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| Home > Publications database > Deriving spin-models from DFT: Challanges and Limitations |
| Conference Presentation (Invited) | FZJ-2021-02691 |
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2020
Abstract: We examine the mapping of density functional theory (DFT) calculations to spin models for the determination of magnetic properties on larger length scales, e.g. for chiral domain walls, skyrmions, or spin-spiral ground states. While careful tests, using different DFT methods and magnetic sampling configurations allow getting converged results for the exchange parameters [1], it is not so clear that they give a reliable account of the material properties. This can be due to a methodologically enforced truncation of the expansion (e.g. finite sampling in real / reciprocal space) or a neglect of terms in the spin model Hamiltonian. E.g. for the B20 compound FeGe some properties like the period of the spin-spiral in the ground state are at variance with experimental findings, while others like the Curie temperature agree reasonably [2]. We argue that in many cases the underlying spin model is too simplified to capture the full complexity embedded in the electronic structure and the recent discovery of new magnetic interactions in these compounds supports this view [3]. [1] B. Zimmermann et al., Phys. Rev. B 99, 214426 (2019)[2] S. Grytsiuk et al., Phys. Rev. B 100, 214406 (2019)[3] S. Grytsiuk et al., Nature Commun. 11, 511 (2020)
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