SKM 2021 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 14: Focus Session: Higher-Order Magnetic Interactions - Implications in 2D and 3D Magnetism II

MA 14.3: Vortrag

Donnerstag, 30. September 2021, 14:15–14:30, H5

Symmetry analysis of multi-spin interactions — •Levente Rózsa — University of Konstanz, Konstanz, Germany

Two-spin interactions including the isotropic exchange and Dzyaloshinsky-Moriya (DM) interactions or the magnetocrystalline anisotropy play a fundamental role in the formation of non-collinear spin structures. Going beyond the two-spin approximation enables the stabilization of, e.g., the zero-field nanoskyrmion lattice attributed to four-spin isotropic interactions [1]. A four-spin generalization of the DM interaction has also been proposed recently [2,3,4].

Multi-spin interactions are conventionally derived based on a perturbative expansion [2,4], which becomes cumbersome if many spins or higher orders of the spin-orbit coupling are involved. Here we present a systematic way of constructing multi-spin interaction terms based on a symmetry analysis. In the case of four spins, besides the isotropic and DM interactions, we identify symmetric second-order and fourth-order anisotropies, as well as a DM-like asymmetric anisotropy term. It is discussed how these coupling terms transform under point group operations, analogously to the Moriya rules; how they can be fitted based on the energies of specific spin configurations; and which types of non-collinear structures emerge based on these interactions.

[1] S. Heinze et al., Nat. Phys. 7, 713 (2011).

[2] S. Brinker et al., New J. Phys. 21, 083015 (2019).

[3] A. Lászlóffy, L. Rózsa et al., Phys. Rev. B 99, 184430 (2019).

[4] S. Grytsiuk et al., Nat. Commun. 11, 511 (2020).