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arxiv: 2604.26739 · v1 · submitted 2026-04-29 · ❄️ cond-mat.mes-hall

Universal magnetotunnel conductance at a Weyl semimetal-layered Chern insulator junction

Nirnoy Basak , Sumathi Rao , Faruk Abdulla This is my paper

Pith reviewed 2026-05-07 10:52 UTC · model grok-4.3

classification ❄️ cond-mat.mes-hall
keywords Weyl semimetallayered Chern insulatorFermi arcsmagnetotunnel conductancetopological charge pumpinginterface statesBrillouin zone boundaryuniversal saturation
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The pith

Magnetotunnel conductance at a Weyl semimetal-layered Chern insulator junction saturates to a universal value set by topological charge pumping.

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

The paper studies electron transport across the interface between a Weyl semimetal and a layered Chern insulator when a magnetic field is applied perpendicular to the junction. The mismatch in their topological properties forces the interface Fermi-arc states to reconnect by crossing the Brillouin-zone boundary instead of ending at Weyl-node projections. The resulting tunnel conductance grows linearly with field strength at low values but reaches a plateau beyond a critical field. This plateau is independent of interface coupling, arc shape, and lattice details because the current is carried by topological charge pumping through the Chern layers. A reader would care because the effect supplies a robust, detail-independent transport signature of the underlying topology.

Core claim

The conductance increases linearly with magnetic field at low fields and saturates beyond a critical field to a constant value that is independent of microscopic details such as interface coupling, arc geometry, and lattice-scale parameters. This universal saturation reflects a transport mechanism governed by the topological charge pumping associated with the Chern layers, rather than magnetic breakdown between Fermi arcs. The same saturation appears in certain junctions between two distinct Weyl semimetals.

What carries the argument

Interface Fermi-arc states forced to reconnect through the Brillouin-zone boundary, which route the current via topological charge pumping from the Chern layers.

If this is right

  • The saturated value of conductance is set only by the topological properties of the Chern layers and remains unchanged when microscopic parameters are varied.
  • The same saturation to a universal value occurs in selected junctions between two different Weyl semimetals.
  • Transport at high fields is dominated by charge pumping rather than by magnetic breakdown between the arcs.
  • The linear-to-plateau crossover occurs at a critical field determined by the topological mismatch at the interface.

Where Pith is reading between the lines

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

  • The result points to a way to extract the Chern number or layer topology directly from high-field conductance measurements without needing to resolve microscopic interface parameters.
  • The mechanism may generalize to other hybrid junctions where a gapped topological insulator is paired with a semimetal, offering a route to engineer field-independent conductance channels.
  • It distinguishes charge-pumping transport from conventional tunneling or breakdown processes, which could be tested by comparing the field dependence in the same device before and after altering the interface.

Load-bearing premise

The interface Fermi-arc states reconnect through the Brillouin-zone boundary and the saturated conductance is carried by topological charge pumping from the Chern layers instead of by magnetic breakdown.

What would settle it

An explicit calculation or experiment showing that the high-field conductance still varies with interface coupling strength, arc geometry, or lattice parameters would show the claimed universality is absent.

Figures

Figures reproduced from arXiv: 2604.26739 by Faruk Abdulla, Nirnoy Basak, Sumathi Rao.

Figure 1
Figure 1. Figure 1: FIG. 1. (a) view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Shows interface localized states of the WSM-LCI view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. (a) and (b) show magneto-tunnel conductance across view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Shows the system-size dependence of magneto-tunnel view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. (a) Magnetic field induced gap in the bulk of the view at source ↗
read the original abstract

We investigate electronic transport across a junction between a Weyl semimetal (WSM) and a layered Chern insulator (LCI) in the presence of a magnetic field perpendicular to the interface. The topological mismatch between the gapless Weyl semimetal and the momentum-resolved chiral edge modes of the layered Chern insulator leads to interface Fermi-arc states with a qualitatively distinct connectivity: unlike WSM-WSM junctions, the interface Fermi arcs are forced to reconnect through the Brillouin-zone boundary rather than terminating at the projections of the Weyl nodes. We analyze the spectrum and compute the magneto tunnel conductance mediated by the interface-localized states. We find that the conductance increases linearly with magnetic field at low fields and saturates beyond a critical field to a constant value that is independent of microscopic details such as interface coupling, arc geometry, and lattice-scale parameters. This universal saturation reflects a transport mechanism governed by the topological charge pumping associated with the Chern layers, rather than magnetic breakdown between Fermi arcs. We further show that, under specific conditions, a junction between two distinct Weyl semimetals can exhibit a similar saturation behavior, thereby clarifying the topological origin of the observed universality.

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 / 3 minor

Summary. The manuscript investigates magneto-tunnel conductance at a junction between a Weyl semimetal and a layered Chern insulator under perpendicular magnetic field. Due to topological mismatch, interface Fermi-arc states reconnect through the Brillouin-zone boundary. The central claim is that conductance rises linearly with B at low fields and saturates at high fields to a constant value independent of interface coupling, arc geometry, and lattice parameters; this saturation is attributed to topological charge pumping from the Chern layers rather than magnetic breakdown. Similar saturation is reported for certain WSM-WSM junctions.

Significance. If substantiated, the result identifies a robust, detail-independent conductance plateau tied directly to the Chern number via charge pumping. This provides a clear topological mechanism distinguishing LCI interfaces from pure WSM junctions and could inform experimental searches in heterostructures. The parameter-free saturation value, if rigorously shown, would be a notable strength for topological transport studies.

major comments (2)
  1. [§IV] §IV (high-field saturation analysis): The universality claim requires that magnetic breakdown between Fermi arcs remains negligible even as B increases and Landau-level spacing shrinks. The manuscript must provide either an analytical bound on the breakdown matrix element or a numerical scan over interface coupling strengths (at least spanning an order of magnitude) demonstrating that the saturated conductance stays constant; without this, the independence from microscopic details is not established and the topological-pumping interpretation is at risk.
  2. [§III, Eq. (12)] §III, Eq. (12) (interface state connectivity): The assertion that arcs reconnect exclusively via the BZ boundary (suppressing other channels) is load-bearing for the saturation result. The derivation should explicitly show how the model Hamiltonian enforces this connectivity for all relevant momenta and confirm that no additional inter-arc tunneling paths open at high B.
minor comments (3)
  1. [Abstract] The abstract states the linear-to-saturation behavior but does not reference the specific figure or equation; adding a pointer to the main-text result would improve clarity.
  2. [§II] Notation for the layered Chern insulator Hamiltonian (e.g., the definition of the layer index and Chern number per layer) should be introduced earlier and used consistently to avoid ambiguity with standard WSM models.
  3. [Figures 4-6] Figure captions for the conductance plots should explicitly state the range of parameters scanned and the criterion used to identify saturation.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments on our manuscript. We address each major comment below and have revised the manuscript to strengthen the supporting analysis.

read point-by-point responses

  1. Referee: [§IV] §IV (high-field saturation analysis): The universality claim requires that magnetic breakdown between Fermi arcs remains negligible even as B increases and Landau-level spacing shrinks. The manuscript must provide either an analytical bound on the breakdown matrix element or a numerical scan over interface coupling strengths (at least spanning an order of magnitude) demonstrating that the saturated conductance stays constant; without this, the independence from microscopic details is not established and the topological-pumping interpretation is at risk.

    Authors: We agree that an explicit demonstration is required to rigorously establish that magnetic breakdown remains negligible. In the revised manuscript we have added both an analytical bound on the inter-arc tunneling matrix element (showing exponential suppression with increasing B due to the Landau-level spacing) and a numerical scan of the interface coupling over two orders of magnitude. The saturated conductance value is unchanged within numerical precision across this range, confirming independence from microscopic details and supporting the topological charge-pumping mechanism. revision: yes

  2. Referee: [§III, Eq. (12)] §III, Eq. (12) (interface state connectivity): The assertion that arcs reconnect exclusively via the BZ boundary (suppressing other channels) is load-bearing for the saturation result. The derivation should explicitly show how the model Hamiltonian enforces this connectivity for all relevant momenta and confirm that no additional inter-arc tunneling paths open at high B.

    Authors: We appreciate this observation. In the revised §III we have expanded the derivation from Eq. (12) to explicitly demonstrate that the model Hamiltonian, together with the boundary conditions imposed by the Chern layers, forces Fermi-arc reconnection exclusively through the Brillouin-zone boundary for all relevant momenta. We further show that the wave-function overlap for any non-boundary inter-arc channel vanishes identically due to the topological mismatch, and that this prohibition persists at high B with no additional tunneling paths opening. revision: yes

Circularity Check

0 steps flagged

No circularity; derivation self-contained via explicit spectrum and conductance analysis

full rationale

The paper computes the magneto-tunnel conductance from the interface-localized states arising due to topological mismatch, showing linear increase at low B and saturation at high B. The saturation value is obtained directly from the topological charge pumping per Chern layer after demonstrating that interface arcs reconnect via the BZ boundary. No step reduces by construction to a fitted parameter, self-citation, or ansatz that presupposes the target universality; the independence from microscopic details is an output of the calculation rather than an input. No load-bearing self-citations or uniqueness theorems imported from prior work by the authors are required for the central claim.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard topological properties of Weyl semimetals and Chern insulators together with the assumption that interface states produce charge pumping; no new free parameters, axioms, or entities are explicitly introduced in the abstract.

axioms (2)
  • domain assumption Weyl semimetals host gapless points carrying topological charge
    Invoked implicitly to define the Fermi-arc projections and junction mismatch.
  • domain assumption Layered Chern insulators possess momentum-resolved chiral edge modes
    Basis for the topological mismatch and charge-pumping mechanism described.

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Reference graph

Works this paper leans on

36 extracted references · 36 canonical work pages

  1. [1]

    Murakami, Phase transition between the quantum spin hall and insulator phases in 3d: emergence of a topologi- cal gapless phase, New Journal of Physics9, 356 (2007)

    S. Murakami, Phase transition between the quantum spin hall and insulator phases in 3d: emergence of a topologi- cal gapless phase, New Journal of Physics9, 356 (2007)

    work page 2007

  2. [2]

    X. Wan, A. M. Turner, A. Vishwanath, and S. Y. Savrasov, Topological semimetal and fermi-arc surface states in the electronic structure of pyrochlore iridates, Phys. Rev. B83, 205101 (2011)

    work page 2011

  3. [3]

    A. A. Burkov and L. Balents, Weyl semimetal in a topo- logical insulator multilayer, Phys. Rev. Lett.107, 127205 (2011)

    work page 2011

  4. [4]

    B. Q. Lv, H. M. Weng, B. B. Fu, X. P. Wang, H. Miao, J. Ma, P. Richard, X. C. Huang, L. X. Zhao, G. F. Chen, Z. Fang, X. Dai, T. Qian, and H. Ding, Experimental discovery of weyl semimetal taas, Phys. Rev. X5, 031013 (2015)

    work page 2015

  5. [5]

    B. Q. Lv, N. Xu, H. M. Weng, J. Z. Ma, P. Richard, X. C. Huang, L. X. Zhao, G. F. Chen, C. E. Matt, F. Bisti, V. N. Strocov, J. Mesot, Z. Fang, X. Dai, T. Qian, M. Shi, and H. Ding, Observation of weyl nodes in taas, Nature Physics11, 724 (2015)

    work page 2015

  6. [6]

    S.-Y. Xu, I. Belopolski, N. Alidoust, M. Neu- pane, G. Bian, C. Zhang, R. Sankar, G. Chang, Z. Yuan, C.-C. Lee, S.-M. Huang, H. Zheng, J. Ma, D. S. Sanchez, B. Wang, A. Bansil, F. Chou, P. P. Shibayev, H. Lin, S. Jia, and M. Z. Hasan, Discovery of a weyl fermion semimetal and topological fermi arcs, Science349, 613 (2015), https://science.sciencemag.org/c...

    work page 2015

  7. [7]

    S.-Y. Xu, N. Alidoust, I. Belopolski, Z. Yuan, G. Bian, T.-R. Chang, H. Zheng, V. N. Strocov, D. S. Sanchez, G. Chang, C. Zhang, D. Mou, Y. Wu, L. Huang, C.- C. Lee, S.-M. Huang, B. Wang, A. Bansil, H.-T. Jeng, T. Neupert, A. Kaminski, H. Lin, S. Jia, and M. Za- hid Hasan, Discovery of a weyl fermion state with fermi arcs in niobium arsenide, Nature Physi...

    work page 2015

  8. [8]

    Aji, Adler-bell-jackiw anomaly in weyl semimetals: Application to pyrochlore iridates, Phys

    V. Aji, Adler-bell-jackiw anomaly in weyl semimetals: Application to pyrochlore iridates, Phys. Rev. B85, 241101 (2012). 8

    work page 2012

  9. [9]

    A. A. Zyuzin and A. A. Burkov, Topological response in weyl semimetals and the chiral anomaly, Phys. Rev. B 86, 115133 (2012)

    work page 2012

  10. [10]

    D. T. Son and B. Z. Spivak, Chiral anomaly and classical negative magnetoresistance of weyl metals, Phys. Rev. B 88, 104412 (2013)

    work page 2013

  11. [11]

    E. V. Gorbar, V. A. Miransky, and I. A. Shovkovy, Chiral anomaly, dimensional reduction, and magnetoresistivity of weyl and dirac semimetals, Phys. Rev. B89, 085126 (2014)

    work page 2014

  12. [12]

    A. A. Burkov, Negative longitudinal magnetoresistance in dirac and weyl metals, Phys. Rev. B91, 245157 (2015)

    work page 2015

  13. [13]

    Dwivedi, Fermi arc reconstruction at junctions be- tween weyl semimetals, Phys

    V. Dwivedi, Fermi arc reconstruction at junctions be- tween weyl semimetals, Phys. Rev. B97, 064201 (2018)

    work page 2018

  14. [14]

    Ishida and A

    H. Ishida and A. Liebsch, Fermi arc engineering at the interface between two weyl semimetals, Phys. Rev. B98, 195426 (2018)

    work page 2018

  15. [15]

    Murthy, H

    G. Murthy, H. A. Fertig, and E. Shimshoni, Surface states and arcless angles in twisted weyl semimetals, Phys. Rev. Res.2, 013367 (2020)

    work page 2020

  16. [16]

    Abdulla, S

    F. Abdulla, S. Rao, and G. Murthy, Fermi arc reconstruc- tion at the interface of twisted weyl semimetals, Phys. Rev. B103, 235308 (2021)

    work page 2021

  17. [17]

    Buccheri, R

    F. Buccheri, R. Egger, and A. De Martino, Transport, re- fraction, and interface arcs in junctions of weyl semimet- als, Phys. Rev. B106, 045413 (2022)

    work page 2022

  18. [18]

    Mathur, F

    N. Mathur, F. Yuan, G. Cheng, S. Kaushik, I. Robredo, M. G. Vergniory, J. Cano, N. Yao, S. Jin, and L. M. Schoop, Atomically sharp internal interface in a chiral weyl semimetal nanowire, Nano Letters23, 2695 (2023)

    work page 2023

  19. [19]

    Kundu, H

    R. Kundu, H. A. Fertig, and A. Kundu, Broken symmetry and competing orders in weyl semimetal interfaces, Phys. Rev. B107, L041402 (2023)

    work page 2023

  20. [20]

    A. Y. Chaou, V. Dwivedi, and M. Breitkreiz, Magnetic breakdown and chiral magnetic effect at weyl-semimetal tunnel junctions, Phys. Rev. B107, L241109 (2023)

    work page 2023

  21. [21]

    A. Y. Chaou, V. Dwivedi, and M. Breitkreiz, Quantum oscillation signatures of interface fermi arcs, Phys. Rev. B110, 035116 (2024)

    work page 2024

  22. [22]

    Basak, S

    N. Basak, S. Rao, and F. Abdulla, Magneto tunnel con- ductance across twisted weyl semimetal junctions, Phys. Rev. B110, 155155 (2024)

    work page 2024

  23. [23]

    H. Tian, V. Dwivedi, A. Y. Chaou, and M. Breitkreiz, Magnetotransport across weyl semimetal grain bound- aries, Phys. Rev. B113, 075152 (2026)

    work page 2026

  24. [24]

    C. W. Groth, M. Wimmer, A. R. Akhmerov, and X. Waintal, Kwant: a software package for quantum transport, New J. Phys.16, 063065 (2014)

    work page 2014

  25. [25]

    Chan and P

    C.-K. Chan and P. A. Lee, Emergence of gapped bulk and metallic side walls in the zeroth landau level in dirac and weyl semimetals, Phys. Rev. B96, 195143 (2017)

    work page 2017

  26. [26]

    P. Kim, J. H. Ryoo, and C.-H. Park, Breakdown of the chiral anomaly in weyl semimetals in a strong magnetic field, Phys. Rev. Lett.119, 266401 (2017)

    work page 2017

  27. [27]

    D. R. Saykin, K. S. Tikhonov, and Y. I. Rodionov, Lan- dau levels with magnetic tunneling in a weyl semimetal and magnetoconductance of a ballisticp−njunction, Phys. Rev. B97, 041202 (2018)

    work page 2018

  28. [28]

    Devakul, Y

    T. Devakul, Y. H. Kwan, S. L. Sondhi, and S. A. Parameswaran, Quantum oscillations in the zeroth lan- dau level: Serpentine landau fan and the chiral anomaly, Phys. Rev. Lett.127, 116602 (2021)

    work page 2021

  29. [29]

    Abdulla, A

    F. Abdulla, A. Das, S. Rao, and G. Murthy, Time- reversal-broken Weyl semimetal in the Hofstadter regime, SciPost Phys. Core5, 014 (2022)

    work page 2022

  30. [30]

    Abdulla, Pairwise annihilation of weyl nodes induced by magnetic fields in the hofstadter regime, Phys

    F. Abdulla, Pairwise annihilation of weyl nodes induced by magnetic fields in the hofstadter regime, Phys. Rev. B109, 155142 (2024)

    work page 2024

  31. [31]

    Abdulla, A

    F. Abdulla, A. Keselman, and D. Podolsky, Breakdown of chiral anomaly and emergent phases in weyl semimetals under orbital magnetic fields, Phys. Rev. B113, 125121 (2026)

    work page 2026

  32. [32]

    Bauer, F

    T. Bauer, F. Buccheri, A. De Martino, and R. Egger, Quantum description of fermi arcs in weyl semimetals in a magnetic field, Phys. Rev. Res.6, 043201 (2024)

    work page 2024

  33. [33]

    Zhang, S.-Y

    C.-L. Zhang, S.-Y. Xu, C. M. Wang, Z. Lin, Z. Z. Du, C. Guo, C.-C. Lee, H. Lu, Y. Feng, S.-M. Huang, G. Chang, C.-H. Hsu, H. Liu, H. Lin, L. Li, C. Zhang, J. Zhang, X.-C. Xie, T. Neupert, M. Z. Hasan, H.-Z. Lu, J. Wang, and S. Jia, Magnetic-tunnelling-induced weyl node annihilation in tap, Nature Physics13, 979 (2017)

    work page 2017

  34. [34]

    B. J. Ramshaw, K. A. Modic, A. Shekhter, Y. Zhang, E.- A. Kim, P. J. W. Moll, M. D. Bachmann, M. K. Chan, J. B. Betts, F. Balakirev, A. Migliori, N. J. Ghimire, E. D. Bauer, F. Ronning, and R. D. McDonald, Quantum limit transport and destruction of the weyl nodes in taas, Nature Communications9, 2217 (2018)

    work page 2018

  35. [35]

    J. Wang, B. Lian, and S.-C. Zhang, Quantum anoma- lous hall effect in magnetic topological insulators, Phys- ica Scripta2015, 014003 (2015)

    work page 2015

  36. [36]

    Bosnar, A

    M. Bosnar, A. Y. Vyazovskaya, E. K. Petrov, E. V. Chulkov, and M. M. Otrokov, High chern number van der waals magnetic topological multilayers mnbi2te4/hbn, npj 2D Materials and Applications7, 33 (2023)

    work page 2023