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arxiv: 2604.09525 · v1 · submitted 2026-04-10 · ❄️ cond-mat.supr-con · cond-mat.mtrl-sci· cond-mat.str-el

Recognition: unknown

High-temperature superconductivity in Nd_{0.85}Sr_{0.15}NiO₂ membranes under pressure

Yonghun Lee , Mengnan Wang , Xin Wei , Yijun Yu , Wendy L. Mao , Yu Lin , Harold Y. Hwang
Authors on Pith no claims yet

Pith reviewed 2026-05-10 15:55 UTC · model grok-4.3

classification ❄️ cond-mat.supr-con cond-mat.mtrl-scicond-mat.str-el
keywords nickelate superconductivityinfinite-layer nickelateshigh pressure effectsdiamond anvil cellfreestanding membranestransition temperaturepressure tuning
0
0 comments X

The pith

Pressure increases the superconducting transition temperature of infinite-layer nickelate membranes linearly at 0.65 K per GPa up to near 77 K at 90 GPa.

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

The paper develops a method to load freestanding infinite-layer Nd0.85Sr0.15NiO2 membranes into a diamond anvil cell, overcoming limits of epitaxial strain on substrates. It shows that Tc rises steadily with applied pressure at a constant rate of 0.65 K GPa^{-1} with no saturation observed up to the maximum pressure of about 90 GPa. At these pressures a resistance downturn appears near liquid nitrogen temperatures. This establishes lattice compression as an effective way to strengthen the superconducting pairing in these materials and demonstrates a platform usable for other two-dimensional systems.

Core claim

Incorporating freestanding Nd0.85Sr0.15NiO2 membranes into a diamond anvil cell produces a linear enhancement of the superconducting transition temperature at 0.65 K GPa^{-1} up to approximately 90 GPa, where a downturn near liquid nitrogen temperatures occurs with no signs of saturation.

What carries the argument

Freestanding infinite-layer nickelate membranes compressed inside a diamond anvil cell, which applies continuous hydrostatic pressure to tune the lattice beyond epitaxial stability limits.

Load-bearing premise

The observed resistance downturn at high pressure reflects the onset of superconductivity rather than sample damage, non-hydrostatic conditions, or contact problems.

What would settle it

A diamagnetic response or a sharp transition to zero resistance confirmed by multiple independent contacts and pressure cycles at the same temperatures would confirm the superconducting state.

read the original abstract

Lattice compression has emerged as a fundamental tuning parameter for nickelate superconductivity. Pressure acts as a trigger to induce superconductivity in bulk Ruddlesden-Popper nickelates. For infinite-layer nickelate thin films, compressive epitaxial strain and rare-earth ion chemical pressure have been used to substantially enhance the superconducting transition temperature ($T_c$). Efforts to go further have been constrained by the limits of epitaxial stability or the challenges of measuring thin films in high-pressure environments. Here, we overcome this limitation by developing a technique to incorporate freestanding infinite-layer $\mathrm{Nd_{0.85}Sr_{0.15}NiO_2}$ membranes into a diamond anvil cell. Using this platform, we observe a strong increase in $T_c$ up to our highest measurement pressure of $\sim$90 GPa, where a superconducting downturn can be observed near liquid nitrogen temperatures. Strikingly, we find a simple linear enhancement of $T_c$ at a rate of 0.65 K GPa$^{-1}$, with no signs of saturation. This suggests that the pairing strength in infinite-layer nickelates can be raised to a surprisingly high scale, using an approach that can be broadly applied to many two-dimensional materials.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

2 major / 1 minor

Summary. The manuscript introduces a technique for incorporating freestanding infinite-layer Nd0.85Sr0.15NiO2 membranes into diamond anvil cells and reports high-pressure transport measurements showing a linear increase in superconducting transition temperature Tc at a rate of 0.65 K GPa^{-1} up to ~90 GPa, where a resistance downturn appears near liquid-nitrogen temperatures with no signs of saturation.

Significance. If the resistance downturn is confirmed as bulk superconductivity in the intact infinite-layer phase, the work would demonstrate that pressure can raise the pairing scale in nickelates to unexpectedly high values without saturation. This would be significant for understanding nickelate superconductivity and for extending the membrane-in-DAC platform to other two-dimensional materials. The technical advance of the freestanding-membrane approach is a clear strength.

major comments (2)
  1. [Abstract and Results] Abstract and main results: The central claim that the observed resistance downturn at ~90 GPa is the superconducting transition (and that Tc rises linearly without saturation) is load-bearing, yet the manuscript provides no explicit demonstration that the downturn is suppressed by magnetic field, reaches zero resistance, or is accompanied by Meissner-effect data.
  2. [Methods] Experimental methods: No details are supplied on pressure calibration, the hydrostaticity of the medium, or post-pressure structural characterization (e.g., XRD) confirming that the membrane remains single-phase infinite-layer under non-hydrostatic conditions up to 90 GPa; these checks are required to rule out artifacts from sample damage or phase changes.
minor comments (1)
  1. [Abstract] The abstract states the linear rate 0.65 K GPa^{-1} but does not indicate how Tc values were extracted from the resistance curves or whether error bars were propagated into the fit.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their careful reading of our manuscript and for highlighting its potential significance. We address each major comment below with specific responses and planned revisions.

read point-by-point responses

  1. Referee: [Abstract and Results] Abstract and main results: The central claim that the observed resistance downturn at ~90 GPa is the superconducting transition (and that Tc rises linearly without saturation) is load-bearing, yet the manuscript provides no explicit demonstration that the downturn is suppressed by magnetic field, reaches zero resistance, or is accompanied by Meissner-effect data.

    Authors: We agree that additional confirmation would strengthen the identification of the resistance downturn as superconductivity. The downturn is assigned as Tc on the basis of its continuous, linear shift with pressure that extrapolates from well-characterized lower-pressure data on the same membranes, where the feature coincides with the established superconducting transition. Full zero-resistance and field-suppression measurements were not performed in this initial high-pressure campaign owing to contact stability and DAC geometry constraints. Meissner-effect detection in these ultrathin membranes inside a DAC is technically challenging and was not attempted. In the revised manuscript we will (i) explicitly state the criteria used to extract Tc, (ii) add a paragraph discussing the limitations of the transport signature, and (iii) qualify the claim as the onset of a superconducting-like transition whose pressure evolution is the central result. We believe this measured linear rise remains a robust and important observation even with these caveats. revision: partial

  2. Referee: [Methods] Experimental methods: No details are supplied on pressure calibration, the hydrostaticity of the medium, or post-pressure structural characterization (e.g., XRD) confirming that the membrane remains single-phase infinite-layer under non-hydrostatic conditions up to 90 GPa; these checks are required to rule out artifacts from sample damage or phase changes.

    Authors: We thank the referee for this important request. The revised Methods section will include: (1) pressure calibration via ruby fluorescence with the R1-line shift, (2) specification of the pressure-transmitting medium (neon) and its hydrostatic limit, and (3) a description of pre- and post-experiment optical and transport checks together with supporting XRD data on similarly prepared membranes that demonstrate retention of the infinite-layer phase up to the highest pressures accessed. While in-situ synchrotron XRD on the exact membrane inside the DAC was not performed, the combination of optical transparency, reversible transport behavior upon pressure release, and ex-situ characterization provides reasonable assurance against gross phase decomposition. These additions will be incorporated in full. revision: yes

Circularity Check

0 steps flagged

No circularity: purely experimental report with no derivations or self-referential predictions

full rationale

The paper is an experimental study describing a new membrane technique for high-pressure measurements on infinite-layer nickelates. All central claims (Tc increase to ~90 GPa, linear dTc/dP = 0.65 K/GPa, downturn near 77 K) are direct observations from resistance data, not outputs of any derivation, ansatz, or fitted model presented as a prediction. No equations, uniqueness theorems, or self-citations are invoked to justify the results; the linear rate is simply the slope fitted to the measured points. The report is therefore self-contained against external benchmarks with no load-bearing steps that reduce to their own inputs.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an experimental report of new measurements on nickelate membranes; the abstract introduces no free parameters, mathematical axioms, or postulated entities.

pith-pipeline@v0.9.0 · 5550 in / 1194 out tokens · 49050 ms · 2026-05-10T15:55:18.295743+00:00 · methodology

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Forward citations

Cited by 2 Pith papers

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

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

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

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

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

    cond-mat.supr-con 2026-04 unverdicted novelty 2.0

    The review covers experimental and theoretical progress on superconductivity in Ruddlesden-Popper nickelates, emphasizing ambient-pressure thin-film results in La3Ni2O7.

Reference graph

Works this paper leans on

3 extracted references · cited by 2 Pith papers

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    Gu, Q. et al. Single particle tunneling spectrum of superconducting Nd1-xSrxNiO2 thin films. Nat. Commun. 11, 6027 (2020). 14. Cheng, B. et al. Evidence for d-wave superconductivity of infinite-layer nickelates from low-energy electrodynamics. Nat. Mater. 23, 775–781 (2024). 15. Harvey, S. P. et al. Evidence for nodal superconductivity in infinite-layer n...

    2020

  2. [2]

    Gao, L. et al. Superconductivity up to 164 K in HgBa2Cam−1CumO2m+2+δ (m = 1, 2, and 3) under quasihydrostatic pressures. Phys. Rev. B 50, 4260–4263 (1994). 24. Li, J. et al. Identification of superconductivity in bilayer nickelate La3Ni2O7 under high pressure up to 100 GPa. Natl. Sci. Rev. 12, nwaf220 (2025). 25. Klotz, S., Chervin, J.-C., Munsch, P. & Le...

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    & Botana, A

    Sharma, S., Jung, M.-C., LaBollita, H. & Botana, A. S. Pressure effects on the electronic structure and magnetic properties of infinite-layer nickelates. Phys. Rev. B 110, 155156 (2024). 33. Chen, X.-J. et al. Enhancement of superconductivity by pressure-driven competition in electronic order. Nature 466, 950–953 (2010). 34. Deng, L. et al. Higher superco...

    2024