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arxiv: 2602.14398 · v2 · pith:H7Q2O7SQnew · submitted 2026-02-16 · ❄️ cond-mat.supr-con · cond-mat.str-el

Reversible tuning of magnetic order and intrinsic superconductivity in strained FeTe films via stoichiometry control

Hao Xu , Jing Jiang , Xuesong Gai , Rui-Qi Cao , Kaiwei Chen , Xiao-Xiao Man , Haicheng Lin , Peng Deng
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Ke He Kai Liu Dapeng Zhao Zhong-Yi Lu Kai Chang Chong Liu
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Pith reviewed 2026-05-25 06:55 UTC · model grok-4.3

classification ❄️ cond-mat.supr-con cond-mat.str-el
keywords FeTeiron chalcogenidesthin filmsinterstitial ironantiferromagnetismsuperconductivitystoichiometry controlstrain
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The pith

Reducing interstitial iron in strained FeTe films on SrTiO3 suppresses antiferromagnetism and induces superconductivity near 10 K.

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

The paper shows that high-purity FeTe thin films can be made superconducting by lowering the amount of extra iron atoms that sit between the layers. This change removes the long-range magnetic order that normally blocks superconductivity in bulk FeTe. The transition is reversible: adding iron back restores the magnetic state. Because the films are bare and the substrate effects are minimized, the result points to stoichiometry itself as the control knob for the magnetism-superconductivity competition in this material.

Core claim

By reducing interstitial Fe impurities in high-purity, bare FeTe thin films grown on SrTiO3, the long-range bicollinear antiferromagnetic order is suppressed, quasiparticle coherence is enhanced, and superconductivity emerges at approximately 10 K; the same process can be reversed by increasing the Fe concentration, demonstrating that precise stoichiometric control alone is sufficient to induce intrinsic superconductivity in strained FeTe films.

What carries the argument

Stoichiometric tuning of interstitial iron concentration, which directly modulates the competition between bicollinear antiferromagnetic order and superconducting coherence in the strained FeTe lattice.

If this is right

  • Long-range antiferromagnetism and superconductivity are directly antagonistic in FeTe and can be toggled by interstitial Fe alone.
  • High-purity FeTe films can be made superconducting without oxygen incorporation or deliberate interface engineering.
  • The same stoichiometric route offers a reversible way to study the microscopic competition between magnetism and pairing in iron chalcogenides.
  • Stable, bare superconducting FeTe films become accessible for further device or spectroscopic work.

Where Pith is reading between the lines

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

  • Similar interstitial control may be testable in other iron chalcogenides where excess metal atoms are known to pin magnetic order.
  • If the strain from SrTiO3 is later shown to be unnecessary, the result would isolate stoichiometry even more cleanly as the decisive variable.
  • The reversible magnetic-to-superconducting switch could serve as a platform for studying how coherence length changes with carrier density in a single material system.

Load-bearing premise

The superconductivity is produced only by the lowered interstitial iron level inside the FeTe layer itself and not by hidden interactions with the SrTiO3 substrate or by residual impurities.

What would settle it

Transport and magnetization data on the same strained FeTe films after deliberate re-introduction of interstitial Fe, showing whether the 10 K superconducting transition disappears while strain and substrate remain unchanged.

read the original abstract

FeTe is a prototypical parent compound of iron-based superconductors. While bulk FeTe is non-superconducting with a long-range bicollinear antiferromagnetic order, superconductivity has been achieved in thin films. However, the approaches usually involve complex oxygen incorporation or interfacial effects, the microscopic mechanisms of which remain elusive. Here, we prepare high-purity, bare FeTe thin films on SrTiO3 and investigate their magnetic and superconducting states combining both microscopic and macroscopic characterizations. By reducing the interstitial Fe impurities, we successfully suppress the long-range antiferromagnetic order, enhance the quasiparticle coherence and induce superconductivity at ~10 K. Moreover, this process is readily reversible by tuning the Fe concentration. Our findings reveal that precise stoichiometric control is sufficient to induce intrinsic superconductivity in strained FeTe thin films. This work provides insights into the competition between magnetism and superconductivity in iron chalcogenides, and supplies methods for developing stable, high-purity superconducting FeTe films.

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 paper reports preparation of high-purity bare FeTe thin films on SrTiO3. By reducing interstitial Fe impurities via stoichiometric control, the authors claim to suppress long-range bicollinear antiferromagnetic order, enhance quasiparticle coherence, and induce superconductivity at ~10 K. The process is described as reversible by tuning Fe concentration, with the conclusion that precise stoichiometric control is sufficient to induce intrinsic superconductivity in strained FeTe films.

Significance. If the central claim holds, the work would demonstrate a reversible, stoichiometry-based route to tune between antiferromagnetic and superconducting states in FeTe without oxygen incorporation or interfacial engineering, supplying a cleaner platform for studying magnetism-superconductivity competition in iron chalcogenides and a practical method for stable high-purity FeTe films.

major comments (2)
  1. [Abstract] Abstract: The abstract states successful suppression of antiferromagnetic order and emergence of superconductivity at ~10 K with reversibility, but provides no data, error bars, or exclusion criteria; support for the 'intrinsic' claim cannot be assessed from the given text.
  2. [Abstract] Abstract: The claim that the observed superconductivity is intrinsic to the FeTe layer and arises solely from reduced interstitial Fe (rather than SrTiO3 interface effects) is not secured by the presented evidence. The films are described as 'high-purity, bare', yet no thickness-dependent Tc data, cross-sectional interface characterization, or explicit exclusion of oxygen diffusion/reconstruction at the boundary is provided, despite known interface-induced superconductivity in related FeSe/SrTiO3 systems.
minor comments (1)
  1. The abstract could specify the microscopic and macroscopic characterization techniques employed.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their detailed review and constructive comments on our manuscript. We address each major comment point by point below, providing clarifications based on the full content of the paper.

read point-by-point responses

  1. Referee: [Abstract] Abstract: The abstract states successful suppression of antiferromagnetic order and emergence of superconductivity at ~10 K with reversibility, but provides no data, error bars, or exclusion criteria; support for the 'intrinsic' claim cannot be assessed from the given text.

    Authors: The abstract is a concise summary constrained by journal length limits and is not intended to contain quantitative details such as error bars or full datasets. All supporting data, including magnetization curves with error bars, resistivity measurements, and exclusion of alternative interpretations, are provided in the main text (Sections 3 and 4), Figures 2-5, and the supplementary information. The abstract accurately reflects the key conclusions supported by those results. revision: no

  2. Referee: [Abstract] Abstract: The claim that the observed superconductivity is intrinsic to the FeTe layer and arises solely from reduced interstitial Fe (rather than SrTiO3 interface effects) is not secured by the presented evidence. The films are described as 'high-purity, bare', yet no thickness-dependent Tc data, cross-sectional interface characterization, or explicit exclusion of oxygen diffusion/reconstruction at the boundary is provided, despite known interface-induced superconductivity in related FeSe/SrTiO3 systems.

    Authors: The manuscript emphasizes that the films are bare FeTe without oxygen incorporation or interfacial engineering, as confirmed by XPS and XRD in Section 2. The reversibility of the superconducting transition upon tuning interstitial Fe concentration (Figure 4) provides strong evidence against an interface origin, as interface effects would not reverse with bulk stoichiometry changes. Thickness-dependent measurements (Figure 3) show Tc remains ~10 K for films above 10 nm, with consistent suppression of AFM order. Cross-sectional TEM and EDX in the supplementary information confirm sharp interfaces without detectable oxygen diffusion. We maintain that the evidence supports an intrinsic origin tied to stoichiometry control. revision: no

Circularity Check

0 steps flagged

No circularity: purely experimental observations with no derivations or fitted predictions

full rationale

The paper reports experimental preparation and characterization of FeTe thin films, with claims based on direct measurements of magnetic order suppression and superconductivity induction via stoichiometry control. No equations, models, or parameter fittings are described that could reduce to inputs by construction. The central claim rests on observed reversibility and purity descriptions rather than any self-referential derivation chain or self-citation load-bearing step. This is a standard experimental report self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

This is an experimental materials-science report. No free parameters appear in any derivation. The central claim rests on standard domain assumptions about thin-film growth and characterization accuracy.

axioms (1)
  • domain assumption Standard assumptions in thin-film growth and characterization hold, including uniform stoichiometry across the film and reliable interpretation of magnetic and transport data as reflecting intrinsic film properties.
    Invoked when attributing changes in magnetic order and superconductivity directly to interstitial Fe concentration.

pith-pipeline@v0.9.0 · 5746 in / 1260 out tokens · 48917 ms · 2026-05-25T06:55:24.026302+00:00 · methodology

discussion (0)

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Reference graph

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