{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"252a9e8d4a86e7df641f424553c010b6f08891c786704e316e198e28d9abc58e","created":"2026-10-03T07:18:01Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"293169647290a9a3a36c12ab7c7c070dc0e2276f1ed09ec6351cfbf060e6211a","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"cm.triangular-kagome-spin-liquids.kappa-cn-ground-state","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"This organic salt was the first proposed triangular-lattice spin liquid. Later experiments suggest a spin gap opens near 6 K, which would mean the spins pair into singlets instead.","posed_since":"2003","precise":"In kappa-(BEDT-TTF)2Cu2(CN)3 at ambient pressure, determine whether the anomaly near $6\\,\\mathrm{K}$ is a transition to a gapped valence-bond-solid state with spin gap $\\Delta_s$, or a crossover within a gapless spin liquid. An answer gives $\\Delta_s$ (or an upper bound) and the symmetry of the low-temperature state.","problem_ref":null,"references":"","settled_by":"Low-temperature ESR, NMR and x-ray diffraction searches for lattice dimerization below 6 K on the same crystals, together with thermal conductivity below 0.1 K.","status_note":"Miksch et al. (Science 2021) reported a gapped magnetic ground state from ESR; a structural confirmation of the singlet pattern is still lacking.","title":"Is $\\kappa$-(BEDT-TTF)2Cu2(CN)3 a spin liquid or a gapped valence-bond state?","topic_ref":"677def6cee2b4310dbf7fc819c31e2f8a08fa4d8676c34fd7ceecf8b863d1df4"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"aca1332662799d0ea25538807c057560b77bf809943a9467373d12573641980c","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"090cba34d696e4026cd4b823ef561d6ce1d58ac33494786780f285508f2d7ace","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"hEmtLLbnq4X7Xm-8g7-QT97HAU-7g_WRF5M_8rfWTxuZRhlLqJGs-aCr9p3z7aTB8-zLfOCTWd9dIpqOrpCcCQ"},"schema":"pubphys.envelope/1"},"record_hash":"aca1332662799d0ea25538807c057560b77bf809943a9467373d12573641980c","leaf_index":1197}