Dresden 2017 – wissenschaftliches Programm

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

MA: Fachverband Magnetismus

MA 45: Focus Session: Magnon Transport in Metallic Spin Textures

MA 45.4: Vortrag

Mittwoch, 22. März 2017, 17:30–17:45, HSZ 04

Magnon-skyrmion scattering in chiral magnets — •Markus Garst — Institut für Theoretische Physik, Technische Universität Dresden, Zellescher Weg 17, 01062 Dresden, Germany

Chiral magnets support topological skyrmion textures due to the Dzyaloshinskii-Moriya spin-orbit interaction. We discuss the interaction between such a magnetic skyrmion and its small-amplitude fluctuations, i.e., the magnons in a two-dimensional chiral magnet. The magnon spectrum includes few magnon-skyrmion bound states, in particular, a breathing mode and a quadrupolar mode, which will give rise to subgap magnetic and electric resonances. Due to the skyrmion topology, the magnons scatter from an emergent flux density that leads to skew and rainbow scattering, characterized by an asymmetric and oscillating differential cross section. As a consequence of the skew scattering, a finite density of skyrmions will generate a topological magnon Hall effect. Using the conservation law for the energy-momentum tensor, we demonstrate that the magnons also transfer momentum to the skyrmion. As a consequence, a magnon current leads to magnon pressure reflected in a momentum-transfer force in the Thiele equation of motion for the skyrmion. This force is reactive and governed by the transport scattering cross sections of the skyrmion; it causes not only a finite skyrmion velocity but also a large skyrmion Hall effect.

[1] C. Schütte and M. Garst, Phys. Rev. B 90, 094423 (2014)

[2] S. Schroeter and M. Garst, Low. Temp. Phys. 41, 817 (2015)