{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2010:NWG6RXPOUXWIY6JRRTKQ5UUCIH","short_pith_number":"pith:NWG6RXPO","canonical_record":{"source":{"id":"1004.4028","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2010-04-22T23:42:22Z","cross_cats_sorted":[],"title_canon_sha256":"54d2f56d46241a37cd095d1e7bb8dcb07f8b5401f4b0eefa39919a01ca671a89","abstract_canon_sha256":"d8fa892e3c20c5c65fd37fe84c0cf108c50c5875c9893bb0d35c2e6835adcdee"},"schema_version":"1.0"},"canonical_sha256":"6d8de8ddeea5ec8c79318cd50ed28241febc4ba399a39d36d451f884ce460ed0","source":{"kind":"arxiv","id":"1004.4028","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1004.4028","created_at":"2026-05-18T02:07:54Z"},{"alias_kind":"arxiv_version","alias_value":"1004.4028v1","created_at":"2026-05-18T02:07:54Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1004.4028","created_at":"2026-05-18T02:07:54Z"},{"alias_kind":"pith_short_12","alias_value":"NWG6RXPOUXWI","created_at":"2026-05-18T12:26:10Z"},{"alias_kind":"pith_short_16","alias_value":"NWG6RXPOUXWIY6JR","created_at":"2026-05-18T12:26:10Z"},{"alias_kind":"pith_short_8","alias_value":"NWG6RXPO","created_at":"2026-05-18T12:26:10Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2010:NWG6RXPOUXWIY6JRRTKQ5UUCIH","target":"record","payload":{"canonical_record":{"source":{"id":"1004.4028","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2010-04-22T23:42:22Z","cross_cats_sorted":[],"title_canon_sha256":"54d2f56d46241a37cd095d1e7bb8dcb07f8b5401f4b0eefa39919a01ca671a89","abstract_canon_sha256":"d8fa892e3c20c5c65fd37fe84c0cf108c50c5875c9893bb0d35c2e6835adcdee"},"schema_version":"1.0"},"canonical_sha256":"6d8de8ddeea5ec8c79318cd50ed28241febc4ba399a39d36d451f884ce460ed0","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:07:54.810221Z","signature_b64":"77aStaB/SuEXu+jaI2jrAJ7O22a4URQ68Oxpy+tDX/AVb+ZfA0pCw/Jh3mtbBzpOh/JWZvhp+PUXUTYDVAwcBA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"6d8de8ddeea5ec8c79318cd50ed28241febc4ba399a39d36d451f884ce460ed0","last_reissued_at":"2026-05-18T02:07:54.809563Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:07:54.809563Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1004.4028","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T02:07:54Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"E2KIDG2zkej5JOG6ZEiul1mjyi2d42MGLPCHPf7+DWfoWsvQfZdLSWlZVTNk4exNO/FYrFg4fplN5AdPMPBPDQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T16:29:20.051260Z"},"content_sha256":"ef23d60ea61c4b62943b21510d5406dafe8b9296d104cebea70e7d3dd4368717","schema_version":"1.0","event_id":"sha256:ef23d60ea61c4b62943b21510d5406dafe8b9296d104cebea70e7d3dd4368717"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2010:NWG6RXPOUXWIY6JRRTKQ5UUCIH","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"First-principles study of competing ferroelectric and antiferroelectric instabilities in BaTiO3/BaO superlattices","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.mtrl-sci","authors_text":"Eric Bousquet, Javier Junquera, Philippe Ghosez","submitted_at":"2010-04-22T23:42:22Z","abstract_excerpt":"We report a first-principles study of (BaTiO${_3}$)$_m$/(BaO)$_n$ superlattices for a wide range of periodicities $m/n$.  We show that such a system develops a polar zone-center instability for sufficiently large \\textit{m}/\\textit{n} ratio, which can be understood, at least qualitatively, from a simple electrostatic model and should lead to a ferroelectric ground-state.  However, the analysis of the phonon dispersion curves also points out the appearance of stronger antiferroelectric instabilities at the zone boundaries around $m=4$, before the critical ratio for ferroelectricity is reached a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1004.4028","kind":"arxiv","version":1},"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"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T02:07:54Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"AjWJzcl1PEALSNJx1b+jSSsMX/pRrKwE7RKcBy7Azw+uFtooH4jaw5vZ7+WViZOgR0ErYh1MuXQDq0TmfC9CBw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T16:29:20.051687Z"},"content_sha256":"a8e45381cbce37a0bd129609bf3fbe7c76528612f1438aac8ce460ca1eff5ebe","schema_version":"1.0","event_id":"sha256:a8e45381cbce37a0bd129609bf3fbe7c76528612f1438aac8ce460ca1eff5ebe"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/NWG6RXPOUXWIY6JRRTKQ5UUCIH/bundle.json","state_url":"https://pith.science/pith/NWG6RXPOUXWIY6JRRTKQ5UUCIH/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/NWG6RXPOUXWIY6JRRTKQ5UUCIH/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":"2026-05-31T16:29:20Z","links":{"resolver":"https://pith.science/pith/NWG6RXPOUXWIY6JRRTKQ5UUCIH","bundle":"https://pith.science/pith/NWG6RXPOUXWIY6JRRTKQ5UUCIH/bundle.json","state":"https://pith.science/pith/NWG6RXPOUXWIY6JRRTKQ5UUCIH/state.json","well_known_bundle":"https://pith.science/.well-known/pith/NWG6RXPOUXWIY6JRRTKQ5UUCIH/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2010:NWG6RXPOUXWIY6JRRTKQ5UUCIH","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":"d8fa892e3c20c5c65fd37fe84c0cf108c50c5875c9893bb0d35c2e6835adcdee","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2010-04-22T23:42:22Z","title_canon_sha256":"54d2f56d46241a37cd095d1e7bb8dcb07f8b5401f4b0eefa39919a01ca671a89"},"schema_version":"1.0","source":{"id":"1004.4028","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1004.4028","created_at":"2026-05-18T02:07:54Z"},{"alias_kind":"arxiv_version","alias_value":"1004.4028v1","created_at":"2026-05-18T02:07:54Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1004.4028","created_at":"2026-05-18T02:07:54Z"},{"alias_kind":"pith_short_12","alias_value":"NWG6RXPOUXWI","created_at":"2026-05-18T12:26:10Z"},{"alias_kind":"pith_short_16","alias_value":"NWG6RXPOUXWIY6JR","created_at":"2026-05-18T12:26:10Z"},{"alias_kind":"pith_short_8","alias_value":"NWG6RXPO","created_at":"2026-05-18T12:26:10Z"}],"graph_snapshots":[{"event_id":"sha256:a8e45381cbce37a0bd129609bf3fbe7c76528612f1438aac8ce460ca1eff5ebe","target":"graph","created_at":"2026-05-18T02:07:54Z","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":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"We report a first-principles study of (BaTiO${_3}$)$_m$/(BaO)$_n$ superlattices for a wide range of periodicities $m/n$.  We show that such a system develops a polar zone-center instability for sufficiently large \\textit{m}/\\textit{n} ratio, which can be understood, at least qualitatively, from a simple electrostatic model and should lead to a ferroelectric ground-state.  However, the analysis of the phonon dispersion curves also points out the appearance of stronger antiferroelectric instabilities at the zone boundaries around $m=4$, before the critical ratio for ferroelectricity is reached a","authors_text":"Eric Bousquet, Javier Junquera, Philippe Ghosez","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2010-04-22T23:42:22Z","title":"First-principles study of competing ferroelectric and antiferroelectric instabilities in BaTiO3/BaO superlattices"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1004.4028","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:ef23d60ea61c4b62943b21510d5406dafe8b9296d104cebea70e7d3dd4368717","target":"record","created_at":"2026-05-18T02:07:54Z","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":"d8fa892e3c20c5c65fd37fe84c0cf108c50c5875c9893bb0d35c2e6835adcdee","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2010-04-22T23:42:22Z","title_canon_sha256":"54d2f56d46241a37cd095d1e7bb8dcb07f8b5401f4b0eefa39919a01ca671a89"},"schema_version":"1.0","source":{"id":"1004.4028","kind":"arxiv","version":1}},"canonical_sha256":"6d8de8ddeea5ec8c79318cd50ed28241febc4ba399a39d36d451f884ce460ed0","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"6d8de8ddeea5ec8c79318cd50ed28241febc4ba399a39d36d451f884ce460ed0","first_computed_at":"2026-05-18T02:07:54.809563Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:07:54.809563Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"77aStaB/SuEXu+jaI2jrAJ7O22a4URQ68Oxpy+tDX/AVb+ZfA0pCw/Jh3mtbBzpOh/JWZvhp+PUXUTYDVAwcBA==","signature_status":"signed_v1","signed_at":"2026-05-18T02:07:54.810221Z","signed_message":"canonical_sha256_bytes"},"source_id":"1004.4028","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:ef23d60ea61c4b62943b21510d5406dafe8b9296d104cebea70e7d3dd4368717","sha256:a8e45381cbce37a0bd129609bf3fbe7c76528612f1438aac8ce460ca1eff5ebe"],"state_sha256":"a4cb3ff7d3eaabd28f96af9d8dfe2ac2374ee21701bd8fdb111ce3ee19cdf1de"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"fnWD4jv6znKhIDW00dWlp+s2/0q/TVAmW4BkccEK0XPYJRGmxKb82AqzzdF+5xiqMTUuU8sjjIT/6C/tZS8dAw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-31T16:29:20.054376Z","bundle_sha256":"084be545ec61b530ab95bbc9391d6a30091492cd01648c885ade23393e1274a0"}}