{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2018:2IHJOLDIE4LNFMM2MF5YD43WYR","short_pith_number":"pith:2IHJOLDI","schema_version":"1.0","canonical_sha256":"d20e972c682716d2b19a617b81f376c44a3697a1c74c13612ee0bab97c82f6b4","source":{"kind":"arxiv","id":"1810.08800","version":4},"attestation_state":"computed","paper":{"title":"First-principles study of phonon anharmonicity and negative thermal expansion in ScF3","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.mtrl-sci","authors_text":"Ryosuke Akashi, Shinji Tsuneyuki, Terumasa Tadano, Yusuke Oba","submitted_at":"2018-10-20T12:56:58Z","abstract_excerpt":"The microscopic origin of the large negative thermal expansion of cubic scandium trifluorides (ScF3) is investigated by performing a set of anharmonic free-energy calculations based on density functional theory. We demonstrate that the conventional quasiharmonic approximation (QHA) completely breaks down for ScF3 and the quartic anharmonicity, treated nonperturbatively by the self-consistent phonon theory, is essential to reproduce the observed transition from negative to positive thermal expansivity and the hardening of the R4+ soft mode with heating. In addition, we show that the contributio"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"1810.08800","kind":"arxiv","version":4},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2018-10-20T12:56:58Z","cross_cats_sorted":[],"title_canon_sha256":"3ccb2a4b25954ddd1a487fced9a43c248d912288ef9377d3b94fce93648ede4a","abstract_canon_sha256":"8f0b98c3eb6c9509027f8d197412473d1f7703250a27526a09dbb8521669a82a"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:51:33.031527Z","signature_b64":"LcbbDAm5tir4NsJPpbtxi8Ij03gvilCYg/9/nmJD/PEHazPFlhuB69fXtadg3Y6r/fyjoNllwY96Bo2SyWxoBA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"d20e972c682716d2b19a617b81f376c44a3697a1c74c13612ee0bab97c82f6b4","last_reissued_at":"2026-05-17T23:51:33.031025Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:51:33.031025Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"First-principles study of phonon anharmonicity and negative thermal expansion in ScF3","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.mtrl-sci","authors_text":"Ryosuke Akashi, Shinji Tsuneyuki, Terumasa Tadano, Yusuke Oba","submitted_at":"2018-10-20T12:56:58Z","abstract_excerpt":"The microscopic origin of the large negative thermal expansion of cubic scandium trifluorides (ScF3) is investigated by performing a set of anharmonic free-energy calculations based on density functional theory. We demonstrate that the conventional quasiharmonic approximation (QHA) completely breaks down for ScF3 and the quartic anharmonicity, treated nonperturbatively by the self-consistent phonon theory, is essential to reproduce the observed transition from negative to positive thermal expansivity and the hardening of the R4+ soft mode with heating. In addition, we show that the contributio"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1810.08800","kind":"arxiv","version":4},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"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"},"aliases":[{"alias_kind":"arxiv","alias_value":"1810.08800","created_at":"2026-05-17T23:51:33.031114+00:00"},{"alias_kind":"arxiv_version","alias_value":"1810.08800v4","created_at":"2026-05-17T23:51:33.031114+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1810.08800","created_at":"2026-05-17T23:51:33.031114+00:00"},{"alias_kind":"pith_short_12","alias_value":"2IHJOLDIE4LN","created_at":"2026-05-18T12:32:02.567920+00:00"},{"alias_kind":"pith_short_16","alias_value":"2IHJOLDIE4LNFMM2","created_at":"2026-05-18T12:32:02.567920+00:00"},{"alias_kind":"pith_short_8","alias_value":"2IHJOLDI","created_at":"2026-05-18T12:32:02.567920+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":0,"internal_anchor_count":0,"sample":[]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR","json":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR.json","graph_json":"https://pith.science/api/pith-number/2IHJOLDIE4LNFMM2MF5YD43WYR/graph.json","events_json":"https://pith.science/api/pith-number/2IHJOLDIE4LNFMM2MF5YD43WYR/events.json","paper":"https://pith.science/paper/2IHJOLDI"},"agent_actions":{"view_html":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR","download_json":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR.json","view_paper":"https://pith.science/paper/2IHJOLDI","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=1810.08800&json=true","fetch_graph":"https://pith.science/api/pith-number/2IHJOLDIE4LNFMM2MF5YD43WYR/graph.json","fetch_events":"https://pith.science/api/pith-number/2IHJOLDIE4LNFMM2MF5YD43WYR/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR/action/timestamp_anchor","attest_storage":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR/action/storage_attestation","attest_author":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR/action/author_attestation","sign_citation":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR/action/citation_signature","submit_replication":"https://pith.science/pith/2IHJOLDIE4LNFMM2MF5YD43WYR/action/replication_record"}},"created_at":"2026-05-17T23:51:33.031114+00:00","updated_at":"2026-05-17T23:51:33.031114+00:00"}