{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"4e6880dc46c435978b1f60562cdca90525b0b4bee7d8695e617eabda06a407ce","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b","e92c9ce32cf39e7cabf49848ec1a7421294e6db52bf374d6a80b7d35394ed1f4"],"salt":"03cf53e0fd23f6aa57a5f0dbdba063af3923696ce792629c3ab5322248fc3365","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":["ai:gpt-5.5"],"external_id":"cm.heavy-fermion-sc.cerh2as2-two-phases","kind":"well-posed","literature_status":"contested","n":"2","parents":[],"plain":"In $\\mathrm{CeRh_2As_2}$ 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":"$\\mathrm{CeRh_2As_2}$ ($T_{c} \\sim 0.26\\ \\mathrm{K}$) shows for $H \\mid\\mid c$ a transition at $H* \\sim 40 \\mathrm{kG}$ between a low-field phase SC1 and a high-field phase SC2 extending to $H_c2 \\sim 140 \\mathrm{kG}$ (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":"e92c9ce32cf39e7cabf49848ec1a7421294e6db52bf374d6a80b7d35394ed1f4","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 $\\mathrm{CeRh_2As_2}$","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"8f091a655e12baa9a3b76472da377436f49b5bd9c38099c6f39ad1fea038a2dc","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"15047ce1d5d7ce64c12e0dc0eb0f774502c4ee0ed78d0966a33bcb4b134b20d8","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"BzFp6EOgRXBrcRKeRm-yP67-ZvuB79x0kK4Q_gZcayf_Swe7INO3r0ZCooMrxbjN2Lg_Bs-18VcQO9s1-jjhAg"},"schema":"pubphys.envelope/1"},"record_hash":"8f091a655e12baa9a3b76472da377436f49b5bd9c38099c6f39ad1fea038a2dc","leaf_index":2832}