TY  - INPR
A1  - Konieczna, Amanda A.
A1  - Kaib, David A. S.
A1  - Winter, Stephen M.
A1  - Valentí, Roser
T1  - Understanding the microscopic origin of the magnetic interactions in CoNb₂O₆
T2  - arXiv
N2  - 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.
Y1  - 2024
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/86013
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-860131
UR  - https://arxiv.org/abs/2406.17854v1
IS  - https://arxiv.org/abs/2406.17854v1
PB  - arXiv
ER  -