Regensburg 2025 – scientific programme

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MA: Fachverband Magnetismus

MA 41: Poster III

MA 41.42: Poster

Thursday, March 20, 2025, 15:00–17:30, P3

A C*-algebraic approach to orbital magnetization in skyrmion crystals and finite magnetic fields — •Pascal Prass¹, Duco van Straten², and Yuriy Mokrousov^1,3 — ¹Institute of Physics, Johannes Gutenberg University Mainz, Germany — ²Institute of Mathematics, Johannes Gutenberg University Mainz, Germany — ³Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, Germany

Skyrmion crystals can induce orbital magnetization even in the absence of spin-orbit coupling [1]. This depends on the skyrmion density determining the strength of the emergent magnetic field. As the length scale of a skyrmion crystal approaches the lattice constant of its host material, topological gaps may open in the associated electronic system similar to the formation of Landau levels. However, the smooth texture approximation for the emergent magnetic field is no longer satisfied [2]. Therefore, we utilize a fully algebraic framework to describe a tight-binding system coupled to a skyrmion crystal, that allows us to numerically evaluate topological gap invariants [3] and orbital magnetization even in the presence of finite magnetic flux. This way, we can describe the dependence of the orbital magnetization on the magnetic field for different skyrmion densities. In the appropriate limit, this approach coincides with the expression from the modern theory of orbital magnetization [4]. [1] Göbel et al. Phys. Rev. B 99, 060406(R) (2019). [2] Lux et al. Phys. Rev. Res. 6, 013102 (2024). [3] Prass et al. SciPost Phys. Core, in press (2024). [4] Schulz-Baldes et al. Commun. Math. Phys. 319, 649-681 (2013)

Keywords: skyrmion crystal; orbital magnetization; Chern number; tight-binding Hamiltonian