{"id":"67bed55f-5ecb-4196-a22e-2b9ae519ab61","arxiv_id":"2501.12646","paper_version":1,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":1,"one_line_summary":"Current-induced magnetoresistance hysteresis and a field-enhanced superconducting diode effect are observed in the kagome superconductor CsV3Sb5, pointing to chiral superconducting domains.","lead":"Applying a DC current to thin flakes of the kagome superconductor CsV3Sb5 produces a hysteresis in the magnetoresistance that exists only in the superconducting state. The effect, along with a magnetic-field-enhanced superconducting diode effect, suggests chiral superconducting domains and may help probe unconventional pairing in kagome metals.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The chiral-domain conclusion relies on excluding vortex physics, but the Appendix E tests target bulk pinning and do not rule out edge-barrier flux entry/exit, which can produce both the hysteresis and the diode effect.","rationale":"I agree with the reader's conditional verdict. The most load-bearing weakness is the vortex exclusion, and I refine it: Appendix E argues against bulk vortex pinning but never addresses the geometrical edge barrier, which is the more relevant vortex mechanism in thin flakes. The proposed Corbino test directly targets this gap. No change to the reader's verdict is needed; the paper's central observation remains reproducible and plausible, but the chiral-domain claim is not yet established over the conventional edge-barrier vortex alternative.","tokens_in":11610,"tokens_out":10807,"duration_ms":127943,"concrete_test":"Fabricate a Corbino-disk geometry on an exfoliated CsV3Sb5 flake with a concentric inner contact and outer ring contact, and repeat the dV/dI vs field sweep at T=1.8 K with the same IDC values used in Fig. 2. In Corbino geometry the transport current is radial and vortices move in closed azimuthal paths without crossing the sample edge, so edge-barrier flux entry/exit is suppressed while bulk pinning is unchanged. If the current-modulated MR hysteresis and the B-driven diode effect disappear or change sign, the observed effects are edge-barrier vortex phenomena and the chiral-domain inference is not supported; if they persist with comparable strength, the edge-barrier alternative is ruled out and the chiral-domain interpretation is substantially strengthened.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The load-bearing step in the argument is not the observation itself (the hysteresis is clearly SC-state-specific and reproducible) but the inference that it points to chiral superconducting domains. That inference requires that conventional vortex mechanisms be excluded. Appendix E does not achieve this. The bulk-pinning arguments there are weak: the 'butterfly' criterion is taken from granular and hydride superconductors and is not a general signature of flux trapping in a clean thin flake; the overlap of I-V curves in Fig. 8 is measured at fixed field and cannot detect field-history-dependent vortex configurations; and sweep-rate independence over 15-25 mT/min is expected for quasi-static critical-state hysteresis, which is intrinsically rate-independent. More importantly, the Appendix E discussion treats only bulk pinning. In a <30 nm flake, the dominant vortex-related hysteresis mechanism is the geometrical surface (Bean-Livingston) barrier for flux entry and exit at the sample edges, which is strong in clean thin crystals even when bulk pinning is negligible. A DC transport current tilts the edge barrier asymmetrically, so the internal flux density during a field up-sweep differs from that during a down-sweep; this produces a sweep-direction-dependent critical field of the observed sign. The same asymmetric edge barrier is a standard source of a field-polarity-reversing superconducting diode (a vortex ratchet), so the diode effect in Fig. 4 does not discriminate. The absence of hysteresis at IDC=0 is also expected for an edge-barrier mechanism, since a transport current is required to convert the metastable flux distribution into a measurable voltage. Thus the empirical evidence does not yet single out chiral superconducting order over conventional edge-barrier vortex physics.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The manuscript reports four-probe transport measurements on exfoliated CsV3Sb5 flakes (devices S1–S3) showing that, below the superconducting transition, applying a DC current produces a magnetic-field-sweep-direction-dependent differential resistance (magnetoresistance hysteresis) that grows with the DC current and disappears when superconductivity is suppressed. The authors define a field difference ΔBc and show that it increases monotonically with current, and they demonstrate that the hysteresis is insensitive to sweep rate. In device S3, a field-driven superconducting diode effect is observed, with the critical-current asymmetry reversing with magnetic-field polarity. The authors interpret the results as evidence for chiral superconducting domains and enhanced electronic magnetochiral anisotropy, arguing that vortex pinning and other extrinsic mechanisms can be excluded.","tokens_in":11901,"tokens_out":4306,"duration_ms":47068,"significance":"If the chiral-domain interpretation is correct, the work would provide useful transport evidence for time-reversal symmetry breaking in the superconducting state of CsV3Sb5 and would strengthen the case for chiral superconductivity in this kagome family. The manuscript benefits from multi-device data, explicit checks of data-acquisition lag and transverse effects, hBN encapsulation to prevent oxidation, and consistency between positive and negative DC currents. However, the central interpretation depends on excluding conventional vortex physics, especially surface-barrier effects, and the exclusion provided in Appendix E is not sufficient. The paper convincingly establishes a reproducible, superconducting-state-specific magnetoresistance hysteresis, but the load-bearing inference to chiral superconducting domains is not established by the present data.","major_comments":[{"comment":"The exclusion of vortex physics is incomplete and does not address the most relevant mechanism for a thin flake. The arguments based on the overlap of I-V curves in Fig. 8 and on sweep-rate independence in Fig. 3(b) test only bulk pinning and quasi-static hysteresis. In a <30 nm flake, the geometrical surface (Bean-Livingston) barrier at the sample edges can produce field-history-dependent flux entry and exit even when bulk pinning is negligible; this gives a sweep-direction-dependent critical field of the observed sign (larger Bc on the down-sweep) and can also produce a field-polarity-reversing superconducting diode effect under an applied transport current. The butterfly criterion cited from Refs. [53,54] is taken from granular and hydride superconductors and is not a general signature of flux trapping in a clean thin flake. Please provide direct evidence against edge-barrier flux dynamics, such as local magnetization or Hall-probe measurements, a Corbino geometry, or a quantitative comparison with a known vortex system of similar geometry.","section":"Appendix E, \"Vortex physics\""},{"comment":"The definition of ΔBc is arbitrary and the associated errors are not described. Appendix B defines ΔBc as the difference of the \"average magnetic fields\" at which dV/dI becomes 45–55% of the normal resistance, but it does not specify how the average is taken, how many crossings are used, or why 45–55% is chosen. The error bars in Fig. 2(f) have no stated origin or propagation method. Because the monotonic increase of ΔBc with current is the main quantitative result, please report ΔBc for several thresholds and give a reproducible error estimate.","section":"Appendix B and Fig. 2(f)"},{"comment":"The statement that the temperature dependence of the hysteresis \"aligns with the chiral superconducting domains\" is not a discriminating test: any dissipative mechanism tied to the superconducting state, including vortex motion or flux entry, would vanish above Tc. Similarly, the abstract's claim that the hysteresis \"directly link[s] magnetoresistance hysteresis to the superconducting order\" overstates the specificity of the data. The data establish that the hysteresis requires superconductivity, not that its microscopic origin is chiral superconducting domains. Please either soften these claims or add a measurement that distinguishes chiral-domain switching from vortex-related hysteresis.","section":"Section III, Discussion"}],"minor_comments":[{"comment":"The heading \"Magmatic fields sweep induced heating effect\" contains a typo; it should read \"Magnetic field sweep induced heating effect.\"","section":"Appendix E, heading 1"},{"comment":"The text says the critical current Ic is \"around ±60 µA,\" but the criterion used to extract Ic from the dV/dI versus IDC curves is not defined; please specify the criterion and state whether the multiple peaks affect the estimate.","section":"Section II, Fig. 1(d)"},{"comment":"Spin-triplet pairing is listed as one of the possible intrinsic mechanisms but is not discussed afterward; either expand this point or remove it from the list.","section":"Section III, Discussion"},{"comment":"The eMChA expression R(I,B)=R0(1+μ²B²+γIB) uses μ and γ without defining their units or relation to the magnetochiral anisotropy coefficient; please define these coefficients precisely and state how they are extracted from the data, if at all.","section":"Section II, eMChA formula"}],"recommendation":"major_revision","confidential_remarks":null},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"The real news here is empirical: below Tc, the magnetoresistance develops a clear, current-tunable hysteresis, and a small magnetic field strongly enhances a superconducting diode effect. The hysteresis is SC-state specific, reproducible across three devices, and robust against sweep-rate changes, so the basic observation deserves to be taken seriously. The temperature and current dependence is shown cleanly, and the paper does a decent job of excluding trivial artifacts like heating, acquisition lag, and transverse voltages. That is worth something.\n\nThe soft spot is the interpretation. The leap from \"hysteretic MR\" to \"chiral superconducting domains\" is not supported by the exclusions presented. Appendix E tries to rule out vortex physics, but the tests are qualitative and, more importantly, they only address bulk pinning. The I-V overlap at fixed field cannot detect field-history-dependent vortex configurations, and sweep-rate independence is expected for quasi-static critical-state hysteresis anyway. The butterfly criterion taken from granular and hydride superconductors is not a general fingerprint of flux trapping in a clean thin flake. What the appendix does not address is the geometrical edge barrier, which dominates flux entry and exit in a <30 nm flake. A DC current tilts that barrier, producing precisely the observed sweep-direction asymmetry, the absence of hysteresis at zero current, and a field-polarity-reversing diode (vortex ratchet). So the diode effect in Fig. 4 does not discriminate between chiral domains and vortex edge physics.\n\nI also agree with the reader that the ΔBc definition in Appendix B is arbitrary (45–55% of normal resistance) and error bars are minimal. That weakens the quantitative claims in Fig. 2(f), but it does not touch the existence of the hysteresis itself. The central observation is defensible; the chiral-domain conclusion is not established.\n\nWho should read this: experimentalists working on transport in kagome superconductors and anyone tracking evidence for time-reversal symmetry breaking in CsV3Sb5. The paper is a useful data point, but not the last word. I would send it to a serious referee: the observation deserves scrutiny, and the interpretation needs to be tightened or softened. I would not cite the chiral-domain claim in my own work, but I would cite the hysteresis as an unexplained experimental fact.\n\nRecommendation: engage with it, but ask for a more direct test of the vortex edge-barrier alternative—or at least a clear statement that the interpretation is speculative.","headline":"New, reproducible hysteresis and field-enhanced diode effect in CsV3Sb5, but the chiral-domain interpretation outruns the vortex exclusions.","tokens_in":12433,"tokens_out":1081,"would_cite":false,"duration_ms":12909,"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":"A DC bias current switches on a tunable magnetoresistance hysteresis below the superconducting transition of the kagome superconductor CsV$_3$Sb$_5$, and a small magnetic field drives a superconducting diode effect—evidence, the paper…","keywords":["kagome superconductor","CsV3Sb5","magnetoresistance hysteresis","superconducting diode effect","chiral superconducting domains","magnetochiral anisotropy","loop currents","time-reversal symmetry breaking"],"falsifier":"Image the local magnetic field (scanning SQUID or Lorentz microscopy) at fixed DC bias below $T_c$ while sweeping the magnetic field: if quantized vortices enter and leave with the same sweep-direction asymmetry as the resistance hysteresis, the vortex-pinning explanation survives; if no vortex motion is detected while the resistance loop persists, the chiral-domain interpretation is supported.","tokens_in":11457,"feed_emoji":"🧲","tokens_out":10460,"duration_ms":100081,"temperature":0.7,"pith_summary":"Below the superconducting transition of the kagome metal CsV$_3$Sb$_5$, a DC bias current switches on a magnetoresistance hysteresis: magnetic-field sweeps up and down give different resistance curves, with a field offset $\\Delta B_c$ that grows monotonically with current. The hysteresis is confined to the superconducting state—it disappears when superconductivity is suppressed by temperature or field—so the paper argues that the effect is directly tied to the superconducting order rather than to normal-state transport. The same devices show a superconducting diode effect that is strongly enhanced by a small magnetic field, which the paper attributes to enhanced electronic magnetochiral anisotropy from scattering by chiral superconducting domain walls. If this reading stands, CsV$_3$Sb$_5$ provides a current-tunable platform for probing a time-reversal-symmetry-broken superconducting state, with implications for unconventional pairing and topological superconductivity.","feed_headline":"DC current controls magnetoresistance hysteresis in CsV3Sb5","feed_subtitle":"The hysteresis appears only with a DC bias and vanishes when superconductivity is destroyed.","key_machinery":"The central experimental object is the magnetic-field sweep dependence of the differential resistance $\\mathrm{d}V/\\mathrm{d}I$ under fixed DC bias, quantified by $\\Delta B_c = B_{c1} - B_{c2}$, the difference in the field at which resistance reaches roughly half the normal-state value during up and down sweeps. The interpretive machinery is the electronic magnetochiral anisotropy form $R(I,B) = R_0(1 + \\mu^2 B^2 + \\gamma I B)$, combined with the idea of chiral superconducting domains whose domain walls act as tunable chiral scattering centers. This machinery is what connects the observed hysteresis to the field-polarity-dependent superconducting diode effect and gives the paper its link to time-reversal-symmetry breaking in the superconducting state.","core_discovery":"The paper's central claim is that the magnetoresistance hysteresis observed below $T_c$ in CsV$_3$Sb$_5$ is intrinsic to its superconducting state. The evidence is that no hysteresis appears without a DC bias, that the loop's size, as measured by $\\Delta B_c$, increases monotonically with bias current, that the loop vanishes once superconductivity is destroyed, that it is insensitive to magnetic-field sweep rate, and that it appears in samples of different thickness. The paper further claims that a small magnetic field—5 mT out-of-plane or 100 mT in-plane—drives a pronounced superconducting diode effect, with opposite field polarities selecting opposite preferred current directions, which it interprets as a magnetic-field-enhanced electronic magnetochiral anisotropy. Taken together, the paper proposes that chiral superconducting domains—regions with opposite loop-current chirality whose balance is shifted by field and current—best explain both the hysteresis and the field-dependent nonreciprocity.","pith_inferences":["If the chiral-domain interpretation is correct, lithographically patterned or locally strained flakes should show hysteresis loops whose sign and amplitude track the initial domain imbalance; the paper does not test this spatial dependence.","Because loop currents are thought to originate in the charge-ordered state, the same mechanism predicts that $\\Delta B_c$ should track the strength of the charge-density-wave order, for example under pressure or doping, a correlation the paper does not examine.","The sweep-rate independence implies the underlying domain realignment is fast on the measurement timescale; pulsed-field or time-resolved measurements could reveal that dynamics and cleanly separate it from slow vortex creep.","A quantitative extraction of the eMChA coefficient $\\gamma$ from the diode data would let future work compare the strength of the anisotropy directly with the magnitude of the hysteresis, a connection the paper leaves implicit."],"forward_implications":["If the hysteresis is intrinsic to the superconducting order, then $\\Delta B_c(I)$ is a direct, current-tunable probe of the symmetry-broken superconducting state in CsV$_3$Sb$_5$.","The small-field superconducting diode effect means a few millitesla can produce a strong direction-selective critical current, a useful property for low-field superconducting circuit elements.","Because the hysteresis disappears exactly when superconductivity is suppressed, the time-reversal-symmetry-broken response the paper sees is tied to the pairing state, not merely to the charge-density-wave order.","The observation in flakes up to roughly 45 nm thick indicates the effect survives in thin devices, supporting the use of exfoliated CsV$_3$Sb$_5$ in further symmetry-breaking and topological-superconductivity experiments."],"supporting_citations":[{"why":"Reports the zero-field superconducting diode effect in CsV3Sb5, the direct predecessor to the field-driven diode effect studied in this paper.","marker":"[22]"},{"why":"Provides switchable chiral transport in CsV3Sb5 and the domain-wall-scattering picture used here to explain the enhanced magnetochiral anisotropy.","marker":"[32]"},{"why":"Supplies the concept of dynamical superconducting order-parameter domains in a chiral superconductor, which the paper applies to CsV3Sb5.","marker":"[43]"},{"why":"Gives time-reversal-symmetry-breaking charge order in the kagome superconductors, the background that motivates chiral order and loop currents.","marker":"[29]"},{"why":"Presents the vortex-pinning model whose I-V hysteresis is cited as the contrast case when ruling out vortex physics.","marker":"[52]"},{"why":"Describes the butterfly-shaped magnetoresistance hysteresis expected from flux trapping, the signature the paper argues is absent.","marker":"[53]"}],"fun_headline_variants":["Current-induced hysteresis tied to superconductivity in CsV3Sb5","Hysteresis appears only with current in superconducting CsV3Sb5","Current tunes magnetoresistance hysteresis in superconducting CsV3Sb5","Superconducting CsV3Sb5 shows current-controlled hysteresis and diode effect","Small field triggers superconducting diode effect in CsV3Sb5"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that vortex pinning and flux trapping are not the source of the hysteresis; the paper excludes them by comparing qualitative curve shapes and sweep-rate behavior rather than by directly imaging or otherwise measuring vortex motion.","fun_headline_variants_meta":{"raw":{"variants":["Current-induced hysteresis tied to superconductivity in CsV3Sb5","Hysteresis appears only with current in superconducting CsV3Sb5","Current tunes magnetoresistance hysteresis in superconducting CsV3Sb5","Superconducting CsV3Sb5 shows current-controlled hysteresis and diode effect","Small field triggers superconducting diode effect in CsV3Sb5"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.001992,"raw_usage":{"total_tokens":7727,"prompt_tokens":850,"completion_tokens":6877,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":466,"completion_tokens_details":{"reasoning_tokens":6784}},"tokens_in":466,"tokens_out":6877,"duration_ms":52692,"temperature":1.0,"reasoning_tokens":6784,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-10T16:56:34.121446+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Image the local magnetic field (scanning SQUID or Lorentz microscopy) at fixed DC bias below $T_c$ while sweeping the magnetic field: if quantized vortices enter and leave with the same sweep-direction asymmetry as the resistance hysteresis, the vortex-pinning explanation survives; if no vortex motion is detected while the resistance loop persists, the chiral-domain interpretation is supported.","supporting_citations":[],"review_version":1}