{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2026:4OXS72RUYDG4DMITNYLLG22XC6","short_pith_number":"pith:4OXS72RU","canonical_record":{"source":{"id":"2605.01651","kind":"arxiv","version":2},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cond-mat.supr-con","submitted_at":"2026-05-03T00:25:25Z","cross_cats_sorted":[],"title_canon_sha256":"80d1c93b2d255410f855c509d2cb293ea05d77c5672929ef8627bfbaf25ad7c0","abstract_canon_sha256":"7e687e68dbecd011d4f29adde550f3762f64a4a7eec420b107667529e68bf640"},"schema_version":"1.0"},"canonical_sha256":"e3af2fea34c0cdc1b1136e16b36b5717b870564945597aa0dad03b89a7de310d","source":{"kind":"arxiv","id":"2605.01651","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2605.01651","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"arxiv_version","alias_value":"2605.01651v2","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2605.01651","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"pith_short_12","alias_value":"4OXS72RUYDG4","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"pith_short_16","alias_value":"4OXS72RUYDG4DMIT","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"pith_short_8","alias_value":"4OXS72RU","created_at":"2026-05-26T01:03:31Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2026:4OXS72RUYDG4DMITNYLLG22XC6","target":"record","payload":{"canonical_record":{"source":{"id":"2605.01651","kind":"arxiv","version":2},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cond-mat.supr-con","submitted_at":"2026-05-03T00:25:25Z","cross_cats_sorted":[],"title_canon_sha256":"80d1c93b2d255410f855c509d2cb293ea05d77c5672929ef8627bfbaf25ad7c0","abstract_canon_sha256":"7e687e68dbecd011d4f29adde550f3762f64a4a7eec420b107667529e68bf640"},"schema_version":"1.0"},"canonical_sha256":"e3af2fea34c0cdc1b1136e16b36b5717b870564945597aa0dad03b89a7de310d","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-26T01:03:31.859724Z","signature_b64":"EqcBNGyizbKbz2vV6kVzM+s8avDCUeuCF460+RhuCWJJLemHHBjgqAkukgkV3wBdMRUE7My3GNUe57H2s36yBg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"e3af2fea34c0cdc1b1136e16b36b5717b870564945597aa0dad03b89a7de310d","last_reissued_at":"2026-05-26T01:03:31.858771Z","signature_status":"signed_v1","first_computed_at":"2026-05-26T01:03:31.858771Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2605.01651","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-26T01:03:31Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"7p0cSy71ym8ggHjnW9r8a6YttY5vsypfoxolLdxZ0dp5rPaGlQRaHdxRyNYRA5UTNdtOuhRDy5buQnjSwOp5Aw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-06T06:48:59.332500Z"},"content_sha256":"beab55755d9fb5190c7701300870aab9097b5550937746b4baebf56e87bb123d","schema_version":"1.0","event_id":"sha256:beab55755d9fb5190c7701300870aab9097b5550937746b4baebf56e87bb123d"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2026:4OXS72RUYDG4DMITNYLLG22XC6","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Metallic crossover through the tilt-free transition in La$_3$Ni$_2$O$_7$ at high pressure and temperature","license":"http://creativecommons.org/licenses/by/4.0/","headline":"The tilt-free structural transition in La3Ni2O7 drives a two-order-of-magnitude increase in carrier density, crossing from bad metal to good metal.","cross_cats":[],"primary_cat":"cond-mat.supr-con","authors_text":"Bastien Michon, Beatrice D'Al\\`o, Bosen Wang, Elena Stellino, Ferenc Borondics, Francesco Capitani, Gergely N\\'emeth, Jianping Sun, Jinguang Cheng, Paolo Postorino, Yingpeng Yu","submitted_at":"2026-05-03T00:25:25Z","abstract_excerpt":"La$_3$Ni$_2$O$_7$, a bilayer nickelate with Ruddlesden-Popper structure, undergoes a pressure-induced structural transition from a tilted Amam phase to an untilted Fmmm (or I4/mmm) phase near 10-15 GPa, concomitant with the emergence of high-T$_c$ superconductivity ($T_c \\sim 80$ K). Despite intense interest, the phase boundaries and the impact of structural changes on the electronic properties remain unclear. Here, we combine high-pressure and high-temperature Raman and synchrotron-based infrared spectroscopies to map the structural and electronic evolutions. Raman measurements confirm the pr"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"Infrared reflectivity measurements evidence a concomitant metallization, with a tremendous two-order-of-magnitude increase in carrier density, marking a crossover from a bad metal to a good metal.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That changes in infrared reflectivity can be interpreted as a direct two-order-of-magnitude carrier density increase without major contributions from scattering rate variations or other optical effects.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A metallic crossover from bad metal to good metal occurs at the tilt-free structural transition in La3Ni2O7 near 10-15 GPa, with carrier density rising by two orders of magnitude and similar signatures appearing above 544 K.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"The tilt-free structural transition in La3Ni2O7 drives a two-order-of-magnitude increase in carrier density, crossing from bad metal to good metal.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"0b30cbe74a709229b556ecc7caeba0a39abb407a921fe746a8c6728947215d56"},"source":{"id":"2605.01651","kind":"arxiv","version":2},"verdict":{"id":"22d23a92-88ae-43ac-a6f3-9a6d2bcfd161","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-09T17:09:55.008130Z","strongest_claim":"Infrared reflectivity measurements evidence a concomitant metallization, with a tremendous two-order-of-magnitude increase in carrier density, marking a crossover from a bad metal to a good metal.","one_line_summary":"A metallic crossover from bad metal to good metal occurs at the tilt-free structural transition in La3Ni2O7 near 10-15 GPa, with carrier density rising by two orders of magnitude and similar signatures appearing above 544 K.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That changes in infrared reflectivity can be interpreted as a direct two-order-of-magnitude carrier density increase without major contributions from scattering rate variations or other optical effects.","pith_extraction_headline":"The tilt-free structural transition in La3Ni2O7 drives a two-order-of-magnitude increase in carrier density, crossing from bad metal to good metal."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2605.01651/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"ai_meta_artifact","ran_at":"2026-05-20T17:38:47.620428Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_title_agreement","ran_at":"2026-05-20T05:01:23.609407Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_compliance","ran_at":"2026-05-19T17:06:49.414918Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"83e281317850a875537335874cac8b837fa2e6198c7bd58d9f76d5bf69240e8d"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":"22d23a92-88ae-43ac-a6f3-9a6d2bcfd161"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-26T01:03:31Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"rEMeAWRcEu4d6mHNeYwP4zqVc1pAp3X5vhodoroG4yWiM/AAdW076f6isN5WeN4l2zgxsYX2kFg43iSS7g0UAQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-06T06:48:59.333619Z"},"content_sha256":"3ed61344ac09edb5284f160332fcad59cd2a141efc2da712d04203538f5a12a6","schema_version":"1.0","event_id":"sha256:3ed61344ac09edb5284f160332fcad59cd2a141efc2da712d04203538f5a12a6"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/4OXS72RUYDG4DMITNYLLG22XC6/bundle.json","state_url":"https://pith.science/pith/4OXS72RUYDG4DMITNYLLG22XC6/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/4OXS72RUYDG4DMITNYLLG22XC6/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-06-06T06:48:59Z","links":{"resolver":"https://pith.science/pith/4OXS72RUYDG4DMITNYLLG22XC6","bundle":"https://pith.science/pith/4OXS72RUYDG4DMITNYLLG22XC6/bundle.json","state":"https://pith.science/pith/4OXS72RUYDG4DMITNYLLG22XC6/state.json","well_known_bundle":"https://pith.science/.well-known/pith/4OXS72RUYDG4DMITNYLLG22XC6/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2026:4OXS72RUYDG4DMITNYLLG22XC6","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"7e687e68dbecd011d4f29adde550f3762f64a4a7eec420b107667529e68bf640","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cond-mat.supr-con","submitted_at":"2026-05-03T00:25:25Z","title_canon_sha256":"80d1c93b2d255410f855c509d2cb293ea05d77c5672929ef8627bfbaf25ad7c0"},"schema_version":"1.0","source":{"id":"2605.01651","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2605.01651","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"arxiv_version","alias_value":"2605.01651v2","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2605.01651","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"pith_short_12","alias_value":"4OXS72RUYDG4","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"pith_short_16","alias_value":"4OXS72RUYDG4DMIT","created_at":"2026-05-26T01:03:31Z"},{"alias_kind":"pith_short_8","alias_value":"4OXS72RU","created_at":"2026-05-26T01:03:31Z"}],"graph_snapshots":[{"event_id":"sha256:3ed61344ac09edb5284f160332fcad59cd2a141efc2da712d04203538f5a12a6","target":"graph","created_at":"2026-05-26T01:03:31Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":4,"items":[{"attestation":"unclaimed","claim_id":"C1","kind":"strongest_claim","source":"verdict.strongest_claim","status":"machine_extracted","text":"Infrared reflectivity measurements evidence a concomitant metallization, with a tremendous two-order-of-magnitude increase in carrier density, marking a crossover from a bad metal to a good metal."},{"attestation":"unclaimed","claim_id":"C2","kind":"weakest_assumption","source":"verdict.weakest_assumption","status":"machine_extracted","text":"That changes in infrared reflectivity can be interpreted as a direct two-order-of-magnitude carrier density increase without major contributions from scattering rate variations or other optical effects."},{"attestation":"unclaimed","claim_id":"C3","kind":"one_line_summary","source":"verdict.one_line_summary","status":"machine_extracted","text":"A metallic crossover from bad metal to good metal occurs at the tilt-free structural transition in La3Ni2O7 near 10-15 GPa, with carrier density rising by two orders of magnitude and similar signatures appearing above 544 K."},{"attestation":"unclaimed","claim_id":"C4","kind":"headline","source":"verdict.pith_extraction.headline","status":"machine_extracted","text":"The tilt-free structural transition in La3Ni2O7 drives a two-order-of-magnitude increase in carrier density, crossing from bad metal to good metal."}],"snapshot_sha256":"0b30cbe74a709229b556ecc7caeba0a39abb407a921fe746a8c6728947215d56"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[{"findings_count":0,"name":"ai_meta_artifact","ran_at":"2026-05-20T17:38:47.620428Z","status":"completed","version":"1.0.0"},{"findings_count":0,"name":"doi_title_agreement","ran_at":"2026-05-20T05:01:23.609407Z","status":"completed","version":"1.0.0"},{"findings_count":0,"name":"doi_compliance","ran_at":"2026-05-19T17:06:49.414918Z","status":"completed","version":"1.0.0"}],"endpoint":"/pith/2605.01651/integrity.json","findings":[],"snapshot_sha256":"83e281317850a875537335874cac8b837fa2e6198c7bd58d9f76d5bf69240e8d","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"La$_3$Ni$_2$O$_7$, a bilayer nickelate with Ruddlesden-Popper structure, undergoes a pressure-induced structural transition from a tilted Amam phase to an untilted Fmmm (or I4/mmm) phase near 10-15 GPa, concomitant with the emergence of high-T$_c$ superconductivity ($T_c \\sim 80$ K). Despite intense interest, the phase boundaries and the impact of structural changes on the electronic properties remain unclear. Here, we combine high-pressure and high-temperature Raman and synchrotron-based infrared spectroscopies to map the structural and electronic evolutions. Raman measurements confirm the pr","authors_text":"Bastien Michon, Beatrice D'Al\\`o, Bosen Wang, Elena Stellino, Ferenc Borondics, Francesco Capitani, Gergely N\\'emeth, Jianping Sun, Jinguang Cheng, Paolo Postorino, Yingpeng Yu","cross_cats":[],"headline":"The tilt-free structural transition in La3Ni2O7 drives a two-order-of-magnitude increase in carrier density, crossing from bad metal to good metal.","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cond-mat.supr-con","submitted_at":"2026-05-03T00:25:25Z","title":"Metallic crossover through the tilt-free transition in La$_3$Ni$_2$O$_7$ at high pressure and temperature"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2605.01651","kind":"arxiv","version":2},"verdict":{"created_at":"2026-05-09T17:09:55.008130Z","id":"22d23a92-88ae-43ac-a6f3-9a6d2bcfd161","model_set":{"reader":"grok-4.3"},"one_line_summary":"A metallic crossover from bad metal to good metal occurs at the tilt-free structural transition in La3Ni2O7 near 10-15 GPa, with carrier density rising by two orders of magnitude and similar signatures appearing above 544 K.","pipeline_version":"pith-pipeline@v0.9.0","pith_extraction_headline":"The tilt-free structural transition in La3Ni2O7 drives a two-order-of-magnitude increase in carrier density, crossing from bad metal to good metal.","strongest_claim":"Infrared reflectivity measurements evidence a concomitant metallization, with a tremendous two-order-of-magnitude increase in carrier density, marking a crossover from a bad metal to a good metal.","weakest_assumption":"That changes in infrared reflectivity can be interpreted as a direct two-order-of-magnitude carrier density increase without major contributions from scattering rate variations or other optical effects."}},"verdict_id":"22d23a92-88ae-43ac-a6f3-9a6d2bcfd161"}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:beab55755d9fb5190c7701300870aab9097b5550937746b4baebf56e87bb123d","target":"record","created_at":"2026-05-26T01:03:31Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"7e687e68dbecd011d4f29adde550f3762f64a4a7eec420b107667529e68bf640","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cond-mat.supr-con","submitted_at":"2026-05-03T00:25:25Z","title_canon_sha256":"80d1c93b2d255410f855c509d2cb293ea05d77c5672929ef8627bfbaf25ad7c0"},"schema_version":"1.0","source":{"id":"2605.01651","kind":"arxiv","version":2}},"canonical_sha256":"e3af2fea34c0cdc1b1136e16b36b5717b870564945597aa0dad03b89a7de310d","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"e3af2fea34c0cdc1b1136e16b36b5717b870564945597aa0dad03b89a7de310d","first_computed_at":"2026-05-26T01:03:31.858771Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-26T01:03:31.858771Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"EqcBNGyizbKbz2vV6kVzM+s8avDCUeuCF460+RhuCWJJLemHHBjgqAkukgkV3wBdMRUE7My3GNUe57H2s36yBg==","signature_status":"signed_v1","signed_at":"2026-05-26T01:03:31.859724Z","signed_message":"canonical_sha256_bytes"},"source_id":"2605.01651","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:beab55755d9fb5190c7701300870aab9097b5550937746b4baebf56e87bb123d","sha256:3ed61344ac09edb5284f160332fcad59cd2a141efc2da712d04203538f5a12a6"],"state_sha256":"46200874a5bff2465232befd2b31ad95ebef183ef00e3ebe286e0236a2204c8a"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ZiZL9tiZilcEyPmdUhjyKk/arEYhDML5Aro/oqdI95LIoS5swfPWTr2HvyxiDRJ7YGyrZsWHET1rPI5FjYVODQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-06T06:48:59.338397Z","bundle_sha256":"60daccf354c523622be69af4f4ed3d9903c6067bccba33aba24e733dbf7cd594"}}