{"id":"a228b3ca-6fc4-4895-8ca0-4266fadfa2f8","arxiv_id":"2509.10398","paper_version":1,"verdict":"REJECT","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"high","formal_verification":"none","parameter_count":5,"one_line_summary":"Disordered WTe2 shows Kondo-like resistivity upturns and a disorder-enhanced zero-field Hall voltage, interpreted as a Weyl-Kondo semimetal phase.","lead":"This paper reports that disordered crystals of the layered metal WTe2 show a resistance rise at low temperature and a spontaneous Hall voltage at zero magnetic field, both stronger in dirtier samples. The authors argue that disorder creates magnetic moments that pin the electrons' energy to the Weyl points, making WTe2 a Weyl-Kondo semimetal.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The Weyl–Kondo phase claim rests on an unverified Kondo interpretation of the resistivity upturn; no magnetic data are shown and no theory demonstrates disorder-induced local moments or Fermi-level pinning.","rationale":"The abstract's central assertion is a two-step causal chain: disorder → local moments → Kondo screening → Fermi-level pinning near Weyl nodes → enhanced Berry curvature transport → spontaneous and nonlinear Hall. For the paper's title to be true, the first two steps must hold. The paper's only direct evidence for local moments is the Hamann fit, which is degenerate with other low-T upturn mechanisms; the magnetic measurements are promised but not presented. The supporting theory is a noninteracting type-II Weyl model and thus does not establish the Kondo-pinning mechanism; the observed charge decompensation can be explained by disorder-induced rigid-band shifts. I therefore agree with the reader that the weakest assumption is the Kondo interpretation. I also note the spontaneous Hall is a model-subtraction residual, but that would mainly weaken the Berry-curvature evidence rather than the existence of the Kondo phase; the Kondo step is the single load-bearing condition. Verdict remains REJECT as the reader stated.","tokens_in":12971,"tokens_out":11822,"duration_ms":140116,"concrete_test":"Inspect SM Secs. S2 and S3 (magnetic susceptibility and heat capacity) for S-3: test for a Curie-like χ(T) with an effective moment near g√(S(S+1)) ≈ 2.8 μB (S≈1) over the same temperature range as the resistivity upturn, and for a corresponding Kondo/residual entropy feature in C_p. If either signature is absent, or if the susceptibility shows only a diamagnetic/Pauli background, the Kondo assignment in Eq. (1) is unsupported and the central claim fails.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim requires that disorder creates local magnetic moments in WTe2 that Kondo-screen, and that this Kondo effect pins the Fermi level near the type-II Weyl nodes. The only evidence offered for the first step is a Hamann fit (Eq. 1 with T_eff) yielding S≈1, T_K≈16 K; the corresponding susceptibility and heat-capacity measurements are mentioned in Methods but their results are never shown in the main text. The fit also needs an RKKY temperature T_W to work, and no competing explanation of the low-temperature upturn (weak localization, electron–electron interaction, or simple disorder-induced doping) is fitted or excluded. The second step—'Kondo interactions pin the Fermi level near the Weyl nodes'—is asserted but not derived: the supporting model in Fig. 4 is a noninteracting tight-binding type-II Weyl model, so it cannot demonstrate Kondo-induced pinning. The observed charge decompensation in S-3 is equally consistent with rigid-band doping by disorder, which would also place the Fermi level closer to the Weyl nodes and enhance Berry-curvature transport without any Kondo physics. If the Kondo identification is wrong, the Weyl–Kondo semimetal phase claim collapses, even if some nonlinear Hall response remains.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper presents transport measurements on three CVT-grown WTe2 crystals with RRR values of about 51, 15, and 6. It interprets a low-temperature resistivity upturn in the disordered samples as anisotropic Kondo screening, using the Hamann expression with an RKKY effective temperature (Eq. 1). It reports a spontaneous zero-field Hall signal extracted as the residual after two-band model fits, and a second-harmonic Hall response with quadratic current scaling. A noninteracting tight-binding type-II Weyl model is then used to argue that charge decompensation is largest near the Weyl nodes and that Berry-curvature nonlinear and spontaneous Hall responses peak there. On this basis the authors claim that disorder-driven Kondo interactions pin the Fermi level near the Weyl nodes, realizing a Weyl-Kondo semimetal phase in WTe2.","tokens_in":13302,"tokens_out":8874,"duration_ms":104589,"significance":"If correct, this would be a significant advance: it would show that a nonmagnetic, weakly correlated semimetal can be tuned by disorder into a correlated topological Weyl-Kondo state, and it would identify transport signatures for such a phase. The paper has useful ingredients: a three-sample disorder series, orientation-dependent transport, Hall-baseline corrections, second-harmonic scaling, and explicit model calculations. However, the load-bearing causal chain is not established: local-moment formation is not directly demonstrated, the spontaneous Hall signal is a model-dependent residual, and the theoretical model does not include Kondo physics. The manuscript therefore cannot currently support the title claim.","major_comments":[{"comment":"The Kondo identification rests on a four-parameter Hamann fit (rho_H, T_K, S, T_W) to a low-temperature resistivity upturn. No magnetic susceptibility or heat-capacity results are shown in the main text (SM S2-S3 are only mentioned), and no competing fits for weak localization or electron-electron interactions are provided. Because local-moment formation is the first step of the claimed disorder-driven Weyl-Kondo chain, this is a load-bearing omission. If the upturn has a nonmagnetic origin, the central claim collapses.","section":"Anisotropic Kondo screening, Eq. (1), Fig. 1"},{"comment":"The spontaneous Hall signal rho_sp^xy is a residual after subtracting a two-band model fit. This extraction assumes that the two-band model captures all ordinary magnetotransport; any even-in-B background, such as contact admixture at 2 K not captured by the 300-K correction factor, thermoelectric offsets, or a nonlinear magnetoresistance contribution, would masquerade as a zero-field spontaneous Hall signal. No goodness-of-fit or alternative field-range analysis is presented, so the intrinsic nature of the zero-field effect is not established.","section":"Spontaneous Hall effect, Fig. 2"},{"comment":"The reasoning is circular in an important sense. The charge decompensation of S-3 in Fig. 2(f) is taken as evidence that the Fermi level sits near the Weyl nodes, and then the same noninteracting tight-binding model that predicts larger decompensation near the nodes [Fig. 4(b)] is used to argue that the enhanced BCD and spontaneous Hall responses [Fig. 4(c,d)] confirm this pinning. The model does not include Kondo interactions or disorder, so it cannot establish Kondo-induced pinning; a rigid-band shift caused by disorder doping would produce the same qualitative behavior.","section":"Spontaneous Hall effect and Fig. 4"},{"comment":"The claim that 'Kondo interactions pin the Fermi level near the Weyl nodes' is asserted but not derived. The WKSM theory in Refs. [12-18] is for periodic Kondo lattices, whereas the present scenario involves dilute disorder-induced moments in a weakly correlated semimetal. No calculation or experiment discriminates Kondo pinning from a disorder-induced chemical-potential shift. The latter explains the charge imbalance and the Berry-curvature transport without invoking Kondo physics, so the central mechanism is not supported.","section":"Conclusion and Fig. 4"},{"comment":"The paper uses RRR as the sole measure of disorder. In a semimetal, RRR can be controlled by carrier-density changes as well as by defect scattering. Since 'disorder-driven' is the central thesis, the manuscript should provide a microscopic disorder characterization, such as SdH Dingle temperatures, vacancy/dopant densities, or quantitative EDS deviations, to separate doping effects from defect-induced disorder.","section":"Experimental methods"}],"minor_comments":[{"comment":"The fourth panel of the caption is labeled 'b)' but should be '(d)'.","section":"Fig. 4 caption"},{"comment":"The text says 'Figure 2(a) clearly shows an anomalous deviation at low magnetic field values,' but the anomaly appears in Fig. 2(b) after the two-band fit. Please correct the cross-reference.","section":"Fig. 2 cross-reference"},{"comment":"Typo: 'V2omega xy singal' should be 'signal'.","section":"Section 'BCD induced non-linear Hall effect'"},{"comment":"Reference [59] duplicates [28], and [60] duplicates [30]; these should be cited once.","section":"References"},{"comment":"No data or code availability statement is included. The model calculations in Fig. 4 would benefit from a reproducibility statement or at least a description of the tight-binding parameters beyond the SM reference.","section":"Reproducibility"}],"recommendation":"reject","confidential_remarks":"This is a high-risk manuscript with an extraordinary central claim. The gaps are not merely presentational: the Kondo identification lacks magnetic evidence, the spontaneous Hall effect is model-dependent, and the pinning mechanism is not theoretically demonstrated. I do not see how a routine revision can fix these within the scope of a Letter. If the authors can provide direct local-moment evidence and a concrete mechanism for Fermi-level pinning, a future submission with a more limited claim might be considered."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Two things to know. First, the transport data are genuinely new: a disorder-dependent low-T resistivity upturn with strong current/field anisotropy, a zero-field Hall residual that grows with disorder, and a second-harmonic Hall signal that scales quadratically in current. Those observations are worth taking seriously. Second, the interpretation is overstretched. The paper calls this a Weyl-Kondo semimetal phase, but the evidence for Kondo physics is a Hamann fit to the upturn with four parameters (T_K, S, T_W, rho_H), and the susceptibility/heat-capacity data that would support local moments are only mentioned as being in the SM, not shown in the main text. Weak localization or electron-electron interactions are not fitted or excluded. The theory section is a noninteracting type-II Weyl model, so it cannot demonstrate that Kondo interactions pin the Fermi level near the nodes. The charge decompensation in S-3 could just as easily be rigid-band doping by disorder, which would also move the Fermi level toward the nodes and enhance Berry-curvature transport without any correlation physics. There is also a whiff of circularity: the same model is used to argue that S-3 is near the Weyl nodes and to explain why the response is enhanced there.\n\nWhat the paper does well: three samples with RRR from 6 to 51, systematic orientation dependence, a careful attempt to subtract contact misalignment, and a clear caveat that trivial carrier pockets near the Fermi level have not been reported. The authors also admit the full theory is incomplete.\n\nThe soft spots are load-bearing. If the upturn has any non-Kondo origin, the WKSM phase claim collapses. The spontaneous Hall is a residual after subtracting a two-band model fit, so its robustness needs checking--e.g., is the fit stable against including a third band or a different low-field form? The second-harmonic data are less controversial, but they are also known in WTe2.\n\nWho is this for? Condensed-matter experimentalists working on WTe2 or Kondo physics in semimetals will want to know about the data, but they should treat the conclusions with caution. This deserves a serious referee, not a desk reject, because the observations are new and the claims are important; a referee can ask for the magnetic data, the competing fits, and a theory that actually includes Kondo screening. My own verdict would be 'major revision and re-review,' with the burden on the authors to supply the missing evidence.","headline":"The transport data are new and worth a look, but the Weyl-Kondo phase claim rests on a Kondo fit whose magnetic evidence is hidden in the SM and a noninteracting model that cannot pin the Fermi level.","tokens_in":13780,"tokens_out":2728,"would_cite":false,"duration_ms":29775,"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":"The paper claims that in disordered bulk WTe2, disorder-driven Kondo screening pins the Fermi level near the Weyl nodes, producing a Weyl-Kondo semimetal phase with spontaneous and nonlinear Hall responses.","keywords":["Weyl-Kondo semimetal","WTe2","Kondo effect","disorder-induced topology","spontaneous Hall effect","Berry curvature dipole","type-II Weyl semimetal","second-harmonic Hall effect"],"falsifier":"A decisive observation would be magnetic susceptibility, electron spin resonance, or muon spin rotation on the same disordered crystals showing localized moments whose density scales with disorder and which are screened below about 16 K. If no such moments appear, or if the resistivity upturn is unchanged under magnetic fields in a way inconsistent with Kondo spin-flip scattering, the disorder-driven Weyl-Kondo explanation would be ruled out.","tokens_in":12884,"feed_emoji":"⚛️","tokens_out":5062,"duration_ms":55423,"temperature":0.7,"pith_summary":"This paper tries to establish that disorder alone can create a Weyl-Kondo semimetal phase in bulk WTe2, a material that starts out nonmagnetic and only weakly correlated. In samples with more disorder, the authors find a low-temperature logarithmic resistivity upturn that fits Kondo scattering, and both the upturn and the magnetoresistance are strongly anisotropic, matching the tilted type-II Weyl band structure. They also observe a spontaneous Hall effect at zero magnetic field and a second-harmonic Hall signal quadratic in current, both stronger in the most disordered sample. Their interpretation is that Kondo interactions pin the Fermi level close to the Weyl nodes, where Berry curvature and Berry curvature dipole are large, making disorder a tuning knob for correlated topology. If correct, WTe2 becomes a platform for Weyl-Kondo fermions outside the usual heavy-fermion compounds.","feed_headline":"Disorder alone pushes WTe2 into a Weyl-Kondo semimetal","feed_subtitle":"Kondo screening pins the Fermi level at Weyl nodes, boosting zero-field and nonlinear Hall signals.","key_machinery":"The load-bearing machinery is the coupling between disorder-induced Kondo screening and the type-II Weyl band structure. The Hamann resistivity formula with an RKKY effective temperature is used to extract Kondo temperature and spin; the tilted, over-tilted Weyl dispersion provides the anisotropy; the Berry curvature Ω_z enters a fully non-equilibrium Boltzmann distribution g(k) to produce the spontaneous Hall current j_y^sp = -(e^2/ℏ) E_x ∫ Ω_z g(k); and the Berry curvature dipole Λ_zx produces the nonlinear Hall conductivity. Two-band model fits are used to extract carrier densities and to show that the Fermi level in disordered samples sits near the Weyl nodes.","core_discovery":"The central claim is that in bulk WTe2, increasing disorder generates local magnetic moments whose Kondo screening becomes the dominant low-temperature scattering channel. The resistivity upturn is fit with the Hamann Kondo expression using an effective temperature for RKKY interactions, giving TK roughly 16 K for in-plane current and spin S near 1. The screening is anisotropic with respect to current and field directions, reflecting the tilted type-II Weyl dispersion. From simultaneous two-band fits to Hall and longitudinal resistivity, the most disordered sample is charge-decompensated, indicating the Fermi level sits near the Weyl nodes. In that regime the authors observe a spontaneous Ha","pith_inferences":["If the Kondo picture is right, local moments should be directly observable in the same disordered crystals—for example, through a Curie-like magnetic susceptibility or a characteristic heat-capacity anomaly; the paper does not report such magnetic characterization in the main text.","The mechanism suggests that controlled defect engineering, such as electron irradiation or ion milling, could tune WTe2 continuously from a clean semimetal to a Weyl-Kondo phase, allowing a systematic map of the spontaneous Hall effect versus Fermi-level position.","Other nonmagnetic type-II Weyl semimetals with low carrier density and a low-temperature resistivity upturn may show similar disorder-induced behavior; reanalyzing existing transport data for zero-field Hall anomalies could reveal further candidates.","A sharper testable prediction is that the spontaneous Hall signal should be suppressed when the Fermi level is moved away from the Weyl nodes by gating or doping, even in disordered samples."],"forward_implications":["Disorder can be used as a deliberate tuning parameter to reach a Weyl-Kondo semimetal phase in a weakly correlated, nonmagnetic Weyl semimetal.","A spontaneous Hall effect at zero field serves as a transport signature that the Fermi level has been pinned near the Weyl nodes by Kondo screening.","The second-harmonic Hall signal, quadratic in current and enhanced at low temperature, provides a measure of Berry curvature dipole strength and Fermi-level position.","The magnitude of the resistivity upturn, its anisotropy, and the strength of both Hall effects should track the disorder level across WTe2 samples.","The observed charge decompensation is consistent with the Fermi level moving toward the Weyl nodes as disorder and Kondo screening increase."],"fun_headline_variants":["Disorder spawns Weyl-Kondo phase in WTe2","WTe2 disorder yields spontaneous Hall effect","Kondo screening turns WTe2 into Weyl semimetal","Disorder-driven Weyl-Kondo fermions in WTe2","Zero-field Hall sign of Weyl-Kondo state"],"cache_read_input_tokens":2304,"weakest_assumption_plain":"The claim rests on the assumption that the low-temperature resistivity upturn in disordered WTe2 comes from Kondo scattering by disorder-induced local magnetic moments; if the upturn instead arises from weak localization or electron-electron interactions, the Weyl-Kondo phase interpretation loses its foundation.","fun_headline_variants_meta":{"raw":{"variants":["Disorder spawns Weyl-Kondo phase in WTe2","WTe2 disorder yields spontaneous Hall effect","Kondo screening turns WTe2 into Weyl semimetal","Disorder-driven Weyl-Kondo fermions in WTe2","Zero-field Hall sign of Weyl-Kondo state"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000542,"raw_usage":{"total_tokens":2406,"prompt_tokens":693,"completion_tokens":1713,"prompt_tokens_details":{"cached_tokens":256},"prompt_cache_hit_tokens":256,"prompt_cache_miss_tokens":437,"completion_tokens_details":{"reasoning_tokens":1630}},"tokens_in":437,"tokens_out":1713,"duration_ms":12886,"temperature":1.0,"reasoning_tokens":1630,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-04T17:52:39.019418+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A decisive observation would be magnetic susceptibility, electron spin resonance, or muon spin rotation on the same disordered crystals showing localized moments whose density scales with disorder and which are screened below about 16 K. If no such moments appear, or if the resistivity upturn is unchanged under magnetic fields in a way inconsistent with Kondo spin-flip scattering, the disorder-driven Weyl-Kondo explanation would be ruled out.","supporting_citations":[],"review_version":1}