{"id":"10c216fa-8a59-40a8-84c3-eadb8939cc02","arxiv_id":"2607.27148","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":3,"one_line_summary":"QPI in CsV3Sb5 finds an isotropic gap on V Mz+ Fermi surfaces, limits anisotropy to other bands, and does not support an extra PDW modulation within experimental sensitivity.","lead":"Sub-Kelvin STM quasiparticle interference shows an isotropic superconducting gap on the vanadium Mz-even Fermi pockets in CsV3Sb5 and finds no clear pair-density-wave signal beyond ordinary CDW-related density-of-states modulations. The result tightens which gap symmetries and intertwined-order scenarios remain viable in this kagome superconductor.","discovery_kind":"extension","skeptic_critique":{"model":"moonshotai/kimi-k3","headline":"The isotropy result is a near-null “same-as-DOS” match; it is load-bearing that the α/λ masks have demonstrated band-specific sensitivity rather than common-mode leakage or normalization-driven agreement.","rationale":"I agree with the reader that the vulnerable point is the k→q/sector assignment and its dependence on DFT plus a modeled CDW potential, but I would phrase the risk one step more operationally: the headline evidence is an equality-to-average-DOS/null-like result, so the burden is to prove the analysis pipeline can actually see anisotropy of the claimed size and is not common-mode dominated. The paper has real strengths: dense 50 µeV sampling, B=0/B=3T comparison, explicit QPI/JDOS/Green’s-function mapping, reproduction with a different junction/area, and a properly scoped PDW statement. These keep the work in CONDITIONAL rather than REJECT territory. The missing piece is not more interpretation but a reproducible sensitivity benchmark and public masks/data: show that synthetic anisotropy survives the exact experimental and analysis chain, and quantify leakage from CDW/Bragg/Mz−/Sb into the α/λ masks. Until then, the qualitative statement “no large anisotropy on the apparent Mz+ QPI channels” is plausible, while the sharper quantitative claim “isotropic Mz+ gap, residual anisotropy <±6%” remains conditional.","tokens_in":17227,"tokens_out":3641,"duration_ms":94928,"concrete_test":"Run a closed-loop synthetic recovery: from the Wannier/DFT model impose a known sign-preserving anisotropy on the Mz+ pocket, e.g. Δ(θ)=Δ0[1+0.10–0.15 cos 2θ], compute B=0 Green’s-function QPI with the same T-matrix, 4×1 CDW/unfolding and Mz−/Sb bands included, then emulate the experiment (520 mK thermal smearing, 50 µeV lock-in/step, 33 nm FOV Fourier window), apply the identical α/λ masks and self-normalization, and vary V0=0–300 meV and mask size. If a 10–15% imposed anisotropy is not recovered beyond leakage/normalization systematics, or if CDW/Mz− leakage into masks exceeds a few percent, the ±6% isotropy bound is not supported; robust recovery would largely close the concern.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The strongest claim depends on more than the Mz+ assignment already flagged: Fig. 4d infers isotropy because masked α and λ spectra are “identical” to the real-space-averaged DOS. That identity is evidential only if the masked signal is dominated by superconducting QPI from distinct Mz+ k regions. Several features can make the match occur without isotropy: (i) a 33×33 nm FOV gives finite Fourier broadening, so sharp CDW/Bragg peaks can leak into extended α/λ masks; the paper itself shows CDW-peak spectra largely track the average DOS (Figs. 4e–g), so leakage would bias α/λ toward the same curve. (ii) Curves are normalized to their own mean over the displayed range, removing absolute suppression scale and leaving only shape. (iii) The exclusion of Mz−/Sb pz rests on surface-projected DFT plus a phenomenological 4×1 on-site potential (V0=200 meV) and unfolding; if those sectors contribute even weakly in the masked q windows, the k-attribution of any residual anisotropy changes. Thus the central quantitative bound, <±6% anisotropy, needs a demonstrated end-to-end sensitivity/recovery test at the same resolution, masks, broadening, and normalization.","agreement_with_reader":"agree"},"referee_report":{"model":"moonshotai/kimi-k3","summary":"The manuscript reports sub-Kelvin STM/STS spectroscopic mapping of CsV3Sb5 with 50 µeV energy sampling through the superconducting gap, at B=0 and B=3 T. Using surface-projected ab initio Green's-function calculations with a phenomenological 4×1 on-site CDW potential (V0=200 meV) and unfolding, the authors establish a k→q mapping attributing the observed α (arc) and λ (line) QPI features entirely to the V Mz-even kagome-derived pockets. Masked, energy-resolved QPI spectra for α and λ are found to be identical in shape to the spatially averaged DOS, from which the authors conclude the gap on the Mz+ pockets is isotropic with residual anisotropy below ±6%; no Bogoliubov QPI is observed. CDW-peak-selected spectra track the average DOS with no subgap enhancement, which the authors take as non-support for a PDW within their sensitivity, while flagging a small kink at Q3/4 as a possible target for future work. Finally, the absence of JDOS-predicted δ scattering vectors is attributed to sublattice-weight overlap on the Fermi surface, constituting a Fermi-level probe of sublattice character.","tokens_in":17536,"tokens_out":2537,"duration_ms":77252,"significance":"If the central result holds, this is a significant contribution: the first densely energy-sampled (50 µeV steps), sub-Kelvin QPI determination of the momentum structure of the superconducting gap in CsV3Sb5, delivering an explicit falsifiable bound (residual anisotropy < ±6%) on the Mz+ kagome pockets and thereby confining any gap anisotropy reported by bulk probes to the Mz−/Sb pz sectors. The careful scoping of the PDW non-observation — distinguishing trivial DOS-modulation effects from genuine gap modulations, and explicitly identifying the Q3/4 kink as the only candidate anomaly while declining to overclaim — is a model of restraint. The k→q mapping from surface-projected ab initio Green's functions with 4×1 CDW unfolding, and the demonstration that sublattice-weight overlap explains the selective absence of JDOS-predicted δ features, are independently valuable methodological results. Strengths include the field-on/field-off comparison, symmetry-equivalent masks, and reproduction across tips and sample areas.","major_comments":[{"comment":"The central claim — gap isotropy on the Mz+ pockets with residual anisotropy below ±6% — is inferred from the near-identity of masked α and λ spectra to the real-space-averaged DOS. As the caption to Fig. 4 states, all curves in b–g are 'normalized to their average over the displayed energy ranges'; this self-normalization removes the absolute suppression scale and leaves only shape, so the match is a near-null result whose evidential weight depends entirely on demonstrated band-specific sensitivity. Two specific mechanisms could produce the observed identity without isotropy: (i) the 33×33 nm field of view (Methods, STS Parameters) implies finite Fourier broadening of the sharp Q1/2, Q1/4, and Bragg peaks, and the paper itself shows (Figs. 4e–g) that CDW-peak spectra track the average DOS — so leakage of these peaks into the extended α/λ masks would bias the masked spectra toward the-a-","section":"Results, 'Momentum Resolved Gap Structure'; Fig. 4d"},{"comment":"The conclusion that the low-energy QPI arises 'entirely from the Mz+ bands' rests on surface-projected DFT plus a phenomenological 4×1 on-site potential on the V kagome layer with V0 = 200 meV and subsequent unfolding (Eq. (3)–(4)). The text asserts that the Mz− sector is 'inconsistent with both the geometry and dispersion' of α/λ and is suppressed by Q1/4 folding, with details deferred to Supplementary Section I D. Since the isotropy claim attaches specifically to the Mz+ pockets, the main text should quantify the robustness of this exclusion: e.g., how the simulated α/λ intensity from the Mz− sector varies with V0 (is 200 meV constrained by experiment?), and an upper limit on residual Mz− or Sb pz spectral weight inside the actual α/λ masks of Fig. 4a. If even weak Mz− weight leaks into the masks, the attribution of any residual anisotropy — and the scope of the ±6% bound — changes.","section":"Results, 'k→q mapping and sublattice effects'; Methods, 'CDW and unfolding'"}],"minor_comments":[{"comment":"The section currently contains the data-availability sentence ('The data that support the findings...') rather than a competing-interests declaration — clearly a copy-paste error.","section":"Competing Interests"},{"comment":"The derivation of the ±6% residual-anisotropy bound is entirely in Supplementary Section VI. The main text should at least enumerate the inputs (electronic temperature 520 mK from Dynes calibration, 50 µeV lock-in modulation, segment-by-segment analysis of the arcs/lines) and state how they combine into the bound, so the reader can assess it without the supplement.","section":"Results, 'Momentum Resolved Gap Structure'"},{"comment":"The statement that there is 'no clear evidence of BQPI' would benefit from a quantitative criterion (e.g., an intensity threshold relative to the normal-state QPI features, or a statement of which new q vectors a nodal or anisotropic gap would have produced in the simulations). As written it is a visual judgment on Fig. 2 and Supplementary Fig. S14.","section":"Results, 'STS measurements near the Fermi level'"},{"comment":"Several typographical/formatting issues: 'RESUL TS' and 'DA T A A V AILABILITY' headers; inconsistent 'ab initio' spacing throughout; the caption of Fig. 2c notes a distinct color scale only in passing — consider stating the reason (low intensity at 0 meV) more prominently; Ref. [27] is a preprint and should carry an arXiv identifier; the data-availability statement ('upon request') may not meet the journal's data policy.","section":"General"}],"recommendation":"major_revision","confidential_remarks":"This is a careful experimental null-result paper from a group with a strong track record in QPI-based gap determination, and it fits the journal's scope well. My main reservation, shared with the reading I have seen, is that the headline ±6% anisotropy bound currently rests on curve identity after self-normalization, with the supporting error analysis in an unseen supplement; the requested sensitivity/recovery test is the difference between a demonstrated bound and an asserted one. The \"Competing Interests\" section containing the data-availability sentence suggests the manuscript was assembled hastily and warrants a proofreading pass. No concerns about novelty disclosure or citation practice beyond that."},"author_rebuttal":null,"desk_editor":{"model":"grok-4.5","letter":"The thing worth knowing is the experimental package: dense 50 µeV sampling through the gap at ~0.5 K, field-on/field-off, plus an ab initio surface FS and Green’s-function QPI that actually assigns the α arcs and λ lines to the V Mz+ pockets. From that they get a clean result—those features show the same gap as the real-space average, with residual anisotropy bounded below ~±6%. That rules out several anisotropic symmetries on those pockets and pushes any reported anisotropy onto Mz− or Sb pz. The missing δ vectors and the sublattice-weight argument are a genuine plus; most kagome STS papers wave at sublattice interference without showing it at EF.\n\nWhat they do well is scope. No clear BQPI, so they stick to intensity vs energy on normal-state QPI. The PDW discussion is not oversold: CDW-peak spectra track the average DOS with no subgap-only enhancement, and they flag tip/location dependence on the small Q3/4 kink. Methods are explicit (V0 choices, unfolding, tip-sweep caveats, second junction check). Citations cover the conflicting gap and PDW literature without cherry-picking.\n\nSoft spots, in proportion. The load-bearing step is still the sector assignment plus the claim that masked α/λ are pure enough Mz+ SC QPI. That rests on surface DFT plus a phenomenological 4×1 on-site CDW (V0 = 200 meV). Finite FOV Fourier leakage from sharp CDW peaks into extended masks, plus per-curve mean normalization, can pull shapes toward the average even without true isotropy. The paper does not show an end-to-end recovery test at the same resolution/masks/normalization. That does not kill the result—it is still the best momentum-resolved bound we have on those pockets—but the ±6% number should be read as an experimental upper limit under their analysis, not a fully hardened gap map. Public grids would help.\n\nThis is for people working AV3Sb5 pairing, PDW claims, and QPI matrix elements in multi-orbital kagome metals. It deserves a serious referee. I would engage, cite the isotropy bound and the sublattice-QPI point, and keep the mask-purity caveat in mind.","headline":"Solid sub-Kelvin QPI with a usable k→q map: isotropic gap on the Mz+ pockets is the real result; PDW is a careful null, and the main soft spot is how cleanly the masks isolate band-specific SC QPI.","tokens_in":18431,"tokens_out":585,"would_cite":true,"duration_ms":14176,"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":"The superconducting gap on the vanadium Mz-even Fermi pockets in CsV3Sb5 is isotropic, which constrains allowed gap symmetries and leaves any anisotropy to other bands.","keywords":["kagome superconductor","CsV3Sb5","quasiparticle interference","superconducting gap","pair-density wave","sublattice interference","charge density wave","scanning tunneling microscopy"],"falsifier":"A gap extraction from the same α and λ QPI masks that differed by more than a few percent from the spatially averaged spectrum, or an independent probe showing substantial mirror-odd or antimony weight in those same scattering channels, would overturn the isotropy claim on the Mz+ pockets.","tokens_in":18250,"feed_emoji":"⚛️","tokens_out":989,"duration_ms":29274,"temperature":0.7,"pith_summary":"This paper maps the momentum structure of superconductivity in the kagome metal CsV3Sb5 with sub-Kelvin scanning tunneling spectroscopy. By densely sampling the gap and matching quasiparticle interference patterns to ab initio surface bands, the authors show that the vanadium mirror-even Fermi pockets carry an isotropic gap identical to the spatially averaged density of states. That result rules out several symmetry-allowed anisotropic gaps on those pockets and forces any reported anisotropy onto the remaining vanadium mirror-odd or antimony pz bands. Spectra locked to the charge-density-wave peaks track the average density of states and show no clear subgap enhancement, so they do not support an extra pair-density-wave modulation within the measurement sensitivity. The same data also show that certain scattering vectors are missing precisely where sublattice weight overlap is weak, giving direct spectroscopic access to Fermi-level sublattice character that theory has long invoked for kagome correlations.","feed_headline":"Isotropic gap found on key vanadium pockets in CsV3Sb5","feed_subtitle":"Dense STM quasiparticle maps pin the gap symmetry and weigh against a pair-density wave","key_machinery":"The k-to-q mapping: ab initio surface Green’s-function quasiparticle interference that assigns the experimental α arcs and λ lines to the rounded corners and flat sides of the Mz+ triangular pockets, while sublattice-resolved wavefunctions explain why other joint-density-of-states vectors are selectively absent.","core_discovery":"Quasiparticle interference, interpreted with a first-principles surface Fermi surface and a model of the stripe charge order, shows that the superconducting gap on the vanadium Mz-even (Mz+) kagome-derived pockets is isotropic to within roughly ±6 percent. The arc and line QPI features that map to the corners and flat sides of those pockets all close at the same energy as the real-space average spectrum. Charge-density-wave peak spectra closely follow that average and do not display a distinct subgap enhancement, so they do not support an additional pair-density-wave modulation within the sensitivity of the experiment.","pith_inferences":["Pairing mechanisms built on fluctuating chiral charge order should now be checked for whether they naturally leave the Mz+ surface isotropic while allowing anisotropy elsewhere.","If a weak pair-density-wave component still exists, the small kink sometimes seen at the Q3/4 peak is the most natural place for higher-sensitivity maps to look next.","The same sublattice-sensitive QPI filter could be applied to other kagome or multi-sublattice superconductors where orbital mixing at the Fermi level is poorly known."],"forward_implications":["Gap symmetries that would produce different magnitudes on the arcs versus the flat sides of the Mz+ pockets are ruled out.","Any reported gap anisotropy in CsV3Sb5 must reside on the Mz-odd or Sb pz bands, not on the Mz+ pockets measured here.","Main charge-density-wave Fourier peaks do not carry a clear pair-density-wave signature beyond ordinary density-of-states modulation.","Missing QPI vectors can be used as a spectroscopic readout of Fermi-level sublattice character in kagome metals.","Realistic theories of intertwined charge order and superconductivity in this family must reproduce an isotropic Mz+ gap."],"fun_headline_variants":["QPI pins isotropic gap on V Mz+ pockets in CsV3Sb5","STM maps rule out strong anisotropy on key kagome bands","CDW-peak spectra show no subgap PDW signature","Isotropic SC gap on vanadium Mz-even Fermi pockets","Sublattice-sensitive QPI constrains CsV3Sb5 gap symmetry"],"cache_read_input_tokens":128,"weakest_assumption_plain":"The claim that the measured arcs and lines come only from the vanadium mirror-even bands rests on surface band calculations plus a model stripe potential; if that band assignment is wrong, the isotropy result does not attach to the stated pockets.","fun_headline_variants_meta":{"raw":{"variants":["QPI pins isotropic gap on V Mz+ pockets in CsV3Sb5","STM maps rule out strong anisotropy on key kagome bands","CDW-peak spectra show no subgap PDW signature","Isotropic SC gap on vanadium Mz-even Fermi pockets","Sublattice-sensitive QPI constrains CsV3Sb5 gap symmetry"]},"model":"grok-4.5","effort":"low","cost_usd":0.003753,"raw_usage":{"total_tokens":1280,"prompt_tokens":873,"num_sources_used":0,"completion_tokens":77,"cost_in_usd_ticks":37528000,"prompt_tokens_details":{"text_tokens":873,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":330,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":873,"tokens_out":77,"duration_ms":5691,"temperature":1.0,"reasoning_tokens":330,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-30T11:20:34.440247+00:00","model_set":{"reader":"grok-4.5"},"falsifier":"A gap extraction from the same α and λ QPI masks that differed by more than a few percent from the spatially averaged spectrum, or an independent probe showing substantial mirror-odd or antimony weight in those same scattering channels, would overturn the isotropy claim on the Mz+ pockets.","supporting_citations":[],"review_version":1}