Pith. sign in

REVIEW 4 major objections 6 minor 55 references

Oxygen sublattice disorder and valence state modulation in infinite-layer nickelate superlattices

T0 review · 4 major / 6 minor · reviewed 2026-08-09 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

Pith's one-line read In topotactically reduced nickelate superlattices, a measurable fraction of the oxygen removed during reduction comes from the wrong (basal) sites, and the interlayer material sets that fraction and with it the metallic versus…

desk verdict Careful XRR study with a plausible new disorder quantity, but the quantitative fractions are model-dependent and sit in tension with 4D-STEM; qualitative conclusions likely hold. read the letter →

arxiv 2502.03873 v1 pith:Z5T2YAAH submitted 2025-02-06 cond-mat.supr-con cond-mat.mtrl-scicond-mat.str-el

R. A. Ortiz , N. Enderlein , K. Fürsich , R. Pons , P. Radhakrishnan , E. Schierle , P. Wochner , G. Logvenov
show 4 more authors
G. Cristiani P. Hansmann B. Keimer E. Benckiser
This is my paper · ORCID
classification cond-mat.supr-concond-mat.mtrl-scicond-mat.str-el
keywords infinite-layernickelatestopotacticreductionoxygensublatticedisorderresonantx-rayreflectivitylineardichroismsuperlatticesnickelvalenceinterlayerengineering
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 topotactic reduction of nickelate superlattices does not simply remove every apical oxygen to make a clean infinite-layer structure. Instead, a significant share of Ni sites lose a basal oxygen, leaving misoriented square-planar plaquettes in the stack interior and pyramidal Ni$^{2+}$ coordination near the interfaces, and the fraction of misoriented sites depends on which perovskite spacer is used. Superlattices with SrTiO$_3$ spacers show less central-layer oxygen disorder (about 70/30 in favor of the correct apical-removed orientation) and become metallic after reduction, while the LaGaO$_3$ superlattice is more disordered (about 60/40) and stays semiconducting. The result matters because it gives a materials-design lever, the spacer selection, on a structural defect that likely shapes transport and may explain contradictory results in capped nickelate films.

What carries the argument

The load-bearing comparison is between the layer-resolved, polarization-dependent imaginary scattering factor $f''(E)$ obtained from resonant x-ray reflectivity and ligand-field cluster spectra computed for $d^8$ and $d^9$ Ni in square-pyramidal and square-planar oxygen fields. A single scalar $\alpha$ first redistributes the XAS-measured linear dichroism between interfacial and central layers; then Equations (3) and (4) express each layer's experimental spectrum as a weighted sum of a cluster spectrum and its polarization-swapped partner, so the weights $N$ and $M$ become quantitative measures of how many oxygen sites removed the basal rather than the apical oxygen. That two-orientation decomposition is the mechanism that converts a spectral discrepancy into a percentage of disordered coordination polyhedra.

What would settle it

Perform quantitative 4D-STEM or atomic-resolution EELS mapping of oxygen columns across the full superlattice stack to count, site by site, whether apical or basal oxygen was removed, and compare the resulting percentages with the reported 45 to 55 percent interfacial and 60 to 70 percent central fractions; a mismatch beyond the stated error bars, or evidence that valence gradients or roughness explain the dichroism reduction, would falsify the central claim.

Watch

Extended reading notes

Core claim

Layer-resolved resonant x-ray reflectivity at the Ni $L_{3,2}$ edges, compared with ligand-field cluster spectra, shows that the reduced superlattices consist of square-pyramidal Ni$^{2+}$ ($3d^8$) layers at each interface and square-planar Ni$^{1+}$ ($3d^9$) layers in the stack centers, with the interfacial reconstruction confined to about one NiO$_2$ layer for LaGaO$_3$ spacers and about 1.5 layers for SrTiO$_3$ spacers. The measured linear dichroism is weaker than the cluster calculations predict, and the authors account for the shortfall by mixing each calculated spectrum with its polarization-swapped counterpart (Eqs. 3 and 4). This yields substantial fractions of misoriented oxygen-removal sites: roughly 45 to 55 percent in the interface layers and, in the central layers, about 30 percent in-plane-oriented for SrTiO$_3$ and about 40 percent for LaGaO$_3$. The two SrTiO$_3$ superlattices, with Nd and with La on the rare-earth site, give the same percentages within error, so the paper concludes the spacer material, not the rare earth, controls the oxygen-sublattice disorder.

Load-bearing premise

The quantitative disorder percentages presume that the only thing reducing the linear dichroism below the cluster-calculation value is a simple two-way mixture of correctly and incorrectly oriented oxygen polyhedra with the same nickel valence, so other defects, valence gradients, or roughness that also weaken dichroism would change the inferred fractions.

Editorial extensions

If this is right

  • Choice of the spacer material becomes a design parameter: SrTiO$_3$ interlayers bias oxygen removal toward the apical site and yield metallic parent-like nickelate stacks, whereas LaGaO$_3$ interlayers leave more misoriented plaquettes and semiconducting transport.
  • Because the interface reconstruction is confined to one or two unit cells, thin nickelate stacks are dominated by interfacial Ni$^{2+}$ and the spacer-dependent disorder should show up most strongly in the thinnest stacks.
  • Quantitative models of infinite-layer nickelates should include a fraction of misoriented, basal-removed oxygen coordination, with the spacer-dependent numbers from this work as input.
  • Superlattice stacks with residual resistivity below the quantum sheet resistance are comparable in phase quality to superconducting thin films, so the oxygen disorder measured here is a candidate contributor to why low resistivity is necessary but not sufficient for superconductivity.
  • Macroscopic x-ray averaging over hundreds of micrometres coexists with real-space probes that sample only tens of nanometres, so the inferred disorder may be invisible to short-range imaging yet still affect transport.

Reading between the lines

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

  • If the spacer sets the misorientation fraction, then the same bias should appear in simple capped films: a SrTiO$_3$ cap should suppress wrong-site oxygen removal near the cap, which would offer a structural explanation for capping-layer-dependent charge order and transport in NdNiO$_2$ films.
  • One can test the microscopic origin by computing the relative energy of removing apical versus basal oxygen at STO and LGO interfaces; the predicted ordering should match the 70/30 versus 60/40 empirical fractions.
  • The correlation suggests a reduction-protocol experiment: slowing the reduction or post-annealing the STO superlattices should lower the misoriented fraction and push resistivity further down, while the same treatment on LGO should show weaker improvement.
  • Only one LaGaO$_3$ superlattice was measured, so the LGO numbers are a single-point comparison; a thickness and strain series across several LGO superlattices would tell whether 60/40 is intrinsic to LGO or sample-specific.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

4 major / 6 minor

Summary. The paper reports a soft x-ray absorption and resonant reflectivity study of reduced infinite-layer nickelate superlattices with different interlayer materials (SrTiO3 vs. LaGaO3). The main claims are (i) a depth-resolved Ni valence modulation with Ni2+ in square-pyramidal coordination at the interfaces and Ni1+ in square-planar coordination in the central layers, (ii) a significant fraction of misoriented oxygen-coordination polyhedra (basal rather than apical oxygen removal) in both interface and central layers, and (iii) a quantitative correlation between this disorder fraction and the interlayer material, with STO interlayers showing less disorder and higher conductivity. The analysis combines a two-step XRR fit with a parameter alpha that redistributes the measured dichroism between layers, ligand-field cluster calculations, and a two-orientation mixing model (Eqs. (3)-(4)) to extract disorder percentages N and M.

Significance. If the quantitative disorder fractions are trustworthy, the work would provide a valuable structure-property correlation for the growing field of infinite-layer nickelate heterostructures, where oxygen coordination disorder is widely suspected to affect superconductivity but has been difficult to quantify. The paper's methodological strengths are the non-destructive depth resolution of XRR, the cross-check with independent multiplet cluster calculations, and the use of sum-rule constraints on the layer-resolved spectra. However, the central quantitative claim rests on a model assumption that is not uniquely validated, and the reported disorder fractions conflict in a non-trivial way with the cited 4D-STEM null result. The qualitative picture (Ni2+ at interfaces, Ni1+ in the center, reduced dichroism) is well supported; the quantitative correlation is not.

major comments (4)
  1. [Section III.C, Eqs. (3)-(4)] The extraction of the disorder fractions N and M assumes that the sole source of reduced dichroism in the layer-resolved f'' spectra is an incoherent mixture of two discrete orientations (basal-removed and apical-removed) of otherwise identical Ni coordination polyhedra. No confidence intervals are reported for N or M, and the fits use only two constant-qz reflectivity curves per sample ((002)/(003) or (001)/(002)). Other defect channels—interfacial roughness, strain gradients, valence mixing, or non-binary orientational disorder—can also reduce dichroism and would be absorbed into the fitted N and M. The quantitative correlation with interlayer material is therefore a fit outcome, not an independent prediction, unless the model exclusivity is demonstrated.
  2. [Conclusions, Ref. 44] The authors cite a 4D-STEM study on one NNO-STO superlattice that detected no significant oxygen disorder on a ~20 nm lateral scale and call this a 'lower limit.' This is difficult to reconcile with the XRR-derived ~30% misoriented plaquettes in the central layers of the same superlattice type: a random 30% site disorder would produce many detectable misoriented sites in a 20 nm field of view. The discrepancy implies either that the misorientation is coherent over domains larger than 20 nm (a domain structure rather than site disorder) or that the reduced dichroism has additional sources that the two-orientation model attributes to disorder. The manuscript needs a quantitative reconciliation or direct structural evidence for the misoriented sites.
  3. [Section III.C and Fig. 4] The central STO-versus-LGO comparison is based on one LGO superlattice and two STO superlattices, and the statement that the two STO samples agree 'within our error bars' is unsupported because no error bars are given for N, M, alpha, or pIF/pC anywhere in the paper. The authors should provide uncertainties from the fitting procedure (e.g., via parameter scans or Monte Carlo sampling) and explicitly state the number of independent measurements underlying each reported percentage. Without this, the claimed quantitative correlation is not established at the precision implied by the abstract.
  4. [Section III.C and Fig. 8] The cross-check using cluster-calculated spectra with polarization mixing (Fig. 8) is evaluated only visually; no goodness-of-fit metric is reported, and the authors acknowledge that the line shape of the individual sigma and pi spectra is 'slightly less well reproduced' than with the alpha-model. This is acceptable as a supporting check, but it does not by itself validate the two-orientation model against other disorder mechanisms. The reader is also referred to 'Appendices G and H of Ref. 31' (a doctoral thesis) for the rejection of mixed-valence models, which is not accessible in the manuscript; the relevant results should be summarized or reproduced.
minor comments (6)
  1. [Section II, Eq. (2)] The definitions of pIF and pC are used in Eq. (2) but not explicitly defined until later; please define them at first use and state the physical constraints that bound alpha.
  2. [Section III.B] The error bars reported for Xav in Fig. 2(d) are attributed only to background subtraction; please clarify whether the plotted uncertainties reflect only that procedure or also include count statistics and polarization-angle uncertainty.
  3. [Section III.C, text near Fig. 4] The sentence 'The results represented by the solid/dashed gray curves in Fig. 3' appears to reference the wrong figure: the cluster-calculated mixing results are shown in Fig. 4, not Fig. 3.
  4. [Section III.C, paragraph on layer fractions] The terminology for plaquette orientation is confusing: 'out-of-plane oriented square-planar configuration' in the central layers versus 'favored in-plane orientation of the plaquettes' in the following paragraph is not self-consistent; please define the orientation convention (e.g., plaquette normal along c vs. in-plane) once and use it throughout.
  5. [Section III.C, paragraph on d9 and d8] The paragraph beginning 'For the d9 configuration...' mixes d9 and d8 statements and is difficult to follow; please rewrite to separate the d9 and d8 cases clearly, since the distinction between Ni-IF (d8) and Ni-C (d9) is central to the interpretation.
  6. [Appendix A, Fig. 5] The XRD patterns are said to suggest square-pyramidal nickel coordination at interfaces with STO, but the figure does not label the relevant superlattice peaks beyond (001) and (002); please add peak indices to support the claim.

Circularity Check

0 steps flagged · score 1.0 of 10

No significant circularity: fitted disorder fractions are matched to independently calculated cluster spectra, not derived from the claims themselves.

full rationale

The derivation chain is not circular. The disorder percentages N and M in Eqs. (3)-(4) are obtained by fitting linear combinations of cluster-calculated spectra f''_cc to the layer-resolved XRR spectra f''_alpha, but the cluster spectra are computed independently from DFT plus QUANTY multiplet calculations with stated parameters (Udd = 6 eV, Delta = 4.5 eV, Hartree-Fock Slater integrals), not from the XRR data. The fit is therefore an inference against independent spectral benchmarks rather than a re-labeling of the measured dichroism. The alpha-redistribution model in Eq. (2) parameterizes the measured layer-averaged dichroism, but the reported interlayer dependence of the fitted N/M is not forced by construction: the same model is applied to all three superlattices and yields different values, and the authors explicitly test alternative mixed Ni1+/Ni2+ valence models and find poor agreement with the data. Citations to prior work by overlapping authors (Refs. 20, 27, 31, 44, 47) concern methods, growth protocols, and interface structures that are externally testable by STEM, DFT+DMFT, or previously established orbital-reflectometry techniques; no load-bearing claim or uniqueness theorem is imported solely from those citations. The paper itself flags the tension with the 4D-STEM null result (Ref. 44) by calling it a lower limit on a ~20 nm lateral scale; that is a correctness and model-identifiability concern about the two-orientation assumption, not a circular step. The absence of confidence intervals for N and M is a reporting limitation, but it does not make the fitted quantities equivalent to their inputs. Overall, the central claim has independent content and the analysis is self-contained with respect to external cluster calculations and structural checks.

Assumptions & free parameters 4 free parameters · 4 assumptions · 0 invented entities

The central quantitative results depend on several fitted parameters (alpha, N, M, pIF/pC) and on modeling assumptions about layer selectivity, structural model fidelity, and the completeness of the two-orientation mixing picture. No new physical entities are introduced. The cluster calculations provide independent spectral benchmarks, which limits the circularity burden.

free parameters (4)
  • alpha (dichroism redistribution parameter) = negative for all reduced samples (exact values not reported)
    Parameter in Eq. (2) that redistributes the measured layer-averaged linear dichroism between interface and central nickelate layers; fitted to constant-qz reflectivity data in Fig. 3.
  • N (fraction of normally oriented IF sites) = 45-55% (approx. 0.5)
    Mixing coefficient in Eq. (3) that matches the XRR-derived IF scattering factor; a fit to the data, not an independent prediction.
  • M (fraction of out-of-plane oriented C sites) = ~0.7 for STO, ~0.6 for LGO
    Mixing coefficient in Eq. (4); fitted to match the XRR-derived central-layer scattering factor; central to the claimed correlation with interlayer material.
  • pIF/pC (interface-to-central layer thickness ratio) = 3/5 for NNO-STO and LNO-STO, 2/6 for LNO-LGO
    Relative thicknesses of interfacial and central nickelate layers, varied in reflectivity simulation to maximize agreement; affects the inferred extent of Ni2+ regions.
assumptions (4)
  • domain assumption The reduction process is layer-selective: STO interlayers remain Ti4+ and are not reduced.
    Supported by Ti-L XAS in Appendix B (Fig. 7), which shows no Ti3+ signal after reduction; this underpins the two-region (IF/C) model with unchanged STO layers.
  • domain assumption Structural parameters from scalar, polarization-averaged reflectivity fits are accurate enough to be fixed during dichroic analysis.
    Used in the two-step analysis: first fit off-resonant and on-resonant qz scans with scalar scattering factors, then fix structure when simulating energy-dependent dichroic reflectivity (Section II, Appendix C).
  • ad hoc to paper The reduced dichroism is fully described by mixing exactly two orientations of the same Ni coordination polyhedra.
    Eqs. (3)-(4) assume the XRR-derived layer spectra are linear combinations of normal and reversed-oriented cluster spectra; alternative mixed-valence models are stated to fail, but other disorder mechanisms are not exhaustively tested.
  • domain assumption Ligand-field cluster calculations with DFT-derived parameters correctly reproduce the relevant Ni L-edge spectra for d8 and d9.
    Used to identify IF as square-pyramidal Ni2+ and C as square-planar Ni1+, and to generate basis spectra for the mixing model; parameters in Table II, robustness to U and Delta variation asserted but not fully shown.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Oxygen sublattice disorder and valence state modulation in infinite-layer nickelate superlattices." pith.science (2026). https://pith.science/paper/Z5T2YAAH

@misc{pith2026250203873,
  author       = {Pith},
  title        = {Pith review of: Oxygen sublattice disorder and valence state modulation in infinite-layer nickelate superlattices},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/Z5T2YAAH}},
  note         = {Machine review of arXiv:2502.03873}
}
read the original abstract

The family of infinite-layer nickelates promises important insights into the mechanism of unconventional superconductivity. Since superconductivity has so far only been observed in epitaxial thin films, heteroepitaxy with the substrate or a capping layer possibly plays an important role. Here, we use soft x-ray spectroscopy to investigate superlattices as a potential approach for a targeted material design of high-temperature superconductors. We observe modulations in valence state and oxygen coordination in topotactically reduced artificial superlattices with repeating interfaces between nickelate layers and layers of materials commonly used as substrates and capping layers. Our results show that depending on the interlayer material metallic conductivity akin to the parent infinite-layer compounds is achieved. Depth-resolved electronic structure measured by resonant x-ray reflectivity reveals a reconstructed ligand field and valence state at the interface, which is confined to one or two unit cells. The central layers show characteristics of monovalent nickel, but linear dichroism analysis reveals considerable disorder in the oxygen removal sites. We observe a quantitative correlation of this disorder with the interlayer material that is important for future modeling and design strategies.

Figures

Figures reproduced from arXiv: 2502.03873 by the authors.

Figure 1
Figure 1. FIG. 1. Temperature-dependent resistivity of three pairs of (a) pristine and (b) reduced superlattices, with different compo [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2. (a-d) Experimental XAS measured with linearly polarized x-rays at room temperature for reduced (a) NNO-STO, (b) [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3. Reflectivity constant-q [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figures from the paper (5 more)
Figure 4
Figure 4. Figure 4: FIG. 4. Layer-resolved scattering factor [PITH_FULL_IMAGE:figures/full_fig_p006_4.png]
Figure 5
Figure 5. Figure 5: FIG. 5. XRD patterns measured on pieces of the same as [PITH_FULL_IMAGE:figures/full_fig_p008_5.png]
Figure 6
Figure 6. Figure 6: FIG. 6. Reflectivity as a function of [PITH_FULL_IMAGE:figures/full_fig_p009_6.png]
Figure 7
Figure 7. Figure 7: FIG. 7. Polarization averaged XAS at the Ti- [PITH_FULL_IMAGE:figures/full_fig_p009_7.png]
Figure 8
Figure 8. Figure 8: FIG. 8. Reflectivity constant-q [PITH_FULL_IMAGE:figures/full_fig_p010_8.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

55 extracted references · 44 canonical work pages

  1. [1]

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

    2019

  2. [2]

    Gutierrez-Llorente, A

    A. Gutierrez-Llorente, A. Raji, D. Zhang, L. Divay, A. Gloter, F. Gallego, C. Galindo, M. Bibes, and L. Igle- sias, Toward reliable synthesis of superconducting infi- nite layer nickelate thin films by topochemical reduction, ADV ANCED SCIENCE 11, 10.1002/advs.202309092 (2024)

    doi:10.1002/advs.202309092 2024

  3. [3]

    M. Xu, Y. Zhao, X. Ding, H. Leng, S. Zhang, J. Gong, H. Xiao, X. Zu, H. Luo, K.-J. Zhou, B. Huang, and L. Qiao, Optimization for epitaxial fabrication of infinite-layer nickelate superconductors, FRONTIERS OF PHYSICS 19, 10.1007/s11467-023-1368-1 (2024)

    work page doi:10.1007/s11467-023-1368-1 2024

  4. [4]

    Osada, B

    M. Osada, B. Y. Wang, B. H. Goodge, K. Lee, H. Yoon, K. Sakuma, D. Li, M. Miura, L. F. Kourkoutis, and H. Y. Hwang, A superconducting praseodymium nickelate with infinite layer structure, Nano Letters 20, 5735 (2020)

    work page 2020

  5. [5]

    Osada, B

    M. Osada, B. Y. Wang, B. H. Goodge, S. P. Harvey, K. Lee, D. Li, L. F. Kourkoutis, and H. Y. Hwang, Nick- elate superconductivity without rare-earth magnetism: (La, Sr)NiO2, Advanced Materials 33, 2104083 (2021)

    work page 2021

  6. [6]

    S. Zeng, C. Li, L. E. Chow, Y. Cao, Z. Zhang, C. S. Tang, X. Yin, Z. S. Lim, J. Hu, P. Yang, and A. Ariando, Su- perconductivity in infinite-layer nickelate La1−xCaxNiO2 thin films, Science Advances 8, eabl9927 (2022)

    work page 2022

  7. [7]

    S. Zeng, C. S. Tang, X. Yin, C. Li, M. Li, Z. Huang, J. Hu, W. Liu, G. J. Omar, H. Jani, Z. S. Lim, K. Han, D. Wan, P. Yang, S. J. Pennycook, A. T. S. Wee, and A. Ariando, Phase diagram and superconducting dome of infinite-layer Nd1−xSrxNiO2 thin films, Phys. Rev. Lett. 125, 147003 (2020)

    2020

  8. [8]

    D. Li, B. Y. Wang, K. Lee, S. P. Harvey, M. Osada, B. H. Goodge, L. F. Kourkoutis, and H. Y. Hwang, Supercon- ducting dome in Nd1−xSrxNiO2 infinite layer films, Phys. Rev. Lett. 125, 027001 (2020)

    2020

Show all 55 references
  1. [9]

    H. Lu, M. Rossi, A. Nag, M. Osada, D. F. Li, K. Lee, B. Y. Wang, M. Garcia-Fernandez, S. Agrestini, Z. X. Shen, E. M. Been, B. Moritz, T. P. Devereaux, J. Zaa- nen, H. Y. Hwang, K.-J. Zhou, and W. S. Lee, Magnetic excitations in infinite-layer nickelates, Science 373, 213 (2021)

    2021

  2. [10]

    Fowlie, M

    J. Fowlie, M. Hadjimichael, M. Martins, D. Li, M. Osada, B. Y. Wang, K. Lee, Y. Lee, Z. Salman, T. Prokscha, J.- M. Triscone, H. Y. Hwang, and A. Suter, Intrinsic mag- netism in superconducting infinite-layer nickelates, Na- ture Physics 18, 1043 (2022)

    2022

  3. [11]

    Charles, J

    C. Charles, J. Choi, X. Ding, S. Agrestini, A. Nag, M. Wu, B. Huang, H. Luo, P. Gao, M. Garcia-Fernandez, L. Qiao, and K.-J. Zhou, Charge density waves in infinite- layer NdNiO 2 nickelates, Nature Materials 21, 1116 (2022)

    2022

  4. [12]

    Krieger, L

    G. Krieger, L. Martinelli, S. Zeng, L. E. Chow, K. Kum- mer, R. Arpaia, M. Moretti Sala, N. B. Brookes, A. Ar- iando, N. Viart, M. Salluzzo, G. Ghiringhelli, and D. Preziosi, Charge and spin order dichotomy in NdNiO2 driven by the capping layer, Phys. Rev. Lett.129, 027002 (2022)

    2022

  5. [13]

    Rossi, M

    M. Rossi, M. Osada, J. Choi, S. Agrestini, D. Jost, Y. Lee, H. Lu, B. Y. Wang, K. Lee, A. Nag, Y.-D. Chuang, C.-T. Kuo, S.-J. Lee, B. Moritz, T. P. Dev- ereaux, Z.-X. Shen, J.-S. Lee, K.-J. Zhou, H. Y. Hwang, and W.-S. Lee, A broken translational symmetry state in an infinite-...

    2022

  6. [14]

    C. T. Parzyck, N. K. Gupta, Y. Wu, V. Anil, L. Bhatt, M. Bouliane, R. Gong, B. Z. Gregory, A. Luo, R. Sutarto, F. He, Y. D. Chuang, T. Zhou, G. Herranz, L. F. Kourk- outis, A. Singer, D. G. Schlom, D. G. Hawthorn, and K. M. Shen, Absence of 3 a0 charge density wave order in th...

    2024

  7. [15]

    Y. Lee, X. Wei, Y. Yu, L. Bhatt, K. Lee, B. H. Goodge, S. P. Harvey, B. Y. Wang, D. A. Muller, L. F. Kourkoutis, W.-S. Lee, S. Raghu, and H. Y. Hwang, Synthesis of superconducting freestanding infinite-layer nickelate het- erostructures on the millimetre scale, Nature Synthesi...

    2025 doi

  8. [16]

    S. Yan, W. Mao, W. Sun, Y. Li, H. Sun, J. Yang, B. Hao, W. Guo, L. Nian, Z. Gu, P. Wang, and Y. Nie, Super- conductivity in freestanding infinite-layer nickelate mem- branes, Advanced Materials 36, 2402916 (2024)

    2024

  9. [17]

    Pelliciari, N

    J. Pelliciari, N. Khan, P. Wasik, A. Barbour, Y. Li, Y. Nie, J. M. Tranquada, V. Bisogni, and C. Mazzoli, Comment on newly found charge density waves in in- finite layer nickelates (2023), arXiv:2306.15086 [cond- mat.supr-con]

    2023 arXiv

  10. [18]

    Benckiser, M

    E. Benckiser, M. Hepting, and B. Keimer, Neighbours in charge, Nature Materials 21, 1476 (2022)

    2022

  11. [19]

    W. Xiao, Z. Yang, S. Hu, Y. He, X. Gao, J. Liu, Z. Deng, Y. Hong, L. Wei, L. Wang, Z. Shen, T. Wang, L. Li, Y. Gan, K. Chen, Q. Zhang, and Z. Liao, Supercon- ductivity in an infinite-layer nickelate superlattice, Nat Commun 15, 10215 (2024)

    2024

  12. [20]

    R. A. Ortiz, H. Menke, F. Misj´ ak, D. T. Man- tadakis, K. F¨ ursich, E. Schierle, G. Logvenov, U. Kaiser, B. Keimer, P. Hansmann, and E. Benckiser, Superlattice approach to doping infinite-layer nickelates, Phys. Rev. B 104, 165137 (2021)

    2021

  13. [21]

    K. Lee, B. H. Goodge, D. Li, M. Osada, B. Y. Wang, Y. Cui, L. F. Kourkoutis, and H. Y. Hwang, Aspects of the synthesis of thin film superconducting infinite-layer nickelates, APL Materials 8, 041107 (2020)

    2020

  14. [22]

    Krieger, A

    G. Krieger, A. Raji, L. Schlur, G. Versini, C. Bouil- let, M. Lenertz, J. Robert, A. Gloter, N. Viart, and D. Preziosi, Synthesis of infinite-layer nickelates and in- fluence of the capping-layer on magnetotransport, Jour- nal of Physics D: Applied Physics 56, 024003 (2022)

    2022

  15. [23]

    C. T. Parzyck, V. Anil, Y. Wu, B. H. Goodge, M. Roddy, L. F. Kourkoutis, D. G. Schlom, and K. M. Shen, Synthe- sis of thin film infinite-layer nickelates by atomic hydro- gen reduction: Clarifying the role of the capping layer, APL Materials 12, 031132 (2024)

    2024

  16. [24]

    Bernardini, L

    F. Bernardini, L. Iglesias, M. Bibes, and A. Cano, Thin- film aspects of superconducting nickelates, Frontiers in Physics 10, 808007 (2022)

    2022

  17. [25]

    Geisler and R

    B. Geisler and R. Pentcheva, Correlated interface elec- tron gas in infinite-layer nickelate versus cuprate films on SrTiO3(001), Phys. Rev. Research 3, 013261 (2021)

    2021

  18. [26]

    A. Raji, A. Gutierrez-Llorente, D. Zhang, X. Li, M. Bibes, L. Iglesias, J.-P. Rueff, and A. Gloter, Un- raveling p-type and n-type interfaces in superconducting 12 infinite-layer nickelate thin films, ADV ANCED FUNC- TIONAL MATERIALS 34, 10.1002/adfm.202409930 (2024)

    2024 doi

  19. [27]

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

    2013

  20. [28]

    St¨ ohr and H

    J. St¨ ohr and H. Siegmann, From Fundamentals to Nanoscale Dynamics (Springer Berlin, 2006)

    2006

  21. [29]

    Macke, A

    S. Macke, A. Radi, J. E. Hamann-Borrero, A. Verna, M. Bluschke, S. Br¨ uck, E. Goering, R. Sutarto, F. He, G. Cristiani, M. Wu, E. Benckiser, H.-U. Habermeier, G. Logvenov, N. Gauquelin, G. A. Botton, A. P. Ka- jdos, S. Stemmer, G. A. Sawatzky, M. W. Haverkort, B. Keimer, and ...

    2014

  22. [30]

    Macke and E

    S. Macke and E. Goering, Magnetic reflectometry of het- erostructures, Journal of Physics: Condensed Matter 26, 363201 (2014)

    2014

  23. [31]

    R. A. Ortiz, Structural, electronic and magnetic proper- ties of infinite-layer nickelate heterostructures and poly- crystals, Ph.D. thesis, Universit¨ at Stuttgart (2022)

    2022

  24. [32]

    M. W. Haverkort, M. Zwierzycki, and O. K. Ander- sen, Multiplet ligand-field theory using wannier orbitals, Phys. Rev. B 85, 165113 (2012)

    2012

  25. [33]

    Y. Lu, M. H¨ oppner, O. Gunnarsson, and M. W. Haverkort, Efficient real-frequency solver for dynamical mean-field theory, Phys. Rev. B 90, 085102 (2014)

    2014

  26. [34]

    M. W. Haverkort, G. Sangiovanni, P. Hansmann, A. Toschi, Y. Lu, and S. Macke, Bands, resonances, edge singularities and excitons in core level spectroscopy in- vestigated within the dynamical mean-field theory, EPL (Europhysics Letters) 108, 57004 (2014)

    2014

  27. [35]

    LaBollita, M.-C

    H. LaBollita, M.-C. Jung, and A. S. Botana, Many-body electronic structure of d9−δ layered nickelates, Phys. Rev. B 106, 115132 (2022)

    2022

  28. [36]

    Giannozzi, S

    P. Giannozzi, S. Baroni, N. Bonini, M. Calandra, R. Car, C. Cavazzoni, D. Ceresoli, G. L. Chiarotti, M. Cococ- cioni, I. Dabo, et al. , Quantum espresso: a modular and open-source software project for quantum simula- tions of materials, Journal of physics: Condensed matter 21,...

    2009

  29. [37]

    Giannozzi, O

    P. Giannozzi, O. Andreussi, T. Brumme, O. Bunau, M. B. Nardelli, M. Calandra, R. Car, C. Cavazzoni, D. Ceresoli, M. Cococcioni, et al. , Advanced capabilities for materials modelling with quantum espresso, Journal of physics: Condensed matter 29, 465901 (2017)

    2017

  30. [38]

    Pizzi, V

    G. Pizzi, V. Vitale, R. Arita, S. Bl¨ ugel, F. Freimuth, G. G´ eranton, M. Gibertini, D. Gresch, C. Johnson, T. Koretsune, et al. , Wannier90 as a community code: new features and applications, Journal of Physics: Con- densed Matter 32, 165902 (2020)

    2020

  31. [39]

    D. R. Hamann, Optimized norm-conserving vanderbilt pseudopotentials, Phys. Rev. B 88, 085117 (2013)

    2013

  32. [40]

    M. J. van Setten, M. Giantomassi, E. Bousquet, M. J. Verstraete, D. R. Hamann, X. Gonze, and G.-M. Rig- nanese, The pseudodojo: Training and grading a 85 ele- ment optimized norm-conserving pseudopotential table, Computer Physics Communications 226, 39 (2018)

    2018

  33. [41]

    Breckenfeld, Z

    E. Breckenfeld, Z. Chen, A. R. Damodaran, and L. W. Martin, Effects of nonequilibrium growth, nonstoichiom- etry, and film orientation on the metal-to-insulator tran- sition in NdNiO 3 thin films, ACS Applied Materials & Interfaces 6, 22436 (2014)

    2014

  34. [42]

    S. J. Allen, A. J. Hauser, E. Mikheev, J. Y. Zhang, N. E. Moreno, J. Son, D. G. Ouellette, J. Kally, A. Kozhanov, L. Balents, and S. Stemmer, Gaps and pseudogaps in perovskite rare earth nickelates, APL Materials3, 062503 (2015)

    2015

  35. [43]

    D. Yao, L. Shi, S. Zhou, H. Liu, J. Zhao, Y. Li, and Y. Wang, Tuning the metal-insulator transition via epitaxial strain and Co doping in NdNiO 3 thin films grown by polymer-assisted deposition, Journal of Applied Physics 119, 035303 (2016)

    2016

  36. [44]

    C. Yang, R. A. Ortiz, Y. Wang, W. Sigle, H. Wang, E. Benckiser, B. Keimer, and P. A. van Aken, Thickness- dependent interface polarity in infinite-layer nickelate su- perlattices, Nano Letters 23, 3291 (2023)

    2023

  37. [45]

    C. T. Parzyck, Y. Wu, L. Bhatt, M. Kang, Z. Arthur, T. M. Pedersen, R. Sutarto, S. Fan, J. Pelliciari, V. Bisogni, G. Herranz, A. B. Georgescu, D. G. Hawthorn, L. F. Kourkoutis, D. A. Muller, D. G. Schlom, and K. M. Shen, Superconductivity in the parent infinite- layer nickela...

    2024 arXiv

  38. [46]

    Matsumoto, M

    K. Matsumoto, M. Haruta, M. Kawai, A. Sakaiguchi, N. Ichikawa, H. Kurata, and Y. Shimakawa, Selective reduction of layers at low temperature in artificial su- perlattice thin films, Scientific Reports 1, 27 (2011)

    2011

  39. [47]

    Benckiser, M

    E. Benckiser, M. W. Haverkort, S. Br¨ uck, E. Goering, S. Macke, A. Fra˜ n´ o, X. Yang, O. K. Andersen, G. Cris- tiani, H.-U. Habermeier, A. V. Boris, I. Zegkinoglou, P. Wochner, H.-J. Kim, V. Hinkov, and B. Keimer, Or- bital reflectometry of oxide heterostructures, Nature Ma-...

    2011

  40. [48]

    M. W. Haverkort, S. I. Csiszar, Z. Hu, S. Altieri, A. Tanaka, H. H. Hsieh, H.-J. Lin, C. T. Chen, T. Hibma, and L. H. Tjeng, Magnetic versus crystal-field linear dichroism in nio thin films, Phys. Rev. B 69, 020408 (2004)

    2004

  41. [49]

    B. H. Goodge, B. Geisler, K. Lee, M. Osada, B. Y. Wang, D. Li, H. Y. Hwang, R. Pentcheva, and L. F. Kourkoutis, Resolving the polar interface of infinite-layer nickelate thin films, Nature Materials 22, 466 (2023)

    2023

  42. [50]

    A. Raji, G. Krieger, N. Viart, D. Preziosi, J.-P. Rueff, and A. Gloter, Charge distribution across capped and uncapped infinite-layer neodymium nickelate thin films, Small 19, 2304872 (2023)

    2023

  43. [51]

    Y. Cao, X. Liu, M. Kareev, D. Choudhury, S. Mid- dey, D. Meyers, J.-W. Kim, P. J. Ryan, J. W. Freeland, and J. Chakhalian, Engineered mott ground state in a LaTiO3+δ/LaNiO3 heterostructure, Nature Communica- tions 7, 10418 (2016)

    2016

  44. [52]

    L. G. Parratt, Surface studies of solids by total reflection of x-rays, Phys. Rev. 95, 359 (1954)

    1954

  45. [53]

    Haverkort, Spin and orbital degrees of freedom in tran- sition metal oxides and oxide thin films studied by soft x-ray absorption spectroscopy , Ph.D

    M. Haverkort, Spin and orbital degrees of freedom in tran- sition metal oxides and oxide thin films studied by soft x-ray absorption spectroscopy , Ph.D. thesis, Universit¨ at zu K¨ oln (2022)

    2022

  46. [54]

    F. M. F. de Groot, J. C. Fuggle, B. T. Thole, and G. A. Sawatzky, 2 p x-ray absorption of 3 d transition- metal compounds: An atomic multiplet description in- cluding the crystal field, Phys. Rev. B 42, 5459 (1990)

    1990

  47. [55]

    Mizokawa and A

    T. Mizokawa and A. Fujimori, Electronic structure and orbital ordering in perovskite-type 3 d transition-metal 13 oxides studied by hartree-fock band-structure calcula- tions, Phys. Rev. B 54, 5368 (1996)

    1996

Pith tools

Reviewed August 9, 2026 · model on record in the stance chip above.