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MA: Fachverband Magnetismus

MA 46: Surface Magnetism

MA 46.8: Vortrag

Freitag, 21. März 2025, 11:30–11:45, H19

Bilayer triple-Q state driven by interlayer higher-order exchange interactions — •Bjarne Beyer, Mara Gutzeit, Tim Drevelow, Isabel Schwermer, Soumyajyoti Haldar, and Stefan Heinze — Institute of Theoretical Physics and Astrophysics, University of Kiel, Germany

Superpositions of spin spirals – so-called multi-Q states – are complex spin structures which are of fundamental interest and promising for future spintronic applications. A prominent example is the triple-Q state predicted more than 20 years ago [1] and only recently observed in Mn monolayers on the Re(0001) surface [2,3]. Here, we predict a triple-Q state as the magnetic ground state of a Mn bilayer on the Ir(111) surface using first-principles calculations based on density functional theory (DFT). In a bilayer two types of the triple-Q state can occur which differ by the spin alignment between the layers. Based on an atomistic spin model, we demonstrate that the triple-Q state favored by DFT is stabilized by the interplay of antiferromagnetic interlayer exchange and interlayer higher-order exchange interactions. In this bilayer triple-Q state nearest-neighbor spins within a layer and between layers exhibit tetrahedron angles and the topological orbital moments of the two Mn layers are aligned in parallel [4].

[1] P. Kurz et al., PRL 86, 1106 (2001).
[2] J. Spethmann et al., PRL 124, 227203 (2020).
[3] F. Nickel et al., PRB 108, L180411 (2023).
[4] V. Saxena et al., arXiv:2408.12580 (2024).

Keywords: Triple-Q state; Higher-order exchange interactions; Density functional theory (DFT); Magnetic bilayer; Manganese (Mn)