{"schemaVersion":"1.0","revision":"414f1e850a9ed04cee70","note":{"id":"romero-parallel-conduction","title":"Parallel conduction and Planckian scattering in FeTeSe","summary":"Connect optical parallel-channel fits with Planckian rate conventions and nonlinear resistance, while keeping the pairing mechanism unresolved.","kind":"research-note-and-cross-topic-analysis","modifiedAt":"2026-10-19T00:19:22.328955+00:00","aliases":["Romero","FeTeSe","parallel conduction channels","Planckian scattering","arXiv:2505.00623"],"evidenceTypes":["experiment","theory","hypothesis"],"relatedCodes":["A8","H2","H8","B5","D4"],"review":{"checkedAt":"2026-10-19","scope":"Selected author-version passages; final-version comparison and independent review pending.","limitations":["Author self-review; no independent scientific review or raw-data reproduction.","Selected preprint passages, not a complete final published-version comparison.","The missing-area normalization and precise condensate fractions remain unresolved."]},"sections":[{"id":"measurement","title":"What was measured","markdown":"Romero and colleagues analyzed complex terahertz conductivity alongside DC resistance in two FeTe1−xSex films. Their model separates a narrow Drude response from a much broader background. Within the measured frequency window, the narrow-channel width is approximately linear in temperature, while the total resistance need not be. The inferred condensate weight is mainly associated with that channel. This is an author-version interpretation, not a unique determination of the pairing interaction.","evidenceType":"experiment","sourceIds":["romero-v1"],"sourceRelationship":"direct-support"},{"id":"frequency-convention","title":"Keep the frequency convention explicit","markdown":"For a Drude denominator $\\Gamma-i\\nu$, both variables use ordinary frequency. The corresponding pole decay rate is $\\gamma=2\\pi\\Gamma$. Thus $\\Gamma=\\alpha k_BT/h$ and $\\gamma=\\alpha k_BT/\\hbar$ express the same coefficient after conversion. The inherited reading note mixed these conventions. Its numerical expressions must not be copied unchanged.","evidenceType":"theory","sourceIds":["romero-v1"],"sourceRelationship":"context-for-local-derivation"},{"id":"parallel-channels","title":"Why parallel channels matter","markdown":"As a separate local illustration, take fixed $S>0$, $\\sigma_0\\geq0$, $c>0$, $\\Gamma_0\\geq0$ and $T>0$:\n\n$$\\sigma_{\\rm DC}=\\sigma_0+\\frac{S}{\\Gamma_0+cT},\\qquad \\rho_{\\rm DC}=\\frac{\\Gamma_0+cT}{S+\\sigma_0(\\Gamma_0+cT)}.$$\n\nDifferentiation gives $d\\rho_{\\rm DC}/dT=cS/[S+\\sigma_0(\\Gamma_0+cT)]^2$. A linear narrow-channel rate therefore need not give linear total resistivity. When $\\sigma_0=0$, this model does recover a linear resistivity. The approximation $\\sigma_{\\rm DC}=a+b/T$ additionally neglects $\\Gamma_0$ and assumes sufficiently constant amplitudes. This algebra is not a fit to the experimental data.","evidenceType":"theory","sourceIds":["romero-v1"],"sourceRelationship":"context-for-local-derivation"},{"id":"limits","title":"What remains unresolved","markdown":"The broad contribution is not resolved as an independent complete Drude peak. Its microscopic origin and a unique relaxation coefficient are therefore not established by this fit. The manuscript discusses nematic pairing qualitatively and leaves the mechanism open. Its printed missing-area prefactor requires comparison with the final paper and normalization before precise condensate fractions are imported. No third-party figures or full text are reproduced here.","evidenceType":"theory","sourceIds":["romero-v1"],"sourceRelationship":"direct-support"}],"sources":[{"id":"romero-v1","title":"Planckian scattering and parallel conduction channels in the iron chalcogenide superconductors FeTe1−xSex","url":"https://arxiv.org/abs/2505.00623v1","publicationStatus":"preprint","submittedAt":"2025-05-01","version":"v1; manuscript dated 2 May 2025","checkedAt":"2026-10-19","scope":"Selected PDF pages 1–5; page 4 figure and equations inspected visually. Final-version comparison pending.","doi":null,"authors":"Ralph Romero III, Hee Taek Yi, Seongshik Oh and N. P. Armitage","date":"2025-05-01","dateLabel":"Submitted","licenseUrl":null,"licenseLabel":null}],"provenance":[{"path":"papers/CROSS_H2_H8_RomeroPlanckian.md","commit":"0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf","sha256":"aef4a2f9efe186b0fc094ab424bba412128be75bae28d4c15fe6ad1797ba478e","disposition":"merge-into","repository":"JackZH26/jzis-superconductivity","coverage":"Whole source-note disposition; the primary scientific review remains limited to the stated scope."},{"path":"papers/library/Romero_Planckian-FeTeSe_READING_NOTES.md","commit":"0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf","sha256":"c26198323fa69f7603870d26b455aca4ee4ae4edbbf7aa9a94ce6bb8f7f4acd5","disposition":"merge-into","repository":"JackZH26/jzis-superconductivity","coverage":"Whole source-note disposition; the primary scientific review remains limited to the stated scope."}],"corrections":[{"issue":"Frequency convention","inherited":"Gamma denominator uses ordinary frequency nu but slope uses kBT/hbar.","resolution":"Use Gamma=Gamma0+alpha*kBT/h; gamma=2*pi*Gamma is the angular pole decay rate. Manuscript p3 and p4 Fig3."},{"issue":"Composition label","inherited":"x labelled Se/Te ratio.","resolution":"x is Se fraction in FeTe(1-x)Se(x); the Se/Te ratio would be x/(1-x)."},{"issue":"Residual-rate omission","inherited":"sigmaDC=sigma0+S/Gamma immediately equals a+b/T.","resolution":"Retain Gamma0; a+b/T is approximate when Gamma0 is negligible and S/background are sufficiently constant."},{"issue":"Condensate attribution","inherited":"All condensate spectral weight and nematic pairing asserted too strongly.","resolution":"Author claims mainly slow-channel origin; pairing mechanism remains open on p4. Treat nematic comparison as qualitative."},{"issue":"Sum-rule normalization","inherited":"Unqualified exact condensate fractions imported.","resolution":"Author p2 numerator implies integral pi*S/2, whereas p4 printed SU=pi/2*integral creates inconsistent normalization. Final-version/calibration comparison unresolved. Do not import fractions as validated measurements."}],"rights":"Original editorial summary and local explanatory calculations. Linked papers retain their own rights; no third-party figures or full text are reproduced.","revision":"ee1e0016dba349182c88"}}