Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 54: Spin Hall Effects and Skyrmions II

MA 54.1: Vortrag

Donnerstag, 23. März 2017, 15:00–15:15, HSZ 04

Dzyaloshinkii-Moriya Iinteraction and Hall Effects in Disordered Bulk Chiral Magnets From First Principle Calculations — •Jacob Gayles¹, Frank Freimuth², Charles Spencer³, Rembert Duine⁴, Chris Marrows³, Yuriy Mokrousov², Stefan Blügel², and Jairo Sinova¹ — ¹Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany — ²Peter Grünberg Institut & Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany — ³Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands — ⁴School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom

We demonstrate that the electron dynamics in the skyrmion phase of Fe-rich MnFeGe and FeCoGe alloys is governed by Berry phase physics. We observe that the magnitude of the Dzyaloshinskii-Moriya interaction, directly related to the mixed space-momentum Berry phases, changes sign and magnitude with concentration x in direct correlation with the data of Shibata et al., Nature Nanotech. 8, 723 (2013). The computed anomalous and topological Hall effects in FeGe are also in good agreement with available experiments. We further develop a simple tight-binding model able to explain these findings. We show that the adiabatic Berry phase picture is violated in the Mn-rich limit of the alloys. Lastly, we make connections between experiment and computation in disordered regime.