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Topotactic oxidation of Ruddlesden-Popper nickelates reveals new structural family: oxygen-intercalated layered perovskites

T0 review · 3 major / 5 minor · reviewed 2026-08-07 · deepseek-v4-flash

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Pith's one-line read Ozone annealing intercalates about 0.7 oxygen atoms per formula unit into Ruddlesden–Popper nickelate films, creating a new layered perovskite family.

desk verdict Genuinely new structural family claim, but the load-bearing oxygen count rests on a single COBRA integration and an unreported SIMS measurement; deserve peer review with that gap addressed. read the letter →

arxiv 2506.10262 v1 pith:BSVFNF4F submitted 2025-06-12 cond-mat.mtrl-sci cond-mat.str-elcond-mat.supr-con

Dan Ferenc Segedin , Jinkwon Kim , Harrison LaBollita , Nicole K. Taylor , Kyeong-Yoon Baek , Suk Hyun Sung , Ari B. Turkiewicz , Grace A. Pan
show 15 more authors
Abigail Y. Jiang Maria Bambrick-Santoyo Tobias Schwaigert Casey K. Kim Anirudh Tenneti Alexander J. Grutter Shin Muramoto Alpha T. N'Diaye Ismail El Baggari Donald A. Walko Hua Zhou Charles M. Brooks Antia S. Botana Darrell G. Schlom Julia A. Mundy
This is my paper
classification cond-mat.mtrl-scicond-mat.str-elcond-mat.supr-con
keywords topotacticoxidationRuddlesden-PoppernickelatesoxygenintercalationlayeredperovskitesozoneannealingcoherentBraggrodanalysisnickelatethinfilmsnickel-oxygenhybridization
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

This paper reports that ozone annealing of Ruddlesden–Popper nickelate thin films, La_{n+1}Ni_nO_{3n+1} with n=1–4, inserts approximately 0.7 oxygen atoms per formula unit into interstitial sites in the rock-salt spacer layers. The authors argue this topotactic oxidation produces a distinct family of layered perovskites whose spacer composition, A2O0.7 with about 35% of interstitial sites occupied, sits structurally between Ruddlesden–Popper and Aurivillius phases. The intercalation expands the c-axis by up to 17.8%, suppresses oxygen octahedral rotations, makes the films metallic, and strongly enhances nickel–oxygen hybridization, a feature associated with high-temperature superconductivity. This matters because it offers a new synthetic route—spacer-layer chemistry via oxygen intercalation—to highly oxidized, metastable layered oxides without cation substitution.

What carries the argument

The central object is the interstitial site in the rock-salt spacer layer: in the parent Ruddlesden–Popper structure these sites are empty, in Aurivillius compounds they are fully occupied, and here they are filled to about 35%. The method that carries the argument is coherent Bragg rod analysis (COBRA) of synchrotron surface X-ray diffraction data, which reconstructs the three-dimensional electron density of the film; integrating the density at the interstitial sites yields the intercalation level δ≈0.7±0.1 and directly visualizes the spacer expansion. Density functional theory calculations with δ=1 reproduce the qualitative c-axis expansion and the reduction in charge-transfer energy, connecting the structural intercalation to the observed metallicity and enhanced hybridization.

What would settle it

Measure the oxygen content of the ozone-annealed films by an independent method such as neutron diffraction, Rutherford backscattering spectrometry, or calibrated SIMS and compare it with δ≈0.7; if the measured uptake is significantly lower, or if aberration-corrected STEM shows that the interstitial columns are not oxygen, the central claim collapses.

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Extended reading notes

Core claim

On its own terms, the paper's central claim is that post-growth ozone annealing of Ruddlesden–Popper nickelates creates a new structural family—oxygen-intercalated layered perovskites—by placing about δ≈0.7±0.1 oxygen atoms per formula unit into the interstitial sites of the A2 rock-salt spacer layers. Surface X-ray diffraction with coherent Bragg rod analysis shows the spacer layer in La2NiO4 expands from 2.77 Å to 3.41 Å, the measured c-axis grows by 17.8%, and the absolute c-axis expansion stays near 2.1 Å across n=1 to 4. The same analysis localizes intercalants at (a,b)=(0.5,0) and (0,0.5) interstitial sites, giving a nominal spacer composition A2O0.7 and a structure intermediate between Ruddlesden–Popper and Aurivillius phases. The oxidized films are metallic, display increased nickel–oxygen hybridization with charge-transfer energy reduced from roughly 3.0–3.5 eV to 1.7–2.0 eV, and show suppressed octahedral rotations and suppressed density-wave order; the transformation is reversible by air annealing.

Load-bearing premise

The argument rests on the assumption that the electron density integrated at the interstitial sites in the COBRA reconstruction is really about 0.7 oxygen atoms per formula unit; the paper reports no independent chemical measurement (no SIMS, neutron, or RBS data are shown) and itself notes an unexpected electron-density feature at (a,b)=(0,0), so if part of that density arises from structural disorder, cation movement, or reconstruction artifacts, the oxygen stoichiometry and the new-family framing weaken.

Editorial extensions

If this is right

  • Oxygen-intercalated nickelates with spacer composition A2O0.7 form a new layered-perovskite family, filling the composition gap between Ruddlesden–Popper (A2) and Aurivillius (A2O2) phases.
  • Single-layer La2NiO4+δ becomes metallic without any A-site cation substitution, the first such observation in a single-layer nickelate.
  • Oxygen intercalation suppresses octahedral rotations and density-wave order in n=2 and n=3 films, mirroring the structural effects linked to pressure-induced superconductivity in Ruddlesden–Popper nickelates.
  • The oxidation is reversible and can be partially staged (every second spacer layer intercalated), so oxygen content δ acts as a tunable doping knob.
  • The same ozone-annealing route is proposed as a general soft-chemical path to highly oxidized metastable phases in layered oxides, and could enable exfoliation of two-dimensional nickelate flakes.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Inference: if the COBRA-derived δ is confirmed, the paper's threshold picture (expansion appears between δ~0.3 and 0.7) implies that partial oxidation could tune the spacer expansion and electronic properties continuously, effectively controlling hole doping like the charge-reservoir layer in cuprates.
  • Inference: the unexpected electron-density feature at (a,b)=(0,0) may indicate oxygen at a nonstandard site or a contribution from structural disorder; resolving it would determine whether the true spacer structure is more complex than a simple A2O0.7 model.
  • Inference: the same ozone-annealing approach might extend to other Ruddlesden–Popper oxides, but prior reports of lower intercalation levels (δ≤0.34) suggest that epitaxial strain and aggressive ozone conditions are likely necessary, a hypothesis the paper does not test.
  • Inference: a metallic single-layer nickelate with strong nickel–oxygen hybridization is a natural candidate for pressure or strain studies searching for superconductivity, though the paper makes no such claim.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The paper reports that post-growth ozone annealing of Ruddlesden–Popper nickelate thin films La_{n+1}Ni_nO_{3n+1} (n=1–4) intercalates approximately 0.7 oxygen atoms per formula unit into interstitial sites of the rock-salt spacer layers. The resulting structures show a large c-axis expansion (17.8% for n=1) that decreases monotonically with n, suppression of octahedral rotations, enhanced Ni–O hybridization, and metallic transport. The authors propose a new layered perovskite family with spacer composition A_2O_{0.7}, structurally intermediate between Ruddlesden–Popper and Aurivillius phases. The central structural and electronic claims are supported by surface X-ray diffraction with COBRA, XAS, transport, and DFT, but the quantitative oxygen content rests on a single electron-density integration.

Significance. If the oxygen stoichiometry holds, this is a genuinely new structural family and a potentially important synthetic route: topotactic oxidation of Ruddlesden–Popper phases could be extended to other layered oxides, and the combination of high hole doping with preserved perovskite blocks is of clear interest for nickelate superconductivity. The manuscript is strong in its multi-technique approach: the c-axis expansion trend across n, the COBRA three-dimensional electron-density reconstruction, the XAS pre-peak and Ni-L2 shifts, the metallicity of La2NiO4+δ, and the reversibility of the oxidation are mutually consistent and independently meaningful. The DFT calculations provide useful qualitative support, though they use δ=1 rather than the experimental δ≈0.7. The main weakness is that the defining quantity—δ≈0.7±0.1—is derived from a single COBRA integration without an independent chemical measurement, and the manuscript itself flags an unexpected density feature and domain-averaging caveats that bear directly on that count.

major comments (3)
  1. [Fig. 3 and Supplementary Fig. S8] The central claim of a new structural family with spacer composition A2O0.7 rests on the conversion of the integrated COBRA electron density at interstitial sites (approximately 5.8 electrons) into δ≈0.7±0.1 oxygen atoms per formula unit. No independent composition measurement is reported: the Author Contributions state that A.J.G. and S.M. performed SIMS measurements, but no SIMS data, calibration, or discussion appears anywhere in the main text or Supplementary Information. Because the electron-density integration is the only quantitative support for the stoichiometry, the authors should either report the SIMS results (or another composition probe such as RBS or neutron reflectometry) or provide a detailed justification of the COBRA electron-count calibration, including the assumed electron count per oxygen and how cations or disorder are excluded.
  2. [Supplementary Fig. S8c and main text Fig. 3c] The main text states that the intercalants occupy interstitial sites at (a,b)=(0,0.5) and (0.5,0), but Supplementary Fig. S8c shows electron density also at an 'unexpected site at (a,b)=(0,0), which does not correspond to a typical interstitial position in the rock salt structure.' The caption further warns that the 3-D density is a statistical average over a macroscopic area and that contributions from multiple structural domains may appear simultaneously. The paper does not state whether the 5.8-electron integral used for δ includes the (0,0) density, nor how structural disorder, cation displacement, or domain averaging are excluded from the oxygen assignment. This is load-bearing for the stoichiometry and should be addressed quantitatively.
  3. [Structural characterization (threshold claim)] The text proposes 'a threshold oxygen intercalation — between δ∼0.3 and 0.7 — required to drive rock salt layer expansion,' citing prior literature values for lower intercalation levels. However, no intermediate composition with a directly measured δ is presented in this work; the half-oxidized phase in Fig. S13 shows two-layer staging but its oxygen content is not quantified. The threshold claim therefore goes beyond the data. Either provide a measured δ for an intermediate phase or soften the claim to a conjecture.
minor comments (5)
  1. [Author Contributions] The Author Contributions list SIMS measurements by A.J.G. and S.M., but no SIMS data or methods are reported. If the measurements were not used or not successful, this should be stated; if they were used, they should be presented.
  2. [Transport section (Fig. 5c)] The sentence 'This suppression is further corroborated by temperature-dependent Hall coefficient measurements, which also show the disappearance of the associated anomaly (Fig. S14). In parallel, half-order diffraction peaks...' contains a missing closing parenthesis after 'Fig. S9, suggesting that...' — the text reads 'Fig. S9, suggesting' where 'Fig. S9)' is intended.
  3. [Supplementary Fig. S4 caption] The caption reads 'Asterisks mark the LaAlO3 substrate Bragg peaks are marked with asterisks,' which is redundant and grammatically broken; it should be 'Asterisks mark the LaAlO3 substrate Bragg peaks.'
  4. [Supplementary Fig. S13] The description of the 'fully-oxidized' film is confusing: the text says it exhibits peaks from both the half-oxidized and pristine film, yet also states that the odd-order staging peaks are 'mostly absent' in that film. Please clarify how the staging model relates to the fully-oxidized diffraction pattern.
  5. [DFT section (Supplementary Note 2)] The DFT calculations use δ=1 while the experimental claim is δ≈0.7. The text notes this is a qualitative model, but a sentence explicitly stating that δ=1 was chosen as a tractable approximation and that partial occupancy was not simulated would help avoid overinterpretation.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: δ≈0.7 is measured from COBRA electron-density integration and used, not assumed; transport and XAS provide independent checks.

full rationale

Assessment: the paper's central claim, oxygen intercalation δ≈0.7, is an output of the COBRA three-dimensional electron-density reconstruction, not an input that the argument requires. The paper reports that 'Integration of the electron density at the interstitial sites yields approximately 5.8 electrons, corresponding to δ∼0.7±0.1 interstitial oxygen atoms', which is a measurement with stated assumptions rather than a fitted parameter renamed as a result. The DFT calculations explicitly adopt δ=1 (Supplementary Note 2) and are used only for qualitative structural comparison; they are not used to derive the experimental δ. XAS and transport results are presented as independent experimental observations compared with the structural model, not as consequences generated from fitted values. The Ni 3.4+ valence estimate does use the COBRA-derived δ, but that is an interpretive step applied to measured spectra, not a prediction forced by construction. The cited prior work is routine synthesis calibration material [43,44]; no load-bearing self-citation or imported uniqueness theorem is invoked. The caveats the paper itself raises—the (a,b)=(0,0) density feature and the macroscopic domain-averaging warning in the Fig. S8 caption—are measurement uncertainties, not circular logic. The unreported SIMS measurements mentioned in the Author Contributions are a data-completeness concern, not evidence that any result reduces to its own input. No circular step can be exhibited, and no equation in the paper equates the conclusion with an assumption.

Assumptions & free parameters 0 free parameters · 3 assumptions · 0 invented entities

The load-bearing assumption is that COBRA electron-density integration measures oxygen intercalation; this is treated as a domain assumption rather than a fitted parameter. DFT enters only as qualitative support. No free parameters are fitted to force the central claims, and no new particles, forces, or dimensions are postulated.

assumptions (3)
  • domain assumption COBRA phase retrieval returns the true electron density from measured crystal truncation rods when initialized with assumed substrate and film models.
    Used to locate and count interstitial oxygen; the method is established, but the reconstruction is model-dependent at interfaces and no independent verification is shown.
  • domain assumption Electron density at interstitial sites corresponds to oxygen atoms and can be converted to δ with a fixed electron count per oxygen atom.
    The central δ≈0.7 claim relies on this conversion; disorder, cation interstitials, or reconstruction artifacts would bias the count.
  • domain assumption DFT with LDA/GGA and a δ=1 ordered supercell captures the qualitative structural and electronic trends of the oxidized films.
    The authors state the agreement is qualitative only; the calculations do not test the disordered δ≈0.7 configuration directly.

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Cite this review

Pith. "Pith review of Topotactic oxidation of Ruddlesden-Popper nickelates reveals new structural family: oxygen-intercalated layered perovskites." pith.science (2026). https://pith.science/paper/BSVFNF4F

@misc{pith2026250610262,
  author       = {Pith},
  title        = {Pith review of: Topotactic oxidation of Ruddlesden-Popper nickelates reveals new structural family: oxygen-intercalated layered perovskites},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/BSVFNF4F}},
  note         = {Machine review of arXiv:2506.10262}
}
read the original abstract

Layered perovskites such as the Dion-Jacobson, Ruddlesden-Popper, and Aurivillius families host a wide range of correlated electron phenomena, from high-temperature superconductivity to multiferroicity. Here we report a new family of layered perovskites, realized through topotactic oxygen intercalation of La_{n+1}Ni_{n}O_{3n+1} (n=1-4) Ruddlesden-Popper nickelate thin films grown by ozone-assisted molecular-beam epitaxy. Post-growth ozone annealing induces a large c-axis expansion - 17.8% for La_{2}NiO_{4} (n=1) - that monotonically decreases with increasing n. Surface X-ray diffraction coupled with Coherent Bragg Rod Analysis reveals that this structural expansion arises from the intercalation of approximately 0.7 oxygen atoms per formula unit into interstitial sites within the rock salt spacer layers. The resulting structures exhibit a spacer layer composition intermediate between that of the Ruddlesden-Popper and Aurivillius phases, defining a new class of layered perovskites. Oxygen-intercalated nickelates exhibit metallicity and significantly enhanced nickel-oxygen hybridization, a feature linked to high-temperature superconductivity. Our work establishes topotactic oxidation as a powerful synthetic approach to accessing highly oxidized, metastable phases across a broad range of layered oxide systems, offering new platforms to tune properties via spacer-layer chemistry.

Figures

Figures reproduced from arXiv: 2506.10262 by the authors.

Figure 1
Figure 1. The single-layer La2NiO4 film, for example, exhibits a 17.8% c-axis expansion from 12.68 ˚A to 14.93 ˚A (see Table S1 for lattice constants). The fractional expansion, ∆c/c, monotonically decreases with increasing n, indicating that expansion occurs mostly within the spacer layers (Fig. 2c). The absolute expansion, ∆c, is approximately 2.1 ˚A for all values of n [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2 [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3 [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗
Figures from the paper (2 more)
Figure 4
Figure 4. Figure 4: FIG. 4 [PITH_FULL_IMAGE:figures/full_fig_p004_4.png]
Figure 5
Figure 5. Figure 5: FIG. 5 [PITH_FULL_IMAGE:figures/full_fig_p005_5.png]

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

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Reference graph

Works this paper leans on

67 extracted references · 59 canonical work pages · cited by 1 Pith paper

  1. [1]

    Sleight, J

    A. Sleight, J. Gillson, and P. Bierstedt, High-temperature superconductivity in the BaPb 1−xBixO3 systems, Solid State Communications17, 27 (1975)

    work page 1975

  2. [2]

    J. Wang, J. B. Neaton, H. Zheng, V. Nagarajan, S. B. Ogale, B. Liu, D. Viehland, V. Vaithyanathan, D. G. Schlom, U. V. Waghmare, N. A. Spaldin, K. M. Rabe, M. Wuttig, and R. Ramesh, Epitaxial BiFeO 3 Multiferroic Thin Film Heterostructures, Science299, 1719 (2003)

    work page 2003

  3. [3]

    S. Jin, T. H. Tiefel, M. McCormack, R. A. Fastnacht, R. Ramesh, and L. H. Chen, Thousandfold Change in Resistivity in Magnetoresistive La-Ca-Mn-O Films, Science264, 413 (1994)

    work page 1994

  4. [4]

    perovskites

    M. Dion, M. Ganne, and M. Tournoux, Nouvelles familles de phases M I MII 2 Nb3O10 a Lewandowski “perovskites”, Materials Research Bulletin16, 1429–1435 (1981)

    work page 1981

  5. [5]

    Jacobson, J

    A. Jacobson, J. W. Johnson, and J. Lewandowski, Interlayer chemistry between thick transition-metal oxide layers: synthesis and intercalation reactions of K[Ca 2Nan−3NbnO3n+1] (3≤n≤7), Inorganic Chemistry24, 3727 (1985)

    work page 1985

  6. [6]

    Balz and K

    D. Balz and K. Plieth, Die Struktur des Kaliumnickelfluorids, K 2NiF4, Zeitschrift f¨ ur Elektrochemie, Berichte der Bunsengesellschaft f¨ ur physikalische Chemie59, 545 (1955)

    work page 1955

  7. [7]

    S. N. Ruddlesden and P. Popper, New compounds of the K2NiF4 type, Acta Crystallographica10, 538 (1957)

    work page 1957

  8. [8]

    Aurivillius, Mixed Bismuth Oxides with Layer lattices I

    B. Aurivillius, Mixed Bismuth Oxides with Layer lattices I. The structure type of CaNb 2Bi2O9, Ark. Kemi1, 463 (1950)

    work page 1950

Show all 67 references
  1. [9]

    Aurivillius, Ark

    B. Aurivillius, Ark. Kemi1, 499 (1950)

    1950

  2. [10]

    Aurivillius, Ark

    B. Aurivillius, Ark. Kemi2, 519 (1951)

    1951

  3. [11]

    Aurivillius, Ark

    B. Aurivillius, Ark. Kemi5, 39 (1953)

    1953

  4. [12]

    H. Sun, M. Huo, X. Hu, J. Li, Z. Liu, Y. Han, L. Tang, Z. Mao, P. Yang, B. Wang, J. Cheng, D.-X. Yao, G.-M. Zhang, and M. Wang, Signatures of superconductivity near 80 K in a nickelate under high pressure, Nature621, 493 (2023)

    2023

  5. [13]

    Y. Zhu, D. Peng, E. Zhang, B. Pan, X. Chen, L. Chen, H. Ren, F. Liu, Y. Hao, N. Li, Z. Xing, F. Lan, J. Han, J. Wang, D. Jia, H. Wo, Y. Gu, Y. Gu, L. Ji, W. Wang, H. Gou, Y. Shen, T. Ying, X. Chen, W. Yang, H. Cao, C. Zheng, Q. Zeng, J.-g. Guo, and J. Zhao, Superconductivity i...

    2024

  6. [14]

    E. K. Ko, Y. Yu, Y. Liu, L. Bhatt, J. Li, V. Thampy, C.-T. Kuo, B. Y. Wang, Y. Lee, K. Lee, J.-S. Lee, B. H. Goodge, D. A. Muller, and H. Y. Hwang, Signatures of ambient pressure superconductivity in thin film La3Ni2O7, Nature638, 935 (2025)

    2025

  7. [15]

    G. Zhou, W. Lv, H. Wang, Z. Nie, Y. Chen, Y. Li, H. Huang, W. Chen, Y. Sun, Q.-K. Xue, and Z. Chen, Ambient-pressure superconductivity onset above 40 K in bilayer nickelate ultrathin films, arXiv 10.48550/arxiv.2412.16622 (2024)

    2024 doi arXiv

  8. [16]

    Hayward, Comprehensive Inorganic Chemistry II (Second Edition), Modern Synthesis , 417 (2013)

    M. Hayward, Comprehensive Inorganic Chemistry II (Second Edition), Modern Synthesis , 417 (2013)

    2013

  9. [17]

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

    2019

  10. [18]

    G. A. Pan, D. F. Segedin, H. LaBollita, Q. Song, E. M. Nica, B. H. Goodge, A. T. Pierce, S. Doyle, S. Novakov, D. C. Carrizales, A. T. N’Diaye, P. Shafer, H. Paik, J. T. Heron, J. A. Mason, A. Yacoby, L. F. Kourkoutis, O. Erten, C. M. Brooks, A. S. Botana, and J. A. Mundy, Sup...

    2021

  11. [19]

    Yilmaz, K

    H. Yilmaz, K. K¨ uster, U. Starke, O. Clemens, M. Isobe, and P. Puphal, Realization of a classical Ruddlesden Popper type bilayer nickelate in Sr 3Ni2−xAlxO7−δ with unusual Ni4+, npj Quantum Materials9, 92 (2024)

    2024

  12. [20]

    Aguadero, J

    A. Aguadero, J. A. Alonso, M. J. Mart ´ ınez-Lope, M. T. Fern´ andez-D ´ ıaz, M. J. Escudero, and L. Daza, In situ high temperature neutron powder diffraction study of oxygen-rich La 2NiO4+δ in air: correlation with the electrical behaviour, Journal of Materials Chemistry16, 3...

    2006

  13. [21]

    Y. Liu, E. K. Ko, Y. Tarn, L. Bhatt, B. H. Goodge, D. A. Muller, S. Raghu, Y. Yu, and H. Y. Hwang, Superconductivity and normal-state transport in compressively strained La 2PrNi2O7 thin films, arXiv 10.48550/arxiv.2501.08022 (2025)

    2025 doi arXiv

  14. [22]

    Yacoby, M

    Y. Yacoby, M. Sowwan, E. Stern, J. O. Cross, D. Brewe, R. Pindak, J. Pitney, E. M. Dufresne, and R. Clarke, Direct determination of epitaxial interface structure in Gd2O3 passivation of GaAs, Nature Materials1, 99 (2002)

    2002

  15. [23]

    H. Zhou, Y. Yacoby, V. Y. Butko, G. Logvenov, I. Boˇ zovi´ c, and R. Pindak, Anomalous expansion of the copper-apical-oxygen distance in superconducting cuprate bilayers, Proceedings of the National Academy of Sciences107, 8103 (2010), 0903.2097

    2010 arXiv

  16. [24]

    S. J. May, J.-W. Kim, J. M. Rondinelli, E. Karapetrova, N. A. Spaldin, A. Bhattacharya, and P. J. Ryan, Quantifying octahedral rotations in strained perovskite oxide films, Physical Review B82, 014110 (2010)

    2010

  17. [25]

    Aguadero, J

    A. Aguadero, J. A. Alonso, and L. Daza, Oxygen Excess in La2CoO4+δ : A Neutron Diffraction Study, Zeitschrift f¨ ur Naturforschung B63, 615 (2008)

    2008

  18. [26]

    J. D. Jorgensen, B. Dabrowski, S. Pei, D. G. Hinks, L. Soderholm, B. Morosin, J. E. Schirber, E. L. Venturini, and D. S. Ginley, Superconducting phase of La 2CuO4+δ: A superconducting composition resulting from phase separation, Physical Review B38, 11337 (1988)

    1988

  19. [27]

    P. R. Slater and R. K. B. Gover, Synthesis and structure of the new oxide fluoride Sr 2TiO3F2 from the low temperature fluorination of Sr 2TiO4 : an example of a staged fluorine substitution/insertion reaction, Journal of Materials Chemistry12, 291 (2001)

    2001

  20. [28]

    M. A. Nowroozi, K. Wissel, J. Rohrer, A. R. Munnangi, and O. Clemens, LaSrMnO4: Reversible Electrochemical Intercalation of Fluoride Ions in the Context of Fluoride Ion Batteries, Chemistry of Materials29, 3441 (2017)

    2017

  21. [29]

    Wissel, T

    K. Wissel, T. Vogel, S. Dasgupta, A. D. Fortes, P. R. Slater, and O. Clemens, Topochemical Fluorination ofn= 2 Ruddlesden–Popper Type Sr 3Ti2O7 to Sr3Ti2O5F4 and Its Reductive Defluorination, Inorganic Chemistry59, 1153 (2020)

    2020

  22. [30]

    H. Hong, T. Lin, Q. Li, H. Bai, S. Choi, C. Liu, J. Sun, S. Chen, T. Cui, D. Rong, Q. Wang, Q. Jin, C. Ge, C. Wang, T. Zhu, J. Wang, Q. Zhang, L. Gu, J. Cheng, 9 K. Jin, and E. Guo, Anion Doping Induced Topotactic Phase Transition in Ruddlesden–Popper Cobaltites, Advanced Mate...

    2025 doi

  23. [31]

    P. R. Slater and R. K. B. Gover, Synthesis and structure of the new oxide fluoride Ba 2ZrO3F2·xH2O (x≈0.5), Journal of Materials Chemistry11, 2035 (2001)

    2001

  24. [32]

    Pelloquin, N

    D. Pelloquin, N. Barrier, D. Flahaut, V. Caignaert, and A. Maignan, Two New Hydrated Oxyhydroxides Sr 3Co1.7Ti0.3O5(OH)2·xH2O and Sr4Co1.6Ti1.4O8(OH)2·xH2O Derived from the RPn= 2 and 3 Members: Structural and Magnetic Behavior versus Temperature, Chemistry of Materials17, 773 (2005)

    2005

  25. [33]

    F. J. Berry, E. Moore, M. Mortimer, X. Ren, R. Heap, P. Slater, and M. F. Thomas, Synthesis and structural investigation of a new oxide fluoride of composition Ba2SnO2.5F3·xH2O (x∼0.5), Journal of Solid State Chemistry181, 2185 (2008)

    2008

  26. [34]

    Wissel, J

    K. Wissel, J. Heldt, P. B. Groszewicz, S. Dasgupta, H. Breitzke, M. Donzelli, A. I. Waidha, A. D. Fortes, J. Rohrer, P. R. Slater, G. Buntkowsky, and O. Clemens, Topochemical Fluorination of La 2NiO4+δ: Unprecedented Ordering of Oxide and Fluoride Ions in La2NiO3F2, Inorganic ...

    2018

  27. [35]

    R. E. Schaak and T. E. Mallouk, Prying Apart Ruddlesden-Popper Phases: Exfoliation into Sheets and Nanotubes for Assembly of Perovskite Thin Films, Chemistry of Materials12, 3427 (2000)

    2000

  28. [36]

    F. M. F. d. Groot, M. Grioni, J. C. Fuggle, J. Ghijsen, G. A. Sawatzky, and H. Petersen, Oxygen 1sX-ray- absorption edges of transition-metal oxides, Physical Review B40, 5715 (1989)

    1989

  29. [37]

    Kuiper, J

    P. Kuiper, J. v. Elp, G. A. Sawatzky, A. Fujimori, S. Hosoya, and D. M. d. Leeuw, Unoccupied density of states of La 2−xSrxNiO4+δ studied by polarization-dependent X-ray-absorption spectroscopy and bremsstrahlung isochromat spectroscopy, Physical Review B44, 4570 (1991)

    1991

  30. [38]

    Mizokawa, D

    T. Mizokawa, D. I. Khomskii, and G. A. Sawatzky, Spin and charge ordering in self-doped Mott insulators, Physical Review B61, 11263 (2000)

    2000

  31. [39]

    Shinomori, Y

    S. Shinomori, Y. Okimoto, M. Kawasaki, and Y. Tokura, Insulator–Metal Transition in La2−xSrxNiO4, Journal of the Physical Society of Japan71, 705 (2002)

    2002

  32. [40]

    Zhang, M

    Z. Zhang, M. Greenblatt, and J. Goodenough, Synthesis, Structure, and Properties of the Layered Perovskite La3Ni2O7−δ, Journal of Solid State Chemistry108, 402 (1994)

    1994

  33. [41]

    Greenblatt, Z

    M. Greenblatt, Z. Zhang, and M. Whangbo, Electronic properties of La 3Ni2O7 and Ln 4Ni3O10, Ln=La, Pr and Nd, Synthetic Metals85, 1451 (1997)

    1997

  34. [42]

    B. O. Wells, Y. S. Lee, M. A. Kastner, R. J. Christianson, R. J. Birgeneau, K. Yamada, Y. Endoh, and G. Shirane, Incommensurate Spin Fluctuations in High-Transition Temperature Superconductors, Science277, 1067 (1997)

    1997

  35. [43]

    G. A. Pan, Q. Song, D. F. Segedin, M.-C. Jung, H. El- Sherif, E. E. Fleck, B. H. Goodge, S. Doyle, D. C. Carrizales, A. T. N’Diaye, P. Shafer, H. Paik, L. F. Kourkoutis, I. E. Baggari, A. S. Botana, C. M. Brooks, and J. A. Mundy, Synthesis and electronic properties of Ndn+1Nin...

    2022

  36. [44]

    2Fipyf2MvEeAQOsSE3TgYCqU4mI=

    Z. Li, W. Guo, T. T. Zhang, J. H. Song, T. Y. Gao, Z. B. Gu, and Y. Nie, Epitaxial growth and electronic structure of Ruddlesden–Popper nickelates (Lan+1NinO3n+1 ,n= 1–5), APL Materials8, 091112 (2020). Methods Thin film synthesis.We use ozone-assisted MBE to synthesize the Ru...

    2020

  37. [45]

    2 R H (mm 3/C) Ozone-annealed As-grown FIG. S14.Transport characterization of the charge/spin density wave transition in pristine and oxidized La 4Ni3O10.Temperature-dependent Hall coefficients for as-grown and ozone-annealed La 4Ni3O10. The arrow marks the charge/spin density...

  38. [46]

    J. B. Nelson and D. P. Riley, An experimental investigation of extrapolation methods in the derivation of accurate unit-cell dimensions of crystals, Proceedings of the Physical Society57, 160 (1945)

    1945

  39. [47]

    G. A. Pan, Q. Song, D. F. Segedin, M.-C. Jung, H. El-Sherif, E. E. Fleck, B. H. Goodge, S. Doyle, D. C. Carrizales, A. T. N’Diaye, P. Shafer, H. Paik, L. F. Kourkoutis, I. E. Baggari, A. S. Botana, C. M. Brooks, and J. A. Mundy, Synthesis and electronic properties of Nd n+1Nin...

    2022

  40. [48]

    J. D. Jorgensen, B. Dabrowski, S. Pei, D. R. Richards, and D. G. Hinks, Structure of the interstitial oxygen defect in La2NiO4+δ, Physical Review B40, 2187 (1989)

    1989

  41. [49]

    Akamatsu, K

    H. Akamatsu, K. Fujita, T. Kuge, A. S. Gupta, A. Togo, S. Lei, F. Xue, G. Stone, J. M. Rondinelli, L.-Q. Chen, I. Tanaka, V. Gopalan, and K. Tanaka, Inversion Symmetry Breaking by Oxygen Octahedral Rotations in the Ruddlesden-Popper NaRTiO4 Family, Physical Review Letters112, ...

    2014

  42. [50]

    Yoshida, H

    S. Yoshida, H. Akamatsu, R. Tsuji, O. Hernandez, H. Padmanabhan, A. S. Gupta, A. S. Gibbs, K. Mibu, S. Murai, J. M. Rondinelli, V. Gopalan, K. Tanaka, and K. Fujita, Hybrid Improper Ferroelectricity in (Sr,Ca) 3Sn2O7 and Beyond: Universal Relationship between Ferroelectric Tra...

    2018

  43. [51]

    Bhattacharya, S

    N. Bhattacharya, S. C. Joshi, R. K. Patel, J. Zhang, A. Saha, P. Mandal, S. K. Ojha, A. Gloskovskii, C. Schlueter, J. W. Freeland, Z. Zhang, H. Zhou, Z. Yang, and S. Middey, Nanoscale Inhomogeneity and Epitaxial Strain Control Metallicity in Single Crystalline Thin Films of Hi...

    2025

  44. [52]

    Y. Park, S. Kang, J. Song, S. W. Hwang, S. Lin, J. M. Ok, F. Yang, H. Kim, A. R. Lupini, M. Yoon, S. Yoon, H. Zhou, and H. N. Lee, Strain Programming of Oxygen Octahedral Symmetry in Perovskite Oxide Thin Films, Advanced Materials Interfaces12, 10.1002/admi.202400697 (2025)

    2025 doi

  45. [53]

    G. H. Lander, P. J. Brown, J. Spal/ek, and J. M. Honig, Structural and magnetization density studies of La 2NiO4, Phys. Rev. B40, 4463 (1989)

    1989

  46. [54]

    Rodriguez-Carvajal, M

    J. Rodriguez-Carvajal, M. T. Fernandez-Diaz, and J. L. Martinez, Neutron diffraction study on structural and magnetic properties of La 2NiO4, Journal of Physics: Condensed Matter3, 3215 (1991)

    1991

  47. [55]

    Kresse and J

    G. Kresse and J. Hafner, Ab initio molecular dynamics for liquid metals, Phys. Rev. B47, 558 (1993)

    1993

  48. [56]

    Kresse and J

    G. Kresse and J. Furthm¨ uller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B54, 11169 (1996)

    1996

  49. [57]

    Kresse and D

    G. Kresse and D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave method, Phys. Rev. B59, 1758 (1999)

    1999

  50. [58]

    J. P. Perdew, K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple, Phys. Rev. Lett.77, 3865 (1996)

    1996

  51. [59]

    Blaha, K

    P. Blaha, K. Schwarz, F. Tran, R. Laskowski, G. K. H. Madsen, and L. D. Marks, WIEN2k: An APW+lo program for calculating the properties of solids, J. Chem. Phys.152, 074101 (2020)

    2020

  52. [60]

    LaBollita, J

    H. LaBollita, J. Kapeghian, M. R. Norman, and A. S. Botana, Electronic structure and magnetic tendencies of trilayer La4Ni3O10 under pressure: Structural transition, molecular orbitals, and layer differentiation, Physical Review B109, 195151 (2024)

    2024

  53. [61]

    J. Fink, T. M¨ uller-Heinzerling, B. Scheerer, W. Speier, F. U. Hillebrecht, J. C. Fuggle, J. Zaanen, and G. A. Sawatzky, 2p absorption spectra of the 3d elements, Physical Review B32, 4899 (1985)

    1985

  54. [62]

    Pellegrin, J

    E. Pellegrin, J. Zaanen, H.-J. Lin, G. Meigs, C. T. Chen, G. H. Ho, H. Eisaki, and S. Uchida, O 1snear-edge X-ray absorption of La 2−xSrxNiO4+δ: Holes, polarons, and excitons, Physical Review B53, 10667 (1995)

    1995

  55. [63]

    Kuiper, J

    P. Kuiper, J. v. Elp, D. E. Rice, D. J. Buttrey, H. J. Lin, and C. T. Chen, Polarization-dependent nickel 2px-ray-absorption spectra of La 2NiO4+δ, Physical Review B57, 1552 (1998)

    1998

  56. [64]

    J. W. Freeland, J. Liu, M. Kareev, B. Gray, J. W. Kim, P. Ryan, R. Pentcheva, and J. Chakhalian, Orbital control in strained ultra-thin LaNiO 3/LaAlO3 superlattices, EPL (Europhysics Letters)96, 57004 (2011)

    2011

  57. [65]

    I. C. Tung, P. V. Balachandran, J. Liu, B. A. Gray, E. A. Karapetrova, J. H. Lee, J. Chakhalian, M. J. Bedzyk, J. M. Rondinelli, and J. W. Freeland, Connecting bulk symmetry and orbital polarization in strainedRNiO 3 ultrathin films, Physical Review B88, 205112 (2013)

    2013

  58. [66]

    M. Wu, E. Benckiser, M. W. Haverkort, A. Frano, Y. Lu, U. Nwankwo, S. Br¨ uck, P. Audehm, E. Goering, S. Macke, V. Hinkov, P. Wochner, G. Christiani, S. Heinze, G. Logvenov, H.-U. Habermeier, and B. Keimer, Strain and composition dependence of orbital polarization in nickel ox...

    2013 arXiv

  59. [67]

    N. K. Taylor, D. F. Segedin, A. B. Turkiewicz, Y. Zhang, S. T. Doyle, G. A. Pan, H. Jiang, A. Bostwick, C. Jozwiak, E. Rotenberg, A. Lanzara, I. E. Baggari, C. M. Brooks, A. T. N’Diaye, L. Moreschini, and J. A. Mundy, Synthesis and electronic characterization of Nd 2−xSrxNiO4 ...

    2025

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