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arxiv: 2605.30050 · v1 · pith:QMMVHBOYnew · submitted 2026-05-28 · ❄️ cond-mat.mes-hall · cond-mat.mtrl-sci

Surface Originated Cross-Field Anomalous Transport in Magnetoelectric Multilayers

Jin Cao , Wei Du , Xue-Jin Zhang , Cong Xiao , Qian Niu , Shengyuan A. Yang This is my paper

Pith reviewed 2026-06-29 05:59 UTC · model grok-4.3

classification ❄️ cond-mat.mes-hall cond-mat.mtrl-sci
keywords surface contributionanomalous Nernst effectmagnetoelectric multilayersband geometric quantitiesMnBi2Te4cross-field transportsurface symmetriesquantum geometry
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0 comments X

The pith

Surface contributions to gate-induced responses remain finite in thick slabs and can dominate when bulk terms are symmetry-forbidden.

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

The paper develops a framework that decomposes gate-induced responses such as orbital and spin magnetization and cross-field anomalous thermoelectric transport into surface and bulk contributions treated equally. It demonstrates that the volume-averaged surface contribution stays finite as slab thickness grows and scales identically with the bulk term. This surface response arises from band geometric quantities that differ from those in the bulk and are limited only by surface symmetries. Consequently the surface part can control the total response in situations where symmetry forbids any bulk contribution. The approach is applied to MnBi2Te4 multilayers to predict a surface-dominated cross-field anomalous Nernst effect driven by surface Berry curvature.

Core claim

In slab geometries the conventional expectation that surface contributions to physical responses vanish rapidly with increasing thickness is violated for a class of gate-induced effects. A general framework decomposes the total response into surface- and bulk-contributions on equal footing. The volume-averaged surface contribution remains finite in the thick-slab limit and exhibits the same thickness scaling as the bulk term. The surface response originates from band geometric quantities distinct from those in the bulk and is constrained solely by surface symmetries, allowing it to dominate when the bulk contribution is symmetry-forbidden. In MnBi2Te4 multilayers this yields a strong surface

What carries the argument

General framework that decomposes total response into surface- and bulk-contributions treated on equal footing, with surface response arising from distinct band geometric quantities constrained only by surface symmetries.

If this is right

  • Surface contribution remains finite and scales with thickness identically to the bulk term in the thick-slab limit.
  • Surface response can dominate the overall effect when bulk contribution is symmetry-forbidden.
  • MnBi2Te4 multilayers exhibit a strong surface-dominated cross-field anomalous Nernst effect arising from surface Berry curvature.
  • Surface response is accessible to experimental detection via transport measurements.

Where Pith is reading between the lines

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

  • The same decomposition may apply to other gate-tunable responses in layered systems beyond the examples given.
  • Varying slab thickness while monitoring response magnitude could isolate the surface geometric contribution experimentally.
  • Surface symmetries could be engineered in other magnetoelectric multilayers to control thermoelectric transport without bulk participation.

Load-bearing premise

The decomposition of the total response into surface and bulk contributions treated on equal footing is valid and the surface response is constrained solely by surface symmetries.

What would settle it

Experimental measurement of the thickness dependence of the anomalous Nernst coefficient in MnBi2Te4 multilayers that shows whether a finite surface contribution persists as thickness increases well beyond typical surface penetration depths.

Figures

Figures reproduced from arXiv: 2605.30050 by Cong Xiao, Jin Cao, Qian Niu, Shengyuan A. Yang, Wei Du, Xue-Jin Zhang.

Figure 1
Figure 1. Figure 1: FIG. 1. A multilayer system under gate field [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Schematics of (a) gate-field-induced orbital magneti [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. (a) Calculated cross-field anomalous Hall coefficient [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
read the original abstract

In material systems with slab geometry, the surface contribution to physical responses is commonly expected to diminish rapidly with increasing thickness, giving way to the bulk response. Here, we show that this conventional wisdom is violated in a class of gate-induced responses, including gate-induced orbital and spin magnetization as well as cross-field anomalous thermoelectric transport. We develop a general framework for these effects, which naturally decomposes the total response into surface- and bulk-contributions treated on equal footing. Remarkably, the volume-averaged surface contribution remains finite in the thick-slab limit and exhibits the same thickness scaling as the bulk term. Furthermore, the surface response originates from band geometric quantities distinct from those in the bulk, being constrained solely by surface symmetries. As a result, it can dominate the overall response when the bulk contribution is symmetry-forbidden. Taking MnBi$_2$Te$_4$ multilayers as an example, we predict a strong surface-dominated cross-field anomalous Nernst effect arising from surface Berry curvature, which is readily accessible to experimental detection. These findings reveal a previously overlooked significance of surface response and open a new direction in the study of surface quantum geometry.

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

0 major / 3 minor

Summary. The manuscript develops a general framework that decomposes gate-induced responses (orbital/spin magnetization and cross-field anomalous thermoelectric transport) in slab geometries into surface and bulk contributions placed on equal footing. It demonstrates that the volume-averaged surface contribution remains finite in the thick-slab limit, exhibits identical thickness scaling to the bulk term, and arises from distinct band-geometric quantities fixed solely by surface symmetries. Consequently the surface term can dominate when the bulk contribution is symmetry-forbidden. The authors apply the framework to MnBi₂Te₄ multilayers and predict a strong, experimentally accessible surface-dominated cross-field anomalous Nernst effect driven by surface Berry curvature.

Significance. If the decomposition and scaling arguments hold, the work would be significant for revealing a previously overlooked finite surface contribution in thick slabs for a class of gate-induced responses, thereby elevating the role of surface quantum geometry in magnetoelectric multilayers. The concrete, falsifiable prediction of a surface-dominated anomalous Nernst effect in MnBi₂Te₄ supplies a clear experimental target and strengthens the central claim.

minor comments (3)
  1. [Framework section] The abstract states that surface symmetries alone constrain the surface geometric quantities; the main text should include an explicit symmetry-table or character-table comparison (e.g., in the section introducing the framework) to make this constraint transparent to readers.
  2. [MnBi₂Te₄ application] The MnBi₂Te₄ prediction would benefit from a brief statement of the slab thickness range (in unit cells) over which the surface term is expected to dominate, together with an estimate of the required gate voltage or Fermi-level position.
  3. A small number of typographical inconsistencies appear in the figure captions (e.g., inconsistent use of “cross-field” versus “cross field”); these should be standardized.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive assessment of our manuscript, the accurate summary of our framework and results, and the recommendation of minor revision. We are pleased that the significance of the surface contribution to gate-induced responses and the concrete prediction for MnBi₂Te₄ are recognized.

Circularity Check

0 steps flagged

No significant circularity identified

full rationale

The provided text is limited to the abstract, which outlines a decomposition framework treating surface and bulk contributions on equal footing without any equations, derivations, or self-citations shown. No load-bearing steps reduce by construction to inputs, fitted parameters, or self-referential definitions. The scaling claim for the volume-averaged surface term is presented as a general result from band geometry constrained by surface symmetries, appearing self-contained and independent of the present paper's own prior results.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review yields no explicit free parameters, axioms, or invented entities. The framework implicitly relies on standard band-geometry concepts (Berry curvature) treated as background; no ad-hoc entities or fitted constants are mentioned.

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