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MA: Fachverband Magnetismus

MA 45: Spin Structures at Surfaces and in thin films I (Skyrmions)

MA 45.1: Vortrag

Donnerstag, 3. April 2014, 15:00–15:15, BEY 118

fcc-Fe monolayer on Ir(111): Atomic-scale meron-antimeron spin-texture predicted from a multi-scale study based on an realistic ab initio spin model — •David Siegfried Georg Bauer, Nicolai Kiselev, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

This research is work in progress and we hope to present here the final answer of the magnetic structure for the Fe/Ir(111) system. We are using a multi-scale approach, employing a classical spin Hamiltonian containing Heisenberg (EX), four-spin (FS), and Dzyaloshinskii-Moriya (DM) interaction as well as magnetic anisotropy with newly fitted exchange parameters obtained from ab initio calculations of Ref. [1].
We found a new class of magnetic patterns consisting of staggered meron-antimeron pairs within a supercell of 128 atoms, containing 9 meron-antimeron pairs and 18 topological defects. We carefully checked the shape and size of the supercell, which is commensurate with the underlying magnetic lattice. The magnetic structure is in very good agreement to the experimental SP-STM data [1]. We explain this structure by an interplay between the EX, FS and DM interaction, where the FS interaction plays a key role making this structure energetically favorable in comparison to a skyrmion lattice. Due to the local topological charges of the (anti-)meron of Q=(−)1/2, the electron may pick up a Berry phase when transversing through such a magnetic structure giving rise to interesting transport properties.
[1] S. Heinze et al., Nature Phys. 7, 713 (2011).