{"paper":{"title":"Spin-orbit driven $J_{eff} = 1/2$ magnetism in a d$^7$ triangular-lattice monolayer cobaltate","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Monolayer CoBr2 realizes spin-orbit entangled J_eff=1/2 magnetism where dominant t2g-eg hopping strengthens ferromagnetic Kitaev exchange and produces a rich J1-J3 phase diagram of competing orders on the triangular lattice.","cross_cats":[],"primary_cat":"cond-mat.str-el","authors_text":"Indra Dasgupta, Mohammad Rezwan Habib, Ritwik Das, Soumen Basak","submitted_at":"2025-11-17T13:01:10Z","abstract_excerpt":"Recent theoretical and experimental advances have identified cobaltates with a high-spin $d^7$ electronic configuration as promising hosts for spin-orbit entangled $J_{eff} = 1/2$ magnetism that can support bond-dependent exchange interactions. In two-dimensional triangular lattices, the coexistence of such exchange frustration along with geometric frustration gives rise to a rich landscape of competing magnetic phases, establishing monolayer triangular $d^7$ cobaltates as a compelling platform for frustrated magnetism. Here we investigate a representative triangular-lattice monolayer cobaltat"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"our results on monolayer CoBr2 establish d7 cobalt dihalides as a promising platform to explore the interplay of long-range Heisenberg and bond-dependent exchange interactions that can stabilize diverse magnetic ground states on a triangular lattice.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The assumption that DFT-derived hopping amplitudes, when fed into an exact-diagonalization effective spin model, accurately capture the dominant magnetic interactions without significant higher-order corrections or sensitivity to the precise treatment of electronic correlations.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Monolayer CoBr2 shows dominant t2g-eg hopping that strengthens ferromagnetic Kitaev interactions, leading to a J1-J3 phase diagram with ferromagnetic, stripy, spiral, 120-degree antiferromagnetic, Z2 vortex crystal, and bond-nematic phases.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Monolayer CoBr2 realizes spin-orbit entangled J_eff=1/2 magnetism where dominant t2g-eg hopping strengthens ferromagnetic Kitaev exchange and produces a rich J1-J3 phase diagram of competing orders on the triangular lattice.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"7d1d384fce5d02b1c4bb428e43cd544b7902bf070ee4500f67d293c7a56ddffa"},"source":{"id":"2511.13325","kind":"arxiv","version":2},"verdict":{"id":"ced039ed-87e5-4e14-b78f-9cc37a6fd33d","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-17T20:59:12.445823Z","strongest_claim":"our results on monolayer CoBr2 establish d7 cobalt dihalides as a promising platform to explore the interplay of long-range Heisenberg and bond-dependent exchange interactions that can stabilize diverse magnetic ground states on a triangular lattice.","one_line_summary":"Monolayer CoBr2 shows dominant t2g-eg hopping that strengthens ferromagnetic Kitaev interactions, leading to a J1-J3 phase diagram with ferromagnetic, stripy, spiral, 120-degree antiferromagnetic, Z2 vortex crystal, and bond-nematic phases.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The assumption that DFT-derived hopping amplitudes, when fed into an exact-diagonalization effective spin model, accurately capture the dominant magnetic interactions without significant higher-order corrections or sensitivity to the precise treatment of electronic correlations.","pith_extraction_headline":"Monolayer CoBr2 realizes spin-orbit entangled J_eff=1/2 magnetism where dominant t2g-eg hopping strengthens ferromagnetic Kitaev exchange and produces a rich J1-J3 phase diagram of competing orders on the triangular lattice."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2511.13325/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":55,"sample":[{"doi":"","year":null,"title":"In this monolayer, Co atoms form a two-dimensional triangular lattice with a Co–Co distance of 3","work_id":"962f424e-85a4-4624-853c-3c7919afb911","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2020,"title":"3(b) together with the ED-derived J1-J3 phase diagram","work_id":"802129a1-ed5a-4b9e-a99d-7d10d62a578c","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2006,"title":"Kitaev, Annals of Physics 321, 2 (2006) , january Special Issue","work_id":"1f969add-fd4f-42e9-b973-7302f272ba19","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2018,"title":"M. Hermanns, I. Kimchi, and J. Knolle, Annual Review of Condensed Matter Physics 9, 17 (2018)","work_id":"3b6b3ac3-3d6f-4cbf-9346-c0351a68ac75","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2019,"title":"H. Takagi, T. Takayama, G. Jackeli, G. Khaliullin, and S. E. Nagler, Nature Reviews Physics 1, 264 (2019)","work_id":"467ccd66-b45f-46fd-b521-d6adaed05b8d","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":55,"snapshot_sha256":"b8695d15670d26226c3e25588951c1e2853c3f02f6e97ccc398c683ee1f656c5","internal_anchors":0},"formal_canon":{"evidence_count":1,"snapshot_sha256":"39a34ce8cdb492096e9a80a05eca9679d9f5d5eecbfbb35d304711ff6bbabd8f"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}