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MA: Fachverband Magnetismus
MA 17: Computational Magnetism II
MA 17.13: Talk
Tuesday, March 19, 2024, 12:45–13:00, EB 202
Unravelling local spin-model parameters based on non-collinear magnetic states — Bendegúz Nyári1,2 and •László Szunyogh2,1 — 1HUN-REN-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Budapest Hungary — 2Department of Theoretical Physics, Budapest University of Technology and Economics, Budapest, Hungary
The theory of local spin-interactions as calculated from non-collinear magnetic states via multiple scattering Green's function technique will be described. Two alternative formalisms is implemented to perform calculations for specific spin-configurations of a Cr trimer deposited on a Au(111) surface. The two calculations provide with the same two-spin rotation energies, however, the local interaction parameters turn out to be remarkably different. The ambiguity between these results occurs due to longitudinal contributions to the interactions and can perfectly be eliminated in terms of projections to the transversal subspace in the local coordinate system. Moreover, a global spin model containing isotropic two-spin and four-spin interactions is used to calculate the two-spin rotation energies and a reasonable agreement is found between the results obtained from the global and local models. An analytic formulation based on a Green's function expansion technique also clearly identifies the higher-order global multispin interactions as the source of the tensorial local spin-model parameters as suggested earlier [1,2].
[1] M. dos Santos Dias et al., Phys. Rev. B 103, L140408 (2021).
[2] M. dos Santos Dias et al., Phys. Rev. B 105, 026402 (2022).
Keywords: multispin interactions; Green's function technique; non-collinear magnetism