{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"8d74f659d51341c3268a3b3cd1747584811a7c2b276d38cbe302e713afafac0b","created":"2026-10-03T07:18:00Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"e6871aea6aada7d9afb07c98d856907144f2c1664477c393230863d4a685c3f1","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"cm.iron-based.nematic-driving-force","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"Electrons in iron-based materials spontaneously choose one crystal direction; it is debated whether magnetism, orbital occupation, or chemical bonds drive this choice, especially in FeSe where no magnetism follows.","posed_since":"","precise":"In iron pnictides and FeSe, determine whether $B1g$ electronic nematic order (measured by elastoresistance and Raman) is driven by spin fluctuations (vestigial order of stripe magnetism), by orbital order ($n_{xz} - n_{yz}$), or by bond order, and in particular explain nematic order at $T_s \\sim 90\\,\\mathrm{K}$ without magnetic order in FeSe. An answer is a theory consistent with the neutron spin-fluctuation spectrum, the ARPES orbital splitting and the absence of magnetic order in FeSe.","problem_ref":null,"references":"","settled_by":"A calculation reproducing $T_s$, the orbital splitting and the spin-fluctuation spectrum of FeSe and BaFe2As2 with one set of interaction parameters.","status_note":"","title":"What drives electronic nematic order in iron-based superconductors","topic_ref":"71fc7a5f7f45e0e897c1da37458bfa12479b8a0797fe32805a586a3c8fc44007"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"14bc878649b69b8875db62824c319078a4d970be2cdb7b3112ce2367d6696176","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8790a734bab35e01467fa01840a9caa738bfa4314b026d734cb4818921b6215a","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"sZxMPDUMkKSDWriPSfS4TSqvhyWwTpj6uZimkzTb-Yk9hFMp9-40pOzBbgrbdpBD1_avI6j61HX2vuDwqt6LDw"},"schema":"pubphys.envelope/1"},"record_hash":"14bc878649b69b8875db62824c319078a4d970be2cdb7b3112ce2367d6696176","leaf_index":1046}