipeline@v0.9.0 · 5468 in / 1013 out tokens · 38555 ms · 2026-05-10T03:14:38.820851+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Forward citations

Cited by 3 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Shear-stress-constrained superconductivity in Ruddlesden-Popper nickelates

    cond-mat.supr-con 2026-05 unverdicted novelty 5.0

    Superconductivity in Ruddlesden-Popper nickelates requires the Ni-O framework to deform within a bounded shear-strain window.

  2. Superconductivity in bilayer La$_3$Ni$_2$O$_7$: A review focusing on the strong-coupling Hund's rule assisted pairing mechanism

    cond-mat.supr-con 2026-04 unverdicted novelty 3.0

    Superconductivity in La3Ni2O7 arises from interlayer Cooper pairs of 3d_x2-y2 electrons driven by effective J_perp from Hund-assisted AFM exchange transfer, while localized 3d_z2 electrons form rung singlets that prod...

  3. Experimental Progress in Ambient-Pressure Superconducting Bilayer Nickelate Films

    cond-mat.supr-con 2026-05 unverdicted novelty 2.0

    Epitaxial strain enables ambient-pressure superconductivity in bilayer nickelate films, facilitating detailed studies of their properties and phase diagrams.

Reference graph

Works this paper leans on

200 extracted references · 28 canonical work pages · cited by 3 Pith papers · 6 internal anchors

  1. [1]

    Bednorz J G and M¨ uller K A 1986 Possible high-T c superconductivity in the Ba-La-Cu-O system Z. Phys. B: Condens. Matter64, 189

  2. [2]

    Dagotto E 1994 Correlated electrons in high-temperature superconductors Rev. Mod. Phys. 66, 763

  3. [3]

    Rep.250, 329

    Scalapino D J 1995 The case ford x2−y2 pairing in the cuprate superconductors Phys. Rep.250, 329

  4. [4]

    Kamihara Y, Watanabe T, Hirano M and Hosono H, 2008 Iron-Based Layered Superconductor La[O1−xFx]FeAs (x= 0.05−0.12) withT c = 26 K J. Am. Chem. Soc.130, 3296

  5. [5]

    Phys.8, 709

    Dai P, Hu J and Dagotto E 2012 Magnetism and its microscopic origin in iron-based high-temperature superconductors Nat. Phys.8, 709

  6. [6]

    Dagotto E 2013 Colloquium: The unexpected properties of alkali metal iron selenide superconductors Rev. Mod. Phys.85, 849

  7. [7]

    Dai P 2015 Antiferromagnetic order and spin dynamics in iron-based superconductors Rev. Mod. Phys.87, 855

  8. [8]

    Luo Q, Martins G, Yao D-X, Daghofer M, Yu R, Moreo A and Dagotto E 2025 Neutron and ARPES constraints on the couplings of the multiorbital Hubbard model for the iron pnictides Phys. Rev. B82, 104508

  9. [9]

    Wang M, Wen H-H, Wu T, Yao D-X and Xiang T 2025 Normal and Superconducting Properties of La 3Ni2O7 Chin. Phys. Lett.41, 077402

  10. [10]

    Today78, 28

    Goodge B H and Norman M R 2025 Nickelates provide answers about high-temperature superconductivity—and raise new questions Phys. Today78, 28

  11. [11]

    Wang Y, Jiang K, Ying J, Wu T, Cheng J, Hu J and Chen X 2025 Recent progress in nickelate superconductors Natl. Sci. Rev.12, nwaf373

  12. [12]

    Puphal P, Sch¨ afer T, Keimer B and Hepting M 2025 Superconductivity in infinite-layer and Ruddlesden–Popper nickelates Nat. Rev. Phys.8, 70

  13. [13]

    Qiu W and Yao D-X 2026 Progress of ambient-pressure superconductivity in bilayer nickelate thin films 2603.11235

  14. [14]

    Oh H, Yang H and Zhang Y-H 2026 Doping a spin-one Mott insulator: possible application to bilayer nickelate 28, 021201

  15. [15]

    Cui Y, Hikita Y and Hwang H Y 2019 26 Superconductivity in an infinite-layer nickelate Nature 572, 624

    Li D, Lee K, Wang B Y, Osada M, Crossley S, Lee H R, Y. Cui Y, Hikita Y and Hwang H Y 2019 26 Superconductivity in an infinite-layer nickelate Nature 572, 624

  16. [16]

    Kumar D, Rajeev K P, Alonso J A and Mart´ ınez-Lope M J 2013 Spin-canted magnetism and decoupling of charge and spin ordering in NdNiO 3 Phys. Rev. B88, 014410

  17. [17]

    Li D, Wang B Y, Lee K, Harvey S P, Osada M, Goodge B H, Kourkoutis L F and Hwang H Y, 2020 Superconducting Dome in Nd1−xSrxNiO2 Infinite Layer Films Phys. Rev. Lett.125, 027001

  18. [18]

    Nomura Y and Arita R 2022 Superconductivity in infinite-layer nickelates Rep. Prog. Phys.85, 052501

  19. [19]

    Zhang Y, Lin L F, Hu W, Moreo A, Dong S and Dagotto E 2020 Similarities and differences between nickelate and cuprate films grown on a SrTiO 3 substrate Phys. Rev. B102, 195117

  20. [20]

    Gu Q and Wen W H H 2022 Superconductivity in nickel-based 112 systems Innovation3, 100202

  21. [21]

    Zhang R, Wang Y, Engel M, Lane C, Miranda H, Hou L, Chowdhury S, Singh B, Barbiellini B, Zhu J-X, Markiewicz R S, Gross E K U, Kresse G, Bansil A and Sun J 2025 Magnetism-enhanced strong electron-phonon coupling in infinite-layer nickelates Phys. Rev. B112, L241115

  22. [22]

    Botana A S and Norman M R 2020 Similarities and Differences between LaNiO 2 and CaCuO 2 and Implications for Superconductivity Phys. Rev. X10, 011024

  23. [23]

    Wu X, Sante D D, Schwemmer T, Hanke W, Hwang H Y, Raghu S and Thomale R 2020 Robustd x2−y2-wave superconductivity of infinite-layer nickelates Phys. Rev. B101, 060504

  24. [24]

    Karp J, Botana A S, Norman M R, Park H, Zingl M and Millis A 2020 Many-Body Electronic Structure of NdNiO2 and CaCuO2 Phys. Rev. X10, 02106

  25. [25]

    Commun.10, 5576

    Gao Q, Fan S, Wang Q, Li J, Ren X, Bialo Z, Drewanowski A, Rothenb¨ uhler A, Choi J, Sutarto R, Wang Y, Xiang T, Hu J, Zhou K-J, Bisogni V, Comin R, Chang J, Pelliciari J, Zhou X J and Zhu Z 2024 Magnetic excitations in strained infinite-layer nickelate PrNiO2 films Nat. Commun.10, 5576

  26. [26]

    Phys.6, 341

    Ren X, Li J, Chen W-C, Gao Q, Sanchez J J, Hales J, Luo H, Rodolakis F, McChesney J L, Xiang T, Hu J, Comin R, Wang Y, Zhou X J and Zhu Z 2023 Possible strain-induced enhancement of the superconducting onset transition temperature in infinite-layer nickelates Commun. Phys.6, 341

  27. [27]

    Lett.41, 117404

    Ren X, Sutarto R, Gao Q, Wang Q, Li J, Wang Y, Xiang T, Hu J, Chang J, Comin R, Zhou X J and Zhu Z 2024 Two Distinct Charge Orders in Infinite-Layer PrNiO2+δ Revealed by Resonant X-Ray Diffraction Chinese Phys. Lett.41, 117404

  28. [28]

    Pan G A, Segedin D F, LaBollita H, Song Q, Nica E M, Goodge B H, Pierce A T, Doyle S, Novakov S, Carrizales D C, N’Diaye A T, Shafer P, Paik H, Heron J T, Mason J A, Yacoby A, Kourkoutis L F, Erten O, Brooks C M, Botana A S and Mundy J A 2022 Superconductivity in a quintuple-layer square-planar nickelate Nat. Mater. 21, 160

  29. [29]

    Pan G A, Segedin D F, TenHuisen S F R, Bhatt L, LaBollita H, Jiang A Y, Song Q, Turkiewicz A B, Baykusheva D R, Nag A, Agrestini S, Zhou K-J, Pelliciari J, Bisogni V, Zhou H, Dean M P M, Paik H, Muller D A, Kourkoutis L F, Brooks C M, Mitrano M, Botana A S, Goodge B H and Mundy J A 2026 Superconducting phase diagram of multi-layer square-planar nickelates...

  30. [30]

    Chow S L E, Luo Z and Ariando A 2025 Bulk superconductivity near 40 K in hole-doped SmNiO 2 at ambient pressure Nature642, 58

  31. [31]

    Lee Y, Wang M, Wei X, Yu Y, Mao W L, Lin Y and Hwang H Y 2026 High-temperature superconductivity in Nd 0.85Sr0.15NiO2 membranes under pressure arXiv 2604.09525

  32. [32]

    Sun H, Huo M, Hu X, Li J, Han Y, Tang L, Mao Z, Yang P, Wang B, Cheng J, Yao D X, Zhang G M and Wang M 2023 Signatures of superconductivity near 80 K in a nickelate under high pressure Nature621493

  33. [33]

    Hou J, Yang P T, Liu Z Y, Li J Y, Shan P F, Ma L, Wang G, Wang N N, Guo H Z, Sun J P, Uwatoko Y, Wang M, Zhang G-M, Wang B S and Cheng J G 2023 Emergence of High-Temperature Superconducting Phase in Pressurized La 3Ni2O7 Crystals Chin. Phys. Lett.40117302

  34. [34]

    Wang G, Wang NN, Shen X L, Hou J, Ma L, Shi L F, Ren Z A, Gu Y D, Ma H M, Yang P T, Liu Z Y, Guo H Z, Sun J P, Zhang G M, Calder S, Yan J-Q, Wang B S, Uwatoko Y and Cheng J G 2024 Pressure-Induced Superconductivity In Polycrystalline La3Ni2O7−δ Phys. Rev. X14011040

  35. [35]

    Wang N, Wang G, Shen X, Hou J, Luo J, Ma X, Yang H, Shi L, Dou J, Feng J, Yang J, Shi Y, Ren Z, Ma H, Yang P, Liu Z, Liu Y, Zhang H, Dong X, Wang Y, Jiang K, Hu J, Nagasaki S, Kitagawa K, Calder S, Yan J, Sun J, Wang B, Zhou R, Uwatoko Y, and Cheng J 2024 Bulk high-temperature superconductivity in pressurized tetragonal La2PrNi2O7 Nature634

  36. [36]

    Lu, Wang M, Wang Y and Chen Z 2024 Visualization of oxygen vacancies and self-doped ligand holes in La 3Ni2O7−δ Nature630847

    Dong Z, Huo M, Li J, Li J, Li P, Sun H, Y. Lu, Wang M, Wang Y and Chen Z 2024 Visualization of oxygen vacancies and self-doped ligand holes in La 3Ni2O7−δ Nature630847

  37. [37]

    Li J, Peng D, Ma P, Zhang H, Xing Z, Huang X, Huang C, Huo M, Hu D, Dong Z, Chen X, Xie T, Dong H, Sun H, Zeng Q, Mao H-k and Wang M 2025 Identification of superconductivity in bilayer nickelate La 3Ni2O7 under high pressure up to 100 GPa Natl. Sci. Rev.12nwaf220

  38. [38]

    Li F, Peng D, Dou J, Guo N, Ma L, Liu C, Wang L, Zhang Y, Luo J, Yang J, Zhang J, Cai W, Cheng J, Zheng Q, Zhou R, Zeng Q, Tao X and Zhang J 2026 Ambient pressure growth of bilayer nickelate single crystals with superconductivity over 90 K under high pressure Nature649, 871

  39. [39]

    Qiu Z, Chen J, Semenok D V, Zhong Q, Zhou D, Li J, Ma P, Huang X, Huo M, Xie T, Chen X, Mao H-k, Struzhkin V, Sun H and Wang M 2025 Interlayer coupling enhanced superconductivity near 100 K in La3−xNdxNi2O7 arXiv arXiv:2510.12359

  40. [40]

    China Phys

    Liu Z, Sun H, Huo M, Ma X, Ji Y, Yi E, Li L, Liu H, Yu J, Zhang Z, Chen Z, Liang F, Dong H, Guo H, Zhong D, Shen B, Li S and Wang M 2023 Evidence for charge and spin density waves in single crystals of La 3Ni2O7 and La3Ni2O6 Sci. China Phys. Mech. Astron.66, 217411 (2023)

  41. [41]

    Chen X, Choi J, Jiang Z, Mei J, Jiang K, Li L, Agrestini S, Garcia-Fernandez M, Huang X, Sun H, Shen D, Wang M, Hu J, Lu Y, Zhou K J and Feng D 2024 Electronic and magnetic excitations in La 3Ni2O7 Nat. Commun. 15, 9597 27

  42. [42]

    Chen K, Liu X, Jiao J, Zou M, Jiang C, Li X, Luo Y, Wu Q, Zhang N, Guo Y and Shu L 2024 Evidence of Spin Density Waves in La 3Ni2O7−δ Phys. Rev. Lett. 132, 256503

  43. [43]

    Bull.70, 1239

    Dan Z, Zhou Y, Huo M, Wang Y, Nie L, Wang M, Wu T and Chen X 2025 Pressure-enhanced spin-density-wave transition in double-layer nickelate La 3Ni2O7−δ Sci. Bull.70, 1239

  44. [44]

    Phys.21, 430

    Khasanov R, Hicken T J, Gawryluk D J, Sazgari V, Plokhikh I, Sorel L P, Bartkowiak M, B¨ otzel S, Lechermann F, Eremin I M, Luetkens H and Guguchia Z 2025 Pressure-enhanced splitting of density wave transitions in La 3Ni2O7−δ Nat. Phys.21, 430

  45. [45]

    Luo Z, Hu X, Wang M, Wu W and Yao D-X 2023 Bilayer Two-Orbital Model of La 3Ni2O7 under Pressure Phys. Rev. Lett.131, 126001

  46. [46]

    Zhang Y, Lin L-F, Moreo A and Dagotto E 2023 Electronic structure, dimer physics, orbital-selective behavior, and magnetic tendencies in the bilayer nickelate superconductor La 3Ni2O7 under pressure Phys. Rev. B108, L180510

  47. [47]

    Christiansson V, Petocchi F and Werner P 2023 Correlated Electronic Structure of La 3Ni2O7 under Pressure Phys. Rev. Lett.131, 206501

  48. [48]

    Zhang Y, Lin L-F, Moreo A, Maier T A and Dagotto E 2023 Trends in electronic structures ands ±-wave pairing for the rare-earth series in bilayer nickelate superconductorR 3Ni2O7 Phys. Rev. B108, 165141

  49. [49]

    Geisler B, Fanfarillo L, Hamlin J J, Stewart G R, Hennig R G and Hirschfeld P J 2024 Optical properties and electronic correlations in La 3Ni2O7 bilayer nickelates under high pressure npj Quantum Mater.9, 89

  50. [50]

    Commun.15, 2470

    Zhang Y, Lin L-F, Moreo A, Maier T A and Dagotto E Structural phase transition,s ±-wave pairing, and magnetic stripe order in bilayered superconductor La3Ni2O7 under pressure Nat. Commun.15, 2470

  51. [51]

    Liao Z, Chen L, Duan G, Wang Y, Liu C, Yu R and Si Q 2023 Electron correlations and superconductivity in La 3Ni2O7 under pressure tuning Phys. Rev. B108, 214522

  52. [52]

    Cao Y and Yang Y-F 2024 Flat bands promoted by Hund’s rule coupling in the candidate double-layer high-temperature superconductor La 3Ni2O7 Phys. Rev. B109, L081105

  53. [53]

    Lechermann F, Gondolf J, B¨ otzel S and Eremin I M 2023 Electronic correlations and superconducting instability in La3Ni2O7 under high pressure Phys. Rev. B108, L201121

  54. [54]

    Geisler B, Hamlin J J, Stewart G R, Hennig R G and Hirschfeld P J 2024 Structural transitions, octahedral rotations, and electronic properties of A3Ni2O7 rare-earth nickelates under high pressure npj Quantum Mater.9, 38

  55. [55]

    Dagotto E, Riera J and Scalapino D 1992 Superconductivity in ladders and coupled planes Phys. Rev. B45, 5744(R)

  56. [56]

    Maier T A and Scalapino D 2011 Pair structure and the pairing interaction in a bilayer Hubbard model for unconventional superconductivity Phys. Rev. B84, 180513

  57. [57]

    Nakata M, Ogura D, Usui H and Kuroki K 2017 Finite-energy spin fluctuations as a pairing glue in systems with coexisting electron and hole bands Phys. Rev. B95, 214509

  58. [58]

    Liu Z, Li J, Huo M, Ji B, Hao J, Dai Y, Ou M, Li Q, Sun H, Xu B, Lu Y, Wang M and Wen H-H, 2025 Evolution of electronic correlations in the Ruddlesden-Popper nickelates Phys. Rev. B111, L220505

  59. [59]

    Commun.15, 7570

    Liu Z, Huo M, Li J, Ji Q, Liu Y, Dai Y, Zhou X, Hao J, Lu Y, Wang M and Wen H-H, 2025 Electronic correlations and partial gap in the bilayer nickelate La3Ni2O7 Nat. Commun.15, 7570

  60. [60]

    Xu S, Chen C-Q, Huo M, Hu D, Wang H, Wu Q, Li R, Wu D, Wang M, Yao D-X, Dong T, and Wang N, 2025 Origin of the density wave instability in trilayer nickelate La 4Ni3O10 revealed by optical and ultrafast spectroscopy Phys. Rev. B111, 075140

  61. [61]

    Phys.201269

    Zhang Y, Su D, Huang Y, Sun H, Huo M, Shan Z, Ye K, Yang Z, Li R, Smidman M, Wang M, Jiao L and Yuan H 2024 High-temperature superconductivity with zero resistance and strange-metal behaviour in La 3Ni2O7−δ Nat. Phys.201269

  62. [62]

    Zhang Y, Lin L-F, Moreo A, Maier T A and Dagotto E 2024 Prediction ofs ±-wave superconductivity enhanced by electronic doping in trilayer nickelates La 4Ni3O10 under pressure Phys. Rev. Lett.133, 136001

  63. [63]

    Jiang P, Li J, Cao Y-H, Cao X, Zhong Z, Lu Y, Wang Q-H 2025 Dual instability of superconductivity from oxygen defects in La 3Ni2O7+δ arXiv 2512.00301

  64. [64]

    Zhang Y, Lin L-F, Moreo A, Maier T A and Dagotto E 2024 Electronic structure, magnetic correlations, and superconducting pairing in the reduced Ruddlesden-Popper bilayer La 3Ni2O6 under pressure: Different role ofd 3z2−r2 orbital compared with La3Ni2O7 Phys. Rev. B109, 045151

  65. [65]

    Commun.15 4373

    Yang J, Sun H, Hu X, Xie Y, Miao T, Luo H, Chen H, Liang B, Zhu W, Qu G, Chen C-Q, Huo M, Huang Y, Zhang S, Zhang F, Yang F, Wang Z, Peng Q, Mao H, Liu G, Xu X, Qian T, Yao D-X, Wang M, Zhao L and Zhou X J 2024 Orbital-dependent electron correlation in double-layer nickelate La 3Ni2O7 Nat. Commun.15 4373

  66. [66]

    Liu Y-B, Sun H, Zhang M, Liu Q, Chen W-Q and Yang F 2025 Origin of the diagonal double-stripe spin density wave and potential superconductivity in bulk La3Ni2O7 at ambient pressure Phys. Rev. B112, 014510

  67. [67]

    Fernandes R M, Pratt D K, Tian W, Zarestky J, Kreyssig A, Nandi S, Kim M G, Thaler A, Ni N, Canfield P C, McQueeney R J, Schmalian J and Goldman A I 2010 Unconventional pairing in the iron arsenide superconductors Phys. Rev. B81, 140501(R)

  68. [68]

    Liang S, Moreo A and Dagotto E 2013 Nematic State of Pnictides Stabilized by Interplay between Spin, Orbital, and Lattice Degrees of Freedom Phys. Rev. Lett.111, 047004

  69. [69]

    Lin L-F, Zhang Y, Alvarez G, Moreo A and Dagotto E 2021 Origin of Insulating Ferromagnetism in Iron Oxychalcogenide Ce 2O2FeSe2 Phys. Rev. Lett.127, 077204

  70. [70]

    Lin L-F, Zhang Y, Alvarez G, Moreo A, Herbrych J and Dagotto E 2022 Prediction of orbital-selective Mott phases and block magnetic states in the quasi-one-dimensional iron chain Ce 2O2FeSe2 under hole and electron doping Phys. Rev. B105, 075119

  71. [71]

    Phys.6, 199 28

    Lin L-F, Zhang Y, Alvarez G, McGuire M A, May A F, Moreo A and Dagotto E 2023 Stability of the interorbital-hopping mechanism for ferromagnetism in multi-orbital Hubbard models Commun. Phys.6, 199 28

  72. [72]

    Bull.693221

    Xie T, Huo M, Ni X, Shen F, Huang X, Sun H, Walker H C, Adroja D, Yu D, Shen B, He L, Cao K and Wang W 2024 Strong interlayer magnetic exchange coupling in La 3Ni2O7−δ revealed by inelastic neutron scattering Sci. Bull.693221

  73. [73]

    Commun.159597

    Chen X, Choi J, Jiang Z, Mei J, Jiang K, Li J, Agrestini S, Garcia-Fernandez M, Sun H, Huang X, Shen D, Wang M, Jiangping Hu, Lu Y, Zhou K-J and Feng D 2024 Electronic and magnetic excitations in La 3Ni2O7 Nat. Commun.159597

  74. [74]

    Phys.852

    Ren X, Sutarto R, Wu X, Zhang J, Huang H, Xiang T, Hu J, Comin R, Zhou X J and Zhu Z 2025 Resolving the electronic ground state of La 3Ni2O7−δ films Commun. Phys.852

  75. [75]

    Zhong H, Hao B, Chen A, Huang X, Li C, Zhang W, Liu C, Kummer K, Brookes N, Nie Y, Schmitt T and Lu X 2026 Doping evolution of spin excitations in La3−xSrxNi2O7/SrLaAlO4 superconducting thin films arXiv 2603.01120

  76. [76]

    Rep.3441

    Dagotto E, Hotta T and Moreo A 2001 Colossal magnetoresistant materials: the key role of phase separation Phys. Rep.3441

  77. [77]

    Wang W-X, Oh H, Helbig T, Wang B Y, Li J, Yu Y, Hwang H Y, Jiang H-C, Wu Y M and Raghu S 2025 Electronic and magnetic excitations in La 3Ni2O7 arXiv 2509.25344

  78. [78]

    Zhang B, Xu C and Xiang H 2025 Spin-charge-orbital order in nickelate superconductors Phys. Rev. B111, 184401

  79. [79]

    LaBollita H, Pardo V, Norman M R and Botana A S 2025 Assessing spin-density wave formation in La3Ni2O7 from electronic structure calculations Phys. Rev. Mater.8, L111801

  80. [80]

    Ni X-S, Ji Y, He L, Xie T, Yao D-X, Wang M and Cao K 2025 Spin density wave in the bilayered nickelate La3Ni2O7−δ at ambient pressure npj Quantum Mater. 10, 17

Showing first 80 references.