{"id":"adc1bd0f-2e89-42aa-a590-3219b1389260","arxiv_id":"2507.21793","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":4.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":5,"one_line_summary":"Nickel-doped TiHfNbTa medium-entropy alloys remain bulk type-II superconductors with Tc rising to about 7.36 K, with heat capacity and Kadowaki-Woods analysis suggesting strong coupling and strong correlations.","lead":"Adding nickel to the medium-entropy superconductor TiHfNbTa keeps the alloy's crystal structure and raises its transition temperature from about 6.6 to 7.4 kelvin. The heat capacity jumps and a large Kadowaki-Woods ratio point to a metal that combines strong electron-phonon coupling with unusually strong electron correlations.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Monotonic-Tc claim is internally inconsistent with the undoped endpoint, and the strong-coupling/KWR conclusions rest on fit parameters without reported windows or uncertainties.","rationale":"The reader's weakest assumption correctly identifies the KWR/strong-correlation leg as the most fragile, and I agree that a single unreported A coefficient in a disordered, low-RRR alloy cannot carry the 'extremely strong electron correlations' conclusion. My stress-test adds that the monotonic-Tc claim is internally at odds with the table: the undoped x=0 value of 6.75 K exceeds Tc(0.014)=6.55 K, so the trend statement 'Tc rises monotonically' is not even consistent with the paper's own numbers. That is a correctness risk in the central materials claim, not just the interpretation. The bulk-superconductivity result itself appears well supported (full Meissner fraction, sharp heat-capacity jump, single AC transition), so the reader's CONDITIONAL verdict stands, but for two independent reasons rather than one: the trend claim needs error bars and consistent inclusion of x=0, and the strong-coupling/KWR parameters need fit documentation and error propagation. I do not see a reason to reject the paper; the request for raw-data-backed fitting details and error analysis is exactly the condition under which the physics claims could be confirmed. The agreement is partial because the reader centered on the KWR assumption while the monotonic-Tc inconsistency is an additional load-bearing issue; both point to the same remedy of reporting uncertainties and fit windows.","tokens_in":11599,"tokens_out":2237,"duration_ms":23017,"concrete_test":"Re-extract Tc and the specific-heat/resistivity fit parameters from the raw data with documented fitting windows and bootstrap uncertainties. Specifically: (a) report Tc with uncertainties for x=0, 0.014, 0.027, 0.042, 0.059, 0.077; if Tc(0.014) is not below Tc(0) at the 2-sigma level, the monotonic-Tc claim fails. (b) Fit Cp/T = gamma + beta T^2 and rho(T) = rho0 + A T^2 over explicitly stated windows and verify stability against window choice; propagate errors into DeltaCel/gammaTc, 2Delta0/kBTc, omega_ln, and KWR. (c) If A/gamma^2 remains above the heavy-fermion line after uncertainty propagation, test whether the same KWR can be reproduced in a proxy alloy with a nonmagnetic 3d dopant (e.g., Cu or Zn) to distinguish Ni magnetism/disorder effects from intrinsic correlation; if the proxy shows a comparable KWR, the strong-correlation interpretation is not specific to Ni doping.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The central materials claim, that BCC (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix is a bulk type-II superconductor with Tc near 7.36 K at x=0.077, is credible and internally consistent: it is supported by resistivity, magnetization, and specific-heat data with demagnetization corrections, full Meissner fraction, and a single AC-susceptibility transition. However, the paper's headline conclusions rest on three fit-derived quantities whose uncertainties are not reported and whose fitting windows are not stated. (1) The monotonic Tc increase in Table 1 is violated by the undoped endpoint: Tc(0)=6.75 K (ref. 18) but Tc(0.014)=6.55 K, so 'Tc increases with the increase of Ni-doped contents' fails at the lowest doping. This is a consistency issue for the central trend claim, not for the existence of superconductivity. (2) The strong-coupling claim uses DeltaCel/gammaTc = 2.89-2.44 and the alpha model, but the alpha-model parameters 2Delta0/kBTc and omega_ln are derived from the same measured specific-heat jump that they are then used to interpret; this is partly circular and none of the fit ranges, residuals, or error bars are shown for the Cp/T = gamma + beta T^2 fits. (3) The strong-correlation claim rests on a single KWR value, A = 1.5e-3 micro-ohm cm K^-2 for x=0.077, with no fitting window for the rho(T) = rho0 + A T^2 fit and no uncertainty. Given RRR near 1 and strong disorder, A can be inflated by multiband scattering, magnetic Ni fluctuations, or a poor choice of temperature window; the authors themselves list anisotropy, Fermi-surface topology, degeneracy, and magnetic correlation as alternative sources of large KWR, so the phrase 'extremely strong electron correlation' is not uniquely supported.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper reports the synthesis and characterization of the body-centered-cubic medium/high-entropy alloy series (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix with x = 0.014, 0.027, 0.042, 0.059, and 0.077, prepared by arc melting. Structural characterization (XRD, SEM-EDX) indicates a single BCC phase with homogeneous elemental distribution up to x = 0.077. Transport, magnetization, AC susceptibility, and specific-heat measurements are used to support three central claims: (i) all compositions are bulk type-II superconductors; (ii) Tc increases monotonically with Ni content, from 6.55 K at x = 0.014 to 7.36 K at x = 0.077, reaching 7.36 K; (iii) the normalized specific-heat jump ΔCel/γTc between 2.44 and 2.89 indicates strong electron-phonon coupling, and a Kadowaki-Woods ratio derived from a single resistivity fit indicates strong electron correlations. The paper concludes that Ni doping raises the valence electron count and thereby enhances Tc.","tokens_in":11935,"tokens_out":5093,"duration_ms":58888,"significance":"The bulk superconducting state in this Ni-doped HEA is credible and experimentally well supported: the combination of zero resistivity, diamagnetic shielding with demagnetization corrections reaching a full Meissner fraction, a single AC-susceptibility transition, and a specific-heat jump is mutually consistent. If the interpretive claims were fully supported, the system would be a notable addition to the small family of magnetic-element-doped HEA superconductors and potentially a platform for studying strong coupling together with strong correlations. However, the headline trend and the two 'strong' conclusions currently rest on an inconsistent composition trend, on alpha-model parameters that are partly circular, and on a single uncharacterized resistivity fit. These issues reduce the paper's current significance to that of a solid materials characterization report, with the physics claims requiring additional analysis and independent support.","major_comments":[{"comment":"The central claim that Tc increases monotonically with Ni content is internally inconsistent with the undoped endpoint. Table 1 lists Tc = 6.75 K for x = 0 (from reference [18]) and Tc = 6.55 K for x = 0.014; the text states that 'the Tc rises from 6.55 K to 7.35 K monotonically as the Ni content increases.' Thus the first doping step decreases Tc by 0.20 K, contradicting the abstract and conclusion that 'Tc increases with the increase of Ni-doped contents' across the series. To support the monotonic trend, the authors must either include the x = 0 point with the same synthesis and measurement conditions, show multiple batches with error bars, or explicitly restrict the claimed monotonicity to the doped range 0.014 ≤ x ≤ 0.077.","section":"Section III, Table 1 and Figure 2(b)"},{"comment":"The strong-coupling analysis is partly circular. The values of ωln are obtained by inverting the relation ΔCel/γTc = 1.43[1 + 53(Tc/ωlog)^2 ln(ωlog/3Tc)] from the measured ΔCel/γTc, and the values of 2Δ0/kBTc are obtained from the same alpha model. Figure 4(a) then plots ΔCel/γTc against ωln/Tc, and Figure 4(b) plots 2Δ0/kBTc against ωln/Tc; these are essentially replots of the defining relation rather than independent tests. The manuscript also does not report the fitting ranges, residuals, or uncertainties for the Cp/T = γ + βT^2 fits from which ΔCel and Tc are extracted. The authors should present the alpha-model fits with residuals, propagate uncertainties, and either compare with an independent probe of the gap (e.g., tunneling or optical conductivity) or explicitly label Figures 4(a) and 4(b) as model inversions rather than empirical correlations.","section":"Section III, alpha-model analysis and Figure 4"},{"comment":"The strong-correlation conclusion rests on a single resistivity coefficient A = 1.5×10^-3 μΩ cm K^-2 reported for x = 0.077, with no fitting window, no residuals, and no uncertainty. No A value is given for the other compositions, and the residual resistivity ratio is close to 1, indicating strong disorder. In such a dirty alloy, the apparent T^2 term can be contaminated by multiband scattering, magnetic fluctuations, or a poorly chosen temperature window, all of which the authors themselves mention as alternative sources of a large KWR. To make the 'extremely strong electron correlation' claim load-bearing, the authors need to show the ρ(T) fit and its residuals, justify the temperature range, report the uncertainty in A, and ideally show A for several compositions. Without this, Figure 5 only locates one derived point, not a systematic correlation effect.","section":"Section III, Figure 5 and Kadowaki-Woods ratio"},{"comment":"The statement that the maximum solid solution of (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix is about 7.7% is not supported by the data presented. The XRD patterns show single-phase BCC behavior for x ≤ 0.077, but no composition with x > 0.077 was synthesized or measured. A maximum solid-solution limit requires evidence of phase separation or a lattice-parameter discontinuity beyond the claimed boundary. The text should be revised to 'single-phase up to x = 0.077' unless additional compositions are studied.","section":"Abstract and Section I"}],"minor_comments":[{"comment":"The text states 'As demonstrated in Figure 5, the normal-state specific heat data can be modeled...' but Figure 5 is the Kadowaki-Woods plot; the normal-state specific-heat fits appear in Figure 3. The cross-reference should be corrected.","section":"Section III, heat capacity paragraph"},{"comment":"The manuscript uses both ωlog and ωln for the logarithmically averaged phonon frequency; please standardize the notation and use it consistently in equations, Table 1, and Figure 4.","section":"Throughout"},{"comment":"There are several typographical errors: 'Kadawaki-Woods' should be 'Kadowaki-Woods'; 'Sommerfield' should be 'Sommerfeld'; 'imgaes' should be 'images'; 'accelerting' should be 'accelerating'; and 'Ti-Zr-Hf-Nb-Ta system' should be 'Ti-Hf-Nb-Ta system'.","section":"Throughout"},{"comment":"The text refers to 'Figure 2(c) and Figure S1' for magnetotransport, but Figure S1 is also used earlier for EDX line scans and point analysis. The supplementary figure numbering needs to be reorganized to avoid ambiguity.","section":"Section III and Supplementary Figures"},{"comment":"The authors state that the KWR is nearly an order of magnitude larger than in V3Si and many heavy-fermion compounds, but they do not quote the numerical A/γ^2 value. The numerical ratio and its uncertainty should be given explicitly.","section":"Section III, KWR paragraph"}],"recommendation":"major_revision","confidential_remarks":"The experimental characterization of the superconducting state appears reliable and the paper is likely publishable after revision. The main risk is over-interpretation: the monotonic-Tc trend, the maximum solid-solution claim, and the strong-coupling/strong-correlation conclusions all need either additional data or careful weakening, and the alpha-model plots should be reframed as model inversions rather than independent evidence. I would encourage revision rather than rejection because the core bulk-superconductivity result is well supported and the identified issues are addressable within the manuscript's scope."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"The basic result here is probably right, and it is worth a referee's time. (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix samples with x up to 0.077 are single-phase BCC, and resistivity, magnetization, and specific heat all point to bulk type-II superconductivity with Tc up to about 7.4 K. That is a sensible, direct extension of the same group's TiHfNbTa work, and the new Ni-doping series is genuinely new data, even if the recipe and analysis framework are familiar. The measurements look internally consistent: full Meissner fraction, single AC-susceptibility transition, heat-capacity jumps with reasonable magnitudes. I would trust the central materials claim.\n\nThe soft spots are real but not fatal. First, the claim that Tc increases monotonically with Ni content breaks at the lowest doping: Tc(0) = 6.75 K from their own ref. [18] but Tc(0.014) = 6.55 K. That is a small non-monotonicity at the first data point, but it is exactly the kind of thing that should be acknowledged or explained if you are going to headline the trend. Second, the alpha-model analysis is partly circular. They use the measured DeltaCel/gammaTc to compute omega_ln and 2Delta0/kBTc, then plot those derived quantities against the same measured ratio. That does not independently confirm strong coupling; the raw ratio being well above 1.43 already suggests strong coupling, so the derived parameters add little. Third, the Kadowaki-Woods argument rests on a single A coefficient, A = 1.5e-3 micro-ohm cm K^-2, for x = 0.077, with no fitting window and no uncertainty, in a sample with RRR near 1. Given that much disorder, the \"extremely strong electron correlation\" language is not justified. The authors themselves list anisotropy, Fermi-surface topology, degeneracy, and magnetic correlation as alternative sources of a large KWR, so the interpretation is not unique.\n\nNone of this undermines the superconductivity itself. The paper is a decent experimental contribution to an active field, but the interpretive claims need to be reined in and the analysis needs more transparency about fits and uncertainties. I would send it to peer review, with the expectation of major revisions before acceptance. A serious referee could also do the field a service by pushing on the x = 0 endpoint and the KWR fitting details.\n\nBottom line: worth engaging, but not as a definitive statement on strong correlation in HEAs.","headline":"Solid new data on Ni-doped TiHfNbTa with a credible bulk-superconductivity result, but the strong-correlation claim is oversold and the monotonic-Tc narrative stumbles on the undoped endpoint.","tokens_in":12673,"tokens_out":1377,"would_cite":false,"duration_ms":18510,"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":"In the medium-entropy alloy (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix, nickel doping preserves the BCC structure, raises the superconducting transition temperature to 7.36 K, and yields specific-heat jumps and Kadowaki-Woods ratios that place the…","keywords":["Medium-entropy alloys","High-entropy alloy superconductors","Strong coupling superconductivity","Kadowaki-Woods ratio","Strong electron correlation","Valence electron count","Nickel doping","Bulk type-II superconductor"],"falsifier":"Measure the resistivity of a higher-purity (annealed or single-crystal) sample of (Ti1/4Hf1/4Nb1/4Ta1/4)0.923Ni0.077 below 2 K and check whether ρ(T) − ρ0 scales as T² over a substantial temperature window; if the exponent deviates from 2 or the fitted A changes by more than experimental uncertainty when the fitting range is varied, the Kadowaki-Woods-based strong-correlation claim would be unsupported. A second falsifying observation would be to dope with a non-magnetic element that raises the VEC by the same amount as nickel and find no corresponding Tc increase, which would contradict the paper's VEC mechanism.","tokens_in":11327,"feed_emoji":"❄️","tokens_out":3746,"duration_ms":42796,"temperature":0.7,"pith_summary":"This paper reports that adding up to 7.7% nickel to the medium-entropy superconductor TiHfNbTa keeps the body-centered-cubic structure intact and turns every measured composition into a bulk type-II superconductor whose critical temperature rises with nickel content, reaching 7.36 K at x = 0.077. The specific-heat jump ratios of 2.44 to 2.89, well above the BCS weak-coupling value of 1.43, mark all compositions as strongly coupled superconductors, with the coupling slightly weakening as nickel increases. The authors further argue that a large Kadowaki-Woods ratio for the x = 0.077 sample indicates extremely strong electron correlations, and they attribute the Tc enhancement to the increase in valence electron count caused by nickel doping. If correct, the paper establishes a new material platform where strong electron-phonon coupling and strong electron correlations coexist, offering a tunable system for studying unconventional superconductivity.","feed_headline":"Nickel doping lifts an alloy's Tc to 7.36 K","feed_subtitle":"Specific-heat jumps and a large Kadowaki-Woods ratio mark the medium-entropy superconductor as strongly coupled and strongly correlated.","key_machinery":"The argument is carried by two dimensionless ratios and one composition parameter. The first is the normalized specific-heat jump ΔCel/γTc, computed through the alpha model, which distinguishes weak (1.43) from strong coupling; the measured values 2.44–2.89 place all samples above the BCS limit. The second is the Kadowaki-Woods ratio KWR = A/γ², formed from the T² resistivity coefficient A and the Sommerfeld coefficient γ, whose placement relative to universal transition-metal and heavy-fermion lines is used to infer electron correlation strength. The composition parameter is the valence electron count (VEC), which increases monotonically with nickel content and is presented as the control variable that raises Tc, following the trend previously established for the parent TiHfNbTa system.","core_discovery":"The central claim is that in (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix with 0 < x ≤ 0.077, nickel is a beneficial dopant: it enters the BCC solid solution up to about 7.7%, all samples are bulk type-II superconductors with a 100% Meissner fraction, and Tc increases monotonically with nickel content from 6.55 K to 7.36 K. The normalized specific-heat jump ΔCel/γTc decreases from 2.89 to 2.44 as x rises, yet remains far above the BCS value of 1.43, so the alloys stay strongly coupled throughout. A single Kadowaki-Woods ratio extracted for x = 0.077, A/γ² ≈ 1.5×10⁻³ μΩ cm K⁻² / (4.297 mJ mol⁻¹ K⁻²)², lies beyond the heavy-fermion line, which the authors interpret as evidence of extremely strong electron correlation. The paper concludes that nickel doping increases the valence electron count and that this VEC increase drives the Tc enhancement, consistent with the Matthias-rule trend for crystalline transition-metal superconductors.","pith_inferences":["The paper reports the Kadowaki-Woods ratio only for x = 0.077; an obvious testable extension is to extract A and γ for every composition to see whether the strong-correlation signature grows monotonically with nickel content or appears only at the highest doping.","A cleaner separation of the VEC effect from nickel's magnetic character could be achieved by substituting a non-magnetic element that raises the VEC by the same amount (for example molybdenum or tungsten) and comparing the Tc trend; if Tc rises identically, magnetism is irrelevant to the enhancement.","The authors attribute the extreme Kadowaki-Woods ratio to strong dynamical electron-phonon coupling rather than to electronic correlations alone, following the A15-compound precedent; this leaves open the question of whether the same alloys would show heavy-fermion-like mass enhancement in direct probes such as magnetic-field-dependent specific heat or de Haas–van Alphen measurements.","Since the Kadowaki-Woods ratio is derived from a single T² fit on a sample with RRR near 1, a natural extension is to measure the resistivity exponent over a wider temperature range on an annealed or higher-purity specimen; if the deviation from T² is large or the coefficient changes with fit window, the correlation claim would need reassessment."],"forward_implications":["If the VEC-driven Tc enhancement is correct, doping medium-entropy superconductors with elements that raise the valence electron count is a predictable route to higher critical temperatures within the BCC family.","The coexistence of strong electron-phonon coupling (ΔCel/γTc ≈ 2.4–2.9) with a very large Kadowaki-Woods ratio suggests that BCC high-entropy alloys can host both conventional strong coupling and correlation effects normally associated with heavy-fermion or unconventional superconductors.","Because Tc increases rather than being suppressed when a magnetic element is added, the paper implies that local magnetic moments from nickel do not destroy Cooper pairing in this highly disordered environment, opening the possibility of tuning magnetic character without losing superconductivity.","The systematic decrease of ΔCel/γTc with nickel content means the coupling strength can be continuously adjusted by composition while remaining in the strong-coupling regime, providing a fine-tuning knob for future experiments.","All measured compositions show bulk superconductivity with a full Meissner fraction, so the series can serve as a clean platform for pressure, disorder, or further substitution studies aimed at the interplay between strong correlations and superconductivity."],"supporting_citations":[{"why":"Provides the base compound TiHfNbTa with extremely strong coupling s-wave superconductivity, which this paper extends by nickel doping.","marker":"[18]"},{"why":"Establishes the VEC-dependence of Tc in Ta-Nb-Hf-Zr-Ti high-entropy alloys, the trend this paper invokes to explain the nickel-driven Tc increase.","marker":"[14]"},{"why":"Supplies the alpha model used to extract the normalized specific-heat jump and coupling strength from heat capacity data.","marker":"[28]"},{"why":"Provides the reference for large Kadowaki-Woods ratios and the discussion of alternative mechanisms (anisotropy, Fermi-surface topology, degeneracy, magnetic correlation) that the paper weighs against its strong-correlation claim.","marker":"[37]"},{"why":"Defines the universal Kadowaki-Woods ratio in heavy-fermion compounds, the baseline against which the measured A/γ² is compared.","marker":"[39]"},{"why":"Gives the analogous (Ti1/3Hf1/3Ta1/3)1-xNbx system whose coupling strength and VEC trends the present results are compared with.","marker":"[31]"}],"fun_headline_variants":["Ni doping lifts Tc to 7.36 K in medium-entropy alloy","Strong coupling and correlation from Ni-doped MEA","Nickel raises superconducting Tc to 7.36 K","Ni-doped TiHfNbTa: Tc 7.36 K, strong coupling","Medium-entropy alloy with Ni: Tc 7.36 K, strong correlation"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The strongest correlation claim rests on a single quadratic resistivity coefficient extracted from a highly disordered sample (residual resistivity ratio near 1), assuming that the low-temperature ρ(T) = ρ0 + A T² form is a genuine Fermi-liquid electron-electron scattering term and that the resulting A/γ² can be compared against universal Kadowaki-Woods lines without correction for disorder or multiband effects.","fun_headline_variants_meta":{"raw":{"variants":["Ni doping lifts Tc to 7.36 K in medium-entropy alloy","Strong coupling and correlation from Ni-doped MEA","Nickel raises superconducting Tc to 7.36 K","Ni-doped TiHfNbTa: Tc 7.36 K, strong coupling","Medium-entropy alloy with Ni: Tc 7.36 K, strong correlation"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000373,"raw_usage":{"total_tokens":2091,"prompt_tokens":1141,"completion_tokens":950,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":757,"completion_tokens_details":{"reasoning_tokens":856}},"tokens_in":757,"tokens_out":950,"duration_ms":11248,"temperature":1.0,"reasoning_tokens":856,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-06T12:22:33.370337+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Measure the resistivity of a higher-purity (annealed or single-crystal) sample of (Ti1/4Hf1/4Nb1/4Ta1/4)0.923Ni0.077 below 2 K and check whether ρ(T) − ρ0 scales as T² over a substantial temperature window; if the exponent deviates from 2 or the fitted A changes by more than experimental uncertainty when the fitting range is varied, the Kadowaki-Woods-based strong-correlation claim would be unsupported. A second falsifying observation would be to dope with a non-magnetic element that raises the VEC by the same amount as nickel and find no corresponding Tc increase, which would contradict the paper's VEC mechanism.","supporting_citations":[{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Provides the base compound TiHfNbTa with extremely strong coupling s-wave superconductivity, which this paper extends by nickel doping."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Establishes the VEC-dependence of Tc in Ta-Nb-Hf-Zr-Ti high-entropy alloys, the trend this paper invokes to explain the nickel-driven Tc increase."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Supplies the alpha model used to extract the normalized specific-heat jump and coupling strength from heat capacity data."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Provides the reference for large Kadowaki-Woods ratios and the discussion of alternative mechanisms (anisotropy, Fermi-surface topology, degeneracy, magnetic correlation) that the paper weighs against its strong-correlation claim."},{"cited_title":"58 507-9","cited_arxiv_id":null,"evidence_quote":"Defines the universal Kadowaki-Woods ratio in heavy-fermion compounds, the baseline against which the measured A/γ² is compared."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Gives the analogous (Ti1/3Hf1/3Ta1/3)1-xNbx system whose coupling strength and VEC trends the present results are compared with."}],"review_version":1}