Understanding the microscopic origin of the magnetic interactions in CoNb2O6
Abstract Motivated by the on-going discussion on the nature of magnetism in the quantum Ising chain CoNb2O6, we present a first-principles-based analysis of its exchange interactions with additional modeling, addressing drawbacks of a purely density functional theory ansatz. This method allows us to...
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Nature Portfolio
2025-01-01
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| Series: | npj Quantum Materials |
| Online Access: | https://doi.org/10.1038/s41535-024-00715-6 |
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| author | Amanda A. Konieczna David A. S. Kaib Stephen M. Winter Roser Valentí |
| author_facet | Amanda A. Konieczna David A. S. Kaib Stephen M. Winter Roser Valentí |
| author_sort | Amanda A. Konieczna |
| collection | DOAJ |
| description | Abstract Motivated by the on-going discussion on the nature of magnetism in the quantum Ising chain CoNb2O6, we present a first-principles-based analysis of its exchange interactions with additional modeling, addressing drawbacks of a purely density functional theory ansatz. This method allows us to extract and understand the origin of the magnetic couplings—including all symmetry-allowed terms - and resolve conflicting model descriptions in CoNb2O6. We find that the twisted Kitaev chain and transverse-field ferromagnetic Ising chain views are mutually compatible, although additional off-diagonal exchanges are required for a complete picture. We show that the dominant exchange interaction is a ligand-centered process—involving e g electrons -, rendered anisotropic by low-symmetry crystal fields in CoNb2O6, resulting in dominant Ising exchange. Smaller bond-dependent anisotropies are found to originate from d − d kinetic exchange processes involving t 2g electrons. We demonstrate the validity of our low-energy model by comparing its predictions to measured THz and INS spectra. |
| format | Article |
| id | doaj-art-243b9c4075724b9fb68673918cd0bca9 |
| 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-243b9c4075724b9fb68673918cd0bca92025-01-19T12:09:00ZengNature Portfolionpj Quantum Materials2397-46482025-01-011011910.1038/s41535-024-00715-6Understanding the microscopic origin of the magnetic interactions in CoNb2O6Amanda A. Konieczna0David A. S. Kaib1Stephen M. Winter2Roser Valentí3Institut für Theoretische Physik, Goethe-UniversitätInstitut für Theoretische Physik, Goethe-UniversitätDepartment of Physics and Center for Functional Materials, Wake Forest UniversityInstitut für Theoretische Physik, Goethe-UniversitätAbstract Motivated by the on-going discussion on the nature of magnetism in the quantum Ising chain CoNb2O6, we present a first-principles-based analysis of its exchange interactions with additional modeling, addressing drawbacks of a purely density functional theory ansatz. This method allows us to extract and understand the origin of the magnetic couplings—including all symmetry-allowed terms - and resolve conflicting model descriptions in CoNb2O6. We find that the twisted Kitaev chain and transverse-field ferromagnetic Ising chain views are mutually compatible, although additional off-diagonal exchanges are required for a complete picture. We show that the dominant exchange interaction is a ligand-centered process—involving e g electrons -, rendered anisotropic by low-symmetry crystal fields in CoNb2O6, resulting in dominant Ising exchange. Smaller bond-dependent anisotropies are found to originate from d − d kinetic exchange processes involving t 2g electrons. We demonstrate the validity of our low-energy model by comparing its predictions to measured THz and INS spectra.https://doi.org/10.1038/s41535-024-00715-6 |
| spellingShingle | Amanda A. Konieczna David A. S. Kaib Stephen M. Winter Roser Valentí Understanding the microscopic origin of the magnetic interactions in CoNb2O6 npj Quantum Materials |
| title | Understanding the microscopic origin of the magnetic interactions in CoNb2O6 |
| title_full | Understanding the microscopic origin of the magnetic interactions in CoNb2O6 |
| title_fullStr | Understanding the microscopic origin of the magnetic interactions in CoNb2O6 |
| title_full_unstemmed | Understanding the microscopic origin of the magnetic interactions in CoNb2O6 |
| title_short | Understanding the microscopic origin of the magnetic interactions in CoNb2O6 |
| title_sort | understanding the microscopic origin of the magnetic interactions in conb2o6 |
| url | https://doi.org/10.1038/s41535-024-00715-6 |
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