{
  "dataset": {
    "schema": "notsolved.roomtempsc-graph-evidence.v1",
    "author": "/root/rsa_final_source_review",
    "problemId": "roomtempsc",
    "preparedDate": "2026-10-05",
    "status": "private-source-proposal",
    "units": {
      "temperature": "K",
      "operatingPressure": "GPa",
      "celsiusOffset": 273.15
    },
    "ambientPlotReference": {
      "gigaPascals": 0.000101325,
      "pascals": 101325,
      "sourceId": "standard-atmosphere",
      "measurement": false
    },
    "points": [
      {
        "id": "hg-1911",
        "year": 1911,
        "dateBasis": "historical experiment",
        "material": "Mercury",
        "shortLabel": "Hg · 4.2 K",
        "temperatureKelvin": 4.2,
        "temperatureQualifier": "approximately",
        "criterion": "electrical-resistance-disappearance",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Historical cryogenic resistance experiment; normal operating-pressure context, no exact sample pressure read"
        },
        "sourceIds": [
          "onnes-history"
        ],
        "preparation": {
          "kind": "purified elemental mercury; cryogenic cooling",
          "pressureUsed": null,
          "pressureQualification": "Exact preparation pressure not established from accessed source; ambient operating condition is separate."
        },
        "evidence": {
          "bulk": "not established by a 1911 Meissner measurement",
          "replication": "historical established material; no new replication audit"
        },
        "error": null
      },
      {
        "id": "pb-context",
        "year": null,
        "dateBasis": "reference context, not a dated discovery",
        "material": "Lead",
        "shortLabel": "Pb · 7.19 K",
        "temperatureKelvin": 7.19,
        "temperatureQualifier": "typical-reference",
        "criterion": "typical-bulk-transition-reference",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Official NBS cavity-material reference, uncompressed elemental material"
        },
        "sourceIds": [
          "nbs-elemental"
        ],
        "preparation": {
          "kind": "clean, smooth, relatively unstrained surface context",
          "pressureUsed": null,
          "pressureQualification": "Exact preparation pressure not established from accessed source; ambient operating condition is separate."
        },
        "evidence": {
          "bulk": "official material reference",
          "replication": "not independently reassessed"
        },
        "error": null
      },
      {
        "id": "nb-context",
        "year": null,
        "dateBasis": "reference context, not a dated discovery",
        "material": "Niobium",
        "shortLabel": "Nb · 9.25 K",
        "temperatureKelvin": 9.25,
        "temperatureQualifier": "typical-reference",
        "criterion": "typical-bulk-transition-reference",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Official NBS cavity-material reference, uncompressed elemental material"
        },
        "sourceIds": [
          "nbs-elemental"
        ],
        "preparation": {
          "kind": "clean, smooth, relatively unstrained surface context",
          "pressureUsed": null,
          "pressureQualification": "Exact preparation pressure not established from accessed source; ambient operating condition is separate."
        },
        "evidence": {
          "bulk": "official material reference",
          "replication": "not independently reassessed"
        },
        "error": null
      },
      {
        "id": "nbge-1974",
        "year": 1974,
        "dateBasis": "paper publication",
        "material": "Nb–Ge sputtered film",
        "shortLabel": "Nb–Ge · 23.2 K",
        "temperatureKelvin": 23.2,
        "temperatureQualifier": "reported-onset",
        "criterion": "transition-onset-measurement-unspecified",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Inference: accessed abstract describes sputtered films, with no continuing applied compression; pressure not numerically measured"
        },
        "sourceIds": [
          "nbge-1974"
        ],
        "preparation": {
          "kind": "nominal Nb3Ge, sputtered onto hot substrates",
          "pressureUsed": null
        },
        "evidence": {
          "bulk": "not assessed from abstract",
          "replication": "not independently reassessed"
        },
        "error": {
          "temperatureKelvin": 0.2,
          "kind": "reported ± range; statistical meaning unspecified",
          "transitionWidthKelvin": 1.2,
          "transitionWidthIsError": false
        }
      },
      {
        "id": "lbco-1986",
        "year": 1986,
        "dateBasis": "historical experiment and original publication",
        "material": "Ba–La–Cu–O mixed-phase material",
        "shortLabel": "Ba–La–Cu–O · 35 K",
        "temperatureKelvin": 35,
        "temperatureQualifier": "reported-onset",
        "criterion": "resistive-onset",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Author lecture distinguishes original 35 K transition from later hydrostatic-pressure enhancement"
        },
        "sourceIds": [
          "lbco-original",
          "lbco-lecture"
        ],
        "preparation": {
          "kind": "composition and thermal-treatment optimization of oxygen-deficient mixed-phase material",
          "pressureUsed": null,
          "pressureQualification": "Exact preparation pressure not established from accessed source; ambient operating condition is separate."
        },
        "evidence": {
          "bulk": "magnetic characterization discussed separately in lecture",
          "replication": "author lecture reports external confirmations; no new replication audit"
        },
        "error": null
      },
      {
        "id": "ybco-1987",
        "year": 1987,
        "dateBasis": "paper publication",
        "material": "Y–Ba–Cu–O mixed-phase material",
        "shortLabel": "Y–Ba–Cu–O · 93 K",
        "temperatureKelvin": 93,
        "temperatureQualifier": "upper-end-of-reported-transition-interval",
        "criterion": "resistive-and-magnetic-reported-transition",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Ambient pressure stated in primary title and abstract"
        },
        "sourceIds": [
          "ybco-1987"
        ],
        "preparation": {
          "kind": "mixed-phase Y–Ba–Cu–O material",
          "pressureUsed": null,
          "pressureQualification": "Exact preparation pressure not established from accessed source; ambient operating condition is separate."
        },
        "evidence": {
          "bulk": "magnetic and resistive observations",
          "replication": "paper calls transition stable and reproducible; not a new independent audit"
        },
        "error": {
          "reportedTransitionIntervalKelvin": [
            80,
            93
          ],
          "intervalIsError": false
        }
      },
      {
        "id": "hg-1993",
        "year": 1993,
        "dateBasis": "paper publication",
        "material": "Hg–Ba–Ca–Cu–O mixed-phase/intergrowth",
        "shortLabel": "Hg cuprate · 133 K",
        "temperatureKelvin": 133,
        "temperatureQualifier": "approximately",
        "criterion": "magnetic-and-resistive-reported-transition",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Ambient-pressure reference established in later primary hydride context; original abstract describes uncompressed multiphase material"
        },
        "sourceIds": [
          "hg-1993",
          "h3s-2015"
        ],
        "preparation": {
          "kind": "multiphase material with Hg cuprate intergrowth",
          "pressureUsed": null
        },
        "evidence": {
          "bulk": "magnetic and resistive observations; purity limit retained",
          "replication": "not independently reassessed"
        },
        "error": null
      },
      {
        "id": "hg-1994",
        "year": 1994,
        "dateBasis": "paper publication",
        "material": "HgBa2Ca2Cu3O8+δ",
        "shortLabel": "Hg-1223 · 164 K",
        "temperatureKelvin": 164,
        "temperatureQualifier": "approximately",
        "criterion": "resistive-onset",
        "operatingPressure": {
          "kind": "compressed",
          "gigaPascals": 31,
          "approximately": true,
          "ongoingCompression": true
        },
        "sourceIds": [
          "hg-1994"
        ],
        "preparation": {
          "kind": "optimally doped, about 80% Hg-1223 phase; quasihydrostatic DAC with MgO medium",
          "pressureUsed": true
        },
        "evidence": {
          "bulk": "ambient magnetic fraction discussed; no 164 K magnetic result assigned",
          "replication": "not independently reassessed"
        },
        "error": {
          "pressureRelative": 0.05,
          "pressureAbsoluteGigaPascalsDerived": 1.55,
          "kind": "reported approximate pressure uncertainty, converted by 31×0.05",
          "instrumentTemperatureKelvin": 0.1,
          "instrumentTemperatureIsTransitionError": false
        }
      },
      {
        "id": "mgb2-2001",
        "year": 2001,
        "dateBasis": "paper publication",
        "material": "Magnesium diboride",
        "shortLabel": "MgB₂ · 39 K",
        "temperatureKelvin": 39,
        "temperatureQualifier": "reported-transition",
        "criterion": "bulk-superconductivity-magnetic-and-resistive",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Uncompressed bulk experiment context; continuing compression not reported in accessed abstract"
        },
        "sourceIds": [
          "mgb2-2001"
        ],
        "preparation": {
          "kind": "specific synthesis conditions not read in accessed abstract",
          "pressureUsed": null
        },
        "evidence": {
          "bulk": "publisher abstract explicitly reports bulk superconductivity",
          "replication": "not independently reassessed"
        },
        "error": null
      },
      {
        "id": "h3s-2015",
        "year": 2015,
        "dateBasis": "final paper publication",
        "material": "Sulfur hydride (H3S assignment)",
        "shortLabel": "H₃S · 203 K",
        "temperatureKelvin": 203,
        "temperatureQualifier": "magnetic-onset",
        "criterion": "zero-field-cooled-magnetic-onset",
        "operatingPressure": {
          "kind": "compressed",
          "gigaPascals": 155,
          "approximately": false,
          "ongoingCompression": true
        },
        "sourceIds": [
          "h3s-2015"
        ],
        "preparation": {
          "kind": "H2S loaded near 200 K, compressed, then annealed to room temperature or higher",
          "pressureUsed": true,
          "version": "author preprint 1506.08190"
        },
        "evidence": {
          "bulk": "ZFC onset and magnetic hysteresis reported; exact 203 point is magnetic",
          "replication": "same-study electrical/isotope/field support; no independent-replication claim"
        },
        "error": {
          "temperatureKelvin": 1,
          "kind": "source reports 203(1) K; statistical meaning not restated"
        },
        "pairedElectricalMeasurement": {
          "temperatureKelvin": 195,
          "operatingPressureGigaPascals": 145,
          "criterion": "resistive-onset",
          "plotDefault": false
        }
      },
      {
        "id": "lah10-2019",
        "year": 2019,
        "dateBasis": "final paper publication, not 2018 preprint",
        "material": "Lanthanum hydride LaH10",
        "shortLabel": "LaH₁₀ · 250 K",
        "temperatureKelvin": 250,
        "temperatureQualifier": "approximately",
        "criterion": "reported-resistive-transition-onset",
        "operatingPressure": {
          "kind": "compressed",
          "gigaPascals": 170,
          "approximately": true,
          "ongoingCompression": true
        },
        "sourceIds": [
          "lah10-2019"
        ],
        "preparation": {
          "kind": "La plus excess H2 in DAC; laser treatment; continuous high pressure",
          "pressureUsed": true,
          "version": "author preprint 1812.01561 v1; generic methods, not exact sample heating value"
        },
        "evidence": {
          "bulk": "zero resistance/field/isotope evidence; preprint says sample too small for Meissner measurement",
          "replication": "no independent-replication claim"
        },
        "error": null,
        "sampleRange": {
          "temperatureKelvin": [
            250,
            252
          ],
          "isError": false,
          "version": "author preprint; maximum across samples"
        }
      },
      {
        "id": "hg-pq5-after-2026",
        "year": 2026,
        "dateBasis": "final paper online publication",
        "material": "Pressure-quenched HgBa2Ca2Cu3O8+δ",
        "shortLabel": "Quenched Hg-1223 · 151 K",
        "temperatureKelvin": 151,
        "temperatureQualifier": "first-warming-onset",
        "criterion": "resistive-onset-dR-dT",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Pressure released; primary Experiment 5 warming curve 15 at ambient pressure"
        },
        "sourceIds": [
          "hg-pq-2026"
        ],
        "sourceLocator": "Experiment 5, Fig. 2E curve 15 and Fig. 2F",
        "preparation": {
          "kind": "pressure quench",
          "pressureUsed": true,
          "pressureGigaPascals": 18.9,
          "quenchTemperatureKelvin": 4.2,
          "experiment": 5
        },
        "evidence": {
          "bulk": "151 K is resistive onset; separately retrieved magnetic transition ~140 K is different state",
          "replication": "multiple within-study experiments; independent replication not assessed"
        },
        "error": null,
        "stability": {
          "kind": "limited",
          "maximumWarmTemperatureKelvinApprox": 170,
          "description": "limited thermal/time retention; no room-temperature stable operation"
        },
        "companionCoolingOnsetKelvin": 150
      },
      {
        "id": "hg-pq3-after-2026",
        "year": 2026,
        "dateBasis": "final paper online publication",
        "material": "Pressure-quenched Hg-1223",
        "shortLabel": "PQ 3 · 147 K",
        "temperatureKelvin": 147,
        "temperatureQualifier": "first-warming-onset",
        "criterion": "resistive-onset-dR-dT",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Primary Experiment 3, Fig. 2C curve 9 after pressure release"
        },
        "sourceIds": [
          "hg-pq-2026"
        ],
        "sourceLocator": "Experiment 3, Fig. 2C curves 8→9",
        "preparation": {
          "kind": "pressure quench",
          "pressureUsed": true,
          "pressureGigaPascals": 10.1,
          "quenchTemperatureKelvin": 4.2,
          "experiment": 3
        },
        "evidence": {
          "bulk": "resistive onset only for this plotted state",
          "replication": "same study"
        },
        "error": null,
        "companionCoolingOnsetKelvin": 147
      },
      {
        "id": "hg-pq4-after-2026",
        "year": 2026,
        "dateBasis": "final paper online publication",
        "material": "Pressure-quenched Hg-1223",
        "shortLabel": "PQ 4 · 149 K",
        "temperatureKelvin": 149,
        "temperatureQualifier": "first-warming-onset",
        "criterion": "resistive-onset-dR-dT",
        "operatingPressure": {
          "kind": "ambient",
          "gigaPascals": null,
          "ongoingCompression": false,
          "plotReferenceGigaPascals": 0.000101325,
          "plotReferenceLabel": "1 atm reference",
          "basis": "Primary Experiment 4, Fig. 2D curve 12 after pressure release"
        },
        "sourceIds": [
          "hg-pq-2026"
        ],
        "sourceLocator": "Experiment 4, Fig. 2D curves 11→12",
        "preparation": {
          "kind": "pressure quench",
          "pressureUsed": true,
          "pressureGigaPascals": 10.9,
          "quenchTemperatureKelvin": 4.2,
          "experiment": 4
        },
        "evidence": {
          "bulk": "resistive onset only for this plotted state",
          "replication": "same study"
        },
        "error": null,
        "companionCoolingOnsetKelvin": 148
      },
      {
        "id": "hg-pq3-before-2026",
        "year": 2026,
        "dateBasis": "final paper online publication",
        "material": "Hg-1223 before pressure release",
        "shortLabel": "Before PQ 3 · 152 K",
        "temperatureKelvin": 152,
        "temperatureQualifier": "cooling-onset",
        "criterion": "resistive-onset-dR-dT",
        "operatingPressure": {
          "kind": "compressed",
          "gigaPascals": 10.1,
          "approximately": false,
          "ongoingCompression": true
        },
        "sourceIds": [
          "hg-pq-2026"
        ],
        "sourceLocator": "Experiment 3, Fig. 2C curve 8",
        "preparation": {
          "kind": "compressed state before quenching",
          "pressureUsed": true,
          "experiment": 3
        },
        "evidence": {
          "bulk": "resistive onset only for this plotted state",
          "replication": "same study"
        },
        "error": null
      },
      {
        "id": "hg-pq4-before-2026",
        "year": 2026,
        "dateBasis": "final paper online publication",
        "material": "Hg-1223 before pressure release",
        "shortLabel": "Before PQ 4 · 154 K",
        "temperatureKelvin": 154,
        "temperatureQualifier": "cooling-onset",
        "criterion": "resistive-onset-dR-dT",
        "operatingPressure": {
          "kind": "compressed",
          "gigaPascals": 10.9,
          "approximately": false,
          "ongoingCompression": true
        },
        "sourceIds": [
          "hg-pq-2026"
        ],
        "sourceLocator": "Experiment 4, Fig. 2D curve 11",
        "preparation": {
          "kind": "compressed state before quenching",
          "pressureUsed": true,
          "experiment": 4
        },
        "evidence": {
          "bulk": "resistive onset only for this plotted state",
          "replication": "same study"
        },
        "error": null
      },
      {
        "id": "hg-pq5-before-2026",
        "year": 2026,
        "dateBasis": "final paper online publication",
        "material": "Hg-1223 before pressure release",
        "shortLabel": "Before PQ 5 · 158 K",
        "temperatureKelvin": 158,
        "temperatureQualifier": "cooling-onset",
        "criterion": "resistive-onset-dR-dT",
        "operatingPressure": {
          "kind": "compressed",
          "gigaPascals": 18.9,
          "approximately": false,
          "ongoingCompression": true
        },
        "sourceIds": [
          "hg-pq-2026"
        ],
        "sourceLocator": "Experiment 5, Fig. 2E curve 14",
        "preparation": {
          "kind": "compressed state before quenching",
          "pressureUsed": true,
          "experiment": 5
        },
        "evidence": {
          "bulk": "resistive onset only for this plotted state",
          "replication": "same study"
        },
        "error": null
      }
    ],
    "views": {
      "pressureTemperature": {
        "pointIds": [
          "hg-1911",
          "pb-context",
          "nb-context",
          "nbge-1974",
          "lbco-1986",
          "ybco-1987",
          "hg-1993",
          "hg-1994",
          "mgb2-2001",
          "h3s-2015",
          "lah10-2019",
          "hg-pq5-after-2026"
        ],
        "x": "operatingPressure",
        "y": "temperatureKelvin"
      },
      "history": {
        "pointIds": [
          "hg-1911",
          "nbge-1974",
          "lbco-1986",
          "ybco-1987",
          "hg-1993",
          "hg-1994",
          "mgb2-2001",
          "h3s-2015",
          "lah10-2019",
          "hg-pq5-after-2026"
        ],
        "x": "year",
        "y": "temperatureKelvin",
        "seriesField": "operatingPressure.kind",
        "recordEnvelope": false
      },
      "quench": {
        "pointIds": [
          "hg-pq3-before-2026",
          "hg-pq3-after-2026",
          "hg-pq4-before-2026",
          "hg-pq4-after-2026",
          "hg-pq5-before-2026",
          "hg-pq5-after-2026"
        ],
        "pairs": [
          [
            "hg-pq3-before-2026",
            "hg-pq3-after-2026"
          ],
          [
            "hg-pq4-before-2026",
            "hg-pq4-after-2026"
          ],
          [
            "hg-pq5-before-2026",
            "hg-pq5-after-2026"
          ]
        ],
        "criterion": "resistive-onset-dR-dT",
        "connectionMeaning": "before/after preparation pair, not a measured pressure trajectory or phase boundary"
      }
    },
    "target": {
      "kind": "research-target-not-observation",
      "temperatureKelvin": [
        293.15,
        298.15
      ],
      "temperatureCelsius": [
        20,
        25
      ],
      "operatingPressure": {
        "kind": "ambient",
        "gigaPascals": null,
        "ongoingCompression": false,
        "plotReferenceGigaPascals": 0.000101325,
        "plotReferenceLabel": "1 atm reference",
        "basis": "Exact existing catalog prospective scope"
      },
      "reproducible": true,
      "stableOperationRequired": true,
      "source": "existing canonical roomtempsc scope and target, unchanged"
    },
    "exclusions": [
      {
        "id": "csh-2020",
        "reason": "Retracted original report",
        "source": "https://www.nature.com/articles/s41586-022-05294-9.pdf",
        "date": "2022-09-26"
      },
      {
        "id": "lu-n-h-2023",
        "reason": "Retracted original report",
        "source": "https://www.nature.com/articles/s41586-023-06774-2",
        "date": "2023-11-07"
      },
      {
        "id": "hg-pq-172",
        "reason": "Unrepeated anomaly in current primary paper; not an accepted plotted transition",
        "sourceId": "hg-pq-2026"
      },
      {
        "id": "theoretical-high-Tc",
        "reason": "Predictions and molecular-dynamics temperature do not supply observed transition coordinates"
      },
      {
        "id": "unassessed-company-claim",
        "reason": "Existing scientific-review hold preserved; no new acceptance or refutation assigned"
      },
      {
        "id": "claimed-current-world-record",
        "reason": "Selected primary-source sample is not an exhaustive current record survey"
      }
    ],
    "researchSessionDateRange": [
      "2026-10-04",
      "2026-10-05"
    ]
  },
  "sources": [
    {
      "id": "onnes-history",
      "title": "Macroscopic quantum phenomena from pairing in superconductors",
      "author": "J. R. Schrieffer",
      "date": "1972-12-11",
      "kind": "primary-researcher Nobel lecture, historical measurement retrospective",
      "url": "https://www.nobelprize.org/uploads/2018/06/schrieffer-lecture.pdf",
      "locator": "Introduction, reproduced Onnes Fig. 17 as Fig. 1; indexed complete introductory passage",
      "readLevel": "indexed selected primary text and figure description; direct PDF open failed",
      "quote": "Thus, mercury at 4.2 K has entered a new state",
      "supports": [
        "Hg 1911 historical discovery; abrupt electrical-resistance disappearance near 4.2 K"
      ],
      "qualification": "1911 is historical experiment year, not this lecture's publication year. Not a 1911 Meissner measurement."
    },
    {
      "id": "nbs-elemental",
      "title": "The role of superconductivity in the space program: an assessment of present capabilities and future potential",
      "author": "D. B. Sullivan (editor)",
      "date": "1978-05",
      "kind": "official NBS technical report",
      "url": "https://nvlpubs.nist.gov/nistpubs/Legacy/IR/nbsir78-885.pdf",
      "locator": "NBSIR 78-885; chapter VII Microwave applications, printed p. 119 (PDF p. 139), lines 3659–3661",
      "readLevel": "full PDF text, selected chapter and report metadata",
      "quote": "Niobium (9.25 K) and lead (7.19 K)",
      "supports": [
        "Typical elemental bulk transition temperatures used as context"
      ],
      "qualification": "Reference temperatures, not dated discoveries or new measurements; surface cleanliness and strain matter."
    },
    {
      "id": "nbge-1974",
      "title": "Superconductivity with onset above 23°K in Nb–Ge sputtered films",
      "author": "L. R. Testardi, J. H. Wernick, W. A. Royer",
      "date": "1974-07-01",
      "kind": "primary experimental paper",
      "doi": "10.1016/0038-1098(74)90002-7",
      "url": "https://www.sciencedirect.com/science/article/abs/pii/0038109874900027",
      "locator": "Complete publisher Abstract and publication metadata",
      "readLevel": "complete indexed publisher abstract; body not accessed",
      "quote": "maximum onset temperature of 23.2 ± 0.2°K",
      "supports": [
        "23.2 ± 0.2 K onset in nominal Nb3Ge sputtered films; transition width about 1.2 K"
      ],
      "qualification": "Abstract does not state which measurement determines onset. Ambient classification is an inference from unpressurized film experiment, not an exact pressure measurement. Do not date this 23.2 value to 1973."
    },
    {
      "id": "lbco-original",
      "title": "Possible high Tc superconductivity in the Ba–La–Cu–O system",
      "author": "J. G. Bednorz, K. A. Müller",
      "date": "1986-06",
      "kind": "primary experimental paper",
      "doi": "10.1007/BF01303701",
      "url": "https://link.springer.com/article/10.1007/BF01303701",
      "locator": "Complete Abstract and publisher publication month",
      "readLevel": "publisher abstract",
      "quote": "onset in the 30 K range",
      "supports": [
        "Original report is resistive onset in mixed-phase oxygen-deficient material"
      ],
      "qualification": "Abstract alone does not establish an exact 35 K value or zero resistance at 35 K."
    },
    {
      "id": "lbco-lecture",
      "title": "Perovskite-type oxides—the new approach to high-Tc superconductivity",
      "author": "J. G. Bednorz, K. A. Müller",
      "date": "1987-12-08",
      "kind": "primary authors' Nobel lecture",
      "url": "https://www.nobelprize.org/uploads/2018/06/bednorz-muller-lecture.pdf",
      "locator": "Printed p. 432, paragraph before Fig. 1.6; Fig. 1.5; p. 439 replication and pressure distinction",
      "readLevel": "indexed selected full primary passages; direct PDF open failed",
      "quote": "shift the onset of the resistivity drop to 35 K",
      "supports": [
        "35 K is resistive onset, retrospectively attributed to 1986 experiment"
      ],
      "qualification": "Lecture describes later magnetic work and external confirmations separately; 35 K point is not recoded as magnetic onset or zero resistance."
    },
    {
      "id": "ybco-1987",
      "title": "Superconductivity at 93 K in a new mixed-phase Y–Ba–Cu–O compound system at ambient pressure",
      "author": "M. K. Wu et al.",
      "date": "1987-03-02",
      "kind": "primary experimental paper",
      "doi": "10.1103/PhysRevLett.58.908",
      "url": "https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.58.908",
      "locator": "Complete publisher Abstract and metadata",
      "readLevel": "publisher abstract",
      "quote": "transition between 80 and 93 K",
      "supports": [
        "Ambient pressure; resistive and magnetic transitions across 80–93 K"
      ],
      "qualification": "93 K is upper end of reported interval, not formal measurement error or a proved zero-resistance threshold. Original material mixed-phase."
    },
    {
      "id": "hg-1993",
      "title": "Superconductivity above 130 K in the Hg–Ba–Ca–Cu–O system",
      "author": "A. Schilling, M. Cantoni, J. D. Guo, H. R. Ott",
      "date": "1993",
      "kind": "primary experimental paper",
      "doi": "10.1038/363056a0",
      "url": "https://www.nature.com/articles/363056a0",
      "locator": "Complete publisher Abstract; later primary hydride reports identify this as ambient-pressure context",
      "readLevel": "publisher abstract",
      "quote": "Both magnetic and resistivity measurements confirm a maximum transition temperature of ∼ 133 K",
      "supports": [
        "Approximate 133 K transition in multiphase mercury cuprate with ordered intergrowth"
      ],
      "qualification": "Not a pure-phase, exact onset or zero-resistance claim. Ambient classification combines this report with later primary context."
    },
    {
      "id": "hg-1994",
      "title": "Superconductivity up to 164 K in HgBa2Ca(m−1)Cu(m)O(2m+2+δ) (m=1,2,3) under quasihydrostatic pressures",
      "author": "L. Gao et al.",
      "date": "1994-08-01",
      "kind": "primary experimental paper",
      "doi": "10.1103/PhysRevB.50.4260",
      "url": "https://journals.aps.org/prb/abstract/10.1103/PhysRevB.50.4260",
      "fullTextUrl": "https://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.50.4260/fulltext",
      "locator": "PDF p. 1 Abstract; p. 2 pressure and temperature calibration, onset definition and 31 GPa maximum",
      "readLevel": "full four-page primary PDF, selected methods/results",
      "quote": "onset of superconductivity up to ∼164 K",
      "supports": [
        "Resistive onset about 164 K at about 31 GPa; pressure uncertainty about 5%; instrumental temperature uncertainty ±0.1 K"
      ],
      "qualification": "Nonzero resistance background and long tail are reported. Instrument uncertainty is not a formal uncertainty on rounded onset."
    },
    {
      "id": "mgb2-2001",
      "title": "Superconductivity at 39 K in magnesium diboride",
      "author": "J. Nagamatsu et al.",
      "date": "2001-03-01",
      "kind": "primary experimental paper",
      "doi": "10.1038/35065039",
      "url": "https://www.nature.com/articles/35065039",
      "locator": "Complete indexed publisher Abstract",
      "readLevel": "indexed publisher abstract; direct open failed",
      "quote": "discovery of bulk superconductivity in magnesium diboride, MgB2",
      "supports": [
        "39 K bulk superconductivity, magnetization and resistivity"
      ],
      "qualification": "Exact onset versus zero-resistance criterion not supplied by accessed abstract. No continuing compression reported in accessed material."
    },
    {
      "id": "h3s-2015",
      "title": "Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system",
      "author": "A. P. Drozdov et al.",
      "date": "2015-08-17",
      "kind": "primary experimental paper with author preprint",
      "doi": "10.1038/nature14964",
      "url": "https://www.nature.com/articles/nature14964",
      "fullTextUrl": "https://arxiv.org/pdf/1506.08190",
      "locator": "Author PDF p. 3 magnetic onset; Fig. 4 caption PDF pp. 11–12 pressure 155 GPa; pp. 2,4–5 preparation and electrical measurements",
      "readLevel": "final publisher abstract plus author preprint selected main text, methods and figure captions",
      "quote": "Tonset = 203(1) K",
      "supports": [
        "Magnetic onset 203(1) K at 155 GPa; linked resistive trace at 145 GPa is 195 K"
      ],
      "qualification": "Exact displayed 203 point is magnetic onset, not zero resistance at 203 K. 155 GPa and 203 K must be paired from Fig. 4. Author preprint methods are version-qualified."
    },
    {
      "id": "lah10-2019",
      "title": "Superconductivity at 250 K in lanthanum hydride under high pressures",
      "author": "A. P. Drozdov et al.",
      "date": "2019-05-22",
      "kind": "primary experimental paper with earlier author preprint",
      "doi": "10.1038/s41586-019-1201-8",
      "url": "https://www.nature.com/articles/s41586-019-1201-8",
      "fullTextUrl": "https://arxiv.org/pdf/1812.01561",
      "locator": "Final Abstract/metadata; author preprint PDF pp. 1–3 transition and maximum near 170 GPa; Fig. 1–2; Methods p. 7",
      "readLevel": "final publisher abstract plus 2018-12-04 author preprint v1 selected results/methods",
      "quote": "at a pressure P ~ 170 GPa",
      "supports": [
        "Published transition approximately 250 K at approximately 170 GPa"
      ],
      "qualification": "Multiple resistive transitions fall to zero, but 250 K is reported transition/onset, not necessarily completed zero resistance. Meissner measurement was not supplied by preprint. Do not substitute later near-room-temperature claims."
    },
    {
      "id": "hg-pq-2026",
      "title": "Ambient-pressure 151-K superconductivity in HgBa2Ca2Cu3O8+δ via pressure quench",
      "author": "Liangzi Deng et al.",
      "date": "2026-03-09",
      "kind": "primary experimental paper",
      "doi": "10.1073/pnas.2536178123",
      "url": "https://www.pnas.org/doi/10.1073/pnas.2536178123",
      "fullTextUrl": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12993975/",
      "locator": "Determination of Target Phases (dR/dT onset); Pressure Quenching Experiments 3/4/5, Fig. 2C/D/E–F; Stability Testing and Methods",
      "readLevel": "indexed relevant complete primary Results/Methods passages; direct PNAS/PMC blocked; SI not accessed",
      "quote": "ambient-pressure T_{c} up to 151 K",
      "supports": [
        "Exp.3 152 K/10.1 GPa→147 K/ambient; Exp.4 154 K/10.9 GPa→149 K/ambient; Exp.5 158 K/18.9 GPa→151 K/ambient, all resistive onset"
      ],
      "qualification": "After quenching at 4.2 K, values are first warming curves. Companion cooling values 147/148/150 K. Limited stability; retrieved magnetic onset about 140 K is a different state; unrepeated 172 K excluded."
    },
    {
      "id": "standard-atmosphere",
      "title": "NIST Guide to the SI, Appendix B: Conversion Factors",
      "date": null,
      "kind": "official unit definition",
      "url": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors",
      "locator": "Section B.3 standard atmosphere conversion example",
      "readLevel": "official source text",
      "quote": "1 atm = 101 325 Pa (exactly)",
      "supports": [
        "Exact plotting-reference conversion 0.000101325 GPa"
      ],
      "qualification": "Reference coordinate only; it is not the measured pressure of each ambient sample."
    }
  ]
}