SKM 2021 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Posters Magnetism V
MA 18.30: Poster
Freitag, 1. Oktober 2021, 10:00–13:00, P
Local spin Hamiltonians from model electronic structure theory — Simon Streib1, Vladislav Borisov1, Manuel Pereiro1, Anders Bergman1, Erik Sjöqvist1, Anna Delin2,3, Mikhail Katsnelson4, Olle Eriksson1,5, and •Danny Thonig5 — 1Department of Physics and Astronomy, Uppsala University, Sweden — 2Department of Applied Physics, KTH Royal Institute of Technology, Sweden — 3Swedish e-Science Research Center (SeRC), KTH Royal Institute of Technology, Sweden — 4Institute for Molecules and Materials, Radboud University, The Netherlands — 5School of Science and Technology, Örebro University, Sweden
The derivation of spin Hamiltonians from ab initio calculations is an important tool for modeling effective precession fields in the dynamics of magnetic materials since a full electronic description of the dynamics is computationally very demanding. In this work, we contrast two different – "local" and "global" – approaches. The global approach aims at describing arbitrary spin configurations, whereas the local approach is only valid for small magnetic fluctuations locally around a given spin configuration. We argue that global symmetry requirements, such as time-reversal symmetry, do not necessarily restrict local spin Hamiltonians if the dependence of the effective exchange parameters on the magnetic state is taken into account. We present a general formalism to map model electronic structure theory to a local spin Hamiltonian and we check our formalism by means of numerical calculations for low-dimensional structures, like dimers and chains [1].
[1] S. Streib et al., Phys. Rev. B 103, 224413 (2021)