{"id":"fa30a557-42b6-4dcd-8b75-8e3e2785b5d1","arxiv_id":"2501.00497","paper_version":1,"verdict":"UNVERDICTED","confidence":"HIGH","novelty_score":1.0,"correctness_risk":"low","formal_verification":"none","parameter_count":0,"one_line_summary":"A review of ARPES studies of topological materials, covering topological insulators, Dirac/Weyl/nodal/chiral semimetals, magnetic and correlated variants, and ultrafast dynamics.","lead":"This paper reviews how a measurement technique called ARPES, which maps the energies and directions of electrons in materials, has revealed the protected surface states of topological insulators and semimetals. It is a survey aimed at readers who want to know which topological phases have been experimentally confirmed by photoemission.","discovery_kind":"review","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Section VI endorses CDAD-derived orbital-momentum winding as topological proof, after Section II.C established CDAD as a final-state effect that changes sign with photon energy, so the 'unambiguous' claim inherits an unresolved internal tension.","rationale":"I read the paper as a survey whose central claim is a disciplinary one: ARPES, with its kz resolution and surface sensitivity, is the primary tool that identified topological surface states and their spin textures. The reader marked it UNVERDICTED as a review. The strongest support is in the classic materials (Bi2Se3, Bi2Te3, Cd3As2, Na3Bi, TaAs), where multiple independent groups and photon energies agree. The soft spot is not the method's role but the word 'unambiguously': the review's own Section II.C shows that spin and dichroism readouts are not direct, and Section VI applies a CDAD-based readout as a topological proof in TaAs without the same caveat. That internal inconsistency is concrete and load-bearing for the bullet claim, though it does not overturn the overall survey. A one-step-model test on TaAs is a tractable, decisive check. The verdict stays UNCHANGED because the central genre-level assessment (a useful, mostly reliable review) is unaffected; the concern argues for adding a caveat, not for rejecting or reclassifying the manuscript.","tokens_in":61702,"tokens_out":4871,"duration_ms":52099,"concrete_test":"Perform one-step-model photoemission calculations for the TaAs measurement in Ref [122], as was done for Bi2Se3 in Ref [47], and compare the computed CDAD-derived orbital-angular-momentum winding with the measured one at multiple photon energies across the soft-x-ray range (e.g., 300-700 eV). If the winding direction and topological charge assignment are stable under final-state effects and match the ground-state DFT OAM texture, the Section VI endorsement survives; if the winding reverses or changes with photon energy, the review must add the same final-state caveat it applies in Section II.C.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim that ARPES 'has unambiguously identified examples for several classes of topological materials' rests on the reliability of the cited assignments. The review itself flags the principal threat: Section II.C documents that circular dichroism in ARPES (CDAD) is a final-state effect, with the CDAD of Bi2Te3 changing sign multiple times with photon energy [37], and that spin-resolved ARPES at 6 eV flips the observed spin texture relative to the ground state [46,47]. Yet Section VI states that in TaAs, 'from the winding of the orbital angular momentum, the Weyl points have been confirmed as Berry flux monopoles' [122], a confirmation derived from CDAD-based orbital-momentum measurements. The same final-state caveat is not applied there. If the TaAs CDAD winding is as photon-energy dependent as the Bi2Te3 case, the claimed confirmation is not unambiguous. The paper's own treatment of SmB6 and FeTe0.55Se0.45 shows that contested assignments are left unresolved rather than audited. Thus the survey's confident taxonomy is more fragile than its internal warnings suggest, although the dispersion-based role of ARPES in the well-established cases (Bi2Se3, TaAs Fermi arcs, etc.) is not in question.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"This manuscript is a review of angle-resolved photoemission spectroscopy (ARPES) studies of three-dimensional topological materials, covering strong and weak topological insulators, topological crystalline insulators, magnetic topological insulators, Dirac and Weyl semimetals, nodal-line and chiral semimetals, correlated topological insulators, topological superconductors, transition metal dichalcogenides as a case study, and ultrafast pump-probe experiments, with a brief outlook. The central claim, stated in the abstract and in the opening bullet list, is that ARPES is the primary experimental method for investigating the electronic structure and topology of 3D topological materials, and that it has unambiguously identified examples for several classes of topological materials while correlated topological insulators and topological superconductors remain outstanding.","tokens_in":62009,"tokens_out":6863,"duration_ms":64666,"significance":"If the central claim is accepted, the paper provides a comprehensive and potentially useful reference for the ARPES community and for researchers working on topological materials. The review includes a valuable critical discussion of final-state effects in spin-resolved ARPES and circular dichroism, and it is careful in places to note unresolved controversies, such as the status of SmB6 and FeTe0.55Se0.45. However, the review is a secondary source, and the reliability of the survey depends on the reliability of the primary assignments it cites. The main weakness is an internal tension between the final-state caveats established in Section II.C and the later use of CDAD-derived orbital-momentum winding in Section VI as a seemingly unqualified confirmation of Weyl-node topology; this tension directly affects the strength of the claim that ARPES has provided unambiguous identifications.","major_comments":[{"comment":"The statement in Section VI that 'from the winding of the orbital angular momentum, the Weyl points have been confirmed as Berry flux monopoles [122]' is not reconciled with Section II.C, where the authors show that the CDAD of the Bi2Te3 topological surface state changes sign several times as a function of photon energy and is understood as a final-state effect [37,39,40]. The TaAs confirmation in Section VI is based on CDAD-derived orbital-momentum measurements, so the same photon-energy dependence may apply. The authors should either demonstrate that the TaAs orbital-momentum winding is independent of photon energy, or replace 'confirmed' with a more cautious term such as 'reported as evidence for' and should explicitly connect the discussion back to the final-state caveats of Section II.C.","section":"VI"},{"comment":"The claim in the abstract and in the bullet list that ARPES 'has unambiguously identified examples for several classes of topological materials' is not fully supported by the manuscript's own presentation of contested cases. In Section XI on correlated topological insulators, the SmB6 discussion reports conflicting spin-texture observations and leaves unresolved whether the observed surface states are topological; in Section XI on topological superconductors, the authors note that FeTe0.55Se0.45 has been argued to be a topologically trivial superconducting Dirac semimetal in Ref. [220], contradicting the earlier report of a topological surface state. These examples are not 'unambiguous' in the sense used in the claim, so the claim should be qualified by specifying which classes have unambiguous ARPES identification and which remain debated.","section":"Abstract / bullet list"}],"minor_comments":[{"comment":"There are numerous typographical errors throughout, including 'for for' in the abstract, 'topologicaly' in the Introduction, 'Moroever' and 'perculiar' in Section VI, and 'chalogen' and 'orhorhombic' in Section VIII; a careful proofread is needed.","section":"Abstract and general"},{"comment":"In Section II.C, 'predicton' and 'photomission' should be corrected to 'prediction' and 'photoemission', respectively.","section":"II.C"},{"comment":"In Section IV, 'suefaces', 'consdered', and 'expriment' should be corrected to 'surfaces', 'considered', and 'experiment', respectively.","section":"IV"},{"comment":"In Section V, the phrase 'for example, , moving' contains a doubled comma that should be removed.","section":"V"},{"comment":"Section XI appears twice, once for 'Correlated topological insulators' and once for 'Topological superconductors'; the second section should be renumbered to avoid confusion.","section":"Section numbering"},{"comment":"The caption of Figure 4 contains 'corrsponding' instead of 'corresponding', and should be corrected.","section":"Figure 4 caption"}],"recommendation":"major_revision","confidential_remarks":"The reference list includes a substantial fraction of the authors' own publications, and many of the highlighted examples (e.g., Refs. [23], [37], [46], [47], [53], [93]-[95], [122], [201], [228], [235], [237], [368]) are authored or co-authored by the reviewers themselves. This is not unusual in a competitive field, but the editors may wish to ensure that the selection of examples and the emphasis on particular results is balanced against independent work, especially in sections where the 'unambiguous' identification claim is made. The manuscript contains no original data or code; its value rests on the accuracy and balance of its literature coverage, so particular attention should be paid to the contested assignments in SmB6 and FeTe0.55Se0.45."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Quick take: this is a broad, mostly careful review of ARPES on topological materials by authors who did a lot of the underlying work. There are no new measurements or calculations, and the freshest conceptual thread—the TMD 'topological ladder'—is recycled from their own papers. Its value is as a structured, one-stop reference and teaching resource, and judged in that genre it largely succeeds.\n\nWhat is genuinely good: the coverage is unusually wide—strong and magnetic TIs, TCIs, Dirac/Weyl/nodal/chiral semimetals, TMDs, correlated candidates, superconductors, and time-resolved work—and the text repeatedly flags places where the literature is contested. The SmB6 section is honest about the competing spin-texture claims and termination issues rather than picking a winner, and FeTe0.55Se0.45 is presented with the trivial-Dirac-semimetal objection included. The Section II.C discussion of CDAD and 6-eV spin-flip final-state effects is exactly the kind of methodological caveat that belongs in a review.\n\nSoft spots are real but not crippling. There is heavy self-citation, especially where the authors' earlier papers are woven into the narrative; for a review this should come with a disclosure or at least a more restrained emphasis. The editing is sloppy in places (duplicated section numbers, repeated words, occasional typos). More substantively, the stress-test concern is fair: Section II.C establishes that CDAD in Bi2Te3 changes sign with photon energy as a final-state effect, yet Section VI says that in TaAs 'from the winding of the orbital angular momentum, the Weyl points have been confirmed as Berry flux monopoles,' citing a CDAD-based measurement. The reader is left to infer that the TaAs result escapes the earlier caveat, and the review never says why. That is an internal tension, though a minor one: the survey's main case for ARPES as a primary tool rests on dispersion, Fermi arcs, and spin-resolved data that are far less sensitive to this problem. The fix is one or two sentences acknowledging the final-state caveat in the TaAs context.\n\nFor whom: newcomers and non-specialists wanting a map of the field, and ARPES practitioners looking for a citation hub. I would cite it as an entry point rather than as an authority on any single contested assignment. It deserves serious peer review; a referee should push on the TaAs sentence, the self-citation balance, and the editing cleanup.","headline":"A solid, wide-ranging review that earns its place as a reference despite no new results; the real blemishes are a CDAD-vs-final-state tension in the TaAs passage and heavy self-citation.","tokens_in":62504,"tokens_out":3240,"would_cite":true,"duration_ms":32823,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":["79.60.-i","71.20.-b","73.20.At"],"model":"deepseek-v4-flash","headline":"Angle-resolved photoemission is the primary experimental method for reading the topology of 3D electronic materials, because it directly images their protected surface states and spin textures.","keywords":["angle-resolved photoemission spectroscopy","topological insulators","Weyl semimetals","Dirac semimetals","spin-momentum locking","topological surface states","transition metal dichalcogenides","bulk-boundary correspondence"],"falsifier":"A concrete check would be to take one assigned topological surface state from a less-settled family, for example the X-point contour in SmB6, and re-measure it with termination-controlled surfaces, spin resolution, photon-energy sweeps, and one-step photoemission calculations; if the spin texture and dispersion disappear or change sign with photon energy, the topological assignment would be falsified for that case. More generally, a survey of published Fermi arcs in Weyl semimetals that re-examines whether the arcs track bulk Weyl nodes when photon energy is varied across a wide range would test whether the assignments are ground-state electronic structure rather than final-state artifacts.","tokens_in":61417,"feed_emoji":"⚛️","tokens_out":8234,"duration_ms":79384,"temperature":0.7,"pith_summary":"This review argues that angle-resolved photoemission spectroscopy (ARPES) is the primary experimental method for establishing the electronic structure and topology of three-dimensional topological materials. The reason is that ARPES directly measures the momentum-resolved occupied states that carry the topology: symmetry-protected surface Dirac cones, Fermi arcs, and their spin-momentum-locked textures, connected to the bulk by the bulk-boundary correspondence. The authors show how photon-energy tuning separates surface from bulk states and locates bulk Dirac and Weyl nodes, and how spin resolution turns measured spin textures into evidence about band inversion, Berry phase, exchange gaps, and pairing symmetry. On that basis the survey counts which topological classes have been unambiguously identified by ARPES, and which remain open, notably correlated topological insulators and topological superconductors. If the claim holds, ARPES is not just one probe among many but the decisive experimental sieve for topological materials.","feed_headline":"ARPES images the surface states that make materials topological","feed_subtitle":"A review shows which topological phases photoemission has confirmed and which remain open.","key_machinery":"The load-bearing mechanism is the bulk-boundary correspondence, the symmetry-mandated fact that a nontrivial bulk band topology forces gapless surface states at an interface with a trivial medium. ARPES measures those states directly: by resolving energy versus parallel momentum it images Dirac cones and Fermi arcs, and by varying photon energy it scans the perpendicular momentum $k_z$, so a surface state's lack of $k_z$ dispersion identifies it as two-dimensional while bulk nodes disperse in all three directions. Spin-resolved ARPES adds the spin polarization of each band, converting a measured spin texture into evidence for spin-momentum locking, Berry phase, or a magnetic exchange gap. The review also uses one-step photoemission calculations to separate ground-state spin textures from final-state effects, which is what makes the assignments credible.","core_discovery":"The central claim is that ARPES is the primary experimental method for investigating 3D topological materials because it gives direct, energy- and momentum-resolved access to the occupied electronic states that define their topology. In a topological insulator the signature is an odd number of spin-polarized Dirac-cone surface-state crossings at the surface Brillouin zone, enforced by the bulk-boundary correspondence; in Dirac and Weyl semimetals it is the observation of bulk nodes together with surface Fermi arcs that connect them. The review documents that spin-resolved ARPES measures the chiral spin-momentum locking and exchange gaps, that photon-energy-dependent measurements locate the states in $k_z$ and separate surface from bulk, and that circular dichroism reports on orbital texture, with the caveat that it is a final-state effect whose sign can change with photon energy. Across the surveyed families the paper asserts that ARPES has unambiguously identified strong topological insulators, topological crystalline insulators, magnetic topological insulators, and 3D Dirac, Weyl, nodal, and chiral semimetals, while correlated topological insulators and topological superconductors remain outstanding.","pith_inferences":["If the review's assignments are sound, then computationally predicted topological materials should be prioritized for ARPES confirmation by the size and orbital character of their band inversions, because the TMD case study suggests single-orbital-manifold inversions are especially robust.","The paper's own warning that circular dichroism is a final-state effect suggests that any spin-texture claim from circular dichroism in a less-studied material should be rechecked with photon-energy sweeps and one-step calculations before being treated as a ground-state property.","A termination-controlled, spin-resolved ARPES study of SmB6 that resolves the conflicting spin-texture reports would be the decisive test of whether the topological Kondo insulator phase can be confirmed spectroscopically; the review leaves this conflict open.","If correlated topological phases require photoemission to observe them, the absence of confirmed examples may reflect surface preparation and final-state complications in strongly correlated materials rather than the absence of the phases."],"forward_implications":["An odd number of Fermi-level crossings of spin-split surface bands in ARPES is a direct experimental signature of a strong topological insulator, so the technique can adjudicate between trivial and nontrivial bulk topology.","Photon-energy-dependent ARPES, including soft-x-ray bulk-sensitive measurements, locates bulk Dirac and Weyl nodes and distinguishes them from surface Fermi arcs, which is how the Weyl semimetal state is established.","Spin-resolved ARPES can measure exchange gaps at the Dirac point of magnetic topological insulators and confirm that the gap closes at the Curie temperature, linking the spectroscopic gap to the magnetic phase transition.","Ultrafast pump-probe ARPES extends the method to unoccupied topological states, spin dynamics, and photon-dressed Floquet states, giving experimental access to transient topological properties.","Correlated topological insulators and topological superconductors have not yet been unambiguously identified by ARPES, and the technique is the expected route to closing that gap."],"supporting_citations":[{"why":"First ARPES demonstration of a 3D topological insulator phase in Bi1−xSbx.","marker":"[8]"},{"why":"ARPES observation of the gapless surface Dirac cone in Bi2Se3.","marker":"[12]"},{"why":"Spin-resolved ARPES measurement of the chiral spin-momentum-locked texture in Bi2Te3.","marker":"[15]"},{"why":"ARPES confirmation of Na3Bi as a 3D Dirac semimetal along all three momentum directions.","marker":"[113]"},{"why":"ARPES detection of surface Fermi arcs connecting bulk Weyl points in TaAs.","marker":"[119]"},{"why":"Establishes the single-orbital-manifold mechanism for topological ladders in transition metal dichalcogenides, the review's central case study.","marker":"[226]"},{"why":"Termination-resolved ARPES of SmB6 that challenges the topological Kondo insulator assignment, supporting the paper's classification of correlated TIs as outstanding.","marker":"[201]"}],"fun_headline_variants":["ARPES maps the spin-textured states that define topology","Photoemission reveals topological surface states and Fermi arcs","Direct probe of topological bands: ARPES takes the lead","ARPES: the key to confirming topological phases","From Dirac cones to Fermi arcs: ARPES probes topology"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The review assumes that the published ARPES assignments it surveys are correct, that the bands, spin polarizations, and Fermi arcs attributed to topological states are not instead dominated by surface-preparation artifacts, termination differences, or distortions introduced by the photoemission process itself.","fun_headline_variants_meta":{"raw":{"variants":["ARPES maps the spin-textured states that define topology","Photoemission reveals topological surface states and Fermi arcs","Direct probe of topological bands: ARPES takes the lead","ARPES: the key to confirming topological phases","From Dirac cones to Fermi arcs: ARPES probes topology"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000216,"raw_usage":{"total_tokens":1409,"prompt_tokens":899,"completion_tokens":510,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":515,"completion_tokens_details":{"reasoning_tokens":430}},"tokens_in":515,"tokens_out":510,"duration_ms":5316,"temperature":1.0,"reasoning_tokens":430,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-10T22:48:51.037403+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A concrete check would be to take one assigned topological surface state from a less-settled family, for example the X-point contour in SmB6, and re-measure it with termination-controlled surfaces, spin resolution, photon-energy sweeps, and one-step photoemission calculations; if the spin texture and dispersion disappear or change sign with photon energy, the topological assignment would be falsified for that case. More generally, a survey of published Fermi arcs in Weyl semimetals that re-examines whether the arcs track bulk Weyl nodes when photon energy is varied across a wide range would test whether the assignments are ground-state electronic structure rather than final-state artifacts.","supporting_citations":[{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Establishes the single-orbital-manifold mechanism for topological ladders in transition metal dichalcogenides, the review's central case study."}],"review_version":1}