Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 38: Electron Theory of Magnetism and Correlations
MA 38.6: Vortrag
Freitag, 9. September 2022, 10:45–11:00, H43
Effective exchange interaction in non-collinear states from electronic structure theory — •Simon Streib1, Ramon Cardias2, Manuel Pereiro1, Anders Bergman1, Erik Sjöqvist1, Cyrille Barreteau3, Anna Delin2, Olle Eriksson1,4, and Danny Thonig4,1 — 1Department of Physics and Astronomy, Uppsala University, Sweden — 2Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Sweden — 3SPEC, CEA, CNRS, Université Paris-Saclay, France — 4School of Science and Technology, Örebro University, Sweden
The determination of exchange parameters in non-collinear magnetic configurations directly from the electronic structure has been a challenge since the initial development of the Lichtenstein-Katsnelson-Antropov-Gubanov (LKAG) formalism for collinear configurations. Usually, the isotropic exchange interaction between two magnetic moments is only taken into account to bilinear order (Heisenberg exchange). We introduce instead a generalized isotropic two-spin exchange interaction, which takes all orders into account, and from which we derive an effective exchange interaction. We demonstrate how in an arbitrary non-collinear configuration this effective exchange interaction can be extracted from the energy curvature tensor, which describes the local energy curvature with respect to the directions of two magnetic moments. We apply our formalism to examples from tight-binding electronic structure and demonstrate strong fluctuations of the effective exchange interaction during spin dynamics simulations [1].
[1] S. Streib et al., arXiv:2203.11759.