Regensburg 2022 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 12: Skyrmions 1 (joint session MA/KFM)

KFM 12.1: Hauptvortrag

Dienstag, 6. September 2022, 09:30–10:00, H37

Topological spin structures at surfaces — •Stefan Heinze — Institute of Theoretical Physics and Astrophysics, University of Kiel, Germany

Magnetic skyrmions are of great interest for future applications ranging from data storage to neuromorphic computing [1]. Fundamental insight into the properties of skyrmions and the underlying microscopic interactions can be obtained by studying them at surfaces [2,3]. Here, I will discuss the stabilization, creation, and annihilation mechanisms of nanoscale topological spin structures based on density functional theory and atomistic spin simulations [4-8]. A novel skyrmion annihilation mechanism, the Chimera collapse [4], is presented which has been confirmed by direct comparison with scanning tunneling microscopy (STM) experiments [5]. It is further shown that skyrmion stability can be tuned via applied electric fields [6] allowing writing and deleting of skyrmions. Higher-order exchange interactions (HOI) beyond Heisenberg exchange also play a role since they can stabilize skyrmion lattices [2] as well as isolated skyrmions or antiskyrmions [7]. Unexpectedly, HOI can induce not only non-collinear but also collinear two-dimensional multi-Q states observed via spin-polarized STM [8].

[1] A. Fert et al., Nat. Rev. Mater. 2, 1 (2017), [2] S. Heinze et al., Nat. Phys. 7, 713 (2011), [3] N. Romming et al., Science 341, 639 (2013), [4] S. Meyer et al., Nat. Commun. 10, 3823 (2019), [5] F. Muckel et al., Nat. Phys. 17, 395 (2021), [6] S. Paul et al., npj Comput. Mater. 8, 105 (2022), [7] S. Paul et al., Nat. Commun. 11, 4756 (2020), [8] M. Gutzeit et al., arxiv:2204.01358 (2022).