Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 55: Electron theory and micromagnetism
MA 55.9: Vortrag
Freitag, 5. April 2019, 11:45–12:00, H38
Spin-model study of magnetism in graphene-based systems — László Oroszlány1,2, Jaime Ferrer3, András Deák4,5, László Udvardi4,5, and •László Szunyogh4,5 — 1Eötvös Loránd University, Budapest, Hungary — 2MTA-BME Lendület Topology and Correlation Research Group, Budapest, Hungary — 3Universidad de Oviedo & CINN, Oviedo, Spain — 4Budapest University of Technology and Economics, Budapest, Hungary — 5MTA-BME Condensed Matter Research Group, Budapest, Hungary
We briefly present the implementation of the method by Lichtenstein et al. [1] for evaluating isotropic exchange interactions from density functional theory based on the SIESTA code. We demonstrate that in case of simple metallic ferromagnets the Heisenberg interactions obtained from well–established computational methods are well reproduced. We then study magnetic correlations in single-side flourinated graphene (C2F) and in zig-zag graphene ribbons representing sp magnetism. Similar to Ref. [2], our calculated exchange interactions support a Néel type of magnetic ground state for C2F. For the graphene ribbons we calculate a stiffness constant over 3000 meV Å2, even larger than in Ref. [3], and find a transition between 1D and 2D long-range behavior depending on the thickness of the ribbon.
[1] A. I. Lichtenstein et al., J. Magn. Magn. Mater. 67, 65 (1987)
[2] A.N. Rudenko et al., Phys. Rev. B 88, 081405(R) (2013)
[3] O. V. Yazyev and M. I. Katsnelson, Phys. Rev. Lett. 100, 047209 (2008)