{"id":"bb0fdbd8-e67c-40c6-8335-7b8604edc821","arxiv_id":"2605.30316","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"NanoSQUID magnetometry visualizes orbital magnetism in rhombohedral multilayer graphene, showing finite orbital moment in the superconducting state and density-tuned magnetic domain switching in the metallic regime.","lead":"The paper maps orbital magnetization in electron-doped rhombohedral multilayer graphene devices using nanoSQUID-on-tip magnetometry, finding density-dependent peaks in the quarter metal and a finite orbital moment in the zero-resistance state. A smart generalist might read it to see how local magnetic measurements can distinguish chiral superconductivity from other zero-resistance phases in tunable 2D materials.","discovery_kind":"new_application","skeptic_critique":{"model":"grok-4.3","headline":"Attribution of zero-resistance magnetization to chiral SC orbital moment is weakened by reported normal-state inhomogeneity","rationale":"The reader's weakest assumption matches the internal tension already flagged in the abstract; the full-text availability does not remove this interpretive gap but would allow checking whether the paper supplies the needed controls. No other load-bearing inconsistency is visible from the provided claims.","tokens_in":1786,"tokens_out":282,"duration_ms":11579,"concrete_test":"Re-analyze the tetralayer nanoSQUID maps at fixed density inside versus outside the zero-resistance window (or at the same gate sequence but with intentional strain variation); if the inhomogeneity pattern and amplitude remain statistically indistinguishable across the SC transition, the orbital-moment attribution requires additional subtraction or modeling.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The abstract states that magnetic inhomogeneity is observed specifically in the apparent normal state of the chiral superconductor and is suggestive of strain-tuned competition between magnetic and non-magnetic ground states. This directly undercuts the claim that the local magnetometry signal correlated with zero resistance originates purely from the finite-momentum Cooper-pair condensate, as opposed to persisting normal-state domains, trapped flux, or strain effects. Without explicit spatial or density-dependent controls separating these contributions in the tetralayer data, the 'direct evidence' interpretation rests on an untested isolation assumption.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.3","summary":"This paper uses nanoSQUID-on-tip magnetometry to map orbital magnetization in electron-doped rhombohedral multilayer graphene devices (3-13 layers). Magnetization in quarter-metal phases peaks at finite density, consistent with Berry curvature concentration in a 'ring of fire'. Correlating transport and local magnetometry in a tetralayer sample shows the superconducting state has a finite orbital magnetic moment, interpreted as direct evidence of its chiral nature with finite-momentum pairing. Stochastic resistivity switching is attributed to density-tuned sign changes in valley-resolved magnetic moments leading to metastable domains, and magnetic inhomogeneity is observed specifically in the apparent normal state of the chiral superconductor, suggestive of strain-tuned competition between magnetic and non-magnetic ground states.","tokens_in":1900,"tokens_out":499,"duration_ms":30711,"significance":"If the attribution of the zero-resistance magnetization signal to the chiral superconducting condensate can be isolated from other sources, the work would provide important direct local-probe evidence linking orbital magnetism to chiral superconductivity in a flat-band system. The spatially resolved visualization of magnetization, electric-field control of orbital moments, and observations of competing orders would strengthen understanding of pairing and ground-state competition in rhombohedral graphene multilayers.","major_comments":[{"comment":"Abstract: The central claim that the local magnetization signal correlated with zero resistance originates purely from the orbital moment of the finite-momentum chiral Cooper pair condensate (providing 'direct evidence' of chirality) is load-bearing, yet the abstract explicitly reports magnetic inhomogeneity specific to the apparent normal state. This raises the possibility of contributions from normal-state domains or strain effects, and the manuscript does not describe explicit spatial mapping, density-dependent controls, or subtraction procedures in the tetralayer data to isolate the superconducting contribution.","section":"Abstract"},{"comment":"Abstract: The presentation of correlations between transport and magnetometry lacks quantitative details on signal magnitudes, error analysis, background subtraction methods, or how the local signal is distinguished from trapped flux or other artifacts, which are required to support the interpretation that the moment proves the chiral nature of the superconducting state.","section":"Abstract"}],"minor_comments":[{"comment":"The abstract would benefit from explicit reference to the specific figures or sections presenting the tetralayer transport-magnetometry correlation data.","section":null}],"recommendation":"major_revision","confidential_remarks":null},"author_rebuttal":{"model":"grok-4.3","summary":"We thank the referee for their careful reading and constructive comments. We address the two major comments point by point below, with planned revisions to improve clarity and support for the central claims.","responses":[{"response":"We agree that the reported normal-state inhomogeneity requires explicit isolation of any superconducting contribution to support the interpretation. The manuscript correlates the appearance of a uniform magnetization signal with the onset of zero resistance in the tetralayer device, and notes that this signal is absent or inhomogeneous above the transition. To strengthen this, the revised manuscript will add a dedicated subsection detailing the spatial maps acquired across the density-tuned transition, the density-dependent controls performed, and the precise subtraction procedures (including reference scans above Tc) used to isolate the superconducting-state moment from normal-state or strain-related backgrounds.","revision_made":"yes","referee_comment":"[Abstract] Abstract: The central claim that the local magnetization signal correlated with zero resistance originates purely from the orbital moment of the finite-momentum chiral Cooper pair condensate (providing 'direct evidence' of chirality) is load-bearing, yet the abstract explicitly reports magnetic inhomogeneity specific to the apparent normal state. This raises the possibility of contributions from normal-state domains or strain effects, and the manuscript does not describe explicit spatial mapping, density-dependent controls, or subtraction procedures in the tetralayer data to isolate the superconducting contribution."},{"response":"We concur that quantitative details are needed to robustly distinguish the observed moment from artifacts. The revised version will report the measured magnetization values (in units of Bohr magnetons per area) in the superconducting regime together with standard errors from repeated scans, describe the background subtraction protocol (including comparison to normal-state and high-temperature reference data to rule out trapped flux), and include an analysis showing that the signal magnitude and spatial uniformity are inconsistent with normal-state domain contributions or flux-trapping artifacts.","revision_made":"yes","referee_comment":"[Abstract] Abstract: The presentation of correlations between transport and magnetometry lacks quantitative details on signal magnitudes, error analysis, background subtraction methods, or how the local signal is distinguished from trapped flux or other artifacts, which are required to support the interpretation that the moment proves the chiral nature of the superconducting state."}],"tokens_in":1521,"tokens_out":478,"duration_ms":18740,"standing_objections":[]},"desk_editor":{"model":"grok-4.3","letter":"The main new result here is the nanoSQUID-on-tip mapping that correlates a finite local orbital magnetic moment with the zero-resistance regime in a tetralayer device. This extends earlier transport-only work on the quarter metal and the putative chiral superconductor. They also map magnetization across 3- to 13-layer samples and tie the peak at finite density to the expected ring of Berry curvature.\n\nThe transport-magnetometry correlation in the tetralayer is the cleanest part of the paper and gives a concrete experimental handle on the orbital moment. The explanation of stochastic resistivity switching via density-tuned sign changes in the valley moment, producing metastable domains, is also useful and points to practical gate control.\n\nThe soft spot is the central interpretation. The abstract itself flags magnetic inhomogeneity specifically in the apparent normal state and links it to strain-tuned competition between magnetic and non-magnetic ground states. That observation directly raises the chance that the signal inside the zero-resistance window includes contributions from persisting normal domains, trapped flux, or strain effects rather than coming purely from the finite-momentum Cooper-pair condensate. Without quantitative spatial controls or density-dependent isolation shown in the data, the \"direct evidence of its chiral nature\" claim rests on an assumption that needs more scrutiny.\n\nThis is experimental work aimed at groups studying flat-band graphene and unconventional pairing. The measurements are new enough that a serious referee should see it, even if the interpretation will likely require revision.","headline":"Tetralayer data shows finite orbital moment inside the zero-resistance state, but normal-state inhomogeneity undercuts the clean attribution to chiral SC.","tokens_in":2478,"tokens_out":363,"would_cite":true,"duration_ms":17830,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.3","headline":"The superconducting state in electron-doped rhombohedral tetralayer graphene carries a finite orbital magnetic moment.","keywords":["rhombohedral graphene","orbital magnetism","chiral superconductivity","quarter metal","nanoSQUID magnetometry","Berry curvature","finite-momentum pairing"],"falsifier":"A scan that finds zero net orbital magnetization throughout the superconducting transition while zero resistance is still observed would falsify the finite-moment claim.","tokens_in":2717,"feed_emoji":"🧲","tokens_out":596,"duration_ms":14893,"temperature":0.7,"pith_summary":"This paper uses local magnetometry to map orbital magnetization in electron-doped rhombohedral graphene devices from three to thirteen layers thick. Magnetization within the quarter-metal phases reaches a peak at finite density, matching the expected concentration of Berry curvature along a ring of finite momentum. In a tetralayer device, simultaneous transport and magnetometry measurements show that the zero-resistance state itself carries a nonzero orbital moment. The same data set links stochastic resistivity jumps in the metallic regime to reversible sign changes in the valley-resolved magnetic moment and reveals extra magnetic inhomogeneity inside the apparent normal state of the superconductor.","feed_headline":"Chiral superconductor carries finite orbital moment in graphene","feed_subtitle":"Local magnetometry in tetralayer rhombohedral graphene links the zero-resistance state to a finite-momentum Cooper-pair condensate.","key_machinery":"NanoSQUID-on-tip magnetometry that resolves the local orbital magnetization and correlates it with simultaneous transport measurements inside the zero-resistance regime.","core_discovery":"Correlating transport and local magnetometry data in a tetralayer sample reveals that the superconducting state has a finite orbital magnetic moment, providing direct evidence of its chiral nature.","pith_inferences":["The same local-magnetometry approach could be applied to other candidate chiral superconductors to test for finite orbital moments.","Gate sequences that avoid crossing the sign-change line may suppress domain formation and stabilize the superconducting state over larger areas.","The narrow layer-number window for chiral superconductivity may reflect a delicate balance between strain and the magnetic energy scale."],"forward_implications":["The quarter-metal magnetization peaks at finite density because Berry curvature concentrates along a ring of finite momentum.","The zero-resistance state is a chiral superconductor formed by a finite-momentum Cooper-pair condensate.","Density-tuned sign reversal of the valley magnetic moment produces metastable domains and enables gate-controlled switching of the orbital moment.","Strain-tuned competition between magnetic and non-magnetic states appears as inhomogeneity inside the apparent normal state of the superconductor."],"fun_headline_variants":["Superconducting graphene carries finite orbital moment","Orbital moment confirms chirality in rhombohedral graphene superconductor","Tetralayer graphene links superconductivity to orbital magnetism","Magnetometry uncovers orbital moment in chiral superconducting graphene"],"cache_read_input_tokens":2112,"weakest_assumption_plain":"The measured local magnetization signal inside the zero-resistance regime originates only from the orbital moment of a finite-momentum chiral Cooper-pair condensate.","fun_headline_variants_meta":{"raw":{"variants":["Superconducting graphene carries finite orbital moment","Orbital moment confirms chirality in rhombohedral graphene superconductor","Tetralayer graphene links superconductivity to orbital magnetism","Magnetometry uncovers orbital moment in chiral superconducting graphene"]},"model":"grok-4.3","cost_usd":0.009987,"raw_usage":{"total_tokens":4371,"prompt_tokens":699,"num_sources_used":0,"completion_tokens":60,"cost_in_usd_ticks":99865500,"prompt_tokens_details":{"text_tokens":699,"audio_tokens":0,"image_tokens":0,"cached_tokens":64},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":3612,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":699,"tokens_out":60,"duration_ms":27019,"temperature":1.0,"reasoning_tokens":3612,"cache_read_input_tokens":64,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-06-29T05:32:21.103564+00:00","model_set":{"reader":"grok-4.3"},"falsifier":"A scan that finds zero net orbital magnetization throughout the superconducting transition while zero resistance is still observed would falsify the finite-moment claim.","supporting_citations":[],"review_version":1}