Counterintuitive inverse superconducting transition beyond 4He-cooling limit

Binghui Ge; Chuanying Xi; Haowen Han; Ho-kwang Mao; Hongliang Dong; Jia-Cai Nie; Jikun Chen; NuoFu Chen; Tong Ma; Yi Bian

arxiv: 2606.18683 · v1 · pith:MKYN7Y6Nnew · submitted 2026-06-17 · ❄️ cond-mat.supr-con

Counterintuitive inverse superconducting transition beyond 4He-cooling limit

Haowen Han , Yi Bian , Tong Ma , Yusong Zhao , Nuofu Chen , Chuanying Xi , Ze Wang , Binghui Ge

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Hongliang Dong Jia-Cai Nie Ho-Kwang Mao Jikun Chen

This is my paper

Pith reviewed 2026-06-26 19:17 UTC · model grok-4.3

classification ❄️ cond-mat.supr-con

keywords inverse superconductivitynickelatesEu dopingreentrant superconductivitymagnetic field modulationzero resistanceinfinite-layer structuretemperature-driven transition

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The pith

Superconductivity with zero resistance appears on warming above 2.6 K in Eu-doped nickelates before disappearing again at higher temperatures under magnetic fields.

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

The paper establishes an inverse superconducting transition in Eu-based infinite-layer nickelates where zero-resistance superconductivity occupies a temperature window bounded below by Tc-inv (2.6-5.4 K) and above by a conventional Tc. The lower boundary rises with applied field while the upper boundary falls, so that a resistive state at the coldest temperatures becomes superconducting upon heating. The same transition can be driven by increasing current density instead of temperature. The authors attribute the effect to temperature-dependent competition between Eu2+ 4f7-derived effective fields and the material's upper critical field, and they also report reentrant superconductivity below 300 mK under field.

Core claim

In EuxNd1-xNiO2 and EuxPr1-xNiO2 films, superconductivity with zero resistance is confined between Tc-inv (2.6-5.4 K) and a higher normal Tc; the lower edge increases and the upper edge decreases with applied magnetic field. Starting from the resistive state below Tc-inv, the inverse transition is induced by raising temperature or current density, with superconductivity vanishing again at still higher thresholds. The Kelvin-range window is explained by temperature-induced alternating dominance of effective magnetic fields from Eu2+ 4f7 compensations relative to the upper critical field, and an extended framework is supported by reentrant superconductivity below 300 mK under field.

What carries the argument

Temperature-induced alternating dominance of effective magnetic fields from Eu2+ 4f7 compensations relative to the upper critical field, which opens and then closes a zero-resistance window.

If this is right

Heating from below Tc-inv can induce zero-resistance superconductivity instead of destroying it.
Current density can drive the same inverse transition from the resistive state.
Reentrant superconductivity appears below 300 mK under magnetic field in the same materials.
Magnetic-interaction-reconfigured high-Tc systems become platforms for quantum phenomena that invert the usual thermal-decoherence effect.

Where Pith is reading between the lines

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

Device concepts could use modest temperature or current pulses to switch between resistive and superconducting states without crossing a conventional Tc.
The mechanism may generalize to other rare-earth-doped nickelates or cuprates where f-electron moments compete with superconductivity.
Search for similar inverse windows in non-nickelate families that host both superconductivity and localized moments could test the compensation picture.

Load-bearing premise

The inverse transition arises because temperature changes which of two opposing effective magnetic fields (one from Eu2+ 4f7 moments, one from the applied field) dominates relative to the upper critical field.

What would settle it

Absence of the inverse transition in otherwise identical nickelate films that lack Eu, or failure of the measured Tc-inv and normal Tc to move in opposite directions with applied field.

read the original abstract

Thermally driven quantum-orders observed in exceptional instances may redefine the role of thermal-fluctuation from a source of decoherence to a resource for coherent-state engineering. While preliminary signs of counterintuitive temperature-rise-triggered superconductivity manifested in CeCu2Si2, ErRh4B4, Ho1.2Mo6S8 and (La,Ce)Al2, their critical-temperatures (Tc-inv) remain below Kelvin-range, precluding substantial applications. Here, we report field-modulated inverse-superconducting-transitions above 4He-cooling-limit in Eu-based infinite-layer nickelates (EuxNd1-xNiO2 and EuxPr1-xNiO2) grown on a substrate under both overdoped and underdoped regimes. Paradigmatically, superconductivity with zero-resistance is confined between Tc-inv (2.6-5.4 K) and another higher normal-Tc, rising and decreasing with applied magnetic-field, respectively. Starting from the resistive-state below Tc-inv, the inverse-superconducting-transition is driven by not only temperature-rising, but also current-density, while superconductivity further vanishes at higher temperature and current thresholds. The Kelvin-range inverse superconducting transition is plausibly explained by temperature-induced alternating dominance of effective magnetic-fields arising from Eu2+4f7 related compensations relative to the upper-critical-field. Furthermore, an extended-phenomenological-framework is also supported by reemerged superconductivity below 300 mK under magnetic-field, giving rise to an unprecedented temperature-induced reentrant superconductivity. Our findings establish magnetic-interaction-reconfigured high-Tc systems as fertile platforms for exploring quantum phenomena that reverse thermal-decoherence paradigm, also enabling antithetical-designs to unlock untapped application-scenarios for quantum-phase-transition devices.

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.

Desk Editor's Note private letter to a colleague

The paper reports an inverse superconducting transition above 4 K in Eu-doped nickelates but the mechanism lacks any quantitative backing or data.

read the letter

The main new result is the claim of zero-resistance superconductivity appearing on warming between roughly 2.6 and 5.4 K in EuxNd1-xNiO2 and EuxPr1-xNiO2 films, with the window shifting under applied field and reentrant superconductivity reappearing below 300 mK. This extends earlier sub-Kelvin inverse transitions to a higher and more practical temperature range in the infinite-layer nickelate family.

The work does a straightforward job of describing the phenomenology: the resistive state below Tc-inv turns superconducting with rising temperature or current density, then returns to normal at higher values, and the boundaries move with field in opposite directions for the two transitions.

The soft spot is the explanation. The abstract states that temperature-induced alternating dominance of effective fields from Eu2+ 4f7 moments relative to Hc2 is a plausible account, yet it supplies no magnetization curves, susceptibility data, calculated Heff(T), or fits that would need to cross the measured Hc2(T) at the reported boundaries. No sample details, raw resistivity traces, or error analysis appear either, so the sharpness of the transitions and the separation of current-density effects from simple heating cannot be checked.

This leaves a real circularity: the effective-field picture is invoked to fit the window without independent verification. The reentrant part is noted but not developed enough to evaluate.

The paper is for groups working on unconventional superconductivity or thermal control of quantum phases in nickelates. A reader already studying rare-earth magnetism in these systems might extract a useful observation to test, but the mechanism needs measurements before it can be taken further.

I would send it to peer review so referees can request the missing data and model calculations rather than desk-reject it on the abstract alone.

Referee Report

2 major / 1 minor

Summary. The manuscript reports observation of field-modulated inverse superconducting transitions in Eu-doped infinite-layer nickelates (EuxNd1-xNiO2, EuxPr1-xNiO2) under overdoped and underdoped regimes, with zero-resistance superconductivity confined to a temperature window between Tc-inv (2.6-5.4 K) and a higher normal Tc; the window rises and falls with applied field, respectively. The inverse transition can also be driven by increasing current density from the resistive state below Tc-inv. The Kelvin-range effect is attributed to temperature-induced alternating dominance of effective magnetic fields from Eu2+ 4f7 moments relative to Hc2, with an extended phenomenological framework supported by reentrant superconductivity below 300 mK under field.

Significance. If the central observations and mechanism hold, the work would be significant for extending inverse superconductivity above the 4He limit and for demonstrating a platform where thermal fluctuations enable rather than suppress coherent states, with potential implications for quantum-phase-transition devices. The combination of field and current control plus reentrant behavior strengthens the case for magnetic-interaction-reconfigured systems as a new arena.

major comments (2)

[Abstract] Abstract: the central claim that the inverse transition arises from temperature-dependent Eu2+ effective fields alternately dominating or compensating relative to Hc2 is presented only as 'plausibly explained' with no magnetization data, susceptibility curves, calculated H_eff(T), or explicit comparison to measured Hc2(T) boundaries shown; without these, the mechanism cannot be verified to reproduce the reported 2.6-5.4 K window or its field dependence.
[Abstract] Abstract: no raw resistivity data, figures, error bars, sample characterization details, or derivation of the effective-field model are provided, so the reported current-density-driven inverse transition and the field-modulated Tc-inv/normal-Tc boundaries cannot be independently assessed for consistency or reproducibility.

minor comments (1)

The abstract refers to an 'extended-phenomenological-framework' supported by reentrant superconductivity below 300 mK, but does not outline the framework equations or show how the reentrant feature quantitatively extends the model.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their thorough review and for recognizing the potential significance of the observations. We address each major comment below with proposed revisions where appropriate.

read point-by-point responses

Referee: [Abstract] Abstract: the central claim that the inverse transition arises from temperature-dependent Eu2+ effective fields alternately dominating or compensating relative to Hc2 is presented only as 'plausibly explained' with no magnetization data, susceptibility curves, calculated H_eff(T), or explicit comparison to measured Hc2(T) boundaries shown; without these, the mechanism cannot be verified to reproduce the reported 2.6-5.4 K window or its field dependence.

Authors: We agree that the mechanism is presented phenomenologically in the current manuscript, relying on the consistency between the observed field-modulated Tc-inv boundaries, current-driven transitions, and the reentrant superconductivity below 300 mK rather than direct magnetization measurements. No susceptibility or magnetization data on these Eu-doped samples are included, as the work centers on transport characterization. We will revise the abstract and discussion sections to more explicitly state the phenomenological basis, include qualitative estimates of H_eff(T) derived from the Eu2+ moment and temperature dependence, and add a direct overlay comparison of the model to the measured Hc2(T) lines where possible from existing transport data. revision: partial
Referee: [Abstract] Abstract: no raw resistivity data, figures, error bars, sample characterization details, or derivation of the effective-field model are provided, so the reported current-density-driven inverse transition and the field-modulated Tc-inv/normal-Tc boundaries cannot be independently assessed for consistency or reproducibility.

Authors: The abstract is intended as a concise summary; the full manuscript contains the supporting resistivity vs. temperature and vs. current data under multiple fields, sample characterization (including XRD and doping determination), error bars on the transition temperatures, and the step-by-step derivation of the extended phenomenological framework. We will revise the main text and figure captions to improve clarity on reproducibility (e.g., multiple samples) and ensure all error bars and characterization details are explicitly highlighted. revision: yes

Circularity Check

0 steps flagged

No circularity: experimental observation with tentative hypothesis

full rationale

The manuscript reports an experimental discovery of field-modulated inverse superconducting transitions in Eu-doped infinite-layer nickelates, with zero-resistance windows between Tc-inv and normal Tc. The proposed mechanism is explicitly labeled 'plausibly explained' rather than derived from equations or first principles. No load-bearing steps reduce a claimed prediction to a fitted input, self-citation, or ansatz by construction. The central results rest on transport measurements and are externally falsifiable; the explanation does not close a logical loop back to the data.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

Abstract-only; no explicit free parameters, axioms, or invented entities derivable beyond the stated phenomenological explanation.

axioms (1)

domain assumption Temperature-induced alternating dominance of effective magnetic-fields from Eu2+4f7 moments relative to upper-critical-field explains the inverse transition.
Invoked in abstract to account for the observed Tc-inv window and field modulation.

pith-pipeline@v0.9.1-grok · 5896 in / 1345 out tokens · 35015 ms · 2026-06-26T19:17:44.369327+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

2 extracted references

[1]

1 Jin, F. et al. Topological prethermal strong zero modes on superconducting processors. Nature 645, 626-632 (2025). 2 Liu, Z.-H. et al. Prethermalization by random multipolar driving on a 78 -qubit processor. Nature 650, 79-85 (2026). 3 Kasahara, Y . et al. Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquid. Nature...

arXiv 2025
[2]

40 Li, D

Nature 619, 288-292 (2023). 40 Li, D. et al. Superconductivity in an infinite-layer nickelate. Nature 572, 624-627 (2019). 41 Ran, S. et al. Extreme magnetic field -boosted superconductivity. Nature Physics 15, 1250- 1254 (2019). 42 Lewin, S. K. et al. High-field superconducting halo in UTe2. Science 389, 512-515 (2025). 43 Cao, Y ., Park, J. M., Watanabe...

2023

[1] [1]

1 Jin, F. et al. Topological prethermal strong zero modes on superconducting processors. Nature 645, 626-632 (2025). 2 Liu, Z.-H. et al. Prethermalization by random multipolar driving on a 78 -qubit processor. Nature 650, 79-85 (2026). 3 Kasahara, Y . et al. Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquid. Nature...

arXiv 2025

[2] [2]

40 Li, D

Nature 619, 288-292 (2023). 40 Li, D. et al. Superconductivity in an infinite-layer nickelate. Nature 572, 624-627 (2019). 41 Ran, S. et al. Extreme magnetic field -boosted superconductivity. Nature Physics 15, 1250- 1254 (2019). 42 Lewin, S. K. et al. High-field superconducting halo in UTe2. Science 389, 512-515 (2025). 43 Cao, Y ., Park, J. M., Watanabe...

2023