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MA: Fachverband Magnetismus
MA 43: Focus Session: Higher-Order Magnetic Interactions – Implications in 2D and 3D Magnetism I
MA 43.7: Vortrag
Donnerstag, 19. März 2020, 12:15–12:30, HSZ 04
Isotropic four-spin interactions in magnetic trimers — •Andras Laszloffy1,2, Bendeguz Nyari2, and Laszlo Szunyogh2 — 1Wigner Research Center for Physics, Budapest, Hungary — 2Department of Theoretical Physics, Budapest University of Technology and Economics, Budapest, Hungary
Recently a rapidly growing interest emerged in investigating the role of higher order spin interactions, both the SU(2) invariant and the chiral ones. In this contribution we study the effect of four-spin interactions along selective paths in the spin-configuration space of magnetic trimers. In order to calculate the SU(2) invariant four-spin interactions we use a Green's function perturbation scheme, where the spinless part of the Hamiltonian defines the unperturbed system, while the spin-dependent part of the Hamiltonian is treated as perturbation. Two-spin and four-spin interactions can then be obtained in second and fourth order perturbation of the Green's function. We demonstrate how the four-spin interactions enter the spin-model parameters obtained from the method of infinitesimal rotations leading to spurious tensorial two-spin interactions. The theory can be straightforwardly implemented in the Korringa-Kohn-Rostoker Green's function technique and in terms of this method we perform calculations for Cr and Mn trimers deposited on heavy metal surfaces. Comparing the energy obtained from the spin model with direct calculations of the band energy proves that the inclusion of the four-spin interactions significantly increases the accuracy of the spin-model description of the magnetic clusters under consideration.