{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"285d43d1d68dec7719c6b6841196967793f9e15ac8af2f1cf9523c69b85d5691","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["6b2c48359751e4225d3f424a4f69791fe8adddf15f7f169702b9f95ba7aed690","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"59bd9d20eae1063f47a32756889b7d99b8bd3aa1e845fbebbfe2a2a9fe451028","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"cm.nickelates.bilayer-pairing-symmetry","kind":"well-posed","literature_status":"contested","n":"2","parents":[],"plain":"In $\\mathrm{La_3Ni_2O_7}$ electrons in two nickel orbitals take part, and it is unknown whether pairs form mainly between the two layers of each bilayer or within each layer as in cuprates.","posed_since":"2023","precise":"For bilayer $\\mathrm{La_3Ni_2O_7}$ (hydrostatic pressure above $\\sim 140\\,\\mathrm{kbar}$, or compressively strained films), determine the gap symmetry (interlayer $s\\pm$ between bonding and antibonding d_z2-derived bands, or d-wave dominated by d_x2-y2) and the dominant pairing interaction (interlayer superexchange of d_z2 orbitals, Hund-coupled spin fluctuations). An answer is a momentum-resolved or phase-sensitive gap measurement plus a model reproducing $T_c \\sim 80\\,\\mathrm{K}$.","problem_ref":"6b2c48359751e4225d3f424a4f69791fe8adddf15f7f169702b9f95ba7aed690","references":"","settled_by":"ARPES or quasiparticle interference on superconducting films resolving gap magnitudes and signs on each Fermi sheet, matched by a model calculation of $T_{\\mathrm{c}}$.","status_note":"Gap-symmetry measurements reported in 2025, including a d-wave claim under pressure, have not converged.","title":"Gap symmetry and pairing mechanism of bilayer $\\mathrm{La_3Ni_2O_7}$","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"c3fac0e79f60a554e646e52dcd0650d0ff71e2934553373dfc2e6bd791cb32dc","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"cdcd61feada15853a9c4b127143ef11fa1a0b9e164bd808ef2f2ffd99785b3dd","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"qMUgO2Nh7R4HvblHUJyFQ92QoPnp-I8foIVXaf7dRSnYESl44U9Rbg5xhmnZHqkKkKHYuw3xEWrfDKXRLq9yAg"},"schema":"pubphys.envelope/1"},"record_hash":"c3fac0e79f60a554e646e52dcd0650d0ff71e2934553373dfc2e6bd791cb32dc","leaf_index":2966}