{"schemaVersion":"1.0","revision":"fa961ab24277a91737c3","article":{"id":"scwiki-e2","topicId":"scwiki-topic-e2","code":"E2","slug":"chemical-doping","title":"Chemical doping: composition, carriers and disorder","summary":"Separate nominal composition, measured site occupancy and mobile carriers when reading superconducting phase diagrams.","aliases":["chemical doping","carrier doping","substitution","oxygen stoichiometry","isovalent doping","WDS","EDX","nominal composition"],"evidenceTypes":["theory","experiment"],"relatedCodes":["D3","D4","D5","E1","A1","A3"],"editorialStatus":"scoped-check","contentState":"pilot","modifiedAt":"2026-10-19T18:24:23.318138+00:00","review":{"checkedAt":"2026-10-20","scope":"Selected YBCO, Co/P Ba122, nickelate and Ni/Zn-YBCO author passages and figures; Takagi publisher title/abstract; bounded composition, charge-balance and Hall/calibration algebra. Version-specific ranges, specimen ambiguity, finite detection and source-label conflicts remain explicit.","limitations":["Complete scientific acceptance, final-version comparisons, full supplements and raw-data reproduction remain open.","Takagi remains title/abstract-only. Sidis now has selected author-v1 pp.1–3 review, not a complete final-method or raw-data audit.","Ni 0.078/0.074 specimen association, Kasahara caption-color/version differences and Sidis Figure 2 caption-panel order conflict remain explicit.","Formal valence, empirical YBCO calibration and illustrative two-band algebra are not a measured carrier-density determination.","Finite-temperature non-observation does not establish exact Tc = 0. No equilibrium certification, raw reanalysis, full supplemental review or digitized nickelate Tc is supplied."]},"provenance":{"repository":"JackZH26/jzis-superconductivity","commit":"0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf","path":"E_tuning_parameters/E2_chemical_doping.md","sha256":"612b84c0c11af76b0ae355518b54a36a3ab3a5d11a315bbee8539de43bde2944","sourceId":"file-344ddb96b528df6b"},"sourceMap":[{"startLine":1,"endLine":139,"targetSections":["scope","mathematical-assumptions","experimental-criteria","limits-and-disputes","discovery-implications","related-topics"],"decision":"edited-with-scoped-evidence","note":"Pinned source preserved. Corrected site-fraction notation and separated nominal composition, analytical composition, valence arithmetic and transport models. Unread background references are not claimed as reviewed."}],"references":[{"id":"source-5030a5999bf0420a","doi":"10.1103/PhysRevB.40.2254","title":"Superconductor-to-nonsuperconductor transition in (La1−xSrx)2CuO4 as investigated by transport and magnetic measurements","year":1989,"url":"https://doi.org/10.1103/PhysRevB.40.2254","publicationStatus":"journal-article","verification":{"scope":"publisher-abstract-and-composition-notation","checkedAt":"2026-10-20","evidenceUrl":"https://journals.aps.org/prb/abstract/10.1103/PhysRevB.40.2254","note":"Published 1 August 1989. Original title and abstract checked: site fraction x <= 0.175 in (La1-xSrx)2CuO4 converts to y <= 0.35 in La2-ySryCuO4. Full methods require authorization and were not read."}},{"id":"source-e24ef58054ac9b71","doi":"10.1103/PhysRevB.73.180505","title":"Evaluation of CuO2 plane hole doping in YBa2Cu3O6+x single crystals","year":2006,"url":"https://doi.org/10.1103/PhysRevB.73.180505","publicationStatus":"journal-article","verification":{"scope":"selected-author-calibration-methods-and-equations","checkedAt":"2026-10-20","evidenceUrl":"https://arxiv.org/pdf/cond-mat/0510674v1","note":"Published 25 May 2006; author v1 selected pp. 1–4 read, p. 3 Eq. 2 and figures visually checked. Chain-order assumptions, 22°C c-axis calibration, magnetization midpoint and empirical parabola exception retained. Independent algebra is not a raw-data fit. Final-version comparison remains open. Follow-up: author v1 pp.1–3 reread, pp.2–3 visually inspected. Oxygen precision ±0.002 belongs to x; 22°C lattice measurement and 1 Oe field-cooled midpoint are distinct. Tc,max 94.3 K and 85.3 K give two algebraic roots; the source selects the slightly overdoped branch. No direct hole-count measurement or raw-data refit."}},{"id":"source-cf1286d7701502f2","doi":"10.1103/PhysRevB.78.214515","title":"Effects of Co substitution on thermodynamic and transport properties and anisotropic Hc2 in Ba(Fe1−xCox)2As2 single crystals","year":2008,"url":"https://doi.org/10.1103/PhysRevB.78.214515","publicationStatus":"journal-article","verification":{"scope":"selected-author-composition-and-transition-criteria","checkedAt":"2026-10-20","evidenceUrl":"https://arxiv.org/pdf/0811.1767v1","note":"Author v1 submitted 11 November 2008; journal published 29 December 2008. Selected pp. 1–7 read; Fig. 10 p. 23 visually checked. WDS/nominal distinction and probe criteria retained. Specific-heat paragraph 0.078 versus phase-summary 0.074 is unresolved; no precise single specimen assigned to the 23 K summary. Printed 2018 date is not publication date. Final version and raw data not reviewed. Follow-up: pp.5–7 reread and Fig.8/p.21 visually inspected; the paragraph, caption and plot itself use 0.078, whereas WDS and phase-summary passages use 0.074. No specimen identity inferred."}},{"id":"source-b9e77d2ee024ff3b","doi":"10.1103/PhysRevB.81.184519","title":"Evolution from non-Fermi- to Fermi-liquid transport via isovalent doping in BaFe2(As1−xPx)2 superconductors","year":2010,"url":"https://doi.org/10.1103/PhysRevB.81.184519","publicationStatus":"journal-article","verification":{"scope":"selected-author-v3-composition-transport-and-figures","checkedAt":"2026-10-20","evidenceUrl":"https://arxiv.org/pdf/0905.4427v3","note":"Author v3 submitted 9 February 2010; journal published 19 May 2010. Selected pp. 1–3 read; p. 2 figures visually checked. EDX composition, separate onset/zero and compensated-model limits retained. v1 to v3 changes and figure-caption color mismatch noted. No exact 31 K criterion assigned from the summary; final author list differs and final-version comparison remains open. Related Physica C DOI on arXiv is not this PRB DOI. Follow-up: v1/v3 pp.1–2 compared, v3 p.2 pixels checked. Ranges 0–0.54/0–0.71 and zero-resistivity thresholds 0.16/0.20 remain version-specific; caption color order conflicts with plotted onset/zero labels. Low-x bulk-character caveat retained."}},{"id":"source-c636cc691b7ff013","doi":"10.1103/PhysRevLett.125.027001","title":"Superconducting Dome in Nd1−xSrxNiO2 Infinite Layer Films","year":2020,"url":"https://doi.org/10.1103/PhysRevLett.125.027001","publicationStatus":"journal-article","verification":{"scope":"selected-author-film-methods-and-phase-diagram","checkedAt":"2026-10-20","evidenceUrl":"https://arxiv.org/pdf/2003.08506v2","note":"Author v2 submitted 23 June 2020; journal published 7 July 2020. Selected pp. 1–4 and Fig. 2 p. 12 read and visually checked: films, reduction/capping, resistance normalization, criterion and sample extrema. Complete supplement, final-version comparison and raw data not reviewed; no exact digitized Tc is introduced. Follow-up: author v2 pp.2–4 and Fig.2/p.12 reread, pp.3/12 visually inspected. Cap/reduction pairings, 3.91 Å substrate constraint, sampled compositions, 10/90 versus 50% criteria, sample-extrema bars and below-50-mK non-observation retained. No exact Tc extracted or continuous boundary inferred."}},{"id":"source-9fd0a423b4e4de89","doi":"10.1103/PhysRevLett.84.5900","title":"Quantum Impurities and the Neutron Resonance Peak in YBa2Cu3O7: Ni versus Zn","year":2000,"url":"https://doi.org/10.1103/PhysRevLett.84.5900","publicationStatus":"journal-article","verification":{"scope":"selected-author-v1-impurity-methods-and-neutron-figures","checkedAt":"2026-10-20","evidenceUrl":"https://arxiv.org/pdf/cond-mat/9912214v1","note":"Author v1 submitted 13 December 1999; journal published 19 June 2000. Selected pp.1–3 read; pp.1/3 visually inspected. Samples selected for close Tc, unequal impurity fractions; ratios inferred from Tc suppression with additional Ni microprobe check. Finite normal-state upper limit and spectral-energy versus Tc distinction retained. Figure 2 caption order conflicts with panels/text; no silent relabeling. Printed 2018 generation date is not publication date. Final version, complete methods and raw neutron analysis remain unchecked."}}],"claims":[{"id":"scwiki-e2-claim-scope-1","sectionId":"scope","statement":"Chemical doping changes a material's composition; it does not supply a universal carrier counter. Distinguish the starting mixture, measured site occupancy, formal ionic charge and mobile carriers. Substitution can also change disorder, bond geometry and competing order. Oxygen removal or chain ordering adds another control variable. A superconducting dome is therefore a relationship among specified samples and criteria, not a recipe transferable between families.","evidenceType":"experiment","sourceIds":["source-e24ef58054ac9b71","source-cf1286d7701502f2","source-b9e77d2ee024ff3b","source-c636cc691b7ff013"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected primary passages, figures and bounded algebra; full scientific acceptance remains open."},{"id":"scwiki-e2-claim-scope-2","sectionId":"scope","statement":"Notation matters even before measurement. Takagi's 1989 abstract uses $(\\mathrm{La}_{1-x}\\mathrm{Sr}_x)_2\\mathrm{CuO}_4$ through $x=0.175$. Expanding the formula gives $\\mathrm{La}_{2-2x}\\mathrm{Sr}_{2x}\\mathrm{CuO}_4$: in $\\mathrm{La}_{2-y}\\mathrm{Sr}_y\\mathrm{CuO}_4$, therefore, $y=2x$ and the same endpoint is $y=0.35$. For example, site fraction $x=0.075$ corresponds to $y=0.15$, or $\\mathrm{La}_{1.85}\\mathrm{Sr}_{0.15}\\mathrm{CuO}_4$. This is a composition conversion, not a measured hole density or an experimentally selected optimum. The publisher title and abstract were checked; full methods remain outside this review.","evidenceType":"experiment","sourceIds":["source-5030a5999bf0420a"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Publisher title/abstract reread; full methods unavailable. Exact formula expansion checked locally.","sourceRelationship":"mixed-source-and-local-derivation","derivationNote":"The source title/abstract supplies the formula and range; the factor of two and worked 0.075 example are local stoichiometric arithmetic, not a carrier measurement."},{"id":"scwiki-e2-claim-mathematical-assumptions-1","sectionId":"mathematical-assumptions","statement":"Charge neutrality is useful bookkeeping under explicit ionic assumptions. Taking La/Nd as $3+$, Sr as $2+$, Ce as $4+$ and O as $2-$ gives formal average Cu valence $2+x+2\\delta$ in $\\mathrm{La}_{2-x}\\mathrm{Sr}_x\\mathrm{CuO}_{4+\\delta}$, and $2-x-2y$ in $\\mathrm{Nd}_{2-x}\\mathrm{Ce}_x\\mathrm{CuO}_{4-y}$. Stoichiometric infinite-layer $\\mathrm{Nd}_{1-x}\\mathrm{Sr}_x\\mathrm{NiO}_2$ gives formal Ni valence $1+x$. These balances do not locate holes among orbitals or establish an itinerant carrier density. Oxygen deviations and compensating defects change the balance.","evidenceType":"theory","sourceIds":["source-5030a5999bf0420a","source-c636cc691b7ff013"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected primary passages, figures and bounded algebra; full scientific acceptance remains open."},{"id":"scwiki-e2-claim-mathematical-assumptions-2","sectionId":"mathematical-assumptions","statement":"Even the elementary weak-field two-band Drude model yields $R_H=(n_h\\mu_h^2-n_e\\mu_e^2)/[e(n_h\\mu_h+n_e\\mu_e)^2]$, with $e>0$. Mobilities weight the response. For compensation, $n_e=n_h=n$, this becomes $(\\mu_h-\\mu_e)/[en(\\mu_h+\\mu_e)]$; its sign can reverse at fixed density. This illustrative identity is not a fit to correlated transport. Kasahara explicitly discusses why that simple model fails for the magnitude of the observed Hall response.","evidenceType":"theory","sourceIds":["source-b9e77d2ee024ff3b"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected primary passages, figures and bounded algebra; full scientific acceptance remains open."},{"id":"scwiki-e2-claim-mathematical-assumptions-3","sectionId":"mathematical-assumptions","statement":"Liang's empirical YBCO calibration uses $p=11.491u+5.17\\times10^9u^6$, $u=1-c/c_0$, with $c_0=1.18447\\,\\mathrm{nm}$ and $c$ measured at 22°C. It depends on chain-order assumptions and reference compositions. The relation $T_c/T_{c,\\max}=1-82.6(p-0.16)^2$ has two algebraic branches and fails near the material's suppressed one-eighth region. Neither expression is a universal oxygen-to-hole conversion; a fitted lattice parameter and a directly measured carrier density are different evidence.","evidenceType":"theory","sourceIds":["source-e24ef58054ac9b71"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected primary passages, figures and bounded algebra; full scientific acceptance remains open."},{"id":"scwiki-e2-claim-experimental-criteria-1","sectionId":"experimental-criteria","statement":"Measure composition on the specimens whose transitions are compared. Ni's Co-substituted Ba122 series used wavelength-dispersive spectroscopy (WDS): actual Co fraction was about 0.74 times the nominal fraction for that growth series. A nominal 0.10 batch averaged approximately 0.074. Its phase diagram distinguishes resistance, magnetization and heat capacity. Resistive offset means maximum-slope extrapolation to zero, rather than an independently established instrumental zero. The reported maximum near 23 K spans measured fractions approximately 0.058–0.074.","evidenceType":"experiment","sourceIds":["source-cf1286d7701502f2"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected primary passages, figures and bounded algebra; full scientific acceptance remains open."},{"id":"scwiki-e2-claim-experimental-criteria-2","sectionId":"experimental-criteria","statement":"For YBCO, oxygen content alone omits chain configuration. Liang determined oxygen content by weight analysis with a stated precision of $\\pm0.002$ in $x$; that is not an uncertainty in planar hole concentration $p$. The chain-ordered ortho-II, ortho-VIII and ortho-III preparations use $x=0.50$, $0.67$ and $0.75$. The superconducting $T_c$ is the midpoint of field-cooled magnetization in 1 Oe along the c axis; the lattice parameter is measured separately at 22°C.\n\nThe fully oxygenated reference has $T_c=85.3$ K. With the paper's $T_{c,\\max}=94.3$ K, algebraic inversion of the empirical parabola gives $p\\approx0.126$ or $0.194$. The paper uses the latter because it treats that reference as slightly overdoped. Temperature alone does not choose a branch; the lower algebraic root also lies near the one-eighth region where the uncorrected calibration is unreliable. The quoted $p$ is a model-dependent estimate, not a directly measured carrier count. Record oxygen/order history, calibration assumptions and uncertainty with the result.","evidenceType":"experiment","sourceIds":["source-e24ef58054ac9b71"],"conditions":"YBCO author-v1 calibration; weight-analysis precision belongs to oxygen x, not plane doping p. The slightly overdoped branch and chain-order assumptions are required.","verificationScope":"Selected author v1 pp.1–3 read; pp.2–3 visually inspected. Reference branch arithmetic checked; no raw magnetization/lattice refit or final-version equivalence claimed.","sourceRelationship":"mixed-source-and-local-derivation","derivationNote":"Liang author v1 pp.2–3 supplies oxygen precision, ordered preparations, probe criteria, Tc,max and the selected overdoped reference. The second algebraic root is calculated here to expose branch ambiguity; it is not a competing measured hole concentration."},{"id":"scwiki-e2-claim-experimental-criteria-3","sectionId":"experimental-criteria","statement":"In the P-substituted Ba122 author manuscript, composition was measured by energy-dispersive X-ray analysis. Figure 2 separates onset and zero-resistivity temperatures. Version 3 reports zero resistance from $x\\geq0.20$ and a maximum transition around 31 K, while observing a narrow transition at $x=0.33$. Do not turn “isovalent” into proof of unchanged Fermi surfaces, scattering or carrier populations. Nor does a similar phase diagram make chemical substitution physically identical to applied pressure.","evidenceType":"experiment","sourceIds":["source-b9e77d2ee024ff3b"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected primary passages, figures and bounded algebra; full scientific acceptance remains open."},{"id":"scwiki-e2-claim-experimental-criteria-4","sectionId":"experimental-criteria","statement":"Li's nickelate study uses 8–10 nm films on SrTiO3, capped and reduced from perovskite precursors. The reported preparation couples approximately 25 nm caps to 280°C for 4–6 h and approximately 2 nm caps to 260°C for 1–3 h. The source reports no notable differences between those cap groups at the same composition; these are its preparation conditions, not a universal synthesis prescription. The in-plane lattice constants are locked to the substrate at 3.91 Å in the checked measurements.\n\nThe sampled superconducting compositions are $x=0.15$, $0.175$, $0.20$ and $0.225$, inside the reported $0.125<x<0.25$ dome. Figure 2 defines $T_{c,10\\%R}$ and $T_{c,90\\%R}$ using 10% and 90% of each sample's resistance at 20 K. Symbols average multiple samples at the same $x$; error bars span the observed extrema, not a stated standard error or confidence interval. The comparison cuprate curve uses a 50% criterion. These temperatures cannot be pooled as one uniform definition of $T_c$.\n\nFor the sampled $x=0$, $0.10$, $0.125$ and $0.25$ films, the caption reports no superconducting sign down to below 50 mK. That is a finite measurement bound, not an exact zero transition temperature or a precisely located continuous phase boundary. The 20 K resistance reference is also not a transition. No numerical nickelate $T_c$ is digitized here, and the small Hall response remains interpreted through multiple bands.","evidenceType":"experiment","sourceIds":["source-c636cc691b7ff013"],"conditions":"Specific capped, reduced thin-film series on SrTiO3. Preserve sampled composition, specimen, criterion, reference temperature and range meaning; below-50-mK bound is not Tc=0.","verificationScope":"Selected author v2 pp.2–4 and p.12 read; pp.3/12 visually inspected. Full supplement, final comparison, raw measurements and continuous-boundary inference remain outside scope.","sourceRelationship":"direct-support","derivationNote":"Li author v2 pp.3–4 and Fig.2/p.12 distinguish cap-dependent preparation, substrate constraint, sample selection, resistance fractions and extrema. No new curve fit or boundary interpolation."},{"id":"scwiki-e2-claim-limits-and-disputes-1","sectionId":"limits-and-disputes","statement":"Sidis's author manuscript compares reported 3% Ni-substituted YBCO ($T_c=80$ K) with 1% Zn-substituted YBCO ($T_c=78$ K). The samples were chosen for similar transition temperatures, not equal impurity fractions. Their reported impurity ratios were inferred from the suppression of $T_c$ relative to the pure system; Ni content and homogeneity were additionally checked by microprobe. A corresponding independent Zn assay is not stated in the selected passage. These two samples alone do not determine an independent dose-response slope or a universal impurity ranking.\n\nIn the checked 20–50 meV neutron window, the Ni sample's normal-state response has a finite detection upper limit; an undetected signal is not exact zero. The low-temperature-minus-above-$T_c$ spectra peak near 35 meV for Ni and 38 meV for Zn. Those are neutron spectral energies, not transition temperatures or direct gap measurements. The manuscript's Figure 2 caption reverses the sample order relative to its panel labels and surrounding text: the panels label (a) 3% Ni and (b) 1% Zn. This account follows the panel labels and text together and flags the disagreement; final-version comparison and raw background subtraction remain unchecked. The proposed impurity scenarios do not uniquely establish a pairing mechanism.","evidenceType":"editorial-analysis","sourceIds":["source-9fd0a423b4e4de89"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected Ni v1 pp.4–7/Fig.8, Kasahara v1/v3 pp.1–2, or Sidis v1 pp.1–3 as cited; original figure pixels inspected. No final-version or raw-data equivalence claimed.","sourceRelationship":"context-for-editorial-analysis","derivationNote":"Primary author passages and displayed figure labels are compared here. Source ambiguity remains explicit; the comparison does not replace missing specimen provenance or establish a unique mechanism."},{"id":"scwiki-e2-claim-limits-and-disputes-2","sectionId":"limits-and-disputes","statement":"Keep author versions and specimen labels attached to every value. Ni's v1 specific-heat paragraph and Figure 8 label $x=0.078$, while its WDS example averages $x=0.074$ and its phase-summary maximum spans $0.058\\leq x\\leq0.074$. Their numerical proximity does not establish one specimen identity; this review does not silently replace 0.078 with 0.074.\n\nKasahara's author versions report different sampled ranges and zero-resistivity thresholds:\n\n| Author version | Composition range stated | Zero resistivity reported from |\n| --- | --- | --- |\n| v1, 27 May 2009 | $0\\leq x\\leq0.54$ | $x\\geq0.16$ |\n| v3, 9 February 2010 | $0\\leq x\\leq0.71$ | $x\\geq0.20$ |\n\nThese are version-specific reports, not a statistical uncertainty interval or a continuously measured phase boundary. Version 3 Figure 2 labels the onset curve above the zero-resistivity curve, but its caption assigns their colors in the opposite order. Read the criteria and labels together; no precise onset/zero value is digitized here. Both versions caution that superconductivity in the low-composition coexistence region may lack bulk character. Neither a zero-resistance path nor simultaneous anomalies alone prove homogeneous microscopic coexistence. Full journal-version comparison and raw-data reproduction remain open.","evidenceType":"editorial-analysis","sourceIds":["source-cf1286d7701502f2","source-b9e77d2ee024ff3b"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected Ni v1 pp.4–7/Fig.8, Kasahara v1/v3 pp.1–2, or Sidis v1 pp.1–3 as cited; original figure pixels inspected. No final-version or raw-data equivalence claimed.","sourceRelationship":"context-for-editorial-analysis","derivationNote":"Primary author passages and displayed figure labels are compared here. Source ambiguity remains explicit; the comparison does not replace missing specimen provenance or establish a unique mechanism."},{"id":"scwiki-e2-claim-limits-and-disputes-3","sectionId":"limits-and-disputes","statement":"A dome does not establish a unique pairing mechanism, homogeneous microscopic coexistence or a universal optimal carrier concentration. The nickelate manuscript notes sample-to-sample resistivity variations associated with microstructure and does not establish the origin of its small dip within the dome. Preserve that uncertainty; numerical resemblance to a cuprate anomaly is not an ordering measurement.","evidenceType":"experiment","sourceIds":["source-c636cc691b7ff013"],"conditions":"Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.","verificationScope":"Selected primary passages, figures and bounded algebra; full scientific acceptance remains open."},{"id":"scwiki-e2-claim-discovery-implications-1","sectionId":"discovery-implications","statement":"Compare the quantities before comparing the domes:\n\n| Reported quantity | Preserve in a reusable record | Do not substitute |\n| --- | --- | --- |\n| YBCO oxygen $x$ | Weight-analysis precision, chain-order preparation and specimen | Direct planar hole concentration $p$ |\n| YBCO lattice calibration | 22°C lattice measurement, empirical model and chosen branch | An independent carrier-density measurement |\n| Nickelate 10% and 90% resistance thresholds | Each fraction and the same sample's 20 K reference | Cuprate 50% thresholds or magnetic midpoints |\n| Nickelate figure error bars | Sample extrema at fixed composition | Standard error or a stated confidence interval |\n| No transition observed down to below 50 mK | Sampled compositions and the reported measurement bound | An exact $T_c=0$ or a continuous phase boundary |\n\nThis table is an editorial comparison of the checked experiments. Keep nominal composition, measured composition, formal valence and transport-model parameters separate; link each value to a specimen, preparation, probe and source version. Reduction, annealing or a static measurement alone is not this review's evidence of thermodynamic equilibrium. For the YBCO reference and nickelate records, equilibrium remains **unknown** at the checked source scope; this does not assert nonequilibrium. The calculations verify only branch arithmetic; they do not optimize a synthesis or validate a carrier-density calibration.","evidenceType":"editorial-analysis","sourceIds":["source-e24ef58054ac9b71","source-c636cc691b7ff013"],"conditions":"Keep the experiment, criterion, composition definition, calibration branch and meaning of an uncertainty attached to the reported value.","verificationScope":"Selected source text and four source pages visually checked; author interpretation only, not independent scientific acceptance.","sourceRelationship":"context-for-editorial-analysis","derivationNote":"Editorial reuse rules derived from contrasting Liang author v1 pp.2–3 and Li author v2 pp.3–4/12. No additional measurement, independent calibration or equilibrium determination."}],"corrections":[{"id":"scwiki-e2-correction-1","description":"Corrected the inherited factor-of-two composition convention: Takagi uses (La1-xSrx)2CuO4 up to x = 0.175, equivalent to La2-ySryCuO4 up to y = 0.35.","sourceId":"source-5030a5999bf0420a","scope":"Original publisher title/abstract and independent formula-expansion algebra; full methods unavailable.","originalSourceLines":[],"targetSectionId":"scope"},{"id":"scwiki-e2-correction-observation-and-equilibrium","description":"Two reviewed YBCO/nickelate records no longer assert an unverified equilibrium state. Nickelate sample extrema and the below-50-mK non-observation bound are explicit; the added measurement record has null Tc and no invented exact base temperature.","sourceId":"source-c636cc691b7ff013","scope":"Scoped source-interpretation correction; no new experiment or phase determination."},{"id":"scwiki-e2-correction-version-and-impurity-scope","description":"Version-specific Ba122 thresholds and specimen labels remain distinct. Sidis author-v1 evidence replaces the abstract-only boundary, preserving unequal dose, inferred composition, finite detection and Figure 2 caption conflict. Two additional equilibrium assertions are withheld.","sourceId":"source-9fd0a423b4e4de89","scope":"Scoped author interpretation; two reported transition records retain unspecified criterion and unknown equilibrium."}],"equationChecks":[{"targetSectionId":"scope","tex":"(La_{1-x}Sr_x)_2CuO_4=La_{2-2x}Sr_{2x}CuO_4","check":"Four substitution fractions including x = 0.175: equivalent La and Sr counts."},{"targetSectionId":"mathematical-assumptions","tex":"R_H=\\frac{n_h\\mu_h^2-n_e\\mu_e^2}{e(n_h\\mu_h+n_e\\mu_e)^2}","check":"Six compensated-model comparisons and a sign reversal at fixed density; illustrative model, not a fit."}],"materialCases":[{"id":"scwiki-e2-material-1","formula":"Ba(Fe1−xCox)2As2","sample":"Ni WDS fractions approximately 0.058–0.074; series summary","recordType":"experiment","reportedTemperatureK":23,"tcK":23,"temperatureKind":"transition","temperatureNote":"Approximate series maximum; no one specimen or common onset/zero criterion is assigned. Specific-heat 0.078/0.074 mismatch remains unresolved. Thermodynamic equilibrium is unverified in this scoped review.","criterion":"series-maximum-multiple-criteria","pressureRegime":"ambient","pressureGPa":null,"equilibrium":"unknown","probe":"Resistance, magnetization and heat capacity phase diagram","sourceId":"source-cf1286d7701502f2","aliases":["iron-based","iron based superconductors"]},{"id":"scwiki-e2-material-2","formula":"YBa2Cu3O7","sample":"Liang fully oxygenated reference","recordType":"experiment","reportedTemperatureK":85.3,"tcK":85.3,"temperatureKind":"transition","temperatureNote":"Calibration reference; hole count inferred through an empirical overdoped branch, not directly measured. Thermodynamic equilibrium is unverified in the checked source scope.","criterion":"field-cooled-magnetization-midpoint","pressureRegime":"ambient","pressureGPa":null,"equilibrium":"unknown","probe":"1 Oe along c","sourceId":"source-e24ef58054ac9b71","aliases":["cuprate","cuprates"]},{"id":"scwiki-e2-material-3","formula":"BaFe2(As1−xPx)2","sample":"Kasahara author v3 phase-summary maximum","recordType":"experiment","reportedTemperatureK":31,"tcK":31,"temperatureKind":"transition","temperatureNote":"Maximum around x = 0.26 in author text; exact onset/zero assignment and final-version comparison remain open. Thermodynamic equilibrium is unverified in this scoped review.","criterion":"transition-summary-unspecified","pressureRegime":"ambient","pressureGPa":null,"equilibrium":"unknown","probe":"Transport phase diagram with separate onset and zero curves","sourceId":"source-b9e77d2ee024ff3b","aliases":["iron-based","iron based superconductors"]},{"id":"scwiki-e2-material-4","formula":"Nd1−xSrxNiO2","sample":"Li films: resistance normalization across composition series","recordType":"experiment","reportedTemperatureK":20,"tcK":null,"temperatureKind":"normal-state","temperatureNote":"Reference temperature for 10% and 90% resistive thresholds; not Tc. No numerical transition temperature digitized from the figure. Thermodynamic equilibrium is unverified in the checked source scope.","criterion":"resistance-normalization-temperature","pressureRegime":"ambient","pressureGPa":null,"equilibrium":"unknown","probe":"Hall-bar magnetotransport","sourceId":"source-c636cc691b7ff013","aliases":["nickelate","nickelates"]},{"id":"scwiki-e2-material-5","formula":"Nd1−xSrxNiO2","sample":"Li author v2 films at sampled x = 0, 0.10, 0.125 and 0.25","recordType":"experiment","reportedTemperatureK":null,"tcK":null,"temperatureKind":"measurement","temperatureNote":"Figure 2 reports no superconducting sign down to below 50 mK. The exact base temperature is not specified in this caption; 50 mK is a bound, not a measured Tc or a claim of Tc = 0. Thermodynamic equilibrium is unverified.","criterion":"no-transition-observed-within-measurement-range","pressureRegime":"ambient","pressureGPa":null,"equilibrium":"unknown","probe":"Thin-film resistance; sampled-composition non-observation","sourceId":"source-c636cc691b7ff013","aliases":["nickelate","nickelates"]},{"id":"scwiki-e2-material-6","formula":"YBa2(Cu0.97Ni0.03)3O7","sample":"Sidis author v1 3% Ni YBCO, selected for Tc close to the other impurity sample","recordType":"experiment","reportedTemperatureK":80,"tcK":80,"temperatureKind":"transition","temperatureNote":"Reported sample Tc; onset/midpoint/zero criterion unspecified in checked passages. Impurity fraction inferred from Tc suppression; additional microprobe check is stated for Ni only. Unequal doses, no independent two-point dose-response slope. Thermodynamic equilibrium unverified.","criterion":"transition-summary-unspecified","pressureRegime":"ambient","pressureGPa":null,"equilibrium":"unknown","probe":"Reported sample transition temperature in a comparative inelastic-neutron study; neutron spectral energy is a separate quantity","sourceId":"source-9fd0a423b4e4de89","aliases":["cuprate","cuprates","YBCO","Ni-substituted YBCO"]},{"id":"scwiki-e2-material-7","formula":"YBa2(Cu0.99Zn0.01)3O7","sample":"Sidis author v1 1% Zn YBCO, selected for Tc close to the other impurity sample","recordType":"experiment","reportedTemperatureK":78,"tcK":78,"temperatureKind":"transition","temperatureNote":"Reported sample Tc; onset/midpoint/zero criterion unspecified in checked passages. Impurity fraction inferred from Tc suppression; additional microprobe check is stated for Ni only. Unequal doses, no independent two-point dose-response slope. Thermodynamic equilibrium unverified.","criterion":"transition-summary-unspecified","pressureRegime":"ambient","pressureGPa":null,"equilibrium":"unknown","probe":"Reported sample transition temperature in a comparative inelastic-neutron study; neutron spectral energy is a separate quantity","sourceId":"source-9fd0a423b4e4de89","aliases":["cuprate","cuprates","YBCO","Zn-substituted YBCO"]}],"body":"## Scope\n\nChemical doping changes a material's composition; it does not supply a universal carrier counter. Distinguish the starting mixture, measured site occupancy, formal ionic charge and mobile carriers. Substitution can also change disorder, bond geometry and competing order. Oxygen removal or chain ordering adds another control variable. A superconducting dome is therefore a relationship among specified samples and criteria, not a recipe transferable between families. [R2](#ref-source-e24ef58054ac9b71) [R3](#ref-source-cf1286d7701502f2) [R4](#ref-source-b9e77d2ee024ff3b) [R5](#ref-source-c636cc691b7ff013)\n\nNotation matters even before measurement. Takagi's 1989 abstract uses $(\\mathrm{La}_{1-x}\\mathrm{Sr}_x)_2\\mathrm{CuO}_4$ through $x=0.175$. Expanding the formula gives $\\mathrm{La}_{2-2x}\\mathrm{Sr}_{2x}\\mathrm{CuO}_4$: in $\\mathrm{La}_{2-y}\\mathrm{Sr}_y\\mathrm{CuO}_4$, therefore, $y=2x$ and the same endpoint is $y=0.35$. For example, site fraction $x=0.075$ corresponds to $y=0.15$, or $\\mathrm{La}_{1.85}\\mathrm{Sr}_{0.15}\\mathrm{CuO}_4$. This is a composition conversion, not a measured hole density or an experimentally selected optimum. The publisher title and abstract were checked; full methods remain outside this review. [R1](#ref-source-5030a5999bf0420a)\n\n## Mathematical assumptions\n\nCharge neutrality is useful bookkeeping under explicit ionic assumptions. Taking La/Nd as $3+$, Sr as $2+$, Ce as $4+$ and O as $2-$ gives formal average Cu valence $2+x+2\\delta$ in $\\mathrm{La}_{2-x}\\mathrm{Sr}_x\\mathrm{CuO}_{4+\\delta}$, and $2-x-2y$ in $\\mathrm{Nd}_{2-x}\\mathrm{Ce}_x\\mathrm{CuO}_{4-y}$. Stoichiometric infinite-layer $\\mathrm{Nd}_{1-x}\\mathrm{Sr}_x\\mathrm{NiO}_2$ gives formal Ni valence $1+x$. These balances do not locate holes among orbitals or establish an itinerant carrier density. Oxygen deviations and compensating defects change the balance. [R1](#ref-source-5030a5999bf0420a) [R5](#ref-source-c636cc691b7ff013)\n\nEven the elementary weak-field two-band Drude model yields $R_H=(n_h\\mu_h^2-n_e\\mu_e^2)/[e(n_h\\mu_h+n_e\\mu_e)^2]$, with $e>0$. Mobilities weight the response. For compensation, $n_e=n_h=n$, this becomes $(\\mu_h-\\mu_e)/[en(\\mu_h+\\mu_e)]$; its sign can reverse at fixed density. This illustrative identity is not a fit to correlated transport. Kasahara explicitly discusses why that simple model fails for the magnitude of the observed Hall response. [R4](#ref-source-b9e77d2ee024ff3b)\n\nLiang's empirical YBCO calibration uses $p=11.491u+5.17\\times10^9u^6$, $u=1-c/c_0$, with $c_0=1.18447\\,\\mathrm{nm}$ and $c$ measured at 22°C. It depends on chain-order assumptions and reference compositions. The relation $T_c/T_{c,\\max}=1-82.6(p-0.16)^2$ has two algebraic branches and fails near the material's suppressed one-eighth region. Neither expression is a universal oxygen-to-hole conversion; a fitted lattice parameter and a directly measured carrier density are different evidence. [R2](#ref-source-e24ef58054ac9b71)\n\n## Experimental criteria\n\nMeasure composition on the specimens whose transitions are compared. Ni's Co-substituted Ba122 series used wavelength-dispersive spectroscopy (WDS): actual Co fraction was about 0.74 times the nominal fraction for that growth series. A nominal 0.10 batch averaged approximately 0.074. Its phase diagram distinguishes resistance, magnetization and heat capacity. Resistive offset means maximum-slope extrapolation to zero, rather than an independently established instrumental zero. The reported maximum near 23 K spans measured fractions approximately 0.058–0.074. [R3](#ref-source-cf1286d7701502f2)\n\nFor YBCO, oxygen content alone omits chain configuration. Liang determined oxygen content by weight analysis with a stated precision of $\\pm0.002$ in $x$; that is not an uncertainty in planar hole concentration $p$. The chain-ordered ortho-II, ortho-VIII and ortho-III preparations use $x=0.50$, $0.67$ and $0.75$. The superconducting $T_c$ is the midpoint of field-cooled magnetization in 1 Oe along the c axis; the lattice parameter is measured separately at 22°C.\n\nThe fully oxygenated reference has $T_c=85.3$ K. With the paper's $T_{c,\\max}=94.3$ K, algebraic inversion of the empirical parabola gives $p\\approx0.126$ or $0.194$. The paper uses the latter because it treats that reference as slightly overdoped. Temperature alone does not choose a branch; the lower algebraic root also lies near the one-eighth region where the uncorrected calibration is unreliable. The quoted $p$ is a model-dependent estimate, not a directly measured carrier count. Record oxygen/order history, calibration assumptions and uncertainty with the result. [R2](#ref-source-e24ef58054ac9b71)\n\nIn the P-substituted Ba122 author manuscript, composition was measured by energy-dispersive X-ray analysis. Figure 2 separates onset and zero-resistivity temperatures. Version 3 reports zero resistance from $x\\geq0.20$ and a maximum transition around 31 K, while observing a narrow transition at $x=0.33$. Do not turn “isovalent” into proof of unchanged Fermi surfaces, scattering or carrier populations. Nor does a similar phase diagram make chemical substitution physically identical to applied pressure. [R4](#ref-source-b9e77d2ee024ff3b)\n\nLi's nickelate study uses 8–10 nm films on SrTiO3, capped and reduced from perovskite precursors. The reported preparation couples approximately 25 nm caps to 280°C for 4–6 h and approximately 2 nm caps to 260°C for 1–3 h. The source reports no notable differences between those cap groups at the same composition; these are its preparation conditions, not a universal synthesis prescription. The in-plane lattice constants are locked to the substrate at 3.91 Å in the checked measurements.\n\nThe sampled superconducting compositions are $x=0.15$, $0.175$, $0.20$ and $0.225$, inside the reported $0.125<x<0.25$ dome. Figure 2 defines $T_{c,10\\%R}$ and $T_{c,90\\%R}$ using 10% and 90% of each sample's resistance at 20 K. Symbols average multiple samples at the same $x$; error bars span the observed extrema, not a stated standard error or confidence interval. The comparison cuprate curve uses a 50% criterion. These temperatures cannot be pooled as one uniform definition of $T_c$.\n\nFor the sampled $x=0$, $0.10$, $0.125$ and $0.25$ films, the caption reports no superconducting sign down to below 50 mK. That is a finite measurement bound, not an exact zero transition temperature or a precisely located continuous phase boundary. The 20 K resistance reference is also not a transition. No numerical nickelate $T_c$ is digitized here, and the small Hall response remains interpreted through multiple bands. [R5](#ref-source-c636cc691b7ff013)\n\n## Limits and disputes\n\nSidis's author manuscript compares reported 3% Ni-substituted YBCO ($T_c=80$ K) with 1% Zn-substituted YBCO ($T_c=78$ K). The samples were chosen for similar transition temperatures, not equal impurity fractions. Their reported impurity ratios were inferred from the suppression of $T_c$ relative to the pure system; Ni content and homogeneity were additionally checked by microprobe. A corresponding independent Zn assay is not stated in the selected passage. These two samples alone do not determine an independent dose-response slope or a universal impurity ranking.\n\nIn the checked 20–50 meV neutron window, the Ni sample's normal-state response has a finite detection upper limit; an undetected signal is not exact zero. The low-temperature-minus-above-$T_c$ spectra peak near 35 meV for Ni and 38 meV for Zn. Those are neutron spectral energies, not transition temperatures or direct gap measurements. The manuscript's Figure 2 caption reverses the sample order relative to its panel labels and surrounding text: the panels label (a) 3% Ni and (b) 1% Zn. This account follows the panel labels and text together and flags the disagreement; final-version comparison and raw background subtraction remain unchecked. The proposed impurity scenarios do not uniquely establish a pairing mechanism. [R6](#ref-source-9fd0a423b4e4de89)\n\nKeep author versions and specimen labels attached to every value. Ni's v1 specific-heat paragraph and Figure 8 label $x=0.078$, while its WDS example averages $x=0.074$ and its phase-summary maximum spans $0.058\\leq x\\leq0.074$. Their numerical proximity does not establish one specimen identity; this review does not silently replace 0.078 with 0.074.\n\nKasahara's author versions report different sampled ranges and zero-resistivity thresholds:\n\n| Author version | Composition range stated | Zero resistivity reported from |\n| --- | --- | --- |\n| v1, 27 May 2009 | $0\\leq x\\leq0.54$ | $x\\geq0.16$ |\n| v3, 9 February 2010 | $0\\leq x\\leq0.71$ | $x\\geq0.20$ |\n\nThese are version-specific reports, not a statistical uncertainty interval or a continuously measured phase boundary. Version 3 Figure 2 labels the onset curve above the zero-resistivity curve, but its caption assigns their colors in the opposite order. Read the criteria and labels together; no precise onset/zero value is digitized here. Both versions caution that superconductivity in the low-composition coexistence region may lack bulk character. Neither a zero-resistance path nor simultaneous anomalies alone prove homogeneous microscopic coexistence. Full journal-version comparison and raw-data reproduction remain open. [R3](#ref-source-cf1286d7701502f2) [R4](#ref-source-b9e77d2ee024ff3b)\n\nA dome does not establish a unique pairing mechanism, homogeneous microscopic coexistence or a universal optimal carrier concentration. The nickelate manuscript notes sample-to-sample resistivity variations associated with microstructure and does not establish the origin of its small dip within the dome. Preserve that uncertainty; numerical resemblance to a cuprate anomaly is not an ordering measurement. [R5](#ref-source-c636cc691b7ff013)\n\n## Discovery implications\n\nCompare the quantities before comparing the domes:\n\n| Reported quantity | Preserve in a reusable record | Do not substitute |\n| --- | --- | --- |\n| YBCO oxygen $x$ | Weight-analysis precision, chain-order preparation and specimen | Direct planar hole concentration $p$ |\n| YBCO lattice calibration | 22°C lattice measurement, empirical model and chosen branch | An independent carrier-density measurement |\n| Nickelate 10% and 90% resistance thresholds | Each fraction and the same sample's 20 K reference | Cuprate 50% thresholds or magnetic midpoints |\n| Nickelate figure error bars | Sample extrema at fixed composition | Standard error or a stated confidence interval |\n| No transition observed down to below 50 mK | Sampled compositions and the reported measurement bound | An exact $T_c=0$ or a continuous phase boundary |\n\nThis table is an editorial comparison of the checked experiments. Keep nominal composition, measured composition, formal valence and transport-model parameters separate; link each value to a specimen, preparation, probe and source version. Reduction, annealing or a static measurement alone is not this review's evidence of thermodynamic equilibrium. For the YBCO reference and nickelate records, equilibrium remains **unknown** at the checked source scope; this does not assert nonequilibrium. The calculations verify only branch arithmetic; they do not optimize a synthesis or validate a carrier-density calibration. [R2](#ref-source-e24ef58054ac9b71) [R5](#ref-source-c636cc691b7ff013)\n\n## Related topics\n\nCompare [cuprates](/scwiki/cuprates), [iron-based superconductors](/scwiki/iron-based-superconductors), [nickelates](/scwiki/nickelates), [pressure tuning](/scwiki/pressure-tuning), [zero resistance](/scwiki/zero-resistance) and [specific heat](/scwiki/specific-heat-jump).","revision":"a36b9df354e399f0a31b","sections":[{"id":"scope","title":"Scope","markdown":"## Scope\n\nChemical doping changes a material's composition; it does not supply a universal carrier counter. Distinguish the starting mixture, measured site occupancy, formal ionic charge and mobile carriers. Substitution can also change disorder, bond geometry and competing order. Oxygen removal or chain ordering adds another control variable. A superconducting dome is therefore a relationship among specified samples and criteria, not a recipe transferable between families. [R2](#ref-source-e24ef58054ac9b71) [R3](#ref-source-cf1286d7701502f2) [R4](#ref-source-b9e77d2ee024ff3b) [R5](#ref-source-c636cc691b7ff013)\n\nNotation matters even before measurement. Takagi's 1989 abstract uses $(\\mathrm{La}_{1-x}\\mathrm{Sr}_x)_2\\mathrm{CuO}_4$ through $x=0.175$. Expanding the formula gives $\\mathrm{La}_{2-2x}\\mathrm{Sr}_{2x}\\mathrm{CuO}_4$: in $\\mathrm{La}_{2-y}\\mathrm{Sr}_y\\mathrm{CuO}_4$, therefore, $y=2x$ and the same endpoint is $y=0.35$. For example, site fraction $x=0.075$ corresponds to $y=0.15$, or $\\mathrm{La}_{1.85}\\mathrm{Sr}_{0.15}\\mathrm{CuO}_4$. This is a composition conversion, not a measured hole density or an experimentally selected optimum. The publisher title and abstract were checked; full methods remain outside this review. [R1](#ref-source-5030a5999bf0420a)"},{"id":"mathematical-assumptions","title":"Mathematical assumptions","markdown":"## Mathematical assumptions\n\nCharge neutrality is useful bookkeeping under explicit ionic assumptions. Taking La/Nd as $3+$, Sr as $2+$, Ce as $4+$ and O as $2-$ gives formal average Cu valence $2+x+2\\delta$ in $\\mathrm{La}_{2-x}\\mathrm{Sr}_x\\mathrm{CuO}_{4+\\delta}$, and $2-x-2y$ in $\\mathrm{Nd}_{2-x}\\mathrm{Ce}_x\\mathrm{CuO}_{4-y}$. Stoichiometric infinite-layer $\\mathrm{Nd}_{1-x}\\mathrm{Sr}_x\\mathrm{NiO}_2$ gives formal Ni valence $1+x$. These balances do not locate holes among orbitals or establish an itinerant carrier density. Oxygen deviations and compensating defects change the balance. [R1](#ref-source-5030a5999bf0420a) [R5](#ref-source-c636cc691b7ff013)\n\nEven the elementary weak-field two-band Drude model yields $R_H=(n_h\\mu_h^2-n_e\\mu_e^2)/[e(n_h\\mu_h+n_e\\mu_e)^2]$, with $e>0$. Mobilities weight the response. For compensation, $n_e=n_h=n$, this becomes $(\\mu_h-\\mu_e)/[en(\\mu_h+\\mu_e)]$; its sign can reverse at fixed density. This illustrative identity is not a fit to correlated transport. Kasahara explicitly discusses why that simple model fails for the magnitude of the observed Hall response. [R4](#ref-source-b9e77d2ee024ff3b)\n\nLiang's empirical YBCO calibration uses $p=11.491u+5.17\\times10^9u^6$, $u=1-c/c_0$, with $c_0=1.18447\\,\\mathrm{nm}$ and $c$ measured at 22°C. It depends on chain-order assumptions and reference compositions. The relation $T_c/T_{c,\\max}=1-82.6(p-0.16)^2$ has two algebraic branches and fails near the material's suppressed one-eighth region. Neither expression is a universal oxygen-to-hole conversion; a fitted lattice parameter and a directly measured carrier density are different evidence. [R2](#ref-source-e24ef58054ac9b71)"},{"id":"experimental-criteria","title":"Experimental criteria","markdown":"## Experimental criteria\n\nMeasure composition on the specimens whose transitions are compared. Ni's Co-substituted Ba122 series used wavelength-dispersive spectroscopy (WDS): actual Co fraction was about 0.74 times the nominal fraction for that growth series. A nominal 0.10 batch averaged approximately 0.074. Its phase diagram distinguishes resistance, magnetization and heat capacity. Resistive offset means maximum-slope extrapolation to zero, rather than an independently established instrumental zero. The reported maximum near 23 K spans measured fractions approximately 0.058–0.074. [R3](#ref-source-cf1286d7701502f2)\n\nFor YBCO, oxygen content alone omits chain configuration. Liang determined oxygen content by weight analysis with a stated precision of $\\pm0.002$ in $x$; that is not an uncertainty in planar hole concentration $p$. The chain-ordered ortho-II, ortho-VIII and ortho-III preparations use $x=0.50$, $0.67$ and $0.75$. The superconducting $T_c$ is the midpoint of field-cooled magnetization in 1 Oe along the c axis; the lattice parameter is measured separately at 22°C.\n\nThe fully oxygenated reference has $T_c=85.3$ K. With the paper's $T_{c,\\max}=94.3$ K, algebraic inversion of the empirical parabola gives $p\\approx0.126$ or $0.194$. The paper uses the latter because it treats that reference as slightly overdoped. Temperature alone does not choose a branch; the lower algebraic root also lies near the one-eighth region where the uncorrected calibration is unreliable. The quoted $p$ is a model-dependent estimate, not a directly measured carrier count. Record oxygen/order history, calibration assumptions and uncertainty with the result. [R2](#ref-source-e24ef58054ac9b71)\n\nIn the P-substituted Ba122 author manuscript, composition was measured by energy-dispersive X-ray analysis. Figure 2 separates onset and zero-resistivity temperatures. Version 3 reports zero resistance from $x\\geq0.20$ and a maximum transition around 31 K, while observing a narrow transition at $x=0.33$. Do not turn “isovalent” into proof of unchanged Fermi surfaces, scattering or carrier populations. Nor does a similar phase diagram make chemical substitution physically identical to applied pressure. [R4](#ref-source-b9e77d2ee024ff3b)\n\nLi's nickelate study uses 8–10 nm films on SrTiO3, capped and reduced from perovskite precursors. The reported preparation couples approximately 25 nm caps to 280°C for 4–6 h and approximately 2 nm caps to 260°C for 1–3 h. The source reports no notable differences between those cap groups at the same composition; these are its preparation conditions, not a universal synthesis prescription. The in-plane lattice constants are locked to the substrate at 3.91 Å in the checked measurements.\n\nThe sampled superconducting compositions are $x=0.15$, $0.175$, $0.20$ and $0.225$, inside the reported $0.125<x<0.25$ dome. Figure 2 defines $T_{c,10\\%R}$ and $T_{c,90\\%R}$ using 10% and 90% of each sample's resistance at 20 K. Symbols average multiple samples at the same $x$; error bars span the observed extrema, not a stated standard error or confidence interval. The comparison cuprate curve uses a 50% criterion. These temperatures cannot be pooled as one uniform definition of $T_c$.\n\nFor the sampled $x=0$, $0.10$, $0.125$ and $0.25$ films, the caption reports no superconducting sign down to below 50 mK. That is a finite measurement bound, not an exact zero transition temperature or a precisely located continuous phase boundary. The 20 K resistance reference is also not a transition. No numerical nickelate $T_c$ is digitized here, and the small Hall response remains interpreted through multiple bands. [R5](#ref-source-c636cc691b7ff013)"},{"id":"limits-and-disputes","title":"Limits and disputes","markdown":"## Limits and disputes\n\nSidis's author manuscript compares reported 3% Ni-substituted YBCO ($T_c=80$ K) with 1% Zn-substituted YBCO ($T_c=78$ K). The samples were chosen for similar transition temperatures, not equal impurity fractions. Their reported impurity ratios were inferred from the suppression of $T_c$ relative to the pure system; Ni content and homogeneity were additionally checked by microprobe. A corresponding independent Zn assay is not stated in the selected passage. These two samples alone do not determine an independent dose-response slope or a universal impurity ranking.\n\nIn the checked 20–50 meV neutron window, the Ni sample's normal-state response has a finite detection upper limit; an undetected signal is not exact zero. The low-temperature-minus-above-$T_c$ spectra peak near 35 meV for Ni and 38 meV for Zn. Those are neutron spectral energies, not transition temperatures or direct gap measurements. The manuscript's Figure 2 caption reverses the sample order relative to its panel labels and surrounding text: the panels label (a) 3% Ni and (b) 1% Zn. This account follows the panel labels and text together and flags the disagreement; final-version comparison and raw background subtraction remain unchecked. The proposed impurity scenarios do not uniquely establish a pairing mechanism. [R6](#ref-source-9fd0a423b4e4de89)\n\nKeep author versions and specimen labels attached to every value. Ni's v1 specific-heat paragraph and Figure 8 label $x=0.078$, while its WDS example averages $x=0.074$ and its phase-summary maximum spans $0.058\\leq x\\leq0.074$. Their numerical proximity does not establish one specimen identity; this review does not silently replace 0.078 with 0.074.\n\nKasahara's author versions report different sampled ranges and zero-resistivity thresholds:\n\n| Author version | Composition range stated | Zero resistivity reported from |\n| --- | --- | --- |\n| v1, 27 May 2009 | $0\\leq x\\leq0.54$ | $x\\geq0.16$ |\n| v3, 9 February 2010 | $0\\leq x\\leq0.71$ | $x\\geq0.20$ |\n\nThese are version-specific reports, not a statistical uncertainty interval or a continuously measured phase boundary. Version 3 Figure 2 labels the onset curve above the zero-resistivity curve, but its caption assigns their colors in the opposite order. Read the criteria and labels together; no precise onset/zero value is digitized here. Both versions caution that superconductivity in the low-composition coexistence region may lack bulk character. Neither a zero-resistance path nor simultaneous anomalies alone prove homogeneous microscopic coexistence. Full journal-version comparison and raw-data reproduction remain open. [R3](#ref-source-cf1286d7701502f2) [R4](#ref-source-b9e77d2ee024ff3b)\n\nA dome does not establish a unique pairing mechanism, homogeneous microscopic coexistence or a universal optimal carrier concentration. The nickelate manuscript notes sample-to-sample resistivity variations associated with microstructure and does not establish the origin of its small dip within the dome. Preserve that uncertainty; numerical resemblance to a cuprate anomaly is not an ordering measurement. [R5](#ref-source-c636cc691b7ff013)"},{"id":"discovery-implications","title":"Discovery implications","markdown":"## Discovery implications\n\nCompare the quantities before comparing the domes:\n\n| Reported quantity | Preserve in a reusable record | Do not substitute |\n| --- | --- | --- |\n| YBCO oxygen $x$ | Weight-analysis precision, chain-order preparation and specimen | Direct planar hole concentration $p$ |\n| YBCO lattice calibration | 22°C lattice measurement, empirical model and chosen branch | An independent carrier-density measurement |\n| Nickelate 10% and 90% resistance thresholds | Each fraction and the same sample's 20 K reference | Cuprate 50% thresholds or magnetic midpoints |\n| Nickelate figure error bars | Sample extrema at fixed composition | Standard error or a stated confidence interval |\n| No transition observed down to below 50 mK | Sampled compositions and the reported measurement bound | An exact $T_c=0$ or a continuous phase boundary |\n\nThis table is an editorial comparison of the checked experiments. Keep nominal composition, measured composition, formal valence and transport-model parameters separate; link each value to a specimen, preparation, probe and source version. Reduction, annealing or a static measurement alone is not this review's evidence of thermodynamic equilibrium. For the YBCO reference and nickelate records, equilibrium remains **unknown** at the checked source scope; this does not assert nonequilibrium. The calculations verify only branch arithmetic; they do not optimize a synthesis or validate a carrier-density calibration. [R2](#ref-source-e24ef58054ac9b71) [R5](#ref-source-c636cc691b7ff013)"},{"id":"related-topics","title":"Related topics","markdown":"## Related topics\n\nCompare [cuprates](/scwiki/cuprates), [iron-based superconductors](/scwiki/iron-based-superconductors), [nickelates](/scwiki/nickelates), [pressure tuning](/scwiki/pressure-tuning), [zero resistance](/scwiki/zero-resistance) and [specific heat](/scwiki/specific-heat-jump)."},{"id":"material-cases","title":"Material cases","markdown":"## Material cases\n\nValues describe individual reports, not a ranking. Unknown means the checked source did not supply the field at this review scope.\n\n| Material and sample | Reported temperature | Criterion | Probe | Pressure | State | Evidence |\n|---|---|---|---|---|---|---|\n| Ba(Fe1−xCox)2As2 (aliases: iron-based, iron based superconductors); Ni WDS fractions approximately 0.058–0.074; series summary | 23 K; Approximate series maximum; no one specimen or common onset/zero criterion is assigned. Specific-heat 0.078/0.074 mismatch remains unresolved. Thermodynamic equilibrium is unverified in this scoped review. | transition; series-maximum-multiple-criteria | Resistance, magnetization and heat capacity phase diagram | ambient; unknown GPa | unknown | experiment; [source](#ref-source-cf1286d7701502f2) |\n| YBa2Cu3O7 (aliases: cuprate, cuprates); Liang fully oxygenated reference | 85.3 K; Calibration reference; hole count inferred through an empirical overdoped branch, not directly measured. Thermodynamic equilibrium is unverified in the checked source scope. | transition; field-cooled-magnetization-midpoint | 1 Oe along c | ambient; unknown GPa | unknown | experiment; [source](#ref-source-e24ef58054ac9b71) |\n| BaFe2(As1−xPx)2 (aliases: iron-based, iron based superconductors); Kasahara author v3 phase-summary maximum | 31 K; Maximum around x = 0.26 in author text; exact onset/zero assignment and final-version comparison remain open. Thermodynamic equilibrium is unverified in this scoped review. | transition; transition-summary-unspecified | Transport phase diagram with separate onset and zero curves | ambient; unknown GPa | unknown | experiment; [source](#ref-source-b9e77d2ee024ff3b) |\n| Nd1−xSrxNiO2 (aliases: nickelate, nickelates); Li films: resistance normalization across composition series | 20 K; Reference temperature for 10% and 90% resistive thresholds; not Tc. No numerical transition temperature digitized from the figure. Thermodynamic equilibrium is unverified in the checked source scope. | normal-state; resistance-normalization-temperature | Hall-bar magnetotransport | ambient; unknown GPa | unknown | experiment; [source](#ref-source-c636cc691b7ff013) |\n| Nd1−xSrxNiO2 (aliases: nickelate, nickelates); Li author v2 films at sampled x = 0, 0.10, 0.125 and 0.25 | Figure 2 reports no superconducting sign down to below 50 mK. The exact base temperature is not specified in this caption; 50 mK is a bound, not a measured Tc or a claim of Tc = 0. Thermodynamic equilibrium is unverified. | measurement; no-transition-observed-within-measurement-range | Thin-film resistance; sampled-composition non-observation | ambient; unknown GPa | unknown | experiment; [source](#ref-source-c636cc691b7ff013) |\n| YBa2(Cu0.97Ni0.03)3O7 (aliases: cuprate, cuprates, YBCO, Ni-substituted YBCO); Sidis author v1 3% Ni YBCO, selected for Tc close to the other impurity sample | 80 K; Reported sample Tc; onset/midpoint/zero criterion unspecified in checked passages. Impurity fraction inferred from Tc suppression; additional microprobe check is stated for Ni only. Unequal doses, no independent two-point dose-response slope. Thermodynamic equilibrium unverified. | transition; transition-summary-unspecified | Reported sample transition temperature in a comparative inelastic-neutron study; neutron spectral energy is a separate quantity | ambient; unknown GPa | unknown | experiment; [source](#ref-source-9fd0a423b4e4de89) |\n| YBa2(Cu0.99Zn0.01)3O7 (aliases: cuprate, cuprates, YBCO, Zn-substituted YBCO); Sidis author v1 1% Zn YBCO, selected for Tc close to the other impurity sample | 78 K; Reported sample Tc; onset/midpoint/zero criterion unspecified in checked passages. Impurity fraction inferred from Tc suppression; additional microprobe check is stated for Ni only. Unequal doses, no independent two-point dose-response slope. Thermodynamic equilibrium unverified. | transition; transition-summary-unspecified | Reported sample transition temperature in a comparative inelastic-neutron study; neutron spectral energy is a separate quantity | ambient; unknown GPa | unknown | experiment; [source](#ref-source-9fd0a423b4e4de89) |"}],"markdown":"# Chemical doping: composition, carriers and disorder\n\nSeparate nominal composition, measured site occupancy and mobile carriers when reading superconducting phase diagrams.\n\n## Scope\n\nChemical doping changes a material's composition; it does not supply a universal carrier counter. Distinguish the starting mixture, measured site occupancy, formal ionic charge and mobile carriers. Substitution can also change disorder, bond geometry and competing order. Oxygen removal or chain ordering adds another control variable. A superconducting dome is therefore a relationship among specified samples and criteria, not a recipe transferable between families. [R2](#ref-source-e24ef58054ac9b71) [R3](#ref-source-cf1286d7701502f2) [R4](#ref-source-b9e77d2ee024ff3b) [R5](#ref-source-c636cc691b7ff013)\n\nNotation matters even before measurement. Takagi's 1989 abstract uses $(\\mathrm{La}_{1-x}\\mathrm{Sr}_x)_2\\mathrm{CuO}_4$ through $x=0.175$. Expanding the formula gives $\\mathrm{La}_{2-2x}\\mathrm{Sr}_{2x}\\mathrm{CuO}_4$: in $\\mathrm{La}_{2-y}\\mathrm{Sr}_y\\mathrm{CuO}_4$, therefore, $y=2x$ and the same endpoint is $y=0.35$. For example, site fraction $x=0.075$ corresponds to $y=0.15$, or $\\mathrm{La}_{1.85}\\mathrm{Sr}_{0.15}\\mathrm{CuO}_4$. This is a composition conversion, not a measured hole density or an experimentally selected optimum. The publisher title and abstract were checked; full methods remain outside this review. [R1](#ref-source-5030a5999bf0420a)\n\n## Mathematical assumptions\n\nCharge neutrality is useful bookkeeping under explicit ionic assumptions. Taking La/Nd as $3+$, Sr as $2+$, Ce as $4+$ and O as $2-$ gives formal average Cu valence $2+x+2\\delta$ in $\\mathrm{La}_{2-x}\\mathrm{Sr}_x\\mathrm{CuO}_{4+\\delta}$, and $2-x-2y$ in $\\mathrm{Nd}_{2-x}\\mathrm{Ce}_x\\mathrm{CuO}_{4-y}$. Stoichiometric infinite-layer $\\mathrm{Nd}_{1-x}\\mathrm{Sr}_x\\mathrm{NiO}_2$ gives formal Ni valence $1+x$. These balances do not locate holes among orbitals or establish an itinerant carrier density. Oxygen deviations and compensating defects change the balance. [R1](#ref-source-5030a5999bf0420a) [R5](#ref-source-c636cc691b7ff013)\n\nEven the elementary weak-field two-band Drude model yields $R_H=(n_h\\mu_h^2-n_e\\mu_e^2)/[e(n_h\\mu_h+n_e\\mu_e)^2]$, with $e>0$. Mobilities weight the response. For compensation, $n_e=n_h=n$, this becomes $(\\mu_h-\\mu_e)/[en(\\mu_h+\\mu_e)]$; its sign can reverse at fixed density. This illustrative identity is not a fit to correlated transport. Kasahara explicitly discusses why that simple model fails for the magnitude of the observed Hall response. [R4](#ref-source-b9e77d2ee024ff3b)\n\nLiang's empirical YBCO calibration uses $p=11.491u+5.17\\times10^9u^6$, $u=1-c/c_0$, with $c_0=1.18447\\,\\mathrm{nm}$ and $c$ measured at 22°C. It depends on chain-order assumptions and reference compositions. The relation $T_c/T_{c,\\max}=1-82.6(p-0.16)^2$ has two algebraic branches and fails near the material's suppressed one-eighth region. Neither expression is a universal oxygen-to-hole conversion; a fitted lattice parameter and a directly measured carrier density are different evidence. [R2](#ref-source-e24ef58054ac9b71)\n\n## Experimental criteria\n\nMeasure composition on the specimens whose transitions are compared. Ni's Co-substituted Ba122 series used wavelength-dispersive spectroscopy (WDS): actual Co fraction was about 0.74 times the nominal fraction for that growth series. A nominal 0.10 batch averaged approximately 0.074. Its phase diagram distinguishes resistance, magnetization and heat capacity. Resistive offset means maximum-slope extrapolation to zero, rather than an independently established instrumental zero. The reported maximum near 23 K spans measured fractions approximately 0.058–0.074. [R3](#ref-source-cf1286d7701502f2)\n\nFor YBCO, oxygen content alone omits chain configuration. Liang determined oxygen content by weight analysis with a stated precision of $\\pm0.002$ in $x$; that is not an uncertainty in planar hole concentration $p$. The chain-ordered ortho-II, ortho-VIII and ortho-III preparations use $x=0.50$, $0.67$ and $0.75$. The superconducting $T_c$ is the midpoint of field-cooled magnetization in 1 Oe along the c axis; the lattice parameter is measured separately at 22°C.\n\nThe fully oxygenated reference has $T_c=85.3$ K. With the paper's $T_{c,\\max}=94.3$ K, algebraic inversion of the empirical parabola gives $p\\approx0.126$ or $0.194$. The paper uses the latter because it treats that reference as slightly overdoped. Temperature alone does not choose a branch; the lower algebraic root also lies near the one-eighth region where the uncorrected calibration is unreliable. The quoted $p$ is a model-dependent estimate, not a directly measured carrier count. Record oxygen/order history, calibration assumptions and uncertainty with the result. [R2](#ref-source-e24ef58054ac9b71)\n\nIn the P-substituted Ba122 author manuscript, composition was measured by energy-dispersive X-ray analysis. Figure 2 separates onset and zero-resistivity temperatures. Version 3 reports zero resistance from $x\\geq0.20$ and a maximum transition around 31 K, while observing a narrow transition at $x=0.33$. Do not turn “isovalent” into proof of unchanged Fermi surfaces, scattering or carrier populations. Nor does a similar phase diagram make chemical substitution physically identical to applied pressure. [R4](#ref-source-b9e77d2ee024ff3b)\n\nLi's nickelate study uses 8–10 nm films on SrTiO3, capped and reduced from perovskite precursors. The reported preparation couples approximately 25 nm caps to 280°C for 4–6 h and approximately 2 nm caps to 260°C for 1–3 h. The source reports no notable differences between those cap groups at the same composition; these are its preparation conditions, not a universal synthesis prescription. The in-plane lattice constants are locked to the substrate at 3.91 Å in the checked measurements.\n\nThe sampled superconducting compositions are $x=0.15$, $0.175$, $0.20$ and $0.225$, inside the reported $0.125<x<0.25$ dome. Figure 2 defines $T_{c,10\\%R}$ and $T_{c,90\\%R}$ using 10% and 90% of each sample's resistance at 20 K. Symbols average multiple samples at the same $x$; error bars span the observed extrema, not a stated standard error or confidence interval. The comparison cuprate curve uses a 50% criterion. These temperatures cannot be pooled as one uniform definition of $T_c$.\n\nFor the sampled $x=0$, $0.10$, $0.125$ and $0.25$ films, the caption reports no superconducting sign down to below 50 mK. That is a finite measurement bound, not an exact zero transition temperature or a precisely located continuous phase boundary. The 20 K resistance reference is also not a transition. No numerical nickelate $T_c$ is digitized here, and the small Hall response remains interpreted through multiple bands. [R5](#ref-source-c636cc691b7ff013)\n\n## Limits and disputes\n\nSidis's author manuscript compares reported 3% Ni-substituted YBCO ($T_c=80$ K) with 1% Zn-substituted YBCO ($T_c=78$ K). The samples were chosen for similar transition temperatures, not equal impurity fractions. Their reported impurity ratios were inferred from the suppression of $T_c$ relative to the pure system; Ni content and homogeneity were additionally checked by microprobe. A corresponding independent Zn assay is not stated in the selected passage. These two samples alone do not determine an independent dose-response slope or a universal impurity ranking.\n\nIn the checked 20–50 meV neutron window, the Ni sample's normal-state response has a finite detection upper limit; an undetected signal is not exact zero. The low-temperature-minus-above-$T_c$ spectra peak near 35 meV for Ni and 38 meV for Zn. Those are neutron spectral energies, not transition temperatures or direct gap measurements. The manuscript's Figure 2 caption reverses the sample order relative to its panel labels and surrounding text: the panels label (a) 3% Ni and (b) 1% Zn. This account follows the panel labels and text together and flags the disagreement; final-version comparison and raw background subtraction remain unchecked. The proposed impurity scenarios do not uniquely establish a pairing mechanism. [R6](#ref-source-9fd0a423b4e4de89)\n\nKeep author versions and specimen labels attached to every value. Ni's v1 specific-heat paragraph and Figure 8 label $x=0.078$, while its WDS example averages $x=0.074$ and its phase-summary maximum spans $0.058\\leq x\\leq0.074$. Their numerical proximity does not establish one specimen identity; this review does not silently replace 0.078 with 0.074.\n\nKasahara's author versions report different sampled ranges and zero-resistivity thresholds:\n\n| Author version | Composition range stated | Zero resistivity reported from |\n| --- | --- | --- |\n| v1, 27 May 2009 | $0\\leq x\\leq0.54$ | $x\\geq0.16$ |\n| v3, 9 February 2010 | $0\\leq x\\leq0.71$ | $x\\geq0.20$ |\n\nThese are version-specific reports, not a statistical uncertainty interval or a continuously measured phase boundary. Version 3 Figure 2 labels the onset curve above the zero-resistivity curve, but its caption assigns their colors in the opposite order. Read the criteria and labels together; no precise onset/zero value is digitized here. Both versions caution that superconductivity in the low-composition coexistence region may lack bulk character. Neither a zero-resistance path nor simultaneous anomalies alone prove homogeneous microscopic coexistence. Full journal-version comparison and raw-data reproduction remain open. [R3](#ref-source-cf1286d7701502f2) [R4](#ref-source-b9e77d2ee024ff3b)\n\nA dome does not establish a unique pairing mechanism, homogeneous microscopic coexistence or a universal optimal carrier concentration. The nickelate manuscript notes sample-to-sample resistivity variations associated with microstructure and does not establish the origin of its small dip within the dome. Preserve that uncertainty; numerical resemblance to a cuprate anomaly is not an ordering measurement. [R5](#ref-source-c636cc691b7ff013)\n\n## Discovery implications\n\nCompare the quantities before comparing the domes:\n\n| Reported quantity | Preserve in a reusable record | Do not substitute |\n| --- | --- | --- |\n| YBCO oxygen $x$ | Weight-analysis precision, chain-order preparation and specimen | Direct planar hole concentration $p$ |\n| YBCO lattice calibration | 22°C lattice measurement, empirical model and chosen branch | An independent carrier-density measurement |\n| Nickelate 10% and 90% resistance thresholds | Each fraction and the same sample's 20 K reference | Cuprate 50% thresholds or magnetic midpoints |\n| Nickelate figure error bars | Sample extrema at fixed composition | Standard error or a stated confidence interval |\n| No transition observed down to below 50 mK | Sampled compositions and the reported measurement bound | An exact $T_c=0$ or a continuous phase boundary |\n\nThis table is an editorial comparison of the checked experiments. Keep nominal composition, measured composition, formal valence and transport-model parameters separate; link each value to a specimen, preparation, probe and source version. Reduction, annealing or a static measurement alone is not this review's evidence of thermodynamic equilibrium. For the YBCO reference and nickelate records, equilibrium remains **unknown** at the checked source scope; this does not assert nonequilibrium. The calculations verify only branch arithmetic; they do not optimize a synthesis or validate a carrier-density calibration. [R2](#ref-source-e24ef58054ac9b71) [R5](#ref-source-c636cc691b7ff013)\n\n## Related topics\n\nCompare [cuprates](/scwiki/cuprates), [iron-based superconductors](/scwiki/iron-based-superconductors), [nickelates](/scwiki/nickelates), [pressure tuning](/scwiki/pressure-tuning), [zero resistance](/scwiki/zero-resistance) and [specific heat](/scwiki/specific-heat-jump).\n\n## Material cases\n\nValues describe individual reports, not a ranking. Unknown means the checked source did not supply the field at this review scope.\n\n| Material and sample | Reported temperature | Criterion | Probe | Pressure | State | Evidence |\n|---|---|---|---|---|---|---|\n| Ba(Fe1−xCox)2As2 (aliases: iron-based, iron based superconductors); Ni WDS fractions approximately 0.058–0.074; series summary | 23 K; Approximate series maximum; no one specimen or common onset/zero criterion is assigned. Specific-heat 0.078/0.074 mismatch remains unresolved. Thermodynamic equilibrium is unverified in this scoped review. | transition; series-maximum-multiple-criteria | Resistance, magnetization and heat capacity phase diagram | ambient; unknown GPa | unknown | experiment; [source](#ref-source-cf1286d7701502f2) |\n| YBa2Cu3O7 (aliases: cuprate, cuprates); Liang fully oxygenated reference | 85.3 K; Calibration reference; hole count inferred through an empirical overdoped branch, not directly measured. Thermodynamic equilibrium is unverified in the checked source scope. | transition; field-cooled-magnetization-midpoint | 1 Oe along c | ambient; unknown GPa | unknown | experiment; [source](#ref-source-e24ef58054ac9b71) |\n| BaFe2(As1−xPx)2 (aliases: iron-based, iron based superconductors); Kasahara author v3 phase-summary maximum | 31 K; Maximum around x = 0.26 in author text; exact onset/zero assignment and final-version comparison remain open. Thermodynamic equilibrium is unverified in this scoped review. | transition; transition-summary-unspecified | Transport phase diagram with separate onset and zero curves | ambient; unknown GPa | unknown | experiment; [source](#ref-source-b9e77d2ee024ff3b) |\n| Nd1−xSrxNiO2 (aliases: nickelate, nickelates); Li films: resistance normalization across composition series | 20 K; Reference temperature for 10% and 90% resistive thresholds; not Tc. No numerical transition temperature digitized from the figure. Thermodynamic equilibrium is unverified in the checked source scope. | normal-state; resistance-normalization-temperature | Hall-bar magnetotransport | ambient; unknown GPa | unknown | experiment; [source](#ref-source-c636cc691b7ff013) |\n| Nd1−xSrxNiO2 (aliases: nickelate, nickelates); Li author v2 films at sampled x = 0, 0.10, 0.125 and 0.25 | Figure 2 reports no superconducting sign down to below 50 mK. The exact base temperature is not specified in this caption; 50 mK is a bound, not a measured Tc or a claim of Tc = 0. Thermodynamic equilibrium is unverified. | measurement; no-transition-observed-within-measurement-range | Thin-film resistance; sampled-composition non-observation | ambient; unknown GPa | unknown | experiment; [source](#ref-source-c636cc691b7ff013) |\n| YBa2(Cu0.97Ni0.03)3O7 (aliases: cuprate, cuprates, YBCO, Ni-substituted YBCO); Sidis author v1 3% Ni YBCO, selected for Tc close to the other impurity sample | 80 K; Reported sample Tc; onset/midpoint/zero criterion unspecified in checked passages. Impurity fraction inferred from Tc suppression; additional microprobe check is stated for Ni only. Unequal doses, no independent two-point dose-response slope. Thermodynamic equilibrium unverified. | transition; transition-summary-unspecified | Reported sample transition temperature in a comparative inelastic-neutron study; neutron spectral energy is a separate quantity | ambient; unknown GPa | unknown | experiment; [source](#ref-source-9fd0a423b4e4de89) |\n| YBa2(Cu0.99Zn0.01)3O7 (aliases: cuprate, cuprates, YBCO, Zn-substituted YBCO); Sidis author v1 1% Zn YBCO, selected for Tc close to the other impurity sample | 78 K; Reported sample Tc; onset/midpoint/zero criterion unspecified in checked passages. Impurity fraction inferred from Tc suppression; additional microprobe check is stated for Ni only. Unequal doses, no independent two-point dose-response slope. Thermodynamic equilibrium unverified. | transition; transition-summary-unspecified | Reported sample transition temperature in a comparative inelastic-neutron study; neutron spectral energy is a separate quantity | ambient; unknown GPa | unknown | experiment; [source](#ref-source-9fd0a423b4e4de89) |\n\n## Sources\n\n### Ref source-5030a5999bf0420a\n\n[R1] Superconductor-to-nonsuperconductor transition in (La1−xSrx)2CuO4 as investigated by transport and magnetic measurements (1989). [DOI 10.1103/PhysRevB.40.2254](https://doi.org/10.1103/PhysRevB.40.2254). Publication: journal-article. Check: publisher-abstract-and-composition-notation. Checked: 2026-10-20. Published 1 August 1989. Original title and abstract checked: site fraction x <= 0.175 in (La1-xSrx)2CuO4 converts to y <= 0.35 in La2-ySryCuO4. Full methods require authorization and were not read.\n### Ref source-e24ef58054ac9b71\n\n[R2] Evaluation of CuO2 plane hole doping in YBa2Cu3O6+x single crystals (2006). [DOI 10.1103/PhysRevB.73.180505](https://doi.org/10.1103/PhysRevB.73.180505). Publication: journal-article. Check: selected-author-calibration-methods-and-equations. Checked: 2026-10-20. Published 25 May 2006; author v1 selected pp. 1–4 read, p. 3 Eq. 2 and figures visually checked. Chain-order assumptions, 22°C c-axis calibration, magnetization midpoint and empirical parabola exception retained. Independent algebra is not a raw-data fit. Final-version comparison remains open. Follow-up: author v1 pp.1–3 reread, pp.2–3 visually inspected. Oxygen precision ±0.002 belongs to x; 22°C lattice measurement and 1 Oe field-cooled midpoint are distinct. Tc,max 94.3 K and 85.3 K give two algebraic roots; the source selects the slightly overdoped branch. No direct hole-count measurement or raw-data refit.\n### Ref source-cf1286d7701502f2\n\n[R3] Effects of Co substitution on thermodynamic and transport properties and anisotropic Hc2 in Ba(Fe1−xCox)2As2 single crystals (2008). [DOI 10.1103/PhysRevB.78.214515](https://doi.org/10.1103/PhysRevB.78.214515). Publication: journal-article. Check: selected-author-composition-and-transition-criteria. Checked: 2026-10-20. Author v1 submitted 11 November 2008; journal published 29 December 2008. Selected pp. 1–7 read; Fig. 10 p. 23 visually checked. WDS/nominal distinction and probe criteria retained. Specific-heat paragraph 0.078 versus phase-summary 0.074 is unresolved; no precise single specimen assigned to the 23 K summary. Printed 2018 date is not publication date. Final version and raw data not reviewed. Follow-up: pp.5–7 reread and Fig.8/p.21 visually inspected; the paragraph, caption and plot itself use 0.078, whereas WDS and phase-summary passages use 0.074. No specimen identity inferred.\n### Ref source-b9e77d2ee024ff3b\n\n[R4] Evolution from non-Fermi- to Fermi-liquid transport via isovalent doping in BaFe2(As1−xPx)2 superconductors (2010). [DOI 10.1103/PhysRevB.81.184519](https://doi.org/10.1103/PhysRevB.81.184519). Publication: journal-article. Check: selected-author-v3-composition-transport-and-figures. Checked: 2026-10-20. Author v3 submitted 9 February 2010; journal published 19 May 2010. Selected pp. 1–3 read; p. 2 figures visually checked. EDX composition, separate onset/zero and compensated-model limits retained. v1 to v3 changes and figure-caption color mismatch noted. No exact 31 K criterion assigned from the summary; final author list differs and final-version comparison remains open. Related Physica C DOI on arXiv is not this PRB DOI. Follow-up: v1/v3 pp.1–2 compared, v3 p.2 pixels checked. Ranges 0–0.54/0–0.71 and zero-resistivity thresholds 0.16/0.20 remain version-specific; caption color order conflicts with plotted onset/zero labels. Low-x bulk-character caveat retained.\n### Ref source-c636cc691b7ff013\n\n[R5] Superconducting Dome in Nd1−xSrxNiO2 Infinite Layer Films (2020). [DOI 10.1103/PhysRevLett.125.027001](https://doi.org/10.1103/PhysRevLett.125.027001). Publication: journal-article. Check: selected-author-film-methods-and-phase-diagram. Checked: 2026-10-20. Author v2 submitted 23 June 2020; journal published 7 July 2020. Selected pp. 1–4 and Fig. 2 p. 12 read and visually checked: films, reduction/capping, resistance normalization, criterion and sample extrema. Complete supplement, final-version comparison and raw data not reviewed; no exact digitized Tc is introduced. Follow-up: author v2 pp.2–4 and Fig.2/p.12 reread, pp.3/12 visually inspected. Cap/reduction pairings, 3.91 Å substrate constraint, sampled compositions, 10/90 versus 50% criteria, sample-extrema bars and below-50-mK non-observation retained. No exact Tc extracted or continuous boundary inferred.\n### Ref source-9fd0a423b4e4de89\n\n[R6] Quantum Impurities and the Neutron Resonance Peak in YBa2Cu3O7: Ni versus Zn (2000). [DOI 10.1103/PhysRevLett.84.5900](https://doi.org/10.1103/PhysRevLett.84.5900). Publication: journal-article. Check: selected-author-v1-impurity-methods-and-neutron-figures. Checked: 2026-10-20. Author v1 submitted 13 December 1999; journal published 19 June 2000. Selected pp.1–3 read; pp.1/3 visually inspected. Samples selected for close Tc, unequal impurity fractions; ratios inferred from Tc suppression with additional Ni microprobe check. Finite normal-state upper limit and spectral-energy versus Tc distinction retained. Figure 2 caption order conflicts with panels/text; no silent relabeling. Printed 2018 generation date is not publication date. Final version, complete methods and raw neutron analysis remain unchecked.\n\n## Claim evidence and conditions\n\n### scwiki-e2-claim-scope-1\n\nChemical doping changes a material's composition; it does not supply a universal carrier counter. Distinguish the starting mixture, measured site occupancy, formal ionic charge and mobile carriers. Substitution can also change disorder, bond geometry and competing order. Oxygen removal or chain ordering adds another control variable. A superconducting dome is therefore a relationship among specified samples and criteria, not a recipe transferable between families.\n\nEvidence: experiment. Sources: source-e24ef58054ac9b71, source-cf1286d7701502f2, source-b9e77d2ee024ff3b, source-c636cc691b7ff013.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected primary passages, figures and bounded algebra; full scientific acceptance remains open.\n\n### scwiki-e2-claim-scope-2\n\nNotation matters even before measurement. Takagi's 1989 abstract uses $(\\mathrm{La}_{1-x}\\mathrm{Sr}_x)_2\\mathrm{CuO}_4$ through $x=0.175$. Expanding the formula gives $\\mathrm{La}_{2-2x}\\mathrm{Sr}_{2x}\\mathrm{CuO}_4$: in $\\mathrm{La}_{2-y}\\mathrm{Sr}_y\\mathrm{CuO}_4$, therefore, $y=2x$ and the same endpoint is $y=0.35$. For example, site fraction $x=0.075$ corresponds to $y=0.15$, or $\\mathrm{La}_{1.85}\\mathrm{Sr}_{0.15}\\mathrm{CuO}_4$. This is a composition conversion, not a measured hole density or an experimentally selected optimum. The publisher title and abstract were checked; full methods remain outside this review.\n\nEvidence: experiment. Sources: source-5030a5999bf0420a.\n\nSource relationship: mixed-source-and-local-derivation. The source title/abstract supplies the formula and range; the factor of two and worked 0.075 example are local stoichiometric arithmetic, not a carrier measurement.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Publisher title/abstract reread; full methods unavailable. Exact formula expansion checked locally.\n\n### scwiki-e2-claim-mathematical-assumptions-1\n\nCharge neutrality is useful bookkeeping under explicit ionic assumptions. Taking La/Nd as $3+$, Sr as $2+$, Ce as $4+$ and O as $2-$ gives formal average Cu valence $2+x+2\\delta$ in $\\mathrm{La}_{2-x}\\mathrm{Sr}_x\\mathrm{CuO}_{4+\\delta}$, and $2-x-2y$ in $\\mathrm{Nd}_{2-x}\\mathrm{Ce}_x\\mathrm{CuO}_{4-y}$. Stoichiometric infinite-layer $\\mathrm{Nd}_{1-x}\\mathrm{Sr}_x\\mathrm{NiO}_2$ gives formal Ni valence $1+x$. These balances do not locate holes among orbitals or establish an itinerant carrier density. Oxygen deviations and compensating defects change the balance.\n\nEvidence: theory. Sources: source-5030a5999bf0420a, source-c636cc691b7ff013.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected primary passages, figures and bounded algebra; full scientific acceptance remains open.\n\n### scwiki-e2-claim-mathematical-assumptions-2\n\nEven the elementary weak-field two-band Drude model yields $R_H=(n_h\\mu_h^2-n_e\\mu_e^2)/[e(n_h\\mu_h+n_e\\mu_e)^2]$, with $e>0$. Mobilities weight the response. For compensation, $n_e=n_h=n$, this becomes $(\\mu_h-\\mu_e)/[en(\\mu_h+\\mu_e)]$; its sign can reverse at fixed density. This illustrative identity is not a fit to correlated transport. Kasahara explicitly discusses why that simple model fails for the magnitude of the observed Hall response.\n\nEvidence: theory. Sources: source-b9e77d2ee024ff3b.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected primary passages, figures and bounded algebra; full scientific acceptance remains open.\n\n### scwiki-e2-claim-mathematical-assumptions-3\n\nLiang's empirical YBCO calibration uses $p=11.491u+5.17\\times10^9u^6$, $u=1-c/c_0$, with $c_0=1.18447\\,\\mathrm{nm}$ and $c$ measured at 22°C. It depends on chain-order assumptions and reference compositions. The relation $T_c/T_{c,\\max}=1-82.6(p-0.16)^2$ has two algebraic branches and fails near the material's suppressed one-eighth region. Neither expression is a universal oxygen-to-hole conversion; a fitted lattice parameter and a directly measured carrier density are different evidence.\n\nEvidence: theory. Sources: source-e24ef58054ac9b71.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected primary passages, figures and bounded algebra; full scientific acceptance remains open.\n\n### scwiki-e2-claim-experimental-criteria-1\n\nMeasure composition on the specimens whose transitions are compared. Ni's Co-substituted Ba122 series used wavelength-dispersive spectroscopy (WDS): actual Co fraction was about 0.74 times the nominal fraction for that growth series. A nominal 0.10 batch averaged approximately 0.074. Its phase diagram distinguishes resistance, magnetization and heat capacity. Resistive offset means maximum-slope extrapolation to zero, rather than an independently established instrumental zero. The reported maximum near 23 K spans measured fractions approximately 0.058–0.074.\n\nEvidence: experiment. Sources: source-cf1286d7701502f2.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected primary passages, figures and bounded algebra; full scientific acceptance remains open.\n\n### scwiki-e2-claim-experimental-criteria-2\n\nFor YBCO, oxygen content alone omits chain configuration. Liang determined oxygen content by weight analysis with a stated precision of $\\pm0.002$ in $x$; that is not an uncertainty in planar hole concentration $p$. The chain-ordered ortho-II, ortho-VIII and ortho-III preparations use $x=0.50$, $0.67$ and $0.75$. The superconducting $T_c$ is the midpoint of field-cooled magnetization in 1 Oe along the c axis; the lattice parameter is measured separately at 22°C.\n\nThe fully oxygenated reference has $T_c=85.3$ K. With the paper's $T_{c,\\max}=94.3$ K, algebraic inversion of the empirical parabola gives $p\\approx0.126$ or $0.194$. The paper uses the latter because it treats that reference as slightly overdoped. Temperature alone does not choose a branch; the lower algebraic root also lies near the one-eighth region where the uncorrected calibration is unreliable. The quoted $p$ is a model-dependent estimate, not a directly measured carrier count. Record oxygen/order history, calibration assumptions and uncertainty with the result.\n\nEvidence: experiment. Sources: source-e24ef58054ac9b71.\n\nSource relationship: mixed-source-and-local-derivation. Liang author v1 pp.2–3 supplies oxygen precision, ordered preparations, probe criteria, Tc,max and the selected overdoped reference. The second algebraic root is calculated here to expose branch ambiguity; it is not a competing measured hole concentration.\n\nConditions: YBCO author-v1 calibration; weight-analysis precision belongs to oxygen x, not plane doping p. The slightly overdoped branch and chain-order assumptions are required.\n\nVerification scope: Selected author v1 pp.1–3 read; pp.2–3 visually inspected. Reference branch arithmetic checked; no raw magnetization/lattice refit or final-version equivalence claimed.\n\n### scwiki-e2-claim-experimental-criteria-3\n\nIn the P-substituted Ba122 author manuscript, composition was measured by energy-dispersive X-ray analysis. Figure 2 separates onset and zero-resistivity temperatures. Version 3 reports zero resistance from $x\\geq0.20$ and a maximum transition around 31 K, while observing a narrow transition at $x=0.33$. Do not turn “isovalent” into proof of unchanged Fermi surfaces, scattering or carrier populations. Nor does a similar phase diagram make chemical substitution physically identical to applied pressure.\n\nEvidence: experiment. Sources: source-b9e77d2ee024ff3b.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected primary passages, figures and bounded algebra; full scientific acceptance remains open.\n\n### scwiki-e2-claim-experimental-criteria-4\n\nLi's nickelate study uses 8–10 nm films on SrTiO3, capped and reduced from perovskite precursors. The reported preparation couples approximately 25 nm caps to 280°C for 4–6 h and approximately 2 nm caps to 260°C for 1–3 h. The source reports no notable differences between those cap groups at the same composition; these are its preparation conditions, not a universal synthesis prescription. The in-plane lattice constants are locked to the substrate at 3.91 Å in the checked measurements.\n\nThe sampled superconducting compositions are $x=0.15$, $0.175$, $0.20$ and $0.225$, inside the reported $0.125<x<0.25$ dome. Figure 2 defines $T_{c,10\\%R}$ and $T_{c,90\\%R}$ using 10% and 90% of each sample's resistance at 20 K. Symbols average multiple samples at the same $x$; error bars span the observed extrema, not a stated standard error or confidence interval. The comparison cuprate curve uses a 50% criterion. These temperatures cannot be pooled as one uniform definition of $T_c$.\n\nFor the sampled $x=0$, $0.10$, $0.125$ and $0.25$ films, the caption reports no superconducting sign down to below 50 mK. That is a finite measurement bound, not an exact zero transition temperature or a precisely located continuous phase boundary. The 20 K resistance reference is also not a transition. No numerical nickelate $T_c$ is digitized here, and the small Hall response remains interpreted through multiple bands.\n\nEvidence: experiment. Sources: source-c636cc691b7ff013.\n\nSource relationship: direct-support. Li author v2 pp.3–4 and Fig.2/p.12 distinguish cap-dependent preparation, substrate constraint, sample selection, resistance fractions and extrema. No new curve fit or boundary interpolation.\n\nConditions: Specific capped, reduced thin-film series on SrTiO3. Preserve sampled composition, specimen, criterion, reference temperature and range meaning; below-50-mK bound is not Tc=0.\n\nVerification scope: Selected author v2 pp.2–4 and p.12 read; pp.3/12 visually inspected. Full supplement, final comparison, raw measurements and continuous-boundary inference remain outside scope.\n\n### scwiki-e2-claim-limits-and-disputes-1\n\nSidis's author manuscript compares reported 3% Ni-substituted YBCO ($T_c=80$ K) with 1% Zn-substituted YBCO ($T_c=78$ K). The samples were chosen for similar transition temperatures, not equal impurity fractions. Their reported impurity ratios were inferred from the suppression of $T_c$ relative to the pure system; Ni content and homogeneity were additionally checked by microprobe. A corresponding independent Zn assay is not stated in the selected passage. These two samples alone do not determine an independent dose-response slope or a universal impurity ranking.\n\nIn the checked 20–50 meV neutron window, the Ni sample's normal-state response has a finite detection upper limit; an undetected signal is not exact zero. The low-temperature-minus-above-$T_c$ spectra peak near 35 meV for Ni and 38 meV for Zn. Those are neutron spectral energies, not transition temperatures or direct gap measurements. The manuscript's Figure 2 caption reverses the sample order relative to its panel labels and surrounding text: the panels label (a) 3% Ni and (b) 1% Zn. This account follows the panel labels and text together and flags the disagreement; final-version comparison and raw background subtraction remain unchecked. The proposed impurity scenarios do not uniquely establish a pairing mechanism.\n\nEvidence: editorial-analysis. Sources: source-9fd0a423b4e4de89.\n\nSource relationship: context-for-editorial-analysis. Primary author passages and displayed figure labels are compared here. Source ambiguity remains explicit; the comparison does not replace missing specimen provenance or establish a unique mechanism.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected Ni v1 pp.4–7/Fig.8, Kasahara v1/v3 pp.1–2, or Sidis v1 pp.1–3 as cited; original figure pixels inspected. No final-version or raw-data equivalence claimed.\n\n### scwiki-e2-claim-limits-and-disputes-2\n\nKeep author versions and specimen labels attached to every value. Ni's v1 specific-heat paragraph and Figure 8 label $x=0.078$, while its WDS example averages $x=0.074$ and its phase-summary maximum spans $0.058\\leq x\\leq0.074$. Their numerical proximity does not establish one specimen identity; this review does not silently replace 0.078 with 0.074.\n\nKasahara's author versions report different sampled ranges and zero-resistivity thresholds:\n\n| Author version | Composition range stated | Zero resistivity reported from |\n| --- | --- | --- |\n| v1, 27 May 2009 | $0\\leq x\\leq0.54$ | $x\\geq0.16$ |\n| v3, 9 February 2010 | $0\\leq x\\leq0.71$ | $x\\geq0.20$ |\n\nThese are version-specific reports, not a statistical uncertainty interval or a continuously measured phase boundary. Version 3 Figure 2 labels the onset curve above the zero-resistivity curve, but its caption assigns their colors in the opposite order. Read the criteria and labels together; no precise onset/zero value is digitized here. Both versions caution that superconductivity in the low-composition coexistence region may lack bulk character. Neither a zero-resistance path nor simultaneous anomalies alone prove homogeneous microscopic coexistence. Full journal-version comparison and raw-data reproduction remain open.\n\nEvidence: editorial-analysis. Sources: source-cf1286d7701502f2, source-b9e77d2ee024ff3b.\n\nSource relationship: context-for-editorial-analysis. Primary author passages and displayed figure labels are compared here. Source ambiguity remains explicit; the comparison does not replace missing specimen provenance or establish a unique mechanism.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected Ni v1 pp.4–7/Fig.8, Kasahara v1/v3 pp.1–2, or Sidis v1 pp.1–3 as cited; original figure pixels inspected. No final-version or raw-data equivalence claimed.\n\n### scwiki-e2-claim-limits-and-disputes-3\n\nA dome does not establish a unique pairing mechanism, homogeneous microscopic coexistence or a universal optimal carrier concentration. The nickelate manuscript notes sample-to-sample resistivity variations associated with microstructure and does not establish the origin of its small dip within the dome. Preserve that uncertainty; numerical resemblance to a cuprate anomaly is not an ordering measurement.\n\nEvidence: experiment. Sources: source-c636cc691b7ff013.\n\nConditions: Formula convention, nominal versus measured composition, oxygen/order history, sample and probe-specific criteria remain distinct. Formal valence and simple Hall models are not direct carrier measurements.\n\nVerification scope: Selected primary passages, figures and bounded algebra; full scientific acceptance remains open.\n\n### scwiki-e2-claim-discovery-implications-1\n\nCompare the quantities before comparing the domes:\n\n| Reported quantity | Preserve in a reusable record | Do not substitute |\n| --- | --- | --- |\n| YBCO oxygen $x$ | Weight-analysis precision, chain-order preparation and specimen | Direct planar hole concentration $p$ |\n| YBCO lattice calibration | 22°C lattice measurement, empirical model and chosen branch | An independent carrier-density measurement |\n| Nickelate 10% and 90% resistance thresholds | Each fraction and the same sample's 20 K reference | Cuprate 50% thresholds or magnetic midpoints |\n| Nickelate figure error bars | Sample extrema at fixed composition | Standard error or a stated confidence interval |\n| No transition observed down to below 50 mK | Sampled compositions and the reported measurement bound | An exact $T_c=0$ or a continuous phase boundary |\n\nThis table is an editorial comparison of the checked experiments. Keep nominal composition, measured composition, formal valence and transport-model parameters separate; link each value to a specimen, preparation, probe and source version. Reduction, annealing or a static measurement alone is not this review's evidence of thermodynamic equilibrium. For the YBCO reference and nickelate records, equilibrium remains **unknown** at the checked source scope; this does not assert nonequilibrium. The calculations verify only branch arithmetic; they do not optimize a synthesis or validate a carrier-density calibration.\n\nEvidence: editorial-analysis. Sources: source-e24ef58054ac9b71, source-c636cc691b7ff013.\n\nSource relationship: context-for-editorial-analysis. Editorial reuse rules derived from contrasting Liang author v1 pp.2–3 and Li author v2 pp.3–4/12. No additional measurement, independent calibration or equilibrium determination.\n\nConditions: Keep the experiment, criterion, composition definition, calibration branch and meaning of an uncertainty attached to the reported value.\n\nVerification scope: Selected source text and four source pages visually checked; author interpretation only, not independent scientific acceptance.\n\n## Revision and review\n\nArticle ID: scwiki-e2. Revision: a36b9df354e399f0a31b. Updated: 2026-10-19T18:24:23.318138+00:00.\n\nReview scope: Selected YBCO, Co/P Ba122, nickelate and Ni/Zn-YBCO author passages and figures; Takagi publisher title/abstract; bounded composition, charge-balance and Hall/calibration algebra. Version-specific ranges, specimen ambiguity, finite detection and source-label conflicts remain explicit.\n\n- Complete scientific acceptance, final-version comparisons, full supplements and raw-data reproduction remain open.\n- Takagi remains title/abstract-only. Sidis now has selected author-v1 pp.1–3 review, not a complete final-method or raw-data audit.\n- Ni 0.078/0.074 specimen association, Kasahara caption-color/version differences and Sidis Figure 2 caption-panel order conflict remain explicit.\n- Formal valence, empirical YBCO calibration and illustrative two-band algebra are not a measured carrier-density determination.\n- Finite-temperature non-observation does not establish exact Tc = 0. No equilibrium certification, raw reanalysis, full supplemental review or digitized nickelate Tc is supplied.\n\nSource: [E_tuning_parameters/E2_chemical_doping.md](https://github.com/JackZH26/jzis-superconductivity/blob/0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf/E_tuning_parameters/E2_chemical_doping.md), commit 0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf, SHA-256 612b84c0c11af76b0ae355518b54a36a3ab3a5d11a315bbee8539de43bde2944.\n","wordCount":1515}}