{"id":"deff2df9-c978-44a7-bbac-1e0320808e46","arxiv_id":"2603.16635","paper_version":2,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"Spin signals antisymmetric about Γ in SARPES on α-MnTe are photoemission artifacts, while symmetric signals under s-polarized light reveal the ground-state d-wave spin texture.","lead":"This paper separates two kinds of spin signals seen in photoemission experiments on the altermagnet α-MnTe: spin splitting that really lives in the material's electronic bands, and spin polarization created by the photoemission process itself. It gives experimentalists a practical rule to tell them apart, and applies it to confirm the predicted d-wave-shaped spin texture of MnTe.","discovery_kind":"new_method","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Ground-state attribution rests on one-step SPR-KKR matrix elements for a Mn-terminated surface (Sec. IV) while films are Te-terminated; the 'symmetric = ground state' rule and ROI are unverified for the real surface, and no balanced-domain control at k||≈0.36 Å⁻¹ is reported.","rationale":"Strengths first: the azimuthal-difference isolation of the matrix-element contribution (Sec. VI.B) is clean — the same ground-state spectral function is used, so the difference is purely geometrical; the p-polarized near-zero spin signal in the ROI (Sec. II.B.2) is a genuine control showing the s-polarized symmetry is not generic; and the qualitative symmetry argument (symmetric vs antisymmetric about Γ) is robust to the fitted domain imbalance of 0.28. SPR-KKR is a mature, established one-step method, so the concern is about an unverified input, not internal inconsistency.\n\nThe load-bearing fault line is the known termination mismatch. The interpretive rule and the ROI are both extracted from a Mn-terminated half-space calculation, although Sec. IV states the films are expected to be Te-terminated. Since the measured bands near EF are Te-p dominated and the ~70 eV photoelectrons are surface-sensitive, the termination plausibly changes the very matrix elements whose symmetry and smallness the argument relies on. The paper performs no termination test — no Te-terminated calculation and no balanced-domain measurement at k||≈0.36 Å⁻¹ — leaving the precondition 'matrix-element spin contributions are antisymmetric and small in the ROI for the real surface' unverified.\n\nBecause the reader's weakest_assumption (fidelity of the SPR-KKR one-step calculations, including the Mn vs Te termination) identifies the same fault line, I mark agreement. My read does not change the verdict: CONDITIONAL remains right. ACCEPT would require the termination check, and REJECT would overstate the case given the clean azimuthal decomposition, the p-polarized control, and the mature method. The condition is explicit: recompute with Te termination; if antisymmetry and ROI smallness survive, the central claim is supported.","tokens_in":12480,"tokens_out":12366,"duration_ms":121021,"concrete_test":"Recompute the one-step SPR-KKR SARPES of Sec. VI.B for a Te-terminated MnTe(0001) surface — same U=4.80 eV, J=0.80 eV, hν≈80 eV, geometry, and domain configurations as in Fig. 2/Fig. 8 — and verify: (i) the s-polarized azimuthal-difference matrix-element spin signal remains purely antisymmetric about Γ; and (ii) the ROI (k||>0.25 Å⁻¹, EB<0.5 eV) still shows minimal matrix-element contamination in Sz. If either property fails under Te termination, the symmetric EDC in Fig. 5(b) cannot be attributed to the ground-state d-wave texture. A complementary, calculation-independent check: measure s-polarized EDCs at k||≈±0.36 Å⁻¹ on the non-field-cooled sample; a nonzero symmetric signal there would also falsify the rule.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim — that the symmetric SARPES EDCs at k||≈0.36 Å⁻¹ (Sec. II.B.2) establish the SOC-induced d-wave Sz texture on the kz=0 nodal plane — stands on two numerical results of the one-step SPR-KKR calculation: (i) under s-polarized light the photoemission-induced spin polarization is purely antisymmetric about Γ, so any symmetric signal is ground state (Sec. II.A, VI.B); and (ii) the ROI (k||>0.25 Å⁻¹, EB<0.5 eV) is minimally contaminated by matrix-element effects (Fig. 8). Both are computed for a Mn-terminated MnTe(0001) surface (Sec. IV), while the authors state the MBE films are expected to be Te-terminated, citing prior work [4]. At hν≈78 eV the photoelectron kinetic energy (~70 eV) falls in the surface-sensitive minimum of the inelastic mean free path, so the top-layer termination directly shapes the spin-dependent matrix elements that generate the photoemission-induced signal. If a Te-terminated calculation yields a symmetric s-polarized matrix-element contribution, or appreciable contamination inside the ROI, the measured symmetric EDC could be photoemission-induced rather than ground-state, and the confirmation of d-wave LKSD fails even though every experimental step is correct. The paper also does not report the balanced-domain (non-field-cooled) spin signal at k||≈0.36 Å⁻¹, which would have provided an independent, calculation-free test: with zero net ground-state polarization, any symmetric signal there would falsify 'symmetric = ground state'. This is an unverified precondition, not an inconsistency; the qualitative symmetry argument is robust to the fitted domain imbalance, and the p-polarized null at k||=−0.36 Å⁻¹ is a genuine consistency check.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper addresses how to separate intrinsic ground-state spin textures from photoemission-induced spin polarization in SARPES studies of the altermagnet α-MnTe. Using one-step SPR-KKR photoemission calculations, the authors propose that under s-polarized light, the component of the out-of-plane photoelectron spin polarization that is symmetric about Γ reflects the ground-state spin texture, while the antisymmetric component is purely a matrix-element artifact. They define a region of interest (k||>0.25 Å⁻¹, EB<0.5 eV) where matrix-element contamination is minimal, and they report spin-resolved EDC measurements on field-cooled films at k||≈0.36 Å⁻¹ showing a symmetric spin signal under s-polarized light, which they interpret as evidence for the SOC-induced d-wave-like lifted Kramers spin degeneracy on the kz=0 nodal plane. They also show that p-polarized light suppresses the ground-state signal, consistent with their calculations.","tokens_in":12746,"tokens_out":4089,"duration_ms":43729,"significance":"If the interpretation is correct, the paper provides a practical methodology for extracting ground-state spin textures from SARPES in altermagnets and delivers experimental support for the d-wave spin texture in α-MnTe. The main strengths are the use of fully relativistic one-step photoemission calculations that include realistic geometry, multiple scattering, and photon energy; the explicit formulation of a symmetry-based interpretive rule; and the combination of spin-integrated and spin-resolved measurements on both field-cooled and non-field-cooled samples. However, the central attribution is not yet secure because the interpretive rule and the region of interest are derived from a Mn-terminated surface calculation while the measured films are expected to be Te-terminated, and because the key experimental test is performed only on an imbalanced-domain sample without a balanced-domain control in the same momentum region.","major_comments":[{"comment":"The one-step SPR-KKR calculations are explicitly performed for the Mn-terminated surface of hexagonal MnTe(0001), while the Methods state that the MBE films are expected to be Te-terminated, citing Ref. [4]. At hν≈78 eV the photoelectron kinetic energy (~70 eV) is in the surface-sensitive range, so the spin-dependent matrix elements that generate the photoemission-induced signal depend directly on the termination. The rule that under s-polarized light the symmetric part of Sz is ground-state, and the identification of the ROI with minimal matrix-element contamination (Fig. 8), are both obtained from this Mn-terminated model. If a Te-terminated calculation yields a symmetric matrix-element contribution under s-polarized light or appreciable contamination inside the ROI, the measured symmetric EDC at k||≈0.36 Å⁻¹ would not establish the ground-state texture. The authors should demonstrate","section":"Sec. IV and Sec. II.A"},{"comment":"The balanced-domain case is calculated and predicted to give vanishing ground-state spin polarization at larger momenta, yet the spin-resolved EDC at k||≈0.36 Å⁻¹ that carries the central claim is only shown for the field-cooled (imbalanced) sample. A non-field-cooled, balanced-domain sample measured under identical conditions would provide a calculation-free control: if a symmetric spin signal appears at k||≈0.36 Å⁻¹ in the balanced case, the rule 'symmetric = ground state' would be falsified. The manuscript only reports balanced-domain spin data at small momenta (k||≈0.2 Å⁻¹) and not in the ROI. This control is essential for the central conclusion.","section":"Sec. II.B.1 and Sec. II.B.2"},{"comment":"The imbalanced-domain simulation uses an ad hoc domain composition of (24;19;19)% versus (10;14;14)% with an effective imbalance of 0.28, and the comparison to experiment is described qualitatively as 'resembling' the calculated EDCs. No justification is given for these percentages, and no sensitivity analysis is provided to show that the predicted symmetric EDC in the ROI is robust to the choice of domain composition or to the Hubbard parameters U=4.80 eV and J=0.80 eV. Because the calculation already contains the d-wave ground state, the resemblance is partly a result of the model's input rather than an independent confirmation. The authors should quantify the robustness of the symmetric signal in the ROI to these choices.","section":"Sec. II.B.2, Fig. 5"}],"minor_comments":[{"comment":"Typo: 'preformed ARPES measurements' should be 'performed ARPES measurements'.","section":"Sec. II.B.1"},{"comment":"Typo: 'deduct the contribution' should be 'deduce the contribution'.","section":"Sec. VI.B"},{"comment":"The text states hν≈80 eV while Fig. 2 and later text use hν=82 eV; please make the values consistent.","section":"Sec. II.A and Fig. 2"},{"comment":"The statement that spin-resolved EDCs at higher momenta possess the same symmetry is supported only by a supplementary figure; adding the quantitative polarization values and statistical uncertainties for those EDCs would strengthen the claim.","section":"Sec. II.B.2"},{"comment":"A rigid 100 meV shift is applied to align calculated and measured bands; the effect of this shift on the extracted spin polarization and the ROI boundaries is not discussed.","section":"Sec. VI.A"}],"recommendation":"major_revision","confidential_remarks":"The paper is potentially valuable, but the termination mismatch between calculation and experiment is a substantive issue because the interpretive rule is derived from the same calculation. The missing balanced-domain control is also a clear gap. I would be willing to accept after the authors provide either Te-terminated one-step calculations or a convincing termination-insensitivity argument, plus the balanced-domain spin-resolved data in the ROI."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Colleague,\n\nThis paper gives the altermagnet SARPES community something it didn't have before: a concrete rule for telling ground-state spin texture apart from photoemission-induced polarization. The rule — antisymmetric Sz about Γ is a matrix-element artifact; under s-polarized light the symmetric part is ground state — is stated cleanly and is not definitionally empty. The calculations could in principle have put artifacts in the symmetric channel, so the rule carries content. The observation that linearly polarized light selectively excites Néel domains is also new and worth chasing.\n\nThe experiment is careful: field cooling generates an imbalance, the p-polarized null at k||=-0.36 Å⁻¹ is a genuine consistency check, and the qualitative agreement between the measured symmetric EDC and the one-step calculation in the ROI is real.\n\nWhere I'd push back: the ground-state attribution rests on the same one-step SPR-KKR calculations that define the ROI, and those calculations use a Mn-terminated surface while the films are expected to be Te-terminated (the authors state both in Methods, without reconciling them). At ~70 eV kinetic energy the photoemission is surface-sensitive, so termination could plausibly change the spin-dependent matrix elements enough to shift symmetric weight into the 'artifact' channel or contaminate the ROI. The paper doesn't test this. A balanced-domain measurement at k||≈0.36 Å⁻¹ would have been a calculation-free falsifier of the rule; they report it only at smaller momenta.\n\nThe other soft spots are minor: the domain imbalance (0.28) is fitted to reproduce the data, though the symmetric character survives a balanced-domain assumption, and the few-percent spin signals have no error bars. Neither breaks the qualitative conclusion.\n\nNet: the rule is a genuine methodological contribution and the paper deserves a serious referee. I'd send it out with a request for a Te-terminated calculation or at least a sensitivity check, and an explicit balanced-domain control. It's honest work, clearly written, and the symmetry argument is robust enough that I'd bet on the conclusion.","headline":"A useful, transferable rule for separating ground-state from matrix-element spin textures in altermagnet SARPES, but the calculation's surface termination mismatch leaves the central confirmation shakier than the text suggests.","tokens_in":13504,"tokens_out":2325,"would_cite":true,"duration_ms":24086,"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":"SARPES signals in altermagnet MnTe split into texture and artifact","keywords":["altermagnetism","α-MnTe","SARPES","spin texture","matrix element effects","one-step photoemission","lifted Kramers spin degeneracy","d-wave spin polarization"],"falsifier":"A decisive check would be to field-cool the same MnTe film in the opposite direction: the symmetric ground-state contribution should flip sign (since the Néel vector reverses) while the antisymmetric artifact should remain unchanged, and the measured polarization should follow this behavior. Alternatively, repeating the one-step calculation with a Te-terminated surface and comparing the predicted symmetric signal at k||≈0.36 Å^-1 to the measured EDC would directly test whether the attribution survives the termination mismatch.","tokens_in":12221,"feed_emoji":"🧲","tokens_out":6714,"duration_ms":53115,"temperature":0.7,"pith_summary":"This paper establishes an interpretive rule for spin-resolved photoemission (SARPES) on the altermagnetic semiconductor α-MnTe: any out-of-plane spin polarization that is antisymmetric with respect to the Γ point is purely a photoemission artifact, while the symmetric part measured with s-polarized light reflects the ground-state spin texture. Using one-step photoemission calculations, the authors identify a region of momentum and binding energy where matrix element effects are minimal, and show that spin-resolved measurements on field-cooled, domain-imbalanced samples display a symmetric spin signal there that matches the calculated ground-state d-wave-like out-of-plane polarization on the kz=0 nodal plane. If correct, this provides experimental confirmation of the spin-orbit-induced lifted Kramers spin degeneracy in an altermagnet and a general method for separating intrinsic from photoemission-induced spin textures in such materials.","feed_headline":"Symmetric spin signal in altermagnet MnTe is ground-state texture","feed_subtitle":"Field-cooled MnTe shows the predicted d-wave out-of-plane spin order once photoemission artifacts are subtracted.","key_machinery":"The key machinery is the symmetry decomposition rule derived from fully relativistic one-step photoemission calculations: within the kz=0 nodal plane, any Sz spin polarization component antisymmetric with respect to Γ is assigned to photoemission matrix element effects, while the symmetric part, for s-polarized light, is assigned to the ground state. The calculations also define a region of interest (k|| > 0.25 Å^-1, EB < 0.5 eV) where matrix element effects are minimal, providing a reliable window for reading ground-state spin polarization in experiments. This rule is applied to interpret spin-resolved EDC measurements on field-cooled samples with imbalanced Néel domains.","core_discovery":"The paper's central claim is that in SARPES experiments on α-MnTe near the kz=0 nodal plane, the measured Sz spin polarization can be decomposed: a component antisymmetric about Γ arises exclusively from photoemission matrix element effects, while the symmetric component measured with s-polarized light reflects the ground-state spin texture. One-step photoemission calculations support this, and field-cooled measurements at k||≈0.36 Å^-1 show a symmetric spin signal in the expected region, matching calculations and attributed to the predicted d-wave out-of-plane polarization from SOC-induced lifted Kramers degeneracy. Balanced domains and p-polarized light, by contrast, give predominantly ant","pith_inferences":["If this decomposition rule generalizes, SARPES might be used to detect altermagnetic order in candidates lacking field-cooling control, simply by checking for the symmetric ground-state component under s-polarized light.","The observed light-induced selective excitation of Néel domains hints at an optical handle for probing or even manipulating domain populations, though the paper does not claim this.","A natural extension would be to test the same symmetric/antisymmetric rule for in-plane spin components or on the other nodal planes, where the non-relativistic splitting dominates.","The method's reliance on a specific region of interest suggests that a two-dimensional mapping of the symmetric spin signal could map the ground-state texture over the whole Brillouin zone, beyond the few cuts measured here."],"forward_implications":["SARPES data from altermagnets can be interpreted by decomposing the measured spin polarization into symmetric and antisymmetric parts; the antisymmetric part never reflects the ground-state texture.","The observed symmetric spin signal on field-cooled α-MnTe supports the predicted spin-orbit-induced d-wave-like lifted Kramers spin degeneracy on the kz=0 nodal plane.","The identified region of interest tells future experiments precisely where to look for ground-state spin textures, minimizing matrix-element contamination.","The coupling between light polarization and Néel vector orientation means that polarization-dependent measurements can be used to sense domain imbalance, and must be accounted for in any altermagnet SARPES study."],"fun_headline_variants":["MnTe spin texture: ground state vs photoemission distortion","Altermagnetic MnTe: d-wave spin order separated from artifacts","SARPES on MnTe: distinguishing intrinsic spin from photoemission","Ground-state spin texture in altermagnet MnTe isolated","MnTe: photoemission-induced spin polarization removed"],"cache_read_input_tokens":2304,"weakest_assumption_plain":"The ground-state interpretation of the symmetric spin signal rests on the accuracy of the one-step photoemission calculations, which assume a Mn-terminated surface and specific Hubbard parameters (U=4.80 eV, J=0.80 eV), while the actual MBE films are expected to be Te-terminated; if these matrix element effects are miscalculated, the symmetric signal could be misattributed.","fun_headline_variants_meta":{"raw":{"variants":["MnTe spin texture: ground state vs photoemission distortion","Altermagnetic MnTe: d-wave spin order separated from artifacts","SARPES on MnTe: distinguishing intrinsic spin from photoemission","Ground-state spin texture in altermagnet MnTe isolated","MnTe: photoemission-induced spin polarization removed"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000197,"raw_usage":{"total_tokens":1220,"prompt_tokens":779,"completion_tokens":441,"prompt_tokens_details":{"cached_tokens":256},"prompt_cache_hit_tokens":256,"prompt_cache_miss_tokens":523,"completion_tokens_details":{"reasoning_tokens":355}},"tokens_in":523,"tokens_out":441,"duration_ms":4779,"temperature":1.0,"reasoning_tokens":355,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-02T18:00:33.923023+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A decisive check would be to field-cool the same MnTe film in the opposite direction: the symmetric ground-state contribution should flip sign (since the Néel vector reverses) while the antisymmetric artifact should remain unchanged, and the measured polarization should follow this behavior. Alternatively, repeating the one-step calculation with a Te-terminated surface and comparing the predicted symmetric signal at k||≈0.36 Å^-1 to the measured EDC would directly test whether the attribution survives the termination mismatch.","supporting_citations":[],"review_version":1}