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Glassy Relaxation Dynamics in the Two-Dimensional Heavy Fermion Antiferromagnet CeSiI

T0 review · 2 major / 4 minor · reviewed 2026-08-12 · deepseek-v4-flash

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Pith's one-line read CeSiI flakes down to two layers host both antiferromagnetic order and a slow glassy relaxation.

desk verdict Solid 2D heavy-fermion confirmation, but the glassy hysteresis claim is not yet separated from instrument lag. read the letter →

arxiv 2411.14722 v1 pith:IFQNY2GU submitted 2024-11-22 cond-mat.str-el

Kierstin Torres , Joon Young Park , Victoria A. Posey , Michael E. Ziebel , Claire E. Casaday , Kevin J. Anderton , Dongtao Cui , Benjamin Tang
show 5 more authors
Takashi Taniguchi Kenji Watanabe Abhay N. Pasupathy Xavier Roy Philip Kim
This is my paper · ORCID
classification cond-mat.str-el
keywords CeSiIheavyfermionantiferromagnetismglassyrelaxationhysteresismagnetotransportvanderWaals2DKondolattice
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

This paper argues that the van der Waals heavy fermion metal CeSiI, thinned to just two layers, retains both its Kondo-lattice heavy fermion behavior and its antiferromagnetic order, making both orders effectively two-dimensional. It further reports that the magnetotransport hysteresis below the Néel temperature splits into two components: a sharp, thickness-independent part tied to the antiferromagnetic metamagnetic transitions, and a broad, sweep-rate-dependent part that relaxes slowly and grows with flake thickness. The authors interpret the second component as glassy relaxation dynamics, possibly a spin-glass phase or multipolar order coexisting with antiferromagnetism. If correct, CeSiI becomes a platform for studying Kondo physics, magnetic order, and slow glassy degrees of freedom in the two-dimensional limit.

What carries the argument

The central object is the field-sweep hysteresis $\Delta\mathrm{MR} = \mathrm{MR}_{\mathrm{FW}} - \mathrm{MR}_{\mathrm{BW}}$, condensed into the root-mean-square quantity $A_{\mathrm{RMS}} = \sqrt{(1/H_R)\int_0^{H_R} (\Delta\mathrm{MR})^2\,dH}$, plotted against the sweep time $\tau = H_R/(dH/dt)$ with $H_R = 7$ T. A power-law decay of $A_{\mathrm{RMS}}$ with $\tau$ separates the slow, time-dependent relaxation from the time-independent antiferromagnetic contribution; thickness and field-angle dependence then separate the two-dimensional ordered component from the isotropic three-dimensional glassy one. The hermetic gallium-solder sealing of the devices is the enabling mechanism that lets these measurements reach two-layer flakes without environmental degradation.

What would settle it

Record the same field sweeps while measuring the field with a calibrated Hall sensor at the sample position and while explicitly varying the lock-in time constant: if the broad hysteresis persists when the true sample field is used and is independent of lock-in lag, the glassy interpretation survives; if it collapses to the known roughly 200 G instrument lag, the central claim fails. A complementary check is an AC susceptibility measurement on a sealed bulk crystal searching for a frequency-dependent peak near 4 K.

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Extended reading notes

Core claim

On its own terms, the paper establishes that atomically thin CeSiI, protected from air by a hermetic gallium-solder seal, shows the same Kondo-lattice onset near 40 K and the same Néel temperature near 8 K from bulk down to 2 layers, with metamagnetic transition fields varying by less than 20%. Below $T_N$ the forward-minus-backward field sweep hysteresis contains a time-independent part pinned to the two metamagnetic transitions and a broad, isotropic, time-dependent part whose root-mean-square magnitude decays as a power law in the sweep time. The time-dependent part peaks near 4 K, vanishes at 0.3 K, grows with flake thickness, and is insensitive to field angle, while field cooling produces no exchange bias. The paper reads these observations as evidence for a two-dimensional antiferromagnetic phase coexisting with a separate three-dimensional glassy relaxation component, and it identifies spin-glass or multipolar order as the plausible microscopic origin.

Load-bearing premise

The broad, sweep-rate-dependent part of the hysteresis is assumed to be an intrinsic magnetic relaxation rather than a lag of the superconducting magnet or lock-in electronics, and the thickness trend rests on single 2 L and 4 L devices.

Editorial extensions

If this is right

  • Heavy-fermion Kondo lattice formation and antiferromagnetic ordering survive down to the bilayer, so the two-dimensional limit of this correlated metal becomes experimentally accessible for quantum-criticality studies.
  • The sweep-rate-dependent hysteresis is a separate magnetic degree of freedom whose relaxation time falls in the seconds-to-minutes window probed by 5 to 100 G/s sweeps, implying slow dynamics absent from the conventional antiferromagnetic response.
  • The glassy component's growth with thickness and its isotropy in field angle point to a three-dimensional, isotropic origin, such as a spin glass or hidden multipolar order, rather than surface or substrate effects.
  • The absence of exchange bias under field cooling constrains any magnetic glass phase to be decoupled or weakly coupled from the antiferromagnetic order, a constraint future models must respect.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the broad component is a true spin glass, a frequency-dependent AC susceptibility peak near 4 K should appear in bulk crystals; transport alone cannot distinguish spin freezing from multipolar order. This is an extension beyond the paper.
  • The vanishing of the time-dependent component at 0.3 K suggests the relaxation time exceeds the measurement window; a wait-and-measure protocol at fixed field could extract the relaxation time directly. This is an extension beyond the paper.
  • The thickness dependence implies interlayer coupling plays a role; a monolayer of CeSiI, if it can be isolated, would test whether the glassy component requires three-dimensionality. This is an extension beyond the paper.
  • The reported power-law exponents differ between the 2 L and 4 L devices; if reproducible, that difference may indicate a thickness-dependent distribution of relaxation times rather than a simple spin-glass transition. This is an extension beyond the paper.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 4 minor

Summary. The manuscript reports magnetotransport measurements on atomically thin CeSiI flakes (2, 4, 8, 15 layers) and bulk samples, using air- and solvent-free fabrication and hermetic sealing. The authors find thickness-independent Kondo-lattice and antiferromagnetic transitions (T* ~ 40 K, TN = 8 K), thickness-independent metamagnetic fields Hm1 ~ 2.5 T and Hm2 ~ 4.5 T, and a sign reversal of the Hall coefficient near T*. Their central claim is that the forward-backward hysteresis in MR and Hall resistance below TN has two components: a time- and thickness-independent component tied to the 2D AFM metamagnetic transitions, and a broad, sweep-rate-dependent, isotropic component that increases with thickness and is interpreted as a hallmark of glassy relaxation dynamics of 3D nature, possibly a spin glass or multipolar order. The absence of exchange bias under field cooling is reported as a constraint on possible magnetic phases.

Significance. If the glassy interpretation is correct, the paper establishes coexisting 2D antiferromagnetic order and a separate slowly relaxing magnetic component in a heavy-fermion van der Waals metal, which is of considerable interest for quantum criticality and frustrated magnetism. The paper has notable strengths: the thickness-dependent R(T) and MR data are clean and support the 2D nature of the Kondo lattice and AFM order; the new hermetic sealing method is a technical advance; the field-angle dependence cleanly shows the metamagnetic features scale with the out-of-plane field component; and the field-cooling experiment is a genuine null result that constrains future models. However, the central claim rests on identifying the broad hysteresis as intrinsic, and the paper's own figure caption acknowledges an instrumental contribution that is not quantitatively excluded.

major comments (2)
  1. [Fig. 2 caption; Fig. 2(e,f); Figs. 3–4 and Fig. S5] The paper's central claim that the broad hysteresis is a signature of intrinsic glassy relaxation is not yet separated from the instrumental hysteresis acknowledged in the Fig. 2 caption, which states that trapped flux in the superconducting magnet and finite lock-in time constants can account for artificial hysteresis of up to ~200 G. No subtraction, calibration, or control measurement is presented. This is load-bearing because a linear low-pass (RC-type) instrument response produces a forward-backward difference proportional to (dH/dt) * (dR/dH) at the same lock-in settings; such a contribution would (i) diminish at the slower sweep rate of 5 G/s, (ii) remain nonzero above H_m2 because dMR/dH is nonzero there, and (iii) track the temperature dependence of dMR/dH, including the apparent suppression of the time-dependent component at 0.3 K (Fig. S5). The power-law fits in Fig. 3(a) cannot distinguish this from material relaxation. To support the glassy interpretation, the authors should either subtract a quantitatively estimated instrument-lag contribution at each sweep rate and temperature, or show a control on a non-hysteretic sample (e.g., a normal-metal or non-magnetic material) measured with identical magnet and lock-in settings, or perform a field-stop relaxation measurement in which R is monitored at fixed field after the sweep is paused.
  2. [Fig. 4(a,b) and SI Methods] The claim that the time-dependent hysteresis has a 3D nature is based on comparing the MR hysteresis of one 2 L and one 4 L device (Fig. 4a,b). Two thicknesses are insufficient to establish a dimensional crossover, and the SI Methods explicitly states that ill-defined channel geometry prohibits quantitative comparison of transport magnitudes between devices. The normalization by zero-field resistance reduces, but does not eliminate, the influence of different contact geometries and flake shapes across the two devices. Data from 8 L and 15 L devices exist (e.g., an 8 L device is used in Fig. S5), so the thickness dependence of the broad hysteresis should be shown for all available thicknesses at the same temperature and sweep rate, and the conclusion should be re-evaluated if the comparison is not quantitatively reliable.
minor comments (4)
  1. [SI captions (Figs. S5–S7)] The Supporting Information contains several typographical errors: 'Figurre S5' in the Fig. S5 heading, 'ploted' in the Fig. S6 caption, and 'suggeting' in the Fig. S7 caption should be corrected.
  2. [Fig. 3(a) and Table S1] The exponent values quoted in the Fig. 3(a) caption (–2.6 and –1.3) do not match the values in Table S1 (–2.64 and –1.28); please make these consistent.
  3. [Main text, page 9] The phrase 'we have not observe d any exchange bias effect' contains a typo, and earlier in the Introduction 'the focus our study presented in this paper' is missing the word 'of'.
  4. [Fig. 3(a) and main text] The three-parameter power-law fit in Fig. 3(a) is applied to only a few points per device, and no fit uncertainties are reported; please provide the number of data points, error bars for the fit parameters, and a discussion of whether a power-law decay is statistically justified.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity: direct experimental measurements; fitted parameters are descriptive, not load-bearing.

full rationale

This paper reports direct magnetotransport measurements of CeSiI flakes; there is no derived theoretical prediction or first-principles calculation whose conclusion reproduces its input by construction. The central claims—2D heavy-fermion behavior, 2D antiferromagnetism, and a time-dependent broad hysteresis attributed to glassy relaxation—are stated as empirical observations of thickness-, temperature-, sweep-rate-, and field-angle-dependent data. The only quantitative fits are the power-law parameters A0, b, and a in ARMS = A0 + bτ^a (Table S1, Fig. 3a); these are descriptive summaries of the measured hysteresis integral and are not fed back into any definition of the target result. The authors explicitly label the integrated ARMS as containing both time-dependent and time-independent contributions, so the saturation offset is acknowledged rather than hidden. The acknowledgment that trapped flux and lock-in time constants can produce artificial hysteresis up to ~200 G (Fig. 2 caption) is a stated caveat about measurement contamination; even if the residual broad hysteresis were later proven instrumental, that would be an experimental-control weakness, not a circularity. Self-citations (refs. 11 and 25) supply prior bulk characterization and a glovebox fabrication method, but the thickness-dependent T*, TN, Hm1,2, MR, and Hall data are independently measured in this work and are not justified solely by those citations. No equation is defined in terms of the claim, no fitted parameter is renamed as a prediction, and no uniqueness theorem or ansatz is imported from same-author work to force the interpretation. Hence no circular step is present.

Assumptions & free parameters 3 free parameters · 3 assumptions · 0 invented entities

The paper is purely experimental; the main numerical inputs are the measured transport curves and the power-law fit parameters in Table S1. No new particles, forces, or entities are introduced. The main assumptions are about what the subtracted hysteresis represents and how thickness and angle data reflect dimensionality.

free parameters (3)
  • ARMS power-law amplitude A0 = 0.27 (2 L), 0.20 (4 L)
    Phenomenological offset in the fit ARMS = A0 + bτ^a; fitted to data, not used in a prediction.
  • ARMS power-law coefficient b = 1.06e7 (2 L), 2.93e3 (4 L)
    Fitted to data to describe the decay of ARMS with τ; no error bars or units are given.
  • ARMS power-law exponent a = -2.64 (2 L), -1.28 (4 L)
    Fitted exponent used to describe relaxation decay; no error bars are provided.
assumptions (3)
  • domain assumption The forward-minus-backward hysteresis remaining after removing the two metamagnetic transition peaks is a magnetic property of CeSiI rather than a measurement artifact.
    The paper notes trapped flux and lock-in lag can contribute up to 200 G of artificial hysteresis but does not deconvolve them quantitatively from the broad component.
  • domain assumption The dimensionality of the time-dependent component can be inferred from comparing 2 L and 4 L devices and from two field angles (0 and 63 degrees).
    Figure 4 relies on one device per thickness, and the SI states the channel geometry is ill-defined, so quantitative contact-independent comparison is limited.
  • domain assumption The Rxy data are properly anti-symmetrized Hall voltages.
    The SI formula adds Vxy at +H and -H, which would suppress an odd Hall signal; the Hall results should be re-checked.

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Cite this review

Pith. "Pith review of Glassy Relaxation Dynamics in the Two-Dimensional Heavy Fermion Antiferromagnet CeSiI." pith.science (2026). https://pith.science/paper/IFQNY2GU

@misc{pith2026241114722,
  author       = {Pith},
  title        = {Pith review of: Glassy Relaxation Dynamics in the Two-Dimensional Heavy Fermion Antiferromagnet CeSiI},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/IFQNY2GU}},
  note         = {Machine review of arXiv:2411.14722}
}
read the original abstract

The recent discovery of the van der Waals (vdW) layered heavy fermion antiferromagnetic metal CeSiI offers promising potential for achieving accessible quantum criticality in the two-dimensional (2D) limit. CeSiI exhibits both heavy fermion behavior and antiferromagnetic (AFM) ordering, while the exact magnetic structure and phase diagram have yet to be determined. Here, we investigate magnetic properties of atomically thin CeSiI devices with thicknesses ranging from 2-15 vdW layers. The thickness-dependent magnetotransport measurement reveals an intrinsic 2D nature of heavy fermion behavior and antiferromagnetism. Notably, we also find an isotropic, time-dependent hysteresis in both magnetoresistance and Hall resistance, showing glassy relaxation dynamics. This glassy behavior in magnetic structures may suggest the presence of spin glass phases or multipolar ordering, further establishing CeSiI as an intriguing material system for investigating the interplay between magnetic orders and the Kondo effect.

Figures

Figures reproduced from arXiv: 2411.14722 by the authors.

Figure 3
Figure 3. (a) Root-mean-square MR hysteresis ARMS for 2 and 4 L devices as a function of τ = 7 T/(μ0dH/dt) at T = 2 K. Dashed lines correspond to power law fits to data with exponents –2.6 and –1.3 for 2 and 4 L devices, respectively (see Table S1 for more detail). (b) ARMS for 2 and 4 L devices as a function of temperature measured with two different field sweep rates of 100 and 10 G/s [PITH_FULL_IMAGE:figures/full_fig_p012… view at source ↗

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Reference graph

Works this paper leans on

7 extracted references · 4 canonical work pages

  1. [1]

    S.; Mishchenko, A.; Carvalho, A.; Castro Neto, A

    (1) Novoselov, K. S.; Mishchenko, A.; Carvalho, A.; Castro Neto, A. H. 2D Materials and van Der Waals Heterostructures. Science 2016, 353 (6298), aac9439. https://doi.org/10.1126/science.aac9439. (2) Geim, A. K.; Grigorieva, I. V. Van Der Waals Heterostructures. Nature 2013, 499 (7459), 419–425. https://doi.org/10.1038/nature12385. (3) Cao, Y.; Fatemi, V....

    doi:10.1126/science.aac9439 2016

  2. [3]

    https://doi.org/10.1126/science.1183376

    Science 2010, 327 (5968), 980 –983. https://doi.org/10.1126/science.1183376. (11) Posey, V. A.; Turkel, S.; Rezaee, M.; Devarakonda, A.; Kundu, A. K.; Ong, C. S.; Thinel, M.; Chica, D. G.; Vitalone, R. A.; Jing, R.; Xu, S.; Needell, D. R.; Meirzadeh, E.; Feuer, M. L.; Jindal, A.; Cui, X.; Valla, T.; Thunström, P.; Yilmaz, T.; Vesco vo, E.; Graf, D.; Zhu, ...

    work page doi:10.1126/science.1183376 2010

  3. [80]

    (19) Fumega, A

    https://doi.org/10.1038/s41699-022-00357-x. (19) Fumega, A. O.; Lado, J. L. Nature of the Unconventional Heavy-Fermion Kondo State in Monolayer CeSiI. Nano Lett. 2024, 24 (14), 4272–4278. https://doi.org/10.1021/acs.nanolett.4c00619. (20) Schröder, A.; Aeppli, G.; Coldea, R.; Adams, M.; Stockert, O.; Löhneysen, H. v; Bucher, E.; Ramazashvili, R.; Coleman,...

    work page doi:10.1038/s41699-022-00357-x 2024

  4. [100]

    Nevertheless, the qualitative evolution of the Hall effect with temperature and magnetic field is valid

    We note that the lack of ability to well-define the channel geometry due to the environmental sensitivity of CeSiI results in invasive contact configuration with ill -defined geometric factors, prohibiting quantitative analysis of the Hall effect between the devices in a consistent manner. Nevertheless, the qualitative evolution of the Hall effect with te...

    work page 2024

  5. [247]

    https://doi.org/10.1088/0022-3727/33/23/201. 18 Supplementary Information for Glassy Relaxation Dynamics in the Two-Dimensional Heavy Fermion Antiferromagnet CeSiI Kierstin Torres1†, Joon Young Park2†, Victoria Posey3, Michael E. Ziebel3, Claire E. Casaday4, Kevin J. Anderton4, Dongtao Cui 4, Benjamin Tang 2, Takashi Taniguchi 5, Kenji Watanabe 6, Abhay N...

    doi:10.1088/0022-3727/33/23/201

  6. [2021]

    https://doi.org/10.1103/PhysRevMaterials.5.L121401 (25) Zhao, S

    5 (12), L121401. https://doi.org/10.1103/PhysRevMaterials.5.L121401 (25) Zhao, S. Y. F.; Poccia, N.; Panetta, M. G.; Yu, C.; Johnson, J. W.; Yoo, H.; Zhong, R.; Gu, G. D.; Watanabe, K.; Taniguchi, T.; Postolova, S. V.; Vinokur, V. M.; Kim, P. Sign-Reversing Hall Effect 17 in Atomically Thin High-Temperature Bi2.1Sr1.9CaCu2.0O8+ δ Superconductors. Phys. Re...

    work page arXiv

  7. [4092]

    (32) Mydosh, J

    https://doi.org/10.1038/s41467-019-11913-3. (32) Mydosh, J. A.; Oppeneer, P. M. Colloquium: Hidden Order, Superconductivity, and Magnetism: The Unsolved Case of URu 2Si2. Rev. Mod. Phys. 2011, 83 (4), 1301 –1322. https://doi.org/10.1103/RevModPhys.83.1301. (33) Starykh, O. A. Unusual Ordered Phases of Highly Frustrated Magnets: A Review. Rep. Prog. Phys. ...

    doi:10.1038/s41467-019-11913-3 2011

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Reviewed August 12, 2026 · model on record in the stance chip above.