Understanding the microscopic origin of the magnetic interactions in CoNb₂O₆

  • 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 by applying an \textit{ab initio} approach with additional modelling that accounts for various drawbacks of a purely density functional theory ansatz. With this method we are able to extract and understand the origin of the magnetic couplings under inclusion of all symmetry-allowed terms, and to resolve the conflicting model descriptions in CoNb2O6. We find that the twisted Kitaev chain and the transverse-field ferromagnetic Ising chain views are mutually compatible, although additional off-diagonal exchanges are necessary to provide a complete picture. We show that the dominant exchange interaction is a ligand-centered exchange process - involving the eg electrons -, which is rendered anisotropic by the low-symmetry crystal fields environments in CoNb2O6, giving rise to the dominant Ising exchange, while the smaller bond-dependent anisotropies are found to originate from d−d kinetic exchange processes involving the t2g electrons. We demonstrate the validity of our approach by comparing the predictions of the obtained low-energy model to measured THz and inelastic neutron scattering spectra.

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Metadaten
Author:Amanda A. KoniecznaORCiD, David Andreas Songzi KaibORCiDGND, Stephen M. WinterORCiD, Roser ValentíORCiDGND
URN:urn:nbn:de:hebis:30:3-860131
URL:https://arxiv.org/abs/2406.17854v1
DOI:https://doi.org/10.48550/ARXIV.2406.17854
ArXiv Id:http://arxiv.org/abs/2406.17854
Parent Title (German):arXiv
Publisher:arXiv
Document Type:Preprint
Language:English
Date of Publication (online):2024/06/25
Date of first Publication:2024/06/25
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2024/07/01
Issue:https://arxiv.org/abs/2406.17854v1
Edition:Version 1
Page Number:14
Institutes:Physik / Physik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - CC BY - Namensnennung 4.0 International