{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"ea75887674e94ec8ad3f5ce69cbd97d0c8a304b13fd8d34cd266dd0b70549254","created":"2026-10-03T07:17:59Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"c91b517fb13c0cd3860f72249c22e954783a9d9aac3f45622da2c09d2634ab89","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"cm.heavy-fermion-sc.cerh2as2-two-phases","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"In CeRh2As2 a magnetic field along one crystal axis switches the superconductor from one state to another, possibly from even-parity to odd-parity pairing, made possible because each cerium layer lacks a center of inversion although the whole crystal has one.","posed_since":"2021","precise":"CeRh2As2 ($T_{c} \\sim 0.26\\ \\mathrm{K}$) shows for $H \\mid\\mid c$ a transition at H* ~ 40 kG between a low-field phase SC1 and a high-field phase SC2 extending to H_c2 ~ 140 kG (Khim et al., Science 2021). Determine whether SC1 and SC2 are the even- and odd-parity states of locally noncentrosymmetric Ce layers, or whether H* is controlled by the quadrupole-density-wave or antiferromagnetic order found near or inside the superconducting phase. An answer identifies the order parameters of both phases by site-resolved NMR Knight shift, field-angle dependence of H*, and the relation of H* to the normal-state order.","problem_ref":null,"references":"","settled_by":"Site-resolved Knight shift in SC1 and SC2 plus a measurement showing whether $H*$ moves with the normal-state ordering field when that order is suppressed (by La substitution or pressure).","status_note":"Field-angle data (Landaeta et al., PRX 2022) support an even-to-odd parity transition, while a possible quadrupole density wave (Hafner et al., PRX 2022) and antiferromagnetism inside the superconducting state offer alternative explanations.","title":"Nature of the two superconducting phases of CeRh2As2","topic_ref":"42e2b4fc8c37f8d74e57ec83f9086a24e04ebe52927fdc7a9b95f3d2fc3088c5"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"e92c9ce32cf39e7cabf49848ec1a7421294e6db52bf374d6a80b7d35394ed1f4","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"4f65ca68e7159dd6a43626411761dc9233ed13396f8147fcae1a4b172d1a5b01","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"mB8NLyaaw229zbT-yVS01TmDRPRZPAuGTb3V5Noc5SexiWMZx8i0xeVaMd7bZKwmRXAOjIJMTkC0USvGsyNtDA"},"schema":"pubphys.envelope/1"},"record_hash":"e92c9ce32cf39e7cabf49848ec1a7421294e6db52bf374d6a80b7d35394ed1f4","leaf_index":1010}