{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"1fb995d123ec840703bb407521d102a6b7681a8a06194fab05e46359e0d1d790","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["088cb2595511506ca5cc1cb2ab67f7a59b54da87f26420aa278e9be699eabd0a","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"3a251bcde045beb62faabce6bb921023266f9ee16548cac9e37f2a2ea0f1e56a","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":["ai:gpt-5.5"],"external_id":"cm.ferroelectric-polar-textures.hfo2-ferroelectricity","kind":"phenomenon","literature_status":"partially-resolved","n":"2","parents":[],"plain":"Hafnium oxide, already used in computer chips, turned out in 2011 to be ferroelectric when made as films a few dozen atoms thick, although its bulk crystal is not. Why the polar crystal phase survives and why the response grows with repeated switching, called wake-up, are open.","posed_since":"2011","precise":"Doped (Si, Zr, La, Y) $\\mathrm{HfO_2}$ films of thickness about $5 \\times 10^{-7}$ to $2 \\times 10^{-6}$ cm show remanent polarization of order $3 \\times 10^{4} \\text{ to } 9 \\times 10^{4}\\,\\mathrm{statC}/\\mathrm{cm}^{2}$, attributed mainly to the metastable orthorhombic $\\mathrm{Pca2}_{1}$ phase. Determine which factors stabilize it (surface and grain-boundary energy, dopants, oxygen vacancies, stress, electrodes), whether other polar phases contribute, and the mechanism of wake-up and fatigue (oxygen-vacancy redistribution versus field-induced transformation from tetragonal or monoclinic grains). An answer is a phase-stability and switching model predicting remanent polarization versus thickness, dopant and cycle number.","problem_ref":"088cb2595511506ca5cc1cb2ab67f7a59b54da87f26420aa278e9be699eabd0a","references":"","settled_by":"In situ structural imaging of individual grains through wake-up cycling, matched by a first-principles phase-stability model that predicts the measured polarization.","status_note":"The orthorhombic $\\mathrm{Pca2}_{1}$ phase is widely accepted as the main polar phase; its stabilization route and the wake-up mechanism remained debated as of 2025.","title":"What stabilizes ferroelectricity and wake-up in thin-film $\\mathrm{HfO_2}$?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"9c6443b6dd62aef99e74e655d983afc0d7f0a729ef66c056bb5c09c08e5f8a5a","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"b4b37193e2104c55aa46bf8fbe732ff08817d0954ad0cfdb941fe483913aa236","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"qs0H3LUDR0CyBNZhNlgG4Vb4p-ihpVURaQ1--9PrYh_ot9-sgUKdbtLPyubE-_CTrDkfaeuFlriZZ-LxyQQaAA"},"schema":"pubphys.envelope/1"},"record_hash":"9c6443b6dd62aef99e74e655d983afc0d7f0a729ef66c056bb5c09c08e5f8a5a","leaf_index":2788}