{"id":"9ded0ec8-9c60-4705-8a2d-40f6f7130b24","arxiv_id":"2411.19660","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":1,"one_line_summary":"Systematic Nernst measurements across five van der Waals tellurides find large linear responses in WTe2 and MoTe2, weaker nonlinear ones in ternaries, and a mobility scaling that deviates from the standard Nernst law.","lead":"This paper measures the Nernst effect, a magnetic-field-induced thermal voltage, in five layered telluride materials and finds very large responses in WTe2 and MoTe2, with weaker, nonlinear responses in three related ternary compounds. It reports that the linear part scales with electron mobility divided by Fermi energy, but with a different prefactor than the standard Nernst scaling law, which could matter for thermoelectric energy conversion.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The claimed new μ/EF scaling rests on Fermi energies that are not measured; for the alloy, EF is chosen to match the trend in Fig. 3b, making the scaling claim partly circular.","rationale":"The reader's weakest-assumption analysis identifies the decisive issue correctly: the entire 'unexpected scaling' is a horizontal placement of five points on a log-log plot, and one of those points is placed by the trend it is supposed to prove. I agree. I considered two alternative concerns: (i) using B=10 T data when μB >> 1 for the high-mobility binaries, and (ii) extracting mobility from a single-band model in compensated semimetals. Both are real, but the paper acknowledges the first explicitly and addresses the second with a stated two-carrier cross-check, and neither is as direct as the circular EF for the alloy. The raw observations—large linear Nernst in WTe2 and MoTe2, superlinear Nernst in the ternaries, and the flake result—are plausible and independently valuable. The theory section also provides a mechanism for the cubic term. What is not secure is the quantitative claim of a new scaling factor with a different prefactor. Since the reader's CONDITIONAL verdict already captures this, I do not propose changing it; the condition should remain explicit: measured Fermi energies (or at least an independent alloy EF) and a fitted, quantified scaling law are required before the scaling claim is accepted.","tokens_in":11712,"tokens_out":10344,"duration_ms":92796,"concrete_test":"Recompute Fig. 3b after replacing all literature/estimated Fermi energies with experimentally measured values: use Shubnikov-de Haas or de Haas-van Alphen frequencies (or ARPES band positions) to set EF for WTe2, MoTe2, TaIrTe4 and TaRhTe4, and compute EF for W0.65Mo0.35Te2 from a supercell or virtual-crystal DFT calculation without any constraint from Fig. 3b. Then refit log[N/(BT)] versus log(μ/EF) for the five samples and, as a robustness check, repeat the fit with the alloy point excluded. If the points collapse onto the literature red line, or if no stable offset or power-law remains, the claimed new scaling factor is an artifact of the assumed Fermi energies.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central scaling claim in Sec. III and Fig. 3b depends on Fermi energies that are not measured in this work. For WTe2, MoTe2, TaIrTe4 and TaRhTe4, EF is taken from published DFT band structures (refs. [29,50,51]); for W0.65Mo0.35Te2 the paper states that EF was 'estimated ... which would be required to match the trend displayed in Fig.3b' (~110 meV). Because the x-axis of the scaling plot is μ/EF, a common multiplicative error in the DFT Fermi energies shifts every point horizontally; if the true Fermi energies are larger, the five points could move onto the established Behnia-Aubin red line and the claimed 'different scaling factor' would disappear. The alloy point is especially dangerous: using the trend to set its EF and then citing the resulting alignment as evidence of a new scaling law is circular. The paper also does not fit or quantify the 'new scaling factor', so the claim rests on visual placement with large, poorly specified error bars. Data and supplementary fits are not deposited, so the mobility extraction and the a vs c decomposition cannot be checked independently.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper reports systematic magneto-thermoelectric measurements on five layered van der Waals tellurides: WTe2, MoTe2, W0.65Mo0.35Te2, TaIrTe4, and TaRhTe4. Large and linear-in-field Nernst coefficients are observed in WTe2 and MoTe2, while the three ternary compounds show smaller linear responses accompanied by a superlinear component at low temperature. The data are decomposed as N = aB + cB^3. The authors find a correlation between the linear coefficient and mobility and plot N/(TB) against mu/EF, claiming a scaling law that deviates from the established Behnia-Aubin line by a different prefactor. They attribute the enhancement to the shared band-structure features of this family, specifically electron-hole compensation and Weyl cones near the Fermi level. A Nernst signal is also demonstrated in an exfoliated TaIrTe4 flake using Joule-heating second-harmonic detection.","tokens_in":11885,"tokens_out":6026,"duration_ms":66246,"significance":"If substantiated, the proposed new scaling of the linear Nernst coefficient with mu/EF would be an interesting addition to the semiclassical Nernst-scaling literature and would strengthen the case for van der Waals tellurides in thermoelectric applications. The paper has clear strengths: the same experimental protocol is used across five isostructural compounds, the linear/cubic decomposition is explicit, the flake device provides a useful proof of concept, and the authors are candid about the provenance of the Fermi energies. However, the central quantitative claim currently rests on only five points, one of which has its Fermi energy chosen to match the trend, and no quantitative fit or error propagation is provided. The significance is therefore conditional on the scaling analysis being made non-circular and properly quantified.","major_comments":[{"comment":"The central scaling claim is partially circular as written. In the paragraph beginning 'Due to difficulties to calculate the EF of the off-stoichiometric W0.65Mo0.35Te2', the authors state that EF for this compound was 'estimated ... which would be required to match the trend displayed in Fig.3b'. Since this compound is one of only five points in Fig. 3b, its placement on the trend cannot be used as evidence for that trend. Please remove this point from the scaling analysis, or determine its Fermi energy independently (e.g., from quantum oscillations, ARPES, or Hall density combined with a band-structure calculation), and rerun the analysis without the fitted point.","section":"Section III, Fig. 3b"},{"comment":"The claimed 'different scaling factor' is never quantified. The paper does not fit a slope or intercept to the five points in Fig. 3b, does not report a correlation coefficient or confidence interval, and does not compare a fitted prefactor with the theoretical value of the Behnia-Aubin line. On a log-log plot, a multiplicative offset in prefactor and a change in functional form cannot be distinguished by eye. Please provide a quantitative fit of log[N/(TB)] versus log(mu/EF), with uncertainties, and state explicitly whether the data are consistent with a line of slope unity but different intercept, or with a genuinely different scaling exponent.","section":"Section III, paragraph on the linear contribution and Fig. 3b"},{"comment":"The x-axis values for WTe2, MoTe2, TaIrTe4, and TaRhTe4 are taken from published DFT band structures, not measured in this work, and no error bars are given for these Fermi energies. Because the scaling variable is mu/EF, a common multiplicative error in the DFT energies shifts all points horizontally; for plausible factors of 2-3, the points could move close to the red line and the claimed deviation could disappear. The authors need to quantify the uncertainty in EF and show that the conclusion is robust within that uncertainty, or replace the literature values with experimentally determined Fermi energies.","section":"Section III, 'We have used the value of the Fermi Energy ...' and Fig. 3b"},{"comment":"With only five compounds, one of which is placed on the trend by construction, the evidence for a material-family correlation is marginal. Figure 3a shows a visual increase of the linear Nernst coefficient with mobility, but no correlation coefficient, fit, or residual analysis is provided, and the points span only about one order of magnitude in mu/EF. The statement that the data 'confirm an evident correlation' is stronger than the analysis supports. Please report the effective number of independent points, the fit quality, and the result of excluding the alloy point.","section":"Section III, Fig. 3a and Fig. 3b"}],"minor_comments":[{"comment":"Reference [60] has no journal, volume, or page; reference [56] lacks volume and page details; reference [55] gives no DOI or URL. Please complete these entries.","section":"References [56], [60], and [55]"},{"comment":"The text states that the maximum Nernst coefficient in WTe2 is about 600 microV/K at T = 20 K, while the Fig. 2 caption reports 700 microV/K at T = 14 K. Please harmonize the quoted values and temperatures.","section":"Abstract and Fig. 2 caption"},{"comment":"This sentence presents a causal statement about Weyl cones and mobility; it is speculative and should be explicitly framed as a hypothesis or supported by a reference.","section":"Section III, 'The linear dispersion of the Weyl cones contributes to high mobility'"},{"comment":"The statement 'available from the corresponding authors upon request' is weaker than current journal norms and prevents independent checking of the N = aB + cB^3 fits and the mobility extraction. Please deposit the raw data and analysis files in a permanent repository.","section":"Data Availability statement"}],"recommendation":"major_revision","confidential_remarks":"The measurements themselves and the flake demonstration are valuable, and I do not think rejection is warranted. The key problem is the fitted Fermi energy for W0.65Mo0.35Te2 being used as evidence for the very trend it was chosen to match; this is acknowledged in the manuscript, so the authors must know it needs to be fixed. If the scaling claim can be made robust by removing that point, adding a quantitative fit, and showing sensitivity to the DFT Fermi energies, the paper would be suitable for publication. The incomplete reference list and weak data-availability statement are secondary but should also be corrected."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Quick take: the experimental core is solid and worth keeping, but the claimed new μ/EF scaling law is not established. One of the five points sits on the trend by construction, and the “new scaling factor” is never quantified. I’d send this to review with a request to fix the scaling analysis, not to reject.\n\nWhat’s new: the dataset across five vdW tellurides; the observation of superlinear Nernst in the three ternary compounds at low T; the flake device result for TaIrTe4; and the attempt to place this family on the Behnia–Aubin scaling plot. The field-dependent data look plausible, the linearity in WTe2 and MoTe2 matches earlier reports, and the aB + cB^3 decomposition is a reasonable phenomenological treatment. The authors also honestly state that the alloy’s Fermi energy was estimated to match the trend — transparent, and it is the main weakness.\n\nWhere it’s soft: the scaling claim rests on published DFT Fermi energies for four compounds and one fitted EF for W0.65Mo0.35Te2. The paper explicitly says that EF ~110 meV was chosen “which would be required to match the trend” — so that point is circular. With only five points, large error bars, and no fitted line or quantified prefactor, the “different scaling factor” is a visual impression, not a result. If the true EF values are larger, the points could slide onto the literature line. This is a real limitation, not a nitpick. I also note the data are not deposited; the mobility extraction and the a/c decomposition can’t be checked independently.\n\nBalance: the paper does not oversell wildly — the discussion speculates about why the scaling may differ (single-band assumption, T << TF, scattering) and cites the high-mobility WTe2 point from ref 70 as another deviant. That helps. But the headline claim is precisely the part that needs more support.\n\nWho it’s for: experimentalists working on magneto-thermoelectric effects in semimetals; anyone using the Behnia–Aubin plot. A referee should see it because the raw data are useful and the scaling question is timely, but they should demand measured Fermi energies (quantum oscillations, ARPES), a fitted scaling law with error propagation, and either data deposition or a proper supplement. My recommendation: engage with it — conditional accept, with the scaling claim softened or substantially strengthened.","headline":"Solid new Nernst data across five vdW tellurides, but the claimed new μ/EF scaling law is not established: one Fermi energy is fitted to the trend, and the new prefactor is never quantified.","tokens_in":12579,"tokens_out":1705,"would_cite":false,"duration_ms":14707,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"This paper claims that five layered van der Waals tellurides share a large linear Nernst response whose strength tracks mobility divided by Fermi energy, but with a prefactor that deviates from the established Fermi-liquid scaling law.","keywords":["Nernst effect","van der Waals tellurides","Weyl semimetal","WTe2","MoTe2","TaIrTe4","thermoelectric conversion","Fermi liquid scaling"],"falsifier":"Perform quantum-oscillation or angle-resolved photoemission measurements on the identical single crystals — especially W0.65Mo0.35Te2, whose Fermi energy is currently fitted — and re-plot the data as $N/(TB)$ versus $\\mu/E_F$ using the measured Fermi energies; if the five points then collapse onto the published universal line, the claimed new scaling factor is falsified.","tokens_in":11470,"feed_emoji":"⚡","tokens_out":12182,"duration_ms":97026,"temperature":0.7,"pith_summary":"This paper reports systematic measurements of the Nernst effect — the voltage that appears perpendicular to both a temperature gradient and a magnetic field — in five layered tellurides that share the same van der Waals crystal structure: WTe2, MoTe2, W0.65Mo0.35Te2, TaIrTe4, and TaRhTe4. The authors find large linear-in-field Nernst signals in the binary compounds (up to about 600–700 uV/K in WTe2 at 10 T) and moderate linear signals in the ternary compounds, plus a superlinear cubic-in-field component in the ternary compounds at low temperature. Across all five materials, the linear component correlates with mobility divided by Fermi energy, $\\mu/E_F$, following the same functional form as the standard Nernst scaling law but with a different prefactor. The paper attributes this systematic enhancement to the shared band structure: Weyl-like linear dispersions near the Fermi energy combined with strong electron–hole compensation. The response also persists in a 20-nm exfoliated flake of TaIrTe4, suggesting the effect is robust enough for device applications.","feed_headline":"Layered tellurides break the standard Nernst scaling law","feed_subtitle":"Systematic Nernst data on five tellurides show a mobility/Fermi-energy scaling that departs from the Fermi-liquid curve.","key_machinery":"The central machinery is a two-carrier semiclassical Boltzmann model for the Nernst coefficient. Up to third order in magnetic field it gives $N \\approx (\\pi^2/6)(k_B/e)(k_B T)\\{ (2\\mu B\\,\\partial_\\epsilon(\\sigma_e\\sigma_h)/\\sigma_0^2)[1-(x_\\sigma\\mu B)^2] + (\\partial_\\epsilon\\mu)B[1-(\\mu B)^2(2-x_\\sigma^2)]\\} + O(B^5)$, where $\\sigma_e$ and $\\sigma_h$ are the electron and hole conductivities, $\\sigma_0=\\sigma_e+\\sigma_h$, and $x_\\sigma=(\\sigma_e-\\sigma_h)/\\sigma_0$. This expression shows how electron–hole compensation can produce both the linear and the cubic-in-field terms, with relative signs set by the energy derivatives of the mobility and the two-band conductivity product at $E_F$. For the linear term, the comparison standard is the Fermi-liquid formula $N/B = (\\pi^2/3)(k_B/e)(k_B T/E_F)\\,\\mu$; the paper evaluates this using mobilities extracted from Hall and longitudinal resistivity in a single-band approximation and Fermi energies taken from published density-functional calculations, with the alloy's $E_F$ estimated to match the observed trend.","core_discovery":"On the paper's own terms, the discovery is that the linear Nernst coefficient of this telluride family obeys the Fermi-liquid scaling form $N/B = (\\pi^2/3)(k_B/e)(k_B T/E_F)\\,\\mu$ but with a prefactor that is systematically different from the universal curve established for bismuth, cuprates, and other semimetals. The linear term is large in WTe2 and MoTe2, reaching about 700 uV/K and 180 uV/K respectively at 10 T, and smaller but still significant in the ternary compounds; the three ternary compounds also show an extra $B^3$ term at low temperature. The authors show that the linear component correlates with carrier mobility across the family, whereas the nonlinear component does not, and they demonstrate through the decomposition $N = S(\\alpha_{xy}/\\alpha_{xx} - \\sigma_{xy}/\\sigma_{xx})$ that the $B^3$ term must come from the thermoelectric angle, not the Hall angle. They conclude that the shared enhancement is intrinsic to the band structure — Weyl-like linear dispersion near $E_F$ plus almost compensated electron and hole pockets — and that the persistence of the Nernst signal in a 20-nm exfoliated flake of TaIrTe4 shows the effect is not a bulk artifact.","pith_inferences":["Beyond the paper, the same $\\mu/E_F$ scaling could be tested on other compensated semimetals with directly measured Fermi energies — such as Dirac semimetals like Cd3As2 or Na3Bi — to decide whether the enhanced prefactor is specific to tellurides or generic to linearly dispersing compensated systems.","Beyond the paper, the cubic Nernst term could be used as a quick experimental diagnostic for strong electron–hole compensation in newly synthesized layered materials: a superlinear low-field Nernst response would flag a compensated two-band state without a full Hall-tomography campaign.","Beyond the paper, if the prefactor change is caused by inelastic scattering rather than band structure, then temperature-dependent measurements should show the prefactor drifting with scattering rate; this gives a direct way to separate the two proposed mechanisms."],"forward_implications":["If the scaling holds, the Nernst coefficient in this family is set by mobility and Fermi energy, so improving crystal quality (higher mobility) should push the linear Nernst signal in WTe2 and MoTe2 toward or beyond the observed 700 uV/K.","The absence of a cubic term in the binary compounds and its presence in the ternary compounds at low temperature means the superlinear component tracks carrier compensation, offering a transport signature that distinguishes compensated from uncompensated tellurides.","Since the Nernst response survives in an exfoliated 20-nm flake of TaIrTe4, the family is compatible with thin-film thermoelectric devices that convert waste heat into a transverse voltage using a single material.","The deviation from the established scaling prefactor implies that the universal Nernst curve needs a material-dependent factor for semimetals with linear dispersion, which would make the Nernst effect a sharper probe of band structure and scattering mechanisms than previously assumed."],"supporting_citations":[{"why":"Reported the very large Nernst coefficient in WTe2; this is the magnitude benchmark the binary compounds are compared against.","marker":"[44]"},{"why":"Earlier observation of a large Nernst effect in WTe2, establishing the parent-compound phenomenology.","marker":"[45]"},{"why":"Provides the standard Nernst scaling law used as the red-line prediction in the comparison plot.","marker":"[67]"},{"why":"The Fermi-liquid scaling picture whose single-band, low-temperature, elastic-scattering assumptions the paper argues are violated here.","marker":"[68]"},{"why":"Supplies the Lorenz-number prefactor for the scaling line and the decomposition used to separate thermoelectric-angle and Hall-angle contributions.","marker":"[65]"},{"why":"High-mobility WTe2 data point that also departs from the universal scaling, reinforcing the new trend.","marker":"[70]"},{"why":"Crystal growth and band-structure data for TaIrTe4 and TaRhTe4; source of the Fermi energies used for the ternary compounds.","marker":"[29]"},{"why":"DFT band-structure calculation providing Fermi energies for the binary tellurides used in the scaling plot.","marker":"[50]"},{"why":"DFT calculation supplying Fermi energies for stoichiometric compounds in the scaling comparison.","marker":"[51]"},{"why":"Establishes the two-carrier compensated transport picture and giant magnetoresistance in WTe2 that underlies the mobility and compensation estimates.","marker":"[7]"}],"fun_headline_variants":["Van der Waals tellurides break Nernst scaling law","Large Nernst effect found in layered tellurides with anomalous scaling","Telluride semimetals show Nernst effect with nonstandard scaling","Layered tellurides yield large Nernst effect, new scaling"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that the Fermi energies used to place the five compounds on the scaling plot are correct even though none of them is measured in this work: three come from published calculations and the value for the mixed compound W0.65Mo0.35Te2 is chosen after the fact to match the reported trend, so inaccurate Fermi energies could erase the claimed deviation.","fun_headline_variants_meta":{"raw":{"variants":["Van der Waals tellurides break Nernst scaling law","Large Nernst effect found in layered tellurides with anomalous scaling","Telluride semimetals show Nernst effect with nonstandard scaling","Layered tellurides yield large Nernst effect, new scaling"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000699,"raw_usage":{"total_tokens":3249,"prompt_tokens":1128,"completion_tokens":2121,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":744,"completion_tokens_details":{"reasoning_tokens":2042}},"tokens_in":744,"tokens_out":2121,"duration_ms":13297,"temperature":1.0,"reasoning_tokens":2042,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-12T05:58:26.700212+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Perform quantum-oscillation or angle-resolved photoemission measurements on the identical single crystals — especially W0.65Mo0.35Te2, whose Fermi energy is currently fitted — and re-plot the data as $N/(TB)$ versus $\\mu/E_F$ using the measured Fermi energies; if the five points then collapse onto the published universal line, the claimed new scaling factor is falsified.","supporting_citations":[{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Reported the very large Nernst coefficient in WTe2; this is the magnitude benchmark the binary compounds are compared against."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Earlier observation of a large Nernst effect in WTe2, establishing the parent-compound phenomenology."},{"cited_title":"Behnia, Journal of Physics: Condensed Matter 21, 113101 (2009)","cited_arxiv_id":null,"evidence_quote":"Provides the standard Nernst scaling law used as the red-line prediction in the comparison plot."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Supplies the Lorenz-number prefactor for the scaling line and the decomposition used to separate thermoelectric-angle and Hall-angle contributions."},{"cited_title":"Shipunov, B","cited_arxiv_id":null,"evidence_quote":"Crystal growth and band-structure data for TaIrTe4 and TaRhTe4; source of the Fermi energies used for the ternary compounds."},{"cited_title":"Di Sante, P","cited_arxiv_id":null,"evidence_quote":"DFT band-structure calculation providing Fermi energies for the binary tellurides used in the scaling plot."},{"cited_title":"Guguchia, F","cited_arxiv_id":null,"evidence_quote":"DFT calculation supplying Fermi energies for stoichiometric compounds in the scaling comparison."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Establishes the two-carrier compensated transport picture and giant magnetoresistance in WTe2 that underlies the mobility and compensation estimates."}],"review_version":1}