{"id":"c0fb5cb3-0372-469c-a990-f589c23e9d45","arxiv_id":"2507.23166","paper_version":1,"verdict":"REJECT","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"high","formal_verification":"none","parameter_count":2,"one_line_summary":"An alpha-tin/(In,Fe)Sb heterostructure shows an odd-parity magnetoresistance of up to 1,150% at 1 T, attributed to proximity-induced tilted topological bands.","lead":"Researchers report a magnetoresistance effect that reaches 1,150% when the magnetic field is reversed at just 1 tesla in an alpha-tin/(In,Fe)Sb layered structure. The effect is explained with tilted 'Weyl cone' electronic bands and proposed for ultra-sensitive magnetic sensors.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The giant OMR ratio depends on an unverified single-layer current assumption; the paper's own SdH data show a conducting InSb shunt, so the antisymmetric voltage cannot yet be attributed to α-Sn.","rationale":"The reader's REJECT is based on missing raw data, a fitted theory parameter, and a crude DFT model. My pass isolates the most load-bearing premise: the assumption that all current is confined to the 3 nm α-Sn layer. This premise is not directly measured; Supplementary Note 2 only shows a current-independent R below 10 μA, and the measurements are made at 10 μA, immediately at the border of the regime where the authors themselves say current leakage into InSb begins. Moreover, Fig. 3e resolves a 3D Fermi surface assigned to bulk InSb, evidence that a parallel conducting channel is present. If a parallel path carries current, R(0 T) = 0.68 Ω is a network resistance rather than an α-Sn property, so the 1,150% OMR ratio and its angular dependence cannot be unambiguously assigned to tilted Weyl cones in α-Sn. This concern can be settled by an α-Sn-free control Hall bar and current-reversed raw traces, so the appropriate disposition remains rejection until that control is provided. The secondary issues noted by the reader—single-Fe DFT surrogate and the tilt ratio fitted to the data—remain valid but are secondary to the measurement attribution. I do not find an independent reason to change the reader's verdict.","tokens_in":12390,"tokens_out":10078,"duration_ms":126224,"concrete_test":"Fabricate an α-Sn-free control Hall bar from the same wafer by selectively etching away the α-Sn layer (stopping at (In,Fe)Sb) and measure R_odd under B // I at 2 K with I = 10 μA using identical contact geometry and both current polarities; if the control shows an antisymmetric longitudinal voltage comparable to the full stack, the top-layer attribution fails. In parallel, record raw R(+B) and R(-B) traces and their current-reversed averages for the full stack.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim rests on the unmeasured premise that, at I = 10 μA, essentially all current flows in the 3-nm α-Sn layer and that the antisymmetric voltage used for OMR is generated there. Supplementary Note 2 is the only support: R(I) is flat below 10 μA and decreases above 10 μA, which the authors attribute to current leakage into InSb. But the operating current is at the stated onset of that leakage-like nonlinearity, and a flat R(I) alone does not exclude a fixed parallel conductance. The paper's own SdH analysis (Fig. 3e) resolves a 3D Fermi surface assigned to bulk InSb, showing that a conducting shunt exists under the same stack; if this buffer carries a fraction of the current, R(0 T) = 0.68 Ω used as the denominator in the 1,150% OMR ratio is not the α-Sn zero-field resistance and the ratio is not a material property of α-Sn. In-plane B // I geometry removes the ordinary Hall contribution, but an antisymmetric longitudinal signal can still be generated by current redistribution between the α-Sn and a magnetized or field-dependent parallel layer, or by contact/thermoelectric asymmetry; raw R(B) and R(-B) traces and current-reversal checks are not reported. Thus the giant OMR magnitude, and hence the need for tilted Weyl cones, is not established unless the single-layer current assumption is verified.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper reports a large odd-parity magnetoresistance (OMR) in a heterostructure of 3-nm α-Sn on the ferromagnetic semiconductor (In,Fe)Sb on an InSb substrate. At 2 K and 1 T, the antisymmetric resistance extracted as [R(B)-R(-B)]/2 is claimed to reach 1,150% of the zero-field resistance R(0)=0.68 Ω. The authors argue that this OMR arises from tilted Weyl cones in the α-Sn layer, induced by the magnetic proximity effect, and support this with Shubnikov-de Haas oscillations showing a 2D Fermi surface with linear dispersion, density-functional band structures, and a Boltzmann transport model fitted to the angular dependence of the OMR.","tokens_in":12628,"tokens_out":9462,"duration_ms":99560,"significance":"If correct, this would be the largest odd-parity magnetoresistance reported to date by about an order of magnitude and would open a new route to sensitive magnetic-field sensing. The manuscript includes useful band-structure calculations and a careful SdH analysis. However, the central quantitative claim depends on the unverified assumption that the measured R(0) is the resistance of the α-Sn layer alone, and the theoretical 'prediction' of the angular dependence is actually obtained by fitting a free parameter to the same data. These issues currently prevent the claims from being accepted.","major_comments":[{"comment":"The OMR ratio is normalized to R(0)=0.68 Ω, but the claim that this is the resistance of the α-Sn layer alone rests on the unverified assumption that at I=10 μA all current flows in α-Sn. The flat R(I) below 10 μA shown in Supplementary Fig. S2(a) is also consistent with a fixed parallel conductance, and the operating current sits at the onset of the nonlinearity attributed to leakage. More critically, the SdH analysis in Methods and Fig. 3(e) detects a 3D Fermi surface assigned to bulk InSb, which demonstrates that a parallel conducting path exists in the same stack. Please quantify the conductance of each layer (e.g., from the SdH carrier densities and mobilities) or show a direct measurement that rules out a shunt; otherwise the 1,150% ratio cannot be assigned to α-Sn.","section":"Supplementary Note 2; Methods (SdH analysis)"},{"comment":"The agreement between the calculated angular dependence and the experimental data is obtained by setting w_y/w_x = 4.29, which is fitted to the same experimental data shown in Fig. 4(a). This is a one-parameter fit, not a parameter-free prediction, and the statement that the model 'well reproduces' and 'strongly supports' the tilted-cone origin is therefore overstated. In addition, the main text says the derivation of Eq. (1) is in the Methods, but the Methods section only presents Eq. (3) from reference 25 and does not derive Eq. (1); either provide the derivation or state explicitly that Eq. (1) is a special case of Eq. (3).","section":"Fig. 4; 'Tilted Weyl cones model' in Methods"},{"comment":"The DFT model is described inconsistently: the main text says 'Fe atoms are distributed on the top layer' of the 18-ML α-Sn slab, whereas Supplementary Note 4 says 'a single Fe atom is embedded as a dopant on the lowest Sn layer.' Since the magnetic proximity effect acts at the α-Sn/(In,Fe)Sb interface, the latter is physically appropriate, but the discrepancy must be corrected. More fundamentally, replacing the (In,Fe)Sb ferromagnetic semiconductor by a single substitutional Fe atom in the α-Sn slab is a strong simplification whose effect on the predicted tilt asymmetry is not benchmarked against any experimental observable other than the fitted OMR angular dependence.","section":"First principles calculations; Supplementary Note 4"},{"comment":"The raw R(B) and R(-B) traces are presented, but without error bars, multiple sweeps, or a current-reversal check. Given that Rodd at 1 T is reported as ~11.5×R(0), which is a surprisingly large antisymmetric component, the reproducibility of the signal and the absence of thermoelectric or contact asymmetries should be explicitly demonstrated.","section":"Fig. 2"}],"minor_comments":[{"comment":"The sentence 'X and Y are on the Brillouin zone boundary in k-space along the kx and kx directions' should read 'along the kx and ky directions'.","section":"Section 3 (after Fig. 3h)"},{"comment":"The claim that the OMR is 'more than three orders of magnitude' larger than previous reports is inconsistent with Supplementary Table S1, where the previous largest value is 40% (bilayer graphene/Cr2Ge2Te6); the present 1,150% value is about 29 times larger, roughly one and a half orders of magnitude. The summary's 'more than two orders of magnitude' is also too strong.","section":"Abstract and Summary"},{"comment":"The statement in the main text that the OMR changes 'approximately as a cosine function' is not consistent with the peak positions in the yz and xy rotations (105° and 35°, respectively); please rephrase to reflect the actual angular dependence.","section":"Fig. 4 and main text"},{"comment":"Reference 19 is an arXiv preprint; if a published version exists, it should be cited, or the preprint status should be noted explicitly.","section":"References"},{"comment":"The on-site Coulomb parameter is given as U = -2.5 eV, which is an unusual sign convention for GGA+U; a brief explanation of this convention and its origin would aid reproducibility.","section":"Methods (First principles calculations)"}],"recommendation":"major_revision","confidential_remarks":"The manuscript reports a striking effect with high potential impact, but the central quantitative claim is currently undermined by two substantial issues: the unverified single-layer current path (with the paper's own SdH data suggesting a conducting InSb buffer) and the circularity of the one-parameter fit to the angular dependence. I would like to see new experimental data or a quantitative parallel-conductance analysis before publication. The paper also contains a clear internal inconsistency in the DFT model description that must be resolved."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"The headline is an antisymmetric resistance in an α-Sn/(In,Fe)Sb stack, normalized to R(0)=0.68 Ω, reaching ~1,150% at 1 T. If that number were a material property of the α-Sn layer, it would beat prior OMR values by more than an order of magnitude. The group's materials work is careful: STEM, EDX, MCD, and SQUID all support a clean epitaxial stack with ferromagnetic (In,Fe)Sb, and the SdH analysis is competently done. The application of the tilted Weyl cone Boltzmann model from ref. 25 to interpret the angular dependence is a reasonable starting point.\n\nBut the soft spots are serious. The paper never verifies its most load-bearing assumption: that essentially all current flows in the α-Sn layer. The authors say (In,Fe)Sb is insulating at low T, but their own SdH angular data (Fig. 3e) resolve a 3D Fermi surface assigned to bulk InSb, showing a conducting shunt exists. The operating current of 10 μA sits exactly at the onset of the current-dependent resistance drop that they attribute to leakage. With a parallel conductor in the stack, R(0)=0.68 Ω is not the α-Sn resistance, and the 1,150% ratio is not a material property. The odd voltage could plausibly come from current redistribution or contact/thermoelectric asymmetry; raw R(B) and R(-B) traces, current-reversal checks, and error bars are absent.\n\nThe model comparison is also weaker than the text claims. The tilt ratio w_y/w_x=4.29 is fitted to the angular data it then reproduces, so the agreement is a one-parameter fit, not a prediction. The paper says the derivation of Eq. (3) is in Methods, but Methods only states the result—the derivation is missing. The DFT surrogate of a single Fe atom in an 18-ML α-Sn slab is crude but probably acceptable for a qualitative band structure. A minor but telling inconsistency: the paper calls the improvement over prior OMR “three orders of magnitude” (and later “two”), while their own Supplementary Table S1 gives a prior maximum of 40%, making the factor ~29, not 100 or 1000.\n\nThis paper deserves peer review because the claim is extraordinary and the group is credible. But the current evidence does not support the central claim as stated. A serious referee would require controls to isolate the α-Sn contribution—for instance, a nominally identical stack without α-Sn, current-reversal and contact-swapping checks, or a gate that depletes the InSb buffer—plus a reanalysis of the OMR normalization and a parameter-free test of the tilted-band model. I would not cite this yet, but I would read it with interest and watch for a revised version with those experiments.","headline":"A credible group reports a potentially record OMR in α-Sn/(In,Fe)Sb, but the giant 1,150% number rests on an unverified single-channel current assumption and a one-parameter model fit, so the central claim is not established.","tokens_in":856,"tokens_out":850,"would_cite":false,"duration_ms":46768,"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 reports odd-parity magnetoresistance up to 1,150% at 1 T in a 3-nm α-Sn film on (In,Fe)Sb, explained by magnetic-proximity-induced tilted Weyl cones.","keywords":["odd-parity magnetoresistance","magnetic proximity effect","Weyl semimetal","tilted Weyl cones","alpha-Sn/(In,Fe)Sb heterostructure","Shubnikov-de Haas oscillations","magnetic field sensor"],"falsifier":"Measure the same Hall-bar geometry at 2 K and 1 T on a control sample in which the (In,Fe)Sb layer is replaced by an equally thick nonmagnetic InSb layer, keeping the α-Sn thickness and growth conditions identical: the 1,150% antisymmetric signal should disappear if it comes from magnetic proximity and tilted Weyl cones, while any residual antisymmetric resistance would point to a current-path or Hall artifact.","tokens_in":12085,"feed_emoji":"🧲","tokens_out":18393,"duration_ms":184985,"temperature":0.7,"pith_summary":"This paper reports that a 3-nanometer film of the narrow-gap semiconductor α-Sn grown on the ferromagnetic semiconductor (In,Fe)Sb shows odd-parity magnetoresistance (OMR)—an antisymmetric resistance change when the magnetic field is reversed—reaching up to 1,150% at 1 T and 2 K. Ordinary magnetoresistance is even under field reversal by Onsager reciprocity, so an antisymmetric component of this size is unexpected. The authors attribute the effect to magnetic proximity from (In,Fe)Sb breaking time-reversal symmetry in the tin layer and creating tilted, Weyl-like linear bands; a Boltzmann transport model with oppositely tilted Weyl cones reproduces the measured angular dependence of the OMR. If correct, the result is the largest OMR reported to date and points toward magnetic sensors with roughly an order of magnitude higher sensitivity than commercial Hall devices.","feed_headline":"Odd-parity magnetoresistance hits 1,150% at 1 T","feed_subtitle":"3-nm tin on a ferromagnetic semiconductor flips resistance with the field, a route to ultrasensitive magnetic sensors.","key_machinery":"The central object is the α-Sn/(In,Fe)Sb heterojunction, where the magnetic proximity effect is argued to transform a nominally trivial 3-nm α-Sn film into one with nearly gapless, tilted linear bands. The named theoretical object is the oppositely tilted Weyl cone: a pair of Weyl nodes of opposite chirality whose Dirac cones are slanted in opposite directions in momentum space. The load-bearing identity is the Boltzmann-transport result that this tilt configuration produces an odd current-density component linear in the magnetic field, $j_{\\mathrm{odd}} \\propto \\alpha_x E_x B_x + \\alpha_y E_x B_y$ for current along x, whose angular dependence is controlled by the tilt constants; fitting that expression to the three-plane rotation data with $\\alpha_y/\\alpha_x = 4.29$ is what connects the measured OMR to the proposed mechanism.","core_discovery":"The central claim is the observation of odd-parity magnetoresistance reaching 1,150% at 1 T in an epitaxial α-Sn/(In,Fe)Sb bilayer, defined as $R_{\\mathrm{odd}}(B)/R(0)$ with $R_{\\mathrm{odd}}(B) = [R(B)-R(-B)]/2$. Shubnikov-de Haas oscillations show a single two-dimensional Fermi surface whose Berry phase of about 0.65 indicates linear dispersion, and density-functional calculations for an 18-monolayer α-Sn slab with Fe near the interface show a nearly gapless, tilted linear band near $-0.25$ eV. The antisymmetric resistance vanishes when the magnetic field is perpendicular to the film and follows the predicted pattern when the field is rotated in three orthogonal planes; a semiclassical Boltzmann model of oppositely tilted Weyl cones, fitted with tilt anisotropy $\\alpha_y/\\alpha_x = 4.29$, reproduces the full angular dependence. The paper concludes that magnetic proximity induces these tilted topological states in the thin tin layer and that the OMR is their transport signature.","pith_inferences":["Because the OMR is argued to scale with the tilt anisotropy of the linear bands, gating the α-Sn layer to move the Fermi level through the band should change the measured angular pattern; that tunable check is not reported in the paper.","The same heterostructure recipe could be tried with other narrow-gap semiconductors or magnetic insulators with higher Curie temperatures, potentially extending the effect toward room temperature.","The estimated sensor sensitivity of 11.5 mV/mT/V assumes the 1-T antisymmetric voltage scales with the bias voltage; a direct noise-equivalent-field measurement would be needed to confirm the practical advantage over commercial Hall sensors."],"forward_implications":["At 1 T and 2 K the OMR ratio reaches 1,150%, more than three orders of magnitude above previously reported odd-parity magnetoresistance values.","Because the antisymmetric resistance grows monotonically with field and is largest for B parallel to the current, the device provides a linear field-direction sensor that does not rely on carrier mobility the way Hall sensors do.","The angular dependence of the OMR in three rotation planes matches a Boltzmann model with a single fitted tilt anisotropy of 4.29, the ratio of the two tilt constants.","The magnetic proximity effect promotes a 3-nm α-Sn film from a trivial narrow-gap semiconductor to a system with a two-dimensional Fermi surface with Berry phase near 0.65, tying thin-film transport to topological band structure."],"supporting_citations":[{"why":"Establishes the baseline α-Sn band structure: thin α-Sn on InSb is a trivial narrow-gap semiconductor, while thicker α-Sn is a topological Dirac semimetal, so the paper can identify what the magnetic proximity effect changes.","marker":"[13]"},{"why":"Shows that a ferromagnetic layer can reinstate band inversion and topological surface states in thin α-Sn, motivating the use of (In,Fe)Sb and the Fe-doped slab model.","marker":"[19]"},{"why":"Provides the (In,Fe)Sb material properties used in the argument: ferromagnetism above room temperature and insulating behavior at low temperature, which both supplies the magnetic proximity and justifies the current-flow assumption.","marker":"[20]"},{"why":"Provides the Lifshitz-Kosevich framework used to extract the Shubnikov-de Haas frequency and effective mass from the oscillatory conductance.","marker":"[23]"},{"why":"Gives the Berry-phase criterion used to interpret the Shubnikov-de Haas fan plot as evidence for linear dispersion in the α-Sn layer.","marker":"[24]"},{"why":"Supplies the Boltzmann transport model for oppositely tilted Weyl cones, giving the odd current density formula that is fitted to the OMR angular dependence.","marker":"[25]"},{"why":"Demonstrates odd-parity magnetoresistance in a magnetic-proximity heterostructure, the closest prior device concept this work extends.","marker":"[10]"},{"why":"Reports the largest previously published OMR value used as the comparison baseline for the claim that 1,150% exceeds prior results by more than three orders of magnitude.","marker":"[12]"}],"fun_headline_variants":["3-nm tin yields 1,150% odd magnetoresistance at 1 T","Odd magnetoresistance jumps to 1,150% via magnetic proximity","Giant odd magnetoresistance from proximity-induced Weyl states","1,150% odd magnetoresistance at just 1 tesla in tin heterostructure","Magnetic proximity gives tin 1,150% odd magnetoresistance"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The measured antisymmetric voltage is treated as an intrinsic property of the α-Sn layer, which requires the (In,Fe)Sb layer to be insulating at 2 K so all 10 μA flows through the α-Sn; if a parallel current path exists through (In,Fe)Sb or the InSb buffer, the odd voltage could include Hall or contact artifacts.","fun_headline_variants_meta":{"raw":{"variants":["3-nm tin yields 1,150% odd magnetoresistance at 1 T","Odd magnetoresistance jumps to 1,150% via magnetic proximity","Giant odd magnetoresistance from proximity-induced Weyl states","1,150% odd magnetoresistance at just 1 tesla in tin heterostructure","Magnetic proximity gives tin 1,150% odd magnetoresistance"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000794,"raw_usage":{"total_tokens":3533,"prompt_tokens":1016,"completion_tokens":2517,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":632,"completion_tokens_details":{"reasoning_tokens":2414}},"tokens_in":632,"tokens_out":2517,"duration_ms":19672,"temperature":1.0,"reasoning_tokens":2414,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-06T10:59:26.397611+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Measure the same Hall-bar geometry at 2 K and 1 T on a control sample in which the (In,Fe)Sb layer is replaced by an equally thick nonmagnetic InSb layer, keeping the α-Sn thickness and growth conditions identical: the 1,150% antisymmetric signal should disappear if it comes from magnetic proximity and tilted Weyl cones, while any residual antisymmetric resistance would point to a current-path or Hall artifact.","supporting_citations":[{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Establishes the baseline α-Sn band structure: thin α-Sn on InSb is a trivial narrow-gap semiconductor, while thicker α-Sn is a topological Dirac semimetal, so the paper can identify what the magnetic proximity effect changes."},{"cited_title":"Topological surface states induced by the magnetic proximity effect","cited_arxiv_id":"2505.07250","evidence_quote":"Shows that a ferromagnetic layer can reinstate band inversion and topological surface states in thin α-Sn, motivating the use of (In,Fe)Sb and the Fe-doped slab model."},{"cited_title":"T., Hai, P","cited_arxiv_id":null,"evidence_quote":"Provides the (In,Fe)Sb material properties used in the argument: ferromagnetism above room temperature and insulating behavior at low temperature, which both supplies the magnetic proximity and justifies the current-flow assumption."},{"cited_title":"Magnetic Oscillations in Metals","cited_arxiv_id":null,"evidence_quote":"Provides the Lifshitz-Kosevich framework used to extract the Shubnikov-de Haas frequency and effective mass from the oscillatory conductance."},{"cited_title":"Topological insulator materials","cited_arxiv_id":null,"evidence_quote":"Gives the Berry-phase criterion used to interpret the Shubnikov-de Haas fan plot as evidence for linear dispersion in the α-Sn layer."},{"cited_title":"B., Yang, H","cited_arxiv_id":null,"evidence_quote":"Supplies the Boltzmann transport model for oppositely tilted Weyl cones, giving the odd current density formula that is fitted to the OMR angular dependence."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Demonstrates odd-parity magnetoresistance in a magnetic-proximity heterostructure, the closest prior device concept this work extends."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Reports the largest previously published OMR value used as the comparison baseline for the claim that 1,150% exceeds prior results by more than three orders of magnitude."}],"review_version":1}