Quantum order by disorder is a key to understanding the magnetic phases of BaCo2(AsO4)2
Abstract BaCo2(AsO4)2 (BCAO), a honeycomb cobaltate, is considered a promising candidate for materials displaying the Kitaev quantum spin liquid state. This assumption is based on the distinctive characteristics of Co2+ ions (3d 7) within an octahedral crystal environment, resulting in spin-orbit-co...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2025-01-01
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| Series: | npj Quantum Materials |
| Online Access: | https://doi.org/10.1038/s41535-025-00728-9 |
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| author | Sangyun Lee Shengzhi Zhang S. M. Thomas L. Pressley C. A. Bridges Eun Sang Choi Vivien S. Zapf Stephen M. Winter Minseong Lee |
| author_facet | Sangyun Lee Shengzhi Zhang S. M. Thomas L. Pressley C. A. Bridges Eun Sang Choi Vivien S. Zapf Stephen M. Winter Minseong Lee |
| author_sort | Sangyun Lee |
| collection | DOAJ |
| description | Abstract BaCo2(AsO4)2 (BCAO), a honeycomb cobaltate, is considered a promising candidate for materials displaying the Kitaev quantum spin liquid state. This assumption is based on the distinctive characteristics of Co2+ ions (3d 7) within an octahedral crystal environment, resulting in spin-orbit-coupled J eff = 1/2 doublet states. However, recent experimental observations and theoretical analyses have raised questions regarding this hypothesis. Despite these uncertainties, reports of continuum excitations reminiscent of spinon excitations have prompted further investigations. In this study, we explore the magnetic phases of BCAO under both in-plane and out-of-plane magnetic fields, employing dc and ac magnetic susceptibilities, capacitance, and torque magnetometry measurement. Our results affirm the existence of multiple field-induced magnetic phases, with strong anisotropy of the phase boundaries between in-plane and out-of-plane fields. To elucidate the nature of these phases, we develop a minimal anisotropic exchange model. This model, supported by combined first principles calculations and theoretical modeling, quantitatively reproduces our experimental data. In BCAO, the combination of strong bond-independent XXZ anisotropy and geometric frustration leads to significant quantum order by disorder effects that stabilize colinear phases under both zero and finite magnetic fields. |
| format | Article |
| id | doaj-art-09d6a9b0456843399d43374f543d9653 |
| institution | Kabale University |
| issn | 2397-4648 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Quantum Materials |
| spelling | doaj-art-09d6a9b0456843399d43374f543d96532025-02-02T12:07:19ZengNature Portfolionpj Quantum Materials2397-46482025-01-0110111010.1038/s41535-025-00728-9Quantum order by disorder is a key to understanding the magnetic phases of BaCo2(AsO4)2Sangyun Lee0Shengzhi Zhang1S. M. Thomas2L. Pressley3C. A. Bridges4Eun Sang Choi5Vivien S. Zapf6Stephen M. Winter7Minseong Lee8National High Magnetic Field Laboratory, Los Alamos National LaboratoryNational High Magnetic Field Laboratory, Los Alamos National LaboratoryLos Alamos National LaboratoryOak Ridge National LaboratoryOak Ridge National LaboratoryNational High Magnetic Field Laboratory, Florida State UniversityNational High Magnetic Field Laboratory, Los Alamos National LaboratoryDepartment of Physics and Center for Functional Materials, Wake Forest UniversityNational High Magnetic Field Laboratory, Los Alamos National LaboratoryAbstract BaCo2(AsO4)2 (BCAO), a honeycomb cobaltate, is considered a promising candidate for materials displaying the Kitaev quantum spin liquid state. This assumption is based on the distinctive characteristics of Co2+ ions (3d 7) within an octahedral crystal environment, resulting in spin-orbit-coupled J eff = 1/2 doublet states. However, recent experimental observations and theoretical analyses have raised questions regarding this hypothesis. Despite these uncertainties, reports of continuum excitations reminiscent of spinon excitations have prompted further investigations. In this study, we explore the magnetic phases of BCAO under both in-plane and out-of-plane magnetic fields, employing dc and ac magnetic susceptibilities, capacitance, and torque magnetometry measurement. Our results affirm the existence of multiple field-induced magnetic phases, with strong anisotropy of the phase boundaries between in-plane and out-of-plane fields. To elucidate the nature of these phases, we develop a minimal anisotropic exchange model. This model, supported by combined first principles calculations and theoretical modeling, quantitatively reproduces our experimental data. In BCAO, the combination of strong bond-independent XXZ anisotropy and geometric frustration leads to significant quantum order by disorder effects that stabilize colinear phases under both zero and finite magnetic fields.https://doi.org/10.1038/s41535-025-00728-9 |
| spellingShingle | Sangyun Lee Shengzhi Zhang S. M. Thomas L. Pressley C. A. Bridges Eun Sang Choi Vivien S. Zapf Stephen M. Winter Minseong Lee Quantum order by disorder is a key to understanding the magnetic phases of BaCo2(AsO4)2 npj Quantum Materials |
| title | Quantum order by disorder is a key to understanding the magnetic phases of BaCo2(AsO4)2 |
| title_full | Quantum order by disorder is a key to understanding the magnetic phases of BaCo2(AsO4)2 |
| title_fullStr | Quantum order by disorder is a key to understanding the magnetic phases of BaCo2(AsO4)2 |
| title_full_unstemmed | Quantum order by disorder is a key to understanding the magnetic phases of BaCo2(AsO4)2 |
| title_short | Quantum order by disorder is a key to understanding the magnetic phases of BaCo2(AsO4)2 |
| title_sort | quantum order by disorder is a key to understanding the magnetic phases of baco2 aso4 2 |
| url | https://doi.org/10.1038/s41535-025-00728-9 |
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