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MA: Fachverband Magnetismus

MA 35: Spin Structures/ Skyrmions (jointly with TT) - Invited Talks

MA 35.2: Hauptvortrag

Mittwoch, 16. März 2011, 14:30–15:00, HSZ 04

Discovery of an atomic-scale skyrmion lattice in an ultrathin magnet: Fe/Ir(111) — •S. Heinze¹, K. von Bergmann², M. Menzel², J. Brede², A. Kubetzka², R. Wiesendanger², G. Bihlmayer³, and S. Blügel³ — ¹Institute of Theoretical Physics and Astrophysics, University of Kiel — ²Institute of Applied Physics, University of Hamburg — ³Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA

Skyrmions are topologically protected field configurations with particle-like properties that play an important role in various fields of science. They have been predicted to exist also in bulk magnets and in recent experiments it was shown that they can be induced by a magnetic field. A key ingredient for their occurrence is the Dzyaloshinskii-Moriya interaction (DMI) which was found to be strong also in ultrathin magnetic films on substrates with large spin-orbit coupling [1]. In these systems the DMI stabilizes spin-spirals with a unique rotational sense propagating along one direction of the surface [1,2]. Here, we go a step beyond and present an atomic-scale skyrmion lattice as the magnetic ground state of a hexagonal Fe monolayer on Ir(111). We develop a spin-model based on density functional theory that explains the interplay of Heisenberg exchange, DMI and the four-spin exchange as the microscopic origin of this intriguing magnetic state. Experiments using spin-polarized scanning tunneling microscopy confirm the skyrmion lattice which is incommensurate with the underlying atomic lattice. [1] M. Bode et al., Nature 447, 190 (2007). [2] P. Ferriani et al., Phys. Rev. Lett. 101, 027201 (2008).