Anomalous Hall Effect in Silicon-Compatible Altermagnetic alpha-MnTe Thin Films

Arijit Mandal; Arindom Das; Aryaman Das; B. R. K. Nanda; Dhavala Suri; Laxmipriya Nanda; Naresh Shyaga; Pankaj Bhardwaj; Rajib Sarkar; Sohini Guin

arxiv: 2605.25953 · v1 · pith:O5DEG37Cnew · submitted 2026-05-25 · ❄️ cond-mat.mtrl-sci

Anomalous Hall Effect in Silicon-Compatible Altermagnetic alpha-MnTe Thin Films

Rajib Sarkar , Subhransu Kumar Negi , Arindom Das , Arijit Mandal , Pankaj Bhardwaj , Sohini Guin , Aryaman Das , Naresh Shyaga

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Laxmipriya Nanda B. R. K. Nanda Dhavala Suri

This is my paper

Pith reviewed 2026-06-29 21:30 UTC · model grok-4.3

classification ❄️ cond-mat.mtrl-sci

keywords altermagnetismanomalous Hall effectalpha-MnTesilicon integrationepitaxial thin filmsBerry curvaturemolecular beam epitaxyspintronics

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The pith

Alpha-MnTe films grown directly on silicon show a hysteretic Hall response from altermagnetic Berry curvature despite zero net magnetization.

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

The paper establishes that epitaxial alpha-MnTe thin films can be grown on Si(111) by molecular beam epitaxy while retaining the altermagnetic state. In this geometry the spin-split bands produce an uncompensated Berry curvature that yields a clear anomalous Hall effect, even though the material carries no net magnetic moment. Structural and transport data confirm phase purity and epitaxial registry, while first-principles calculations tie the observed Hall signal to the altermagnetic symmetry. If correct, the result supplies a concrete route to embed Berry-phase spintronics inside conventional silicon device flows.

Core claim

Epitaxial alpha-MnTe thin films on Si(111) exhibit a pronounced hysteretic anomalous Hall effect generated by finite, uncompensated Berry curvature that arises from the breaking of compensation symmetry in the thin-film geometry; first-principles calculations confirm that the altermagnetic spin-split band structure supplies this curvature, establishing MnTe/Si(111) as a silicon-compatible platform for Berry-phase-driven functionalities.

What carries the argument

Uncompensated Berry curvature arising from the altermagnetic spin-split bands in the thin-film geometry.

If this is right

MnTe can be integrated directly into silicon-based device flows without buffer layers.
The anomalous Hall response persists across a range of temperatures with correlated longitudinal and transverse hysteresis.
First-principles band calculations reproduce the measured Hall conductivity from the altermagnetic band structure.
The thin-film geometry supplies the symmetry breaking needed to generate net Berry curvature in an otherwise compensated altermagnet.

Where Pith is reading between the lines

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

Similar symmetry-breaking routes may allow other altermagnetic candidates to be integrated on silicon once suitable epitaxial conditions are identified.
Device architectures that rely on Hall readout rather than magnetization reversal could be tested directly on these films.
Temperature-dependent scaling of the Hall conductivity offers a way to separate intrinsic Berry-phase contributions from extrinsic scattering terms.

Load-bearing premise

The measured hysteretic Hall signal is produced by intrinsic Berry curvature of the altermagnetic state rather than by defects, interfaces, or measurement artifacts.

What would settle it

Observation of identical hysteretic Hall response in polycrystalline or randomly oriented MnTe films of the same thickness would indicate that the effect does not require the epitaxial altermagnetic symmetry.

Figures

Figures reproduced from arXiv: 2605.25953 by Arijit Mandal, Arindom Das, Aryaman Das, B. R. K. Nanda, Dhavala Suri, Laxmipriya Nanda, Naresh Shyaga, Pankaj Bhardwaj, Rajib Sarkar, Sohini Guin, Subhransu Kumar Negi.

**Figure 2.** Figure 2: (a) Schematic of the Hall bar device fabricated from epitaxial MnTe film of thickness [PITH_FULL_IMAGE:figures/full_fig_p018_2.png] view at source ↗

**Figure 3.** Figure 3: (a) Stacking arrangements of config-I, where extra Te capping at the top with Mn [PITH_FULL_IMAGE:figures/full_fig_p019_3.png] view at source ↗

**Figure 4.** Figure 4: Layer projected DOS for config-I (left) and config-II (right). Except the capping [PITH_FULL_IMAGE:figures/full_fig_p020_4.png] view at source ↗

read the original abstract

Integrating spin-dependent functionality with mainstream semiconductor technology is a central goal of modern spintronics, yet most candidate materials remain incompatible with silicon-based platforms. Here, we report the direct epitaxial integration of alpha-MnTe thin films on Si(111) via molecular beam epitaxy and demonstrate a robust anomalous Hall effect (AHE) in this silicon-compatible altermagnetic system. Despite the absence of net magnetization, the films exhibit a pronounced hysteretic Hall response, providing clear evidence of finite Berry curvature generated by symmetry breaking in the thin-film geometry. High resolution structural and spectroscopic characterization confirms phase-pure, epitaxial growth with hexagonal NiAs-type symmetry, while magnetotransport measurements reveal correlated hysteresis in both transverse and longitudinal channels with systematic temperature evolution. First-principles calculations reveal substantial uncompensated Berry curvature arising from the spin-split band structure consistent with altermagnetic symmetry and the origin of the observed Hall response. These results establish MnTe/Si(111) as a silicon-compatible altermagnetic platform and chart a concrete pathway for embedding Berry-phase-driven functionalities into scalable semiconductor device architectures.

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

Epitaxial alpha-MnTe on Si(111) with observed AHE is the concrete step forward, but the case for intrinsic Berry curvature over extrinsic sources is not yet tight.

read the letter

The paper grows phase-pure alpha-MnTe films on Si(111) by MBE and reports hysteretic Hall response with no net magnetization. Structural and spectroscopic data confirm the NiAs-type structure, and the temperature dependence of the transverse and longitudinal hysteresis is shown together. First-principles results are presented as consistent with uncompensated Berry curvature from the altermagnetic band structure.

That combination is new: prior MnTe work did not include direct silicon integration with this transport signature. The growth and basic characterization appear reproducible from the description, and the absence of net moment is stated clearly.

The remaining issue is whether the Hall signal is generated by the altermagnetic symmetry breaking or by interface states, minor defects, or measurement effects. The abstract and stress-test note both flag that the calculations are only described as consistent rather than quantitatively matched to the measured magnitude and its temperature scaling. No control samples that deliberately break the altermagnetic order are mentioned, so the exclusion of extrinsic channels stays incomplete.

The work is aimed at groups trying to bring altermagnets onto CMOS-compatible lines. Readers focused on materials integration and transport will find the growth details and raw hysteresis data useful even if they want tighter controls.

It should go to peer review. The platform result is specific enough to be checked, and the central claim can be strengthened or corrected with additional data.

Referee Report

2 major / 1 minor

Summary. The manuscript reports molecular-beam-epitaxy growth of phase-pure α-MnTe thin films on Si(111), structural confirmation of hexagonal NiAs-type symmetry, and the observation of a hysteretic anomalous Hall effect (AHE) in the absence of net magnetization. The AHE is attributed to uncompensated Berry curvature arising from altermagnetic symmetry breaking in the thin-film geometry, with first-principles calculations cited as consistent with the measured transport response and temperature evolution.

Significance. If the central interpretation holds, the work establishes a silicon-compatible altermagnetic platform that integrates Berry-phase-driven spintronic functionality with mainstream semiconductor technology, addressing a key materials bottleneck for scalable altermagnetic devices.

major comments (2)

[Abstract / magnetotransport measurements] Abstract and magnetotransport section: the claim that the observed hysteretic Hall response constitutes 'clear evidence' of intrinsic uncompensated Berry curvature is not secured by quantitative comparison of the measured Hall resistivity magnitude or its temperature dependence against the first-principles Berry-curvature integral; without such scaling or error analysis, extrinsic interface or defect contributions cannot be excluded at the level required for the central claim.
[High resolution structural and spectroscopic characterization] Structural and spectroscopic characterization: while phase purity and epitaxial registry are reported, no quantitative bounds are given on possible minority phases, interface reconstruction, or strain-induced moments that could produce an extrinsic AHE; these bounds are load-bearing for the assertion that the response originates solely from altermagnetic symmetry breaking.

minor comments (1)

[Abstract] The abstract refers to 'correlated hysteresis in both transverse and longitudinal channels' without specifying the longitudinal resistivity component or its scaling with the Hall signal; a brief clarification would improve readability.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their careful reading and constructive feedback. We address each major comment point by point below.

read point-by-point responses

Referee: [Abstract / magnetotransport measurements] Abstract and magnetotransport section: the claim that the observed hysteretic Hall response constitutes 'clear evidence' of intrinsic uncompensated Berry curvature is not secured by quantitative comparison of the measured Hall resistivity magnitude or its temperature dependence against the first-principles Berry-curvature integral; without such scaling or error analysis, extrinsic interface or defect contributions cannot be excluded at the level required for the central claim.

Authors: We agree that the manuscript would benefit from a more explicit quantitative comparison between the measured Hall resistivity and the Berry-curvature integral from first-principles calculations. The existing calculations demonstrate that altermagnetic symmetry breaking produces uncompensated Berry curvature whose sign and temperature evolution are consistent with the data, but we did not perform a direct scaling or error analysis. In the revised manuscript we will add this comparison, including an estimate of the expected AHE magnitude from the calculated Berry curvature and a discussion of possible extrinsic contributions. We will also revise the abstract wording from 'clear evidence' to language that reflects the consistency with the intrinsic mechanism while acknowledging the need for further exclusion of extrinsic effects. revision: partial
Referee: [High resolution structural and spectroscopic characterization] Structural and spectroscopic characterization: while phase purity and epitaxial registry are reported, no quantitative bounds are given on possible minority phases, interface reconstruction, or strain-induced moments that could produce an extrinsic AHE; these bounds are load-bearing for the assertion that the response originates solely from altermagnetic symmetry breaking.

Authors: We acknowledge that explicit quantitative bounds on minority phases and potential extrinsic sources are necessary to support the central claim. The reported XRD and TEM data indicate phase-pure epitaxial growth, yet upper limits on minority-phase fractions were not quantified. In the revision we will extract and report quantitative bounds from the XRD peak intensities (e.g., minority phases <1 %) and will add discussion of the absence of detectable interface reconstruction or strain-induced moments, based on the measured lattice parameters, rocking-curve widths, and the lack of net magnetization in SQUID magnetometry. These additions will directly address the load-bearing requirement identified by the referee. revision: yes

Circularity Check

0 steps flagged

No significant circularity; central claim is experimental observation supported by independent measurements.

full rationale

The paper reports epitaxial growth and magnetotransport data on MnTe/Si(111) films, with the AHE observation presented as direct experimental evidence. First-principles calculations are described only as revealing Berry curvature 'consistent with' the altermagnetic state and the observed response; they function as a post-hoc check rather than a derivation from which the result is obtained. No equations reduce a fitted parameter to a 'prediction,' no self-citation chain supplies a uniqueness theorem or ansatz, and the structural/transport data are externally falsifiable. The derivation chain is therefore self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

The central claim rests on the assumption that the measured Hall hysteresis is intrinsic to altermagnetic Berry curvature and that the MBE growth produces phase-pure epitaxial films; no free parameters, invented entities, or additional axioms are stated in the abstract.

pith-pipeline@v0.9.1-grok · 5775 in / 1186 out tokens · 24705 ms · 2026-06-29T21:30:46.699929+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

1 extracted references

[1]

In-plane Hall effect in a RuO2 single crystal

(1) Zhou, X.; Yao, Y.; Li, Z.; Cao, J.; Wu, W.; Luo, J. In-plane Hall effect in a RuO2 single crystal. J. Phys. Chem. Lett.2025, 16, 7883–7888. (2) Wang, M.; Zhang, J.; Tian, D.; Yu, P.; Kagawa, F. Unveiling an in-plane Hall effect in rutile RuO2 films. Commun. Phys.2025, 8, 28. (3) ˇSmejkal, L.; Sinova, J.; Jungwirth, T. Beyond Conventional Ferromagnetis...

2025

[1] [1]

In-plane Hall effect in a RuO2 single crystal

(1) Zhou, X.; Yao, Y.; Li, Z.; Cao, J.; Wu, W.; Luo, J. In-plane Hall effect in a RuO2 single crystal. J. Phys. Chem. Lett.2025, 16, 7883–7888. (2) Wang, M.; Zhang, J.; Tian, D.; Yu, P.; Kagawa, F. Unveiling an in-plane Hall effect in rutile RuO2 films. Commun. Phys.2025, 8, 28. (3) ˇSmejkal, L.; Sinova, J.; Jungwirth, T. Beyond Conventional Ferromagnetis...

2025