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Geometrical Frustration Versus Kitaev Interactions in BaCo2(AsO4)2



Thomas Halloran, Felix Desrochers, Emily Zhang, Tong Chen, Li E. Chern, Zhijun Xu, Barry Winn, Melissa Graves-Brook, M. B. Stone, Alexander I. Kolesnikov, Yiming Qiu, Ruidan Zhong, Robert Cava, Yong Kim, Collin L. Broholm


Recently, Co-based honeycomb magnets have been proposed as promising candidate materials to host the Kitaev spin liquid state. One of the front-runners is BaCo2(AsO4)2 (BCAO), where it was suggested that the exchange processes between Co2+ ions via the surrounding edge-sharing oxygen octahedra could give rise to bond-dependent Kitaev interactions. In this work, we present and analyze comprehensive inelastic neutron scattering studies 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 JKΓΓ′ model and the XXZ-J1-J3 model. We show that the existing experimental data can be consistently accounted for by the XXZ-J1-J3 model but not by the JKΓΓ′ 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.
Proceedings of the National Academy of Sciences of the United States of America


Kitaev spin liquid, inelastic neutron scattering, cobaltate


Halloran, T. , Desrochers, F. , Zhang, E. , Chen, T. , Chern, L. , Xu, Z. , Winn, B. , Graves-Brook, M. , Stone, M. , Kolesnikov, A. , Qiu, Y. , Zhong, R. , Cava, R. , Kim, Y. and Broholm, C. (2023), Geometrical Frustration Versus Kitaev Interactions in BaCo<sub>2</sub>(AsO<sub>4</sub>)<sub>2</sub>, Proceedings of the National Academy of Sciences of the United States of America, [online], (Accessed July 23, 2024)


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Created January 10, 2023, Updated January 27, 2024