Berlin 2024 – scientific programme

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MA: Fachverband Magnetismus

MA 2: Computational Magnetism I

MA 2.7: Talk

Monday, March 18, 2024, 11:15–11:30, H 1058

Are Magnons Just The Van Der Waals Interaction In Disguise? — •Robert Lawrence — School of Physics, Engineering and Technology, University of York, Heslington, North Yorks. YO10 5DD, UK

For systems without significant magnetism (such as non-magnetic, carbon-based molecules) it is well-known that correctly capturing the properties of the system – such as the interlayer spacing of graphite – requires considering the dynamical correlations, such as the van der Waals interactions. These dynamical correlations lead to quantised electric dipole waves throughout the system [1]. In magnetic systems magnetic correlations are also possible, in addition to the electric dipole-induced electric dipole interactions.

In this talk, we present our work extending semi-empirical van der Waals models to include both the magnetic and electric parts simultaneously, and demonstrate how this can naturally lead to the emergence of the Heisenberg model of magnetism. Finally, we discuss how this model leads to the ability to predict long-range magnetic coupling (and hence parameterise magnons) in a more computationally efficient manner than finite displacements on large supercells.

[1] A. Ambrosetti, N. Ferri, R.A. Distasio Jr. , A. Tkatchenko, Wavelike charge density fluctuations and van der Waals interactions at the nanoscale, Science, 351, 6278, 2016

Keywords: Magnetism; Dynamical Correlation; Van der Waals