{"id":"2cd16d99-c17a-4125-86be-b5d5b998719c","arxiv_id":"2607.28425","paper_version":1,"verdict":"ACCEPT","confidence":"HIGH","novelty_score":6.0,"correctness_risk":"low","formal_verification":"none","parameter_count":4,"one_line_summary":"Gate-tuned rhombohedral graphene hosts adjacent zero-resistance superconducting and finite-resistance anomalous-metal pockets with similar Tc but distinct critical fields, constraining extrinsic origins of anomalous metals.","lead":"Rhombohedral graphene shows neighboring gate-tuned pockets of true zero-resistance superconductivity and finite-resistance “anomalous metal” with nearly identical critical temperatures. The clean, tunable platform tightens constraints on decades-old explanations of anomalous metals in thin-film superconductors.","discovery_kind":"extension","skeptic_critique":{"model":"grok-4.5","headline":"No significant objection that overturns the claim; the extrinsic-saturation caveat is real but already the paper’s own soft spot and does not break the phenomenology.","rationale":"The paper’s strongest claim is experimental phenomenology: adjacent gate-tuned zero-resistance SC and finite-saturation AM pockets with shared sharp T/B/I onsets, a sharp SC–AM boundary under small B∥, ~10× larger AM B⊥c, non-monotonic Idc response, and reproduction across voltage pairs and a second eight-layer device. That map and the field hierarchy are directly supported by the figures and Extended Data; extrinsic contact and simple percolation stories are hard to square with the multi-probe and two-device checks. The reader correctly isolates the residual non-equilibrium / exotic-inhomogeneity assumption as the weakest link. A mild internal tension (similar Tc used to argue equal noise susceptibility, while distinct Bc is used to argue distinct paired states) slightly sharpens that caveat but does not introduce a new failure mode or contradict the data as reported. For a mesoscale transport phenomenology paper that already acknowledges the open microscopic question, ACCEPT with high confidence remains appropriate; no adjustment is warranted.","tokens_in":18486,"tokens_out":555,"duration_ms":33426,"concrete_test":"In both devices, at fixed gate points deep in SC and deep in AM with matched Tc, measure saturation ρxx while deliberately varying RF/microwave filtering and cold attenuation (or add a calibrated weak broadband noise source above the estimated gap) at base T; if AM saturation resistance tracks the noise environment while neighboring SC stays zero-resistance, the differential extrinsic scenario is supported and the intrinsic-AM reading weakens.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim’s load-bearing step is that finite low-T saturation is intrinsic AM rather than residual non-equilibrium pair-breaking or a reproducible ~30 nm SC/normal texture. The Methods argument that stray photons should hit adjacent SC and AM equally because they share similar Tc is in mild tension with the paper’s own conclusion (Discussion; Fig. 4) that the two states have order-of-magnitude different B⊥c and B∥c and are therefore not the same paired state—so gap structure, DOS for pair-breaking, or vortex pinning need not be comparable. SNS/domain-wall and percolation pictures are constrained by multi-probe and two-device reproducibility, but an unrecognized sub-Tc scale or electronic texture at the AM orbital length (~30 nm) is not fully closed by existing data. This is the same soft spot the authors flag; it limits microscopic interpretation, not the reported SC/AM map or field hierarchy.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.5","summary":"The manuscript reports a systematic transport study of eight-layer rhombohedral graphene on WSe2, mapping isolated gate-tuned pockets that exhibit either true zero-resistance superconductivity (SC) or finite low-T resistance saturation (anomalous metal, AM). Both classes show sharp transitions versus T, B⊥, and Idc; a small in-plane field expands and merges the pockets while preserving a sharp SC/AM boundary at base temperature. The AM reproduces classic anomalous-metal phenomenology (finite saturation resistance, critical fields/currents) but with roughly an order-of-magnitude larger perpendicular critical field and a factor-of-four larger in-plane critical field than the adjacent SC, plus a non-monotonic current response. Multi-contact consistency and a second device reproduce the phase boundaries and hierarchy. The authors argue that extrinsic origins (noise, contacts, percolation, SNS domain walls) are strongly constrained, and that the platform’s cleanliness and tunability make it a useful setting for the long-standing anomalous-metal problem.","tokens_in":18716,"tokens_out":1412,"duration_ms":36927,"significance":"If the reported SC/AM adjacency, field hierarchy, and reproducibility hold, this is a substantial experimental contribution. Anomalous metals have been studied for decades without consensus; most prior systems are disordered thin films near RQ, whereas here the normal-state sheet conductivity reaches ~1000 e²/h in an ultra-clean, continuously gate-tunable platform. The ability to place zero-resistance SC and finite-resistance AM side-by-side under nearly identical external conditions, with distinct Bc scales and a non-monotonic Idc response, supplies concrete constraints that any microscopic theory must satisfy. Strengths include the multi-probe and two-device reproducibility, Landau-fan placement relative to half-metal vs unpolarized metal, BKT comparison, and an explicit Methods treatment of extrinsic alternatives. The work does not solve the microscopic origin of the AM, but it meaningfully reframes the problem in a cleaner setting.","major_comments":[{"comment":"Methods, “Considerations of extrinsic origins of the finite resistance”: the argument that residual non-equilibrium excitation (e.g. stray photons) should affect adjacent SC and AM pockets comparably rests on their similar Tc as a proxy for pairing robustness. This sits in mild tension with the Discussion and Fig. 4, which conclude from the ~10× B⊥c and ~4× B∥c hierarchy that the paired states are “not identical in their orbital and/or spin structure.” If gap structure, DOS available for pair-breaking, or vortex pinning differ, external pair-breaking need not hit both pockets equally. Please either (i) qualify the similar-Tc argument explicitly in light of the distinct critical-field scales, or (ii) add a concrete control (e.g. excitation-amplitude / filtering dependence comparing SC vs AM at matched Tc) that closes this loophole. This does not overturn the phenomenology, but it is load-","section":"Methods; Discussion; Fig. 4"},{"comment":"Main text and Methods on the AM orbital length ξ_AM ≈ 30 nm (from B⊥c ≈ 300 mT via ξ = √(Φ0/2πB⊥c)): the manuscript correctly notes that an inhomogeneous SC/normal texture of this scale cannot be fully excluded, and that simple percolation is hard to reconcile with multi-probe and two-device reproducibility. Given that this length is the main quantitative handle distinguishing AM from SC, the paper should state more clearly what future measurement (superfluid stiffness, gap spectroscopy, or real-space imaging) would falsify a ~30 nm electronic texture versus a homogeneous Bose-metal-like state. A short, explicit falsification criterion would strengthen the Discussion without requiring new data in this manuscript.","section":"Distinct magnetic field scales; Discussion"}],"minor_comments":[{"comment":"Fig. 1a inset and device schematic: layer stack order is stated in Methods but a labeled cross-section in the main figure would help readers unfamiliar with the dual-graphite-gated WSe2 geometry.","section":"Fig. 1"},{"comment":"Extended Data Fig. 6 and Methods BKT analysis: the authors already note that BKT is of questionable validity for micron-scale samples. Consider moving that caveat into the main-text sentence that introduces the BKT comparison, so readers do not over-interpret α→3 in the SC pocket.","section":"Methods, BKT analysis; Extended Data Fig. 6"},{"comment":"Estimation of key superconducting parameters: the 90% normal-state resistance criterion for Tc and Bc is standard but should be stated once in the main text (or figure captions) where Tc ≈ 100 mK and the Bc hierarchy are quoted, not only in Methods.","section":"Methods; Figs. 2–4"},{"comment":"Typographical/spacing issues in the compiled text (e.g. “regionsappearasisolatedpockets”, “differenceintheirlow-temperatureresistance”, “superconductingstateisfullysuppressed”) should be cleaned in production; they do not affect substance but reduce readability.","section":"Throughout"},{"comment":"Fig. 2c: light vs dark traces (single vs averaged) are useful; a one-line note in the caption that averaging is over nine adjacent Vt would make the figure self-contained.","section":"Fig. 2"},{"comment":"References to related rhombohedral-graphene SC work are thorough; a brief pointer in the Discussion to how the present AM differs from finite-resistance reports in those works (beyond the WSe2 substrate) would help non-specialists.","section":"Discussion"}],"recommendation":"minor_revision","confidential_remarks":"Strong experimental paper appropriate for a high-profile condensed-matter venue. The central phenomenology (adjacent SC/AM pockets, field hierarchy, non-monotonic Idc, two-device reproducibility) is convincing. The only interpretive soft spot—the residual possibility of sub-Tc non-equilibrium excitation or a ~30 nm texture—is already largely flagged by the authors; my major comments ask for tighter wording and an explicit falsification path rather than new experiments. I would not hold the paper for a full microscopic theory. Fit to scope is excellent for mesoscopic/2D superconductivity audiences."},"author_rebuttal":null,"desk_editor":{"model":"grok-4.5","letter":"The real addition here is not “another graphene superconductor,” but a careful side-by-side of true zero-resistance SC and finite-saturation “anomalous metal” pockets in the same ultra-clean, gate-tunable platform. They sit next to each other with matched Tc-scale onsets, merge under small B∥ into a sharp zero/finite boundary, show a clear hierarchy of B⊥c and B∥c (roughly 10× and 4×), and a non-monotonic current response in the AM. That package, plus multi-probe consistency and a second eight-layer device that reproduces the phase boundaries, is what makes the paper useful.\n\nThey do the experimental work properly. Gate maps, T/B/I cuts, Landau fans pinning the half-metal vs unpolarized metal, BKT check on the SC side, and an honest Methods section on photons, contacts, percolation, and SNS/domain-wall strips. Classifications are operational (zero vs finite saturation), not model-fitted circularity. Citations cover the thin-film AM literature and the recent rhombohedral SC papers without obvious gaps.\n\nSoft spot is the one they already flag: you still cannot fully kill residual non-equilibrium pair-breaking at an unrecognized scale far below Tc, or a reproducible ~30 nm electronic texture that would inflate the AM orbital field. The “adjacent pockets share Tc so stray photons should hit both equally” argument is a bit soft once the paper itself argues the two states are not the same paired state (different critical fields). Multi-device/multi-probe data constrain ordinary disorder and contact artifacts well; they do not close every exotic inhomogeneity story. That limits microscopic interpretation, not the reported map or field hierarchy.\n\nThis is for people who care about anomalous metals, 2D SC, or rhombohedral graphene phase diagrams. Worth a serious referee. I would bring it to reading group and cite the phenomenology when discussing AM constraints. Send it out.","headline":"Clean, systematic map of adjacent zero-R SC and finite-R AM pockets in rhombohedral graphene; data package is strong, microscopic claim stays open.","tokens_in":19412,"tokens_out":501,"would_cite":true,"duration_ms":14834,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.5","headline":"Gate-tuned rhombohedral graphene hosts adjacent zero-resistance superconductivity and finite-resistance anomalous metal pockets with the same sharp critical transitions.","keywords":["rhombohedral graphene","anomalous metal","two-dimensional superconductivity","gate-tuned superconductivity","spin-triplet pairing","WSe2 proximity","critical field hierarchy"],"falsifier":"A measurement showing that the finite-resistance pockets ultimately reach true zero resistance at still lower temperature or lower excitation, or a local probe that finds a reproducible ~30 nm superconducting texture whose size matches the anomalous-metal coherence length extracted from the perpendicular critical field.","tokens_in":19342,"feed_emoji":"⚛️","tokens_out":1003,"duration_ms":14696,"temperature":0.7,"pith_summary":"In ultra-clean eight-layer rhombohedral graphene on WSe2, electrostatic gates can select either true zero-resistance superconductivity or a neighboring state whose resistance drops sharply below a critical temperature yet saturates at a finite value. Both pockets show the same abrupt transitions out of the low-resistance regime when temperature, perpendicular field, or current is raised, and a small in-plane field expands and merges them while leaving a sharp boundary between zero and finite resistance at base temperature. The finite-resistance state matches the long-standing anomalous-metal phenomenology seen in thin-film superconductors, yet here the normal-state sheet resistance is far below the pair quantum and disorder is low, so standard fluctuation theories struggle to explain it. Distinct critical-field scales (roughly an order of magnitude larger perpendicular field for the anomalous metal) and a non-monotonic current response further suggest the two paired states are not simply the same condensate with and without phase coherence. Because the platform is continuously tunable and the SC/AM boundary reproduces across voltage probes and a second device, the work supplies tight experimental constraints that any microscopic theory of the anomalous metal must satisfy.","feed_headline":"Graphene hosts side-by-side superconductivity and anomalous metal","feed_subtitle":"Gate-tuned pockets share sharp critical transitions yet one saturates at finite resistance, constraining theories of the anomalous metal.","key_machinery":"Gate-tuned SC and AM pockets in the (n, D) plane of dual-gated rhombohedral graphene, distinguished by whether low-T resistance reaches zero or saturates, and characterized by nested critical-current and critical-field domes whose characteristic perpendicular-field scales differ by roughly an order of magnitude.","core_discovery":"Rhombohedral graphene on WSe2 supports isolated gate-tuned pockets of zero-resistance superconductivity adjacent to pockets that exhibit essentially identical superconducting-like critical behavior in temperature, perpendicular field, and current yet saturate at finite low-temperature resistance; a small in-plane field merges the pockets into a contiguous region with an abrupt zero/finite-resistance boundary, and the finite-resistance state reproduces anomalous-metal phenomenology while remaining difficult to attribute to extrinsic noise or inhomogeneity.","pith_inferences":["If the anomalous metal is a Bose metal of uncondensed pairs, stiffness or gap measurements should show finite pairing amplitude without long-range phase coherence precisely inside the finite-resistance pockets.","The adjacency of the SC pocket to the half-metal and the AM pocket to the unpolarized metal suggests valley or spin polarization may tip the balance between coherent and fluctuating paired states.","The same gate-space footprint appearing in a second, less homogeneous device implies the SC/AM distinction is set by band filling and displacement field rather than sample-specific disorder landscapes."],"forward_implications":["Any viable theory of the anomalous metal must operate in a clean, highly conducting 2D metal whose normal-state resistance is far below the pair quantum.","The order-of-magnitude difference in perpendicular critical field between adjacent SC and AM pockets implies distinct orbital or spin structure of the paired states rather than simple phase disorder of one condensate.","The non-monotonic current response (moderate dc current sometimes restoring zero differential resistance) becomes a required signature that microscopic models must reproduce.","Rhombohedral graphene supplies a continuously tunable platform in which the SC/AM boundary can be crossed by gate voltage, in-plane field, or temperature while holding other parameters fixed."],"fun_headline_variants":["Rhombohedral graphene holds side-by-side SC and anomalous metal pockets","Gate-tuned graphene: zero-resistance SC next to finite-resistance twins","In-plane field merges graphene's SC and anomalous-metal pockets","Clean rhombohedral graphene constrains anomalous-metal explanations","Isolated pockets in graphene share critical jumps yet split on resistance"],"cache_read_input_tokens":128,"weakest_assumption_plain":"That stray high-frequency noise and mesoscopic inhomogeneity can be ruled out as the source of the finite saturation resistance, because neighboring zero- and finite-resistance pockets share similar critical temperatures at the same base temperature and because any normal strips should become dissipationless as temperature goes to zero.","fun_headline_variants_meta":{"raw":{"variants":["Rhombohedral graphene holds side-by-side SC and anomalous metal pockets","Gate-tuned graphene: zero-resistance SC next to finite-resistance twins","In-plane field merges graphene's SC and anomalous-metal pockets","Clean rhombohedral graphene constrains anomalous-metal explanations","Isolated pockets in graphene share critical jumps yet split on resistance"]},"model":"grok-4.5","effort":"low","cost_usd":0.004394,"raw_usage":{"total_tokens":1298,"prompt_tokens":794,"num_sources_used":0,"completion_tokens":96,"cost_in_usd_ticks":43944000,"prompt_tokens_details":{"text_tokens":794,"audio_tokens":0,"image_tokens":0,"cached_tokens":128},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":408,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":794,"tokens_out":96,"duration_ms":7199,"temperature":1.0,"reasoning_tokens":408,"cache_read_input_tokens":128,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-31T07:45:15.544754+00:00","model_set":{"reader":"grok-4.5"},"falsifier":"A measurement showing that the finite-resistance pockets ultimately reach true zero resistance at still lower temperature or lower excitation, or a local probe that finds a reproducible ~30 nm superconducting texture whose size matches the anomalous-metal coherence length extracted from the perpendicular critical field.","supporting_citations":[],"review_version":1}