{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"8345307d09abd71e256564a095f6e983dc9ba3208f2190bbd6a047a8c806280c","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["4097ed23a73eae6a370132ab9bb6fc8b5d0087843eba3cf0183c2a4e88bb3a1e","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"a9b6d686b612c7e559ba4ab44a8c4938516f46d2699752c8f45c108a5a7a8ce6","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"cm.dilute-superconductivity.ferroelectric-critical-enhancement","kind":"phenomenon","literature_status":"open","n":"2","parents":[],"plain":"$\\mathrm{SrTiO_3}$ is close to becoming ferroelectric, meaning its ions almost shift to create a permanent electric dipole. Pushing it closer, by replacing oxygen-16 with oxygen-18 or adding calcium, raises its superconducting temperature, and the reason is debated.","posed_since":"2015","precise":"18O substitution, Ca substitution and strain move n-doped $\\mathrm{SrTiO_3}$ toward its ferroelectric quantum critical point and raise $T_c$, in some reports by about a factor of 2. Determine whether the enhancement is caused by pairing through the critical soft transverse-optical mode, which electron-phonon coupling is responsible (linear Rashba-type or bilinear two-phonon), and where $T_c$ peaks relative to the critical point (paraelectric side, at criticality, or inside the polar phase). An answer is a mechanism with a quantitative fit of $T_c$ versus distance to criticality and carrier density.","problem_ref":"4097ed23a73eae6a370132ab9bb6fc8b5d0087843eba3cf0183c2a4e88bb3a1e","references":"","settled_by":"Measurement of $T_{c}$ across the ferroelectric critical point at fixed n under continuous tuning (stress or isotope fraction) compared with a soft-mode pairing calculation with no free couplings.","status_note":"","title":"Does ferroelectric quantum criticality raise the $T_{c}$ of 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