PGI-1 Talk: Pascal Praß

Quantum Theory of Materials Seminar

A C*-algebraic approach to electronic state topology and orbital magnetization in skyrmion crystals

As the length scale of a two-dimensional skyrmion crystal approaches the lattice constant of its host material, topological gaps may form in the associated electronic system. However, the smooth texture approximation for the usual geometric approach of emergent magnetic fields is no longer satisfied.
Instead, we adopt a fully algebraic view to describe a class of multi-$q$ textures [1], including skyrmion crystals, and apply noncommutative $K$-theory to compute all admissible Chern numbers [2].
As a central application, we tune the texture parameters, creating discontinuous jumps in the real-space winding number [3,4] for which we observe the relation with the Chern numbers of the electronic spectrum [2]. The noncommutative framework also provides easy access to the calculation of orbital magnetization in accordance with modern theory.

[1] Lux et al. Phys. Rev. Res. 6, 013102 (2024).
[2] Prass et al. arXiv:2403.11912 (2024).
[3] Hayami et al. Nat. Commun. 12, 6927 (2021).
[4] Shimizu et al. Phys. Rev. B 105, 224405 (2022). 

Contact

Prof. Dr. Yuriy Mokrousov
Phone: +49 2461 61- 4434
Email: y.mokrousov@fz-juelich.de

Pascal Praß
Johannes Gutenberg-Universität Mainz
Email: pprass@uni-mainz.de