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The same paper concludes two opposite things: its abstract rules out the tetragonal I4/mmm phase for superconducting La3Ni2O7, while its main text says I4/mmm is the host structure.

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2026-08-03 21:25 UTC pith:TTB64IY7

load-bearing objection New high-pressure Raman data that could help settle the nickelate structure debate, but the paper's own abstract and full text claim opposite structures — needs major revision before it can be taken seriously. the 4 major comments →

arxiv 2511.15265 v2 pith:TTB64IY7 submitted 2025-11-19 cond-mat.supr-con cond-mat.str-el

Identifying the structure of La3Ni2O7 in the pressurized superconducting state

Hengyuan Zhang , Jielong Zhang , Mengwu Huo , Junfeng Chen , Deyuan Hu , Dao-Xin Yao , Hualei Sun , Kun Cao
show 1 more author
Meng Wang
This is my paper
classification cond-mat.supr-con cond-mat.str-el
keywords La3Ni2O7bilayer nickelatehigh-pressure Ramanstructural transitionsuperconducting crystal structureI4/mmmFmmmphonon symmetry
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

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

The paper attempts to resolve the long-running debate over which crystal structure hosts superconductivity in pressurized La3Ni2O7, using high-pressure Raman spectroscopy (up to 32.7 GPa, down to 3 K) combined with first-principles phonon calculations. The main text identifies a transition sequence from the orthorhombic Amam phase through a mixed Amam+Fmmm state to a tetragonal I4/mmm phase at about 14.5 GPa, exactly where superconductivity emerges, and concludes that the superconducting state is I4/mmm. The abstract, however, states the opposite: that the persistence of orthorhombic D2h symmetry across the transition rules out I4/mmm and establishes the orthorhombic Fmmm structure as the intrinsic host of superconductivity. A careful reader therefore faces two mutually exclusive central claims in the same manuscript. The paper also offers a probe-depth argument — Raman sees the near-surface region while synchrotron XRD averages over the bulk — to explain why the two techniques have disagreed.

Core claim

On the terms of the full text, the discovery is that the pressurized superconducting state of La3Ni2O7 is the tetragonal I4/mmm phase, signaled by a pronounced phonon renormalization at 14.5 GPa that matches DFT-computed I4/mmm phonon frequencies; low-temperature spectra at 17.3 GPa are identical to room-temperature spectra, confirming the structure persists into the superconducting state. On the terms of the abstract, the discovery is the opposite: the survival of D2h symmetry across the transition rules out I4/mmm, and the orthorhombic Fmmm phase is the intrinsic host. Because both statements appear in the same submission, the paper as a whole does not settle the controversy; it contains t

What carries the argument

The central machinery is symmetry analysis of Raman tensors: in the backscattering geometry with light along the c axis, only modes of Ag, A1g, and B1g symmetry are Raman-active for the three candidate structures (Amam, Fmmm, I4/mmm). Observed peaks are assigned to computed DFPT phonon frequencies (PBE+U) for each phase, and the abrupt appearance and disappearance of peaks at 14.5 GPa is read as a first-order structural transition. A secondary mechanism is the optical probe-depth estimate (633 nm Raman, effective depth about 219 nm) contrasted with X-ray penetration (about 159 μm), used to attribute the Raman-versus-XRD structure discrepancy to strain gradients in single crystals.

Load-bearing premise

The load-bearing premise is that matching Raman peak positions to DFT-computed phonon frequencies for each candidate structure is enough to uniquely distinguish Fmmm from I4/mmm in an unpolarized backscattering measurement; without a quantitative error budget, the distinction may be smaller than the combined experimental resolution and computational uncertainty.

What would settle it

Perform polarization-resolved Raman spectroscopy on a La3Ni2O7 single crystal at about 19 GPa, rotating the linear polarization of incident and scattered light in the ab-plane. In tetragonal I4/mmm the in-plane Raman tensor has a = b, so A1g-mode intensities should be independent of rotation angle; in orthorhombic Fmmm, a ≠ b would give a periodic intensity modulation. A clear modulation would confirm orthorhombic symmetry, while flat intensities would confirm tetragonal symmetry, settling the contradiction without relying on DFT frequency matching.

Watch this falsifier — get emailed when new claim-graph text bears on it.

If this is right

  • The full text's identification of I4/mmm at 14.5 GPa, if correct, makes the orthorhombic-to-tetragonal transition a structural prerequisite for superconductivity and predicts equivalent a and b axes in the superconducting state.
  • The abstract's identification of Fmmm, if correct, instead predicts that the superconducting state retains orthorhombic D2h symmetry with a ≠ b, and that the 'tetragonal' assignment in the main text is an artifact of frequency matching.
  • Either way, the probe-depth argument implies that Raman and synchrotron XRD probe different regions of the sample, so structure determinations on pressurized single crystals depend on which probe is used.
  • The coincidence of the 14.5 GPa transition with the onset of superconductivity is asserted in both sections, so the structural-superconducting correlation is a claim that stands independent of which phase is correct.

Where Pith is reading between the lines

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

  • The internal contradiction suggests a revision gap: the abstract appears to reflect an earlier analysis (Fmmm) while the main text reports a later assignment (I4/mmm); readers should treat the phase assignment as unresolved until the authors specify which analysis is final.
  • A decisive and cheap experiment would be polarization-resolved Raman in the ab-plane at about 19 GPa: I4/mmm forces a = b in the in-plane Raman tensor, so A1g-mode intensities would be invariant under rotation of the linear polarization, while Fmmm's a ≠ b would produce a periodic modulation — bypassing the DFT frequency-matching uncertainty entirely.
  • The probe-depth argument is testable: measuring Raman on the same crystal before and after thinning, or with different excitation wavelengths, should shift the apparent transition pressure if the surface and bulk differ.
  • If the true structure is Fmmm, many published electronic-structure calculations that assume I4/mmm symmetry would need to be redone; if it is I4/mmm, transport and XRD studies that assume orthorhombic strain fields would need reinterpretation.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

4 major / 4 minor

Summary. The paper reports high-pressure Raman spectroscopy (up to 32.7 GPa, down to 3 K) on La3Ni2O7 single crystals, combined with PBE+U phonon calculations, and identifies a structural sequence: ambient Amam, a mixed Amam+Fmmm region near 4 GPa, and a transition at 14.5 GPa to a phase assigned as tetragonal I4/mmm. The full text concludes that the superconducting state is hosted by the I4/mmm structure, with superconductivity emerging at the same pressure. However, the arXiv abstract states the opposite: the high-pressure phase remains orthorhombic Fmmm and the I4/mmm phase is ruled out in the superconducting state. This internal contradiction is central and unresolved in the submitted manuscript.

Significance. If the identification of the high-pressure superconducting phase as tetragonal I4/mmm were reliable, it would resolve a major controversy in the bilayer nickelate field and provide a structural parallel to cuprates and iron-based superconductors. The paper has useful ingredients: high-quality single-crystal Raman data under hydrostatic conditions, symmetry analysis of Raman tensors for the candidate phases, and DFT phonon calculations at pressure. However, the central claim is currently ambiguous because the abstract and full text are mutually exclusive, and the technical evidence does not quantitatively distinguish between Fmmm and I4/mmm. The manuscript in its present form cannot be accepted; the core conclusion must be either corrected or demonstrated with adequate quantitative and polarization-resolved analysis.

major comments (4)
  1. [Abstract vs Full text, Summary] The arXiv abstract explicitly states: 'the persistence of D2h symmetry across the transition rules out the tetragonal I4/mmm phase in the superconducting state' and 'establish the orthorhombic Fmmm structure as the intrinsic host of superconductivity.' The full text Abstract and Summary instead claim 'a complete transition to the tetragonal I4/mmm phase at 14.5 GPa' and 'definitively identify the tetragonal I4/mmm structure as the crystalline framework for superconductivity.' These are opposite central claims. The manuscript as submitted does not present a single coherent thesis; this must be resolved before any further evaluation.
  2. [Supplemental Section 1C and Section 3] The experiment uses unpolarized backscattering geometry with no polarizer or analyzer. The Raman tensors listed in Supplemental Section 3 show that both Fmmm (D2h) and I4/mmm (D4h) have diagonal Ag/A1g modes and xy-type B1g/B2g modes; in an unpolarized measurement the only tensor-level distinction is a≠b (Fmmm) versus a=b (I4/mmm), which is invisible without polarization resolution. The identification therefore reduces to matching peak positions I1–I5 at 19.2 GPa to calculated frequencies. No quantitative comparison is given: no RMS deviation, no confidence interval, no comparison of the same experimental peaks against Fmmm calculated frequencies at 19.2 GPa, and no stated uncertainty for the PBE+U phonon frequencies. Given the stated resolution of 1.5 cm−1 and typical DFT phonon errors of several cm−1, the frequency match alone cannot uniquely determine the space group.
  3. [Fig. S4 and U choice] The DFT phonon calculations use an effective Hubbard U of 1 eV, and Supplemental Fig. S4 shows that calculated frequencies depend on U. The choice of U=1 eV is not independently justified; if this value was chosen to improve agreement with the observed spectra, then the peak matching is partly a fitting procedure. This circularity is not complete, since the measured peaks are not used to fit force constants, but it weakens the evidential weight of the frequency match. The authors should show that the Fmmm vs I4/mmm distinction is robust over a range of U and that U=1 eV is not selected to produce the desired phase assignment.
  4. [Results, probe-depth argument] The paper estimates the Raman probe depth at ~219 nm and the XRD probe depth at ~159 μm, and argues that the surface may transform to I4/mmm while the bulk remains orthorhombic, explaining discrepancies with XRD. But superconductivity is a bulk property. If the surface-sensitive Raman signal differs from the bulk structure, then the measured Raman spectra do not directly establish the structure of the superconducting bulk. The strain-gradient argument is used to reconcile conflicting results, but it also undermines the central claim that the observed I4/mmm assignment applies to the superconducting state. The manuscript needs to justify why the surface phase, rather than the bulk phase, is the relevant host of superconductivity, or provide bulk-sensitive evidence.
minor comments (4)
  1. [General] The phrase 'definitively identify' in the Summary is too strong given the caveats in the probe-depth argument and the lack of quantitative comparison. Rephrase to reflect the level of evidence.
  2. [Fig. 3 caption] The caption says 'The whole spectra in (d) and (e) were magnified 15 and 1.5, respectively.' The text is ambiguous: 'magnified by a factor of (a, b) 15, (c) 7.5' is also unclear. Please specify the multiplication factors separately for each panel and clarify which panels refer to intensity magnifications.
  3. [References] Some references are incomplete: Ref. [7] lacks year/page information, and Ref. [32] is an arXiv preprint without a year. Update these entries.
  4. [Supplementary Section 2] The derivation of the effective probe depth uses the absorption coefficient of LaNiO3 as a proxy for La3Ni2O7. This approximation should be stated as an assumption with a caveat about its uncertainty, rather than as a precise numerical estimate.

Circularity Check

0 steps flagged

No circularity: Raman-to-DFT comparison is an independent assignment; the abstract/full-text structural contradiction is a consistency problem, not a circular reduction.

full rationale

The paper's central derivation chain is: measured Raman spectra at selected pressures are compared with independent PBE+U DFT phonon calculations for candidate space groups (Amam, Fmmm, I4/mmm). The measured Raman frequencies are not used to fit force constants or to optimize the DFT Hamiltonian; the Hubbard U = 1 eV is set in the Supplemental Material (Section 3F), and the paper gives no indication that U was tuned to reproduce the target high-pressure peak assignments. The symmetry-selection-rule filtering is standard group theory applied to the published Raman tensors, not an imported result from the authors' prior work. The self-references to Refs. [3,14,16] serve only for sample provenance and contextual transport/XRD characterization; the transport data showing Tc are also reproduced in Fig. S1, so the superconductivity connection does not rest on a self-citation. There is a serious internal inconsistency: the arXiv abstract concludes Fmmm and rules out I4/mmm, while the full-text Summary concludes I4/mmm; moreover, in the unpolarized backscattering geometry the Fmmm/I4/mmm tensor difference (a ≠ b vs a = b) is not observable, so the abstract's symmetry argument is underdetermined. These are correctness and consistency concerns, not circular reductions: no prediction in the paper is equivalent by construction to its input data or to a fitted parameter. Thus no significant circularity is found.

Axiom & Free-Parameter Ledger

1 free parameters · 5 axioms · 0 invented entities

The phase identification rests on an assumed DFT accuracy, an assumed probe-depth model, and an assumed equivalence of structural and superconducting transition pressures measured under different conditions. The abstract/full-text contradiction is an additional unresolved logical dependence.

free parameters (1)
  • Hubbard U = 1 eV
    Used in PBE+U phonon calculations; Fig. S4 shows frequencies for different U, so U=1 eV may be chosen to match observed Raman peaks. The phase identification depends on calculated frequencies.
axioms (5)
  • standard math Raman backscattering with unpolarized light along c probes only in-plane polarizability components; modes with B2g/B3g/Eg symmetry (xz/yz tensor elements) are inactive.
    Used to argue that certain modes disappear in the high-pressure phase (Supplementary Section 3, Fig. S5).
  • domain assumption DFT-PBE+U phonon frequencies (U=1 eV) are accurate enough to distinguish Fmmm from I4/mmm at the ~1.5 cm−1 experimental resolution.
    The identification of phases I1–I5 and F1–F5 is based on matching observed peak positions to calculated vertical lines (Fig. 3c,d).
  • ad hoc to paper The optical absorption coefficient of LaNiO3 (k=0.69) approximates that of La3Ni2O7, giving a Raman probe depth of ~219 nm.
    Supplementary Section 2; used to argue Raman sees the surface phase while XRD sees the bulk stressed phase.
  • ad hoc to paper The surface region of the single crystal represents the intrinsic pressure state; the internal strain gradient explains discrepancies with XRD.
    Results and Discussions: 'This gradient in internal lattice stress leads to a distribution of structural states within single crystals.' This is a load-bearing reconciliation.
  • domain assumption The structural transition at 14.5 GPa (Ne/He PTM, Raman) coincides with the superconducting onset measured at 15.1 GPa (KBr PTM, transport).
    Supports 'coincides precisely' claim; different PTMs and samples were used.

pith-pipeline@v1.3.0-alltime-deepseek · 14618 in / 15412 out tokens · 139148 ms · 2026-08-03T21:25:41.159063+00:00 · methodology

0 comments
read the original abstract

The crystal structure of La3Ni2O7 in its high-pressure superconducting state has been the subject of intense debate, with conflicting reports proposing orthorhombic (Amam or Fmmm) and tetragonal (I4/mmm) symmetries. Here, using high-pressure Raman spectroscopy down to 3 K, we resolve this controversy by tracking the structural evolution of La3Ni2O7 up to 32.7 GPa. Leveraging rigorous symmetry-based selection rules, we identify a single structural transition from the orthorhombic Amam phase to the Fmmm phase at ~14.5 GPa, signaled by a profound phonon renormalization. Crucially, the persistence of D2h symmetry across the transition rules out the tetragonal I4/mmm phase in the superconducting state in our measurements. The emergence of bulk superconductivity coincides precisely with this transition. Our results establish the orthorhombic Fmmm structure as the intrinsic host of superconductivity in La3Ni2O7 below 19.45 GPa, resolving a central structural controversy and providing a critical foundation for understanding the superconducting mechanism in bilayer nickelates.

Figures

Figures reproduced from arXiv: 2511.15265 by Dao-Xin Yao, Deyuan Hu, Hengyuan Zhang, Hualei Sun, Jielong Zhang, Junfeng Chen, Kun Cao, Meng Wang, Mengwu Huo.

Figure 1
Figure 1. Figure 1: FIG. 1 [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2 [PITH_FULL_IMAGE:figures/full_fig_p002_2.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4 [PITH_FULL_IMAGE:figures/full_fig_p003_4.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3 [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗

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Forward citations

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Reference graph

Works this paper leans on

56 extracted references · 5 linked inside Pith · cited by 5 Pith papers

  1. [1]

    M. Wang, H. H. Wen, T. Wu, D.-X. Yao, and T. Xiang, Normal and superconducting properties of La 3Ni2O7, Chin. Phys. Lett. 41, 077402 (2024)

    2024

  2. [2]

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

    2025

  3. [3]

    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, Nature 621, 493 (2023)

    2023

  4. [4]

    For the primary Raman peak A8 ( B1g) in the Amam phase, the asso- ciated phonon mode involves vibrations localized on half of the in-plane oxygen atoms within the NiO 6 octahe- dra (Fig. 4a). These vibrations directly modulate the in-plane bond lengths, resulting in relatively high Ra- man intensity due to strong coupling with the in-plane polarizability,...

  5. [5]

    Zhang, D

    Y. Zhang, D. Su, Y. Huang, Z. Shan, H. Sun, M. Huo, K. Ye, J. Zhang, Z. Yang, Y. Xu, Y. Su, R. Li, M. Smid- man, M. Wang, L. Jiao, and H. Yuan, High-temperature superconductivity with zero resistance and strange-metal behaviour, Nat. Phys. 20, 1269 (2024)

    2024

  6. [6]

    Hou, P.-T

    J. Hou, P.-T. Yang, Z. Y. Liu, J.-Y. Li, P.-F. Shan, L. Ma, G. Wang, N.-N. Wang, H.-Z. Guo, J.-P. Sun, Y. Uwatoko, M. Wang, G.-M. Zhang, B.-S. Wang, and J.-G. Cheng, Emergence of high-temperature superconducting phase in pressurized La 3Ni2O7 crystals, Chin. Phys. Lett. 40, 117302 (2023)

    2023

  7. [7]

    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, Superconduc- tivity in pressurized trilayer La 4Ni3O10−δ single crystals, Nature 631, 531 (2024)

    2024

  8. [8]

    M. Shi, D. Peng, K. Fan, Z. Xing, S. Yang, Y. Wang, H. Li, R. Wu, M. Du, B. Ge, Z. Zeng, Q. Zeng, J. Ying, T. Wu, and X. Chen, Superconductivity of the hy- brid Ruddlesden–Popper La 5Ni3O11 single crystals under high pressure, arXiv:2502.01018 ()

    Pith/arXiv arXiv

  9. [9]

    Huang, J

    C. Huang, J. Li, X. Huang, H. Zhang, D. Hu, M. Huo, X. Chen, Z. Chen, H. Sun, and M. Wang, Supercon- ductivity in monolayer-trilayer phase of La 3Ni2O7 under high pressure, arXiv:2510.12250

    arXiv

  10. [10]

    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, Signa- tures of ambient pressure superconductivity in thin film La3Ni2O7, Nature 638, 935 (2025)

    2025

  11. [11]

    G. Zhou, W. Lv, H. Wang, Z. Nie, Y. Chen, Y. Li, H. Huang, W.-Q. Chen, Y.-J. Sun, Q.-K. Xue, and Z. Chen, Ambient-pressure superconductivity onset above 40 K in (La,Pr) 3Ni2O7 films, Nature 640, 641 (2025)

    2025

  12. [12]

    F. Li, Z. Xing, D. Peng, J. Dou, N. Guo, L. Ma, Y. Zhang, L. Wang, J. Luo, J. Yang, J. Zhang, T. Chang, Y.-S. Chen, W. Cai, J. Cheng, Y. Wang, Z. Zeng, Q. Zheng, R. Zhou, Q. Zeng, X. Tao, and J. Zhang, Am- bient pressure growth of bilayer nickelate single crystals with superconductivity over 90 K under high pressure, arXiV:2501.14584

    Pith/arXiv arXiv

  13. [13]

    Zhong, J

    Q. Zhong, J. Chen, Z. Qiu, J. Li, X. Huang, P. Ma, M. Huo, H. Dong, H. Sun, and M. Wang, Evolution of the superconductivity in pressurized La 3−xSmxNi2O7, arXiv:2510.13342

    arXiv

  14. [14]

    Z. Qiu, J. Chen, D. V. Semenok, Q. Zhong, D. Zhou, J. Li, P. Ma, X. Huang, M. Huo, T. Xie, X. Chen, H. kwang Mao, V. Struzhkin, H. Sun, and M. Wang, Interlayer coupling enhanced superconductivity near 100 K in La 3−xNdxNi2O7, arXiv:2510.12359

    arXiv

  15. [15]

    J. Li, D. Peng, P. Ma, H. Zhang, Z. Xing, X. Huang, C. Huang, M. Huo, D. Hu, Z. Dong, X. Chen, T. Xie, H. Dong, H. Sun, Q. Zeng, H.-k. Mao, and M. Wang, Identification of superconductivity in bilayer nickelate La3Ni2O7 under high pressure up to 100 GPa, Natl. Sci. Rev. , nwaf220 (2025)

    2025

  16. [16]

    G. Wang, N. Wang, T. Lu, S. Calder, J. Yan, L. Shi, J. Hou, L. Ma, L. Zhang, J. Sun, B. Wang, S. Meng, M. Liu, and J. Cheng, Chemical versus physical pressure effects on the structure transition of bilayer nickelates, npj Quantum Mater. 10, 1 (2025)

    2025

  17. [17]

    L. Wang, Y. Li, S. Y. Xie, F. Liu, H. Sun, C. Huang, Y. Gao, T. Nakagawa, B. Fu, B. Dong, Z. Cao, R. Yu, S. I. Kawaguchi, H. Kadobayashi, M. Wang, C. Jin, H. K. Mao, and H. Liu, Structure responsible for the super- conducting state in La 3Ni2O7 at high-pressure and low- temperature conditions, J. Am. Chem. Soc. 146, 7506 (2024)

    2024

  18. [18]

    Zhang, C

    M. Zhang, C. Pei, Q. Wang, Y. Zhao, C. Li, W. Cao, S. Zhu, J. Wu, and Y. Qi, Effects of pressure and doping on Ruddlesden-Popper phases La n+1NinO3n+1, J. Mater. Sci. Technol. 185, 147 (2024)

    2024

  19. [19]

    Z. Luo, X. Hu, M. Wang, W. W´ u, and D.-X. Yao, Bilayer two-orbital model of La 3Ni2O7 under pressure, Phys. Rev. Lett. 131, 126001 (2023)

    2023

  20. [20]

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

    2024

  21. [21]

    Z. Liu, M. Huo, J. Li, Q. Li, Y. Liu, Y. Dai, X. Zhou, J. Hao, Y. Lu, M. Wang, and H.-H. Wen, Electronic correlations and partial gap in the bilayer nickelate La3Ni2O7, Nat. Commun. 15, 7570 (2024)

    2024

  22. [22]

    Qu, D.-W

    X.-Z. Qu, D.-W. Qu, J. Chen, C. Wu, F. Yang, W. Li, and G. Su, Bilayer t − J − J⊥ model and magnetically mediated pairing in the pressurized nickelate La 3Ni2O7, Phys. Rev. Lett. 132, 036502 (2024)

    2024

  23. [23]

    C. Lu, Z. Pan, F. Yang, and C. Wu, Interlayer-coupling- driven high-temperature superconductivity in La 3Ni2O7 under pressure, Phys. Rev. Lett. 132, 146002 (2024)

    2024

  24. [24]

    Sakakibara, N

    H. Sakakibara, N. Kitamine, M. Ochi, and K. Kuroki, 6 Possible high Tc superconductivity in La 3Ni2O7 under high pressure through manifestation of a nearly half-filled bilayer Hubbard model, Phys. Rev. Lett. 132, 106002 (2024)

    2024

  25. [25]

    Zhang, L.-F

    Y. Zhang, L.-F. Lin, A. Moreo, T. A. Maier, and E. Dagotto, Structural phase transition, s±-wave pair- ing, and magnetic stripe order in bilayered superconduc- tor La 3Ni2O7 under pressure, Nat. Commun. 15, 2470 (2024)

    2024

  26. [26]

    Jiang, Y.-H

    K.-Y. Jiang, Y.-H. Cao, Q.-G. Yang, H.-Y. Lu, and Q.-H. Wang, Theory of pressure dependence of superconductiv- ity in bilayer nickelate La 3Ni2O7, Phys. Rev. Lett. 134, 76001 (2025)

    2025

  27. [27]

    Yang, G.-M

    Y.-f. Yang, G.-M. Zhang, and F.-C. Zhang, Interlayer valence bonds and two-component theory for high- Tc su- perconductivity of La 3Ni2O7 under pressure, Phys. Rev. B 108, L201108 (2023)

    2023

  28. [28]

    Lechermann, J

    F. Lechermann, J. Gondolf, S. B¨ otzel, and I. M. Eremin, Electronic correlations and superconducting instability in La 3Ni2O7 under high pressure, Phys. Rev. B 108, L201121 (2023)

    2023

  29. [29]

    M. K. Crawford, R. L. Harlow, S. Deemyad, V. Tis- sen, J. S. Schilling, E. M. Mccarron, S. W. Tozer, D. E. Cox, N. Ichikawa, and S. Uchida, High-pressure study of structural phase transitions and superconductivity in La1.48Nd0.4Sr0.12CuO4, Phys. Rev. B 71, 104513 (2005)

    2005

  30. [30]

    J. B. Zhang, V. V. Struzhkin, W. Yang, H. K. Mao, H. Q. Lin, Y. C. Ma, N. L. Wang, and X. J. Chen, Ef- fects of pressure and distortion on superconductivity in Tl2Ba2CaCu2O8+δ, Journal of Physics:Condensed Mat- ter 27, 445701 (2015)

    2015

  31. [31]

    Massidda, Sandro, Martinelli, Alberto, Bernardini, and Fabio, The phase diagrams of iron-based supercon- ductors: Theory and experiments, Comptes Rendus Physique 17, 5 (2016)

    2016

  32. [32]

    Medvedev, T

    S. Medvedev, T. M. Mcqueen, and I. A. Troyan, Elec- tronic and magnetic phase diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure, Nature ma- terials 8, 630 (2009)

    2009

  33. [33]

    M. Shi, D. Peng, Y. Li, Z. Xing, Y. Wang, K. Fan, H. Li, R. Wu, Z. Zeng, Q. Zeng, J. Ying, T. Wu, and X. Chen, Prerequisite of superconductivity : SDW rather than tetragonal structure in double-layer La 3Ni2O7−x, arXiv:2501.14202 ()

    Pith/arXiv arXiv

  34. [34]

    Puphal, P

    P. Puphal, P. Reiss, N. Enderlein, Y.-M. Wu, G. Khal- iullin, V. Sundaramurthy, T. Priessnitz, M. Knauft, A. Suthar, L. Richter, M. Isobe, P. A. Van Aken, H. Tak- agi, B. Keimer, Y. E. Suyolcu, B. Wehinger, P. Hans- mann, and M. Hepting, Unconventional crystal structure of the high-pressure superconductor La 3Ni2O7, Phys. Rev. Lett. 133, 146002 (2024)

    2024

  35. [35]

    Y. Li, Y. Cao, L. Liu, P. Peng, H. Lin, C. Pei, M. Zhang, H. Wu, X. Du, W. Zhao, K. Zhai, X. Zhang, J. Zhao, M. Lin, P. Tan, Y. Qi, G. Li, H. Guo, L. Yang, and L. Yang, Distinct ultrafast dynamics of bilayer and tri- layer nickelate superconductors regarding the density- wave-like transitions, Sci. Bull. 70, 180 (2025)

    2025

  36. [36]

    Suthar, V

    A. Suthar, V. Sundaramurthy, M. Bejas, C. Le, P. Puphal, P. Sosa-Lizama, A. Schulz, J. Nuss, M. Isobe, P. A. van Aken, Y. E. Suyolcu, M. Minola, A. P. Schny- der, X. Wu, B. Keimer, G. Khaliullin, A. Greco, and M. Hepting, Multiorbital character of the density wave instability in La 4Ni3O10, arXiv:2508.06440

    Pith/arXiv arXiv

  37. [37]

    D.-H. Gim, C. H. Park, and K. H. Kim, Orbital-selective quasiparticle depletion across the density wave transition in trilayer nickelate La 4Ni3O10, Phys. Rev. Lett. 135, 136505 (2025)

    2025

  38. [38]

    Zhang, H

    S. Zhang, H. Zhang, Z. Dong, J. Li, Q. Xiao, M. Huo, H.-Y. Huang, D.-J. Huang, Y. Wang, Y. Lu, Z. Chen, M. Wang, and Y. Peng, Distinct orbital contributions to electronic and magnetic structures in La 4Ni3O10, arXiv:2509.20727

    Pith/arXiv arXiv

  39. [39]

    Z. Liu, H. Sun, M. Huo, X. Ma, Y. Ji, E. Yi, L. Li, H. Liu, J. Yu, Z. Zhang, Z. Chen, F. Liang, H. Dong, H. Guo, D. Zhong, B. Shen, S. Li, and M. Wang, Evidence for charge and spin density waves in single crystals of La3Ni2O7 and La3Ni2O6, Sci. China-Phys. Mech. Astron. 66, 217411 (2023)

    2023

  40. [40]

    Kresse and J

    G. Kresse and J. Hafner, Ab initio molecular dynamics for liquid metals, Phys. Rev. B 47, 558 (1993)

    1993

  41. [41]

    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. B 54, 11169 (1996)

    1996

  42. [42]

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

    1996

  43. [43]

    A. Togo, L. Chaput, T. Tadano, and I. Tanaka, Imple- mentation strategies in phonopy and phono3py, J. Phys. Condens. Matter 35, 353001 (2023)

    2023

  44. [44]

    Togo, First-principles phonon calculations with phonopy and phono3py, J

    A. Togo, First-principles phonon calculations with phonopy and phono3py, J. Phys. Soc. Jpn. 92, 012001 (2023)

    2023

  45. [45]

    Momma and F

    K. Momma and F. Izumi, VESTA3 for three-dimensional visualization of crystal, volumetric and morphology data, Journal of Applied Crystallography 44, 1272 (2011)

    2011

  46. [46]

    Porezag and M

    D. Porezag and M. R. Pederson, Infrared intensities and raman-scattering activities within density-functional the- ory, Phys. Rev. B 54, 7830 (1996)

    1996

  47. [47]

    Zhang, X.-F

    X. Zhang, X.-F. Qiao, W. Shi, J.-B. Wu, D.-S. Jiang, and P.-H. Tan, Phonon and raman scattering of two- dimensional transition metal dichalcogenides from mono- layer, multilayer to bulk material, Chem. Soc. Rev. 44, 2757 (2015)

    2015

  48. [48]

    J. Wen, Y. Xu, G. Wang, Z.-X. He, Y. Chen, N. Wang, T. Lu, X. Ma, F. Jin, L. Chen, M. Liu, J.-W. Fan, X. Liu, X. Yu Pan, G.-Q. Liu, J. Cheng, and X. Yu, Imaging the Meissner effect in pressurized bilayer nickelate with integrated multi-parameter quantum sensor, Natl. Sci. Rev. , nwaf268 (2025)

    2025

  49. [49]

    Y. Meng, Y. Yang, H. Sun, S. Zhang, J. Luo, L. Chen, X. Ma, M. Wang, F. Hong, X. Wang, and X. Yu, Density- wave-like gap evolution in La 3Ni2O7 under high pressure revealed by ultrafast optical spectroscopy, Nat. Commun. 15, 10408 (2024)

    2024

  50. [50]

    Holzer, W

    W. Holzer, W. Murphy, and H. Bernstein, Raman spectra of negative molecular ions doped in alkali halide crystals, Journal of Molecular Spectroscopy 32, 13 (1969)

    1969

  51. [51]

    P. Borowicz, Depth-sensitive raman investigation of metal-oxide-semiconductor structures: Absorption as a tool for variation of exciting light penetration depth, Journal of Spectroscopy 2016, 1617063 (2016) . Supplementary: Identifying the structure of La 3Ni2O7 in the pressurized superconducting state Hengyuan Zhang, 1, ∗ Jielong Zhang, 1, ∗ Mengwu Huo, ...

    2016

  52. [52]

    P. Borowicz, Depth-sensitive raman investigation of metal - oxide-semiconductor structures: Absorption as a tool for variation of exciting light penetration depth, Journal of Spectroscopy 2016, 1617063 (2016)

    2016

  53. [53]

    J. Yu, J. L. Sun, X. J. Meng, Z. M. Huang, and Q. Liang, Ultraviolet-infrared optical properties of highly (100)- oriented LaNiO3 thin films on Pt–Ti–SiO 2–Si wafer, Jour- nal of Applied Physics 90, 2699 (2001)

    2001

  54. [54]

    National Institute of Standards and Technology (NIST), XCOM: Photon cross sections database (2025), accessed on 2025-09-21

    2025

  55. [55]

    P. E. Bl¨ ochl, Projector augmented-wave method, Phys. Rev. B 50, 17953 (1994)

    1994

  56. [56]

    Kroumova, M

    E. Kroumova, M. Aroyo, J. Perez-Mato, A. Kirov, C. Capillas, S. Ivantchev, and H. Wondratschek, Bilbao crystallographic server : Useful databases and tools for phase-transition studies, Phase Transitions 76, 155 (2003)

    2003