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Main Authors: Skovhus, Thorbjørn, Pavizhakumari, Varun Rajeev, Olsen, Thomas
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2507.11374
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author Skovhus, Thorbjørn
Pavizhakumari, Varun Rajeev
Olsen, Thomas
author_facet Skovhus, Thorbjørn
Pavizhakumari, Varun Rajeev
Olsen, Thomas
contents We present an efficient implementation of the magnetic force theorem which allows for direct evaluation of exchange parameters in q-space. The exchange parameters are calculated directly from Bloch states and the implementation does not rely on any mapping onto localized orbitals. This renders the approach well suited for high-throughput computations, where the construction of a localized basis set (for example Wannier functions) often is impractical. We demonstrate the versatility of the method by applying it to yttrium iron garnet, where we obtain excellent agreement with the experimental magnon dispersion and Curie temperature without any prior assumptions of important exchange pathways. In particular, the calculations reveal the existence of several inequivalent exchange pathways associated with the same interatomic distances. Performing such calculations in q-space fully accounts for long-range exchange interactions and provides a convenient route for validating models obtained by fitting to inelastic neutron scattering data.
format Preprint
id arxiv_https___arxiv_org_abs_2507_11374
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Implementation of the magnetic force theorem for large-scale calculations of magnon bands: application to yttrium iron garnet
Skovhus, Thorbjørn
Pavizhakumari, Varun Rajeev
Olsen, Thomas
Materials Science
We present an efficient implementation of the magnetic force theorem which allows for direct evaluation of exchange parameters in q-space. The exchange parameters are calculated directly from Bloch states and the implementation does not rely on any mapping onto localized orbitals. This renders the approach well suited for high-throughput computations, where the construction of a localized basis set (for example Wannier functions) often is impractical. We demonstrate the versatility of the method by applying it to yttrium iron garnet, where we obtain excellent agreement with the experimental magnon dispersion and Curie temperature without any prior assumptions of important exchange pathways. In particular, the calculations reveal the existence of several inequivalent exchange pathways associated with the same interatomic distances. Performing such calculations in q-space fully accounts for long-range exchange interactions and provides a convenient route for validating models obtained by fitting to inelastic neutron scattering data.
title Implementation of the magnetic force theorem for large-scale calculations of magnon bands: application to yttrium iron garnet
topic Materials Science
url https://arxiv.org/abs/2507.11374