Geometrical frustration versus Kitaev interactions in BaCo ₂ (AsO ₄ ) ₂

Journal Article · Fri Jan 06 00:00:00 EST 2023 · Proceedings of the National Academy of Sciences of the United States of America

DOI:https://doi.org/10.1073/pnas.2215509119· OSTI ID:1907999

Halloran, Thomas  ^[1]; Desrochers, Félix  ^[2]; Zhang, Emily Z.  ^[2]; Chen, Tong  ^[1]; Chern, Li Ern  ^[3]; Xu, Zhijun  ^[4]; Winn, Barry  ^[5]; Graves-Brook, M. ^[5]; Stone, M. B.  ^[5]; Kolesnikov, Alexander I. ^[5]; Qiu, Yiming  ^[6]; Zhong, Ruidan  ^[7]; Cava, Robert ^[8]; Kim, Yong Baek ^[2]; Broholm, Collin  ^[9]

---

1. Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218
2. Department of Physics, University of Toronto, Toronto ON M5S 1A7, Canada
3. Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
4. National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899, Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742
5. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
6. National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899
7. Department of Chemistry, Princeton University, Princeton, NJ 08544, Tsung-Dao Lee Institute, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
8. Department of Chemistry, Princeton University, Princeton, NJ 08544
9. Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, MD 21218

Recently, Co-based honeycomb magnets have been proposed as promising candidate materials to host the Kitaev spin liquid (KSL) state. One of the front-runners is BaCo ₂ (AsO ₄ ) ₂ (BCAO), where it was suggested that the exchange processes between Co ²⁺ ions via the surrounding edge-sharing oxygen octahedra could give rise to bond-dependent Kitaev interactions. In this work, we present and analyze a comprehensive inelastic neutron scattering (INS) study of BCAO with fields in the honeycomb plane. Combining the constraints from the magnon excitations in the high-field polarized state and the inelastic spin structure factor measured in zero magnetic field, we examine two leading theoretical models: the Kitaev-type $\mathrm{JK}\mathrm{\Gamma }{\mathrm{\Gamma }}^{\prime }$ model and the XXZ $\text{-}{J}_1\text{-}{J}_3$ model. We show that the existing experimental data can be consistently accounted for by the XXZ $\text{-}{J}_1\text{-}{J}_3$ model but not by the $\mathrm{JK}\mathrm{\Gamma }{\mathrm{\Gamma }}^{\prime }$ model, and we discuss the implications of these results for the realization of a spin liquid phase in BCAO and more generally for the realization of the Kitaev model in cobaltates.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Institute for Quantum Matter
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); Gordon and Betty Moore Foundation (GBMF); Natural Sciences and Engineering Research Council of Canada (NSERC)
• Grant/Contract Number: SC0019331; AC05-00OR22725; GBMF9456; DMR-1508249
• OSTI ID: 1907999
• Alternate ID(s): OSTI ID: 1928929
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Vol. 120 Journal Issue: 2; ISSN 0027-8424
• Publisher: Proceedings of the National Academy of Sciences
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
frustrated magnetism
Kitaev model
inelastic neutron scattering
molecular dynamics