Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 34: Magnetic textures: Transport and dynamics II
MA 34.8: Vortrag
Mittwoch, 3. April 2019, 17:15–17:30, H37
Spin eigen-excitations of the antiferromagnetic skyrmion — •Volodymyr Kravchuk1,4, Helen Gomonay2, Denis Sheka3, Karin Everschor-Sitte2, Davi Rodrigues2, Jeroen van den Brink1, and Yuri Gaididei4 — 1Leibniz-Institut für Festkörper- und Werkstoffforschung, Dresden, Germany — 2Institut für Physik, Johannes Gutenberg-Universität Mainz, Germany — 3Taras Shevchenko National University of Kyiv, Ukraine — 4Bogolyubov Institute for Theoretical Physics, Kyiv, Ukraine
The spectrum of eigen-excitations of a skyrmion in a uniaxial collinear antiferromagnet with the easy-axis perpendicular to the film plane is analyzed. Two branches of the bounded eigenstates are found in the gap: the low-frequency modes demonstrate significant dependence of the eigenfrequencies on the skyrmion radius R with the characteristic asymptotic behavior ω∝ R−2 for large R. While the high-frequency modes are close to the magnon continuum and weakly depend on the skyrmion radius. In the absence of an external magnetic field all modes, except the radially symmetrical one, are doubly degenerate with respect to the sense of rotation, clockwise or counterclockwise. The perpendicular magnetic field results in a splitting of the degenerate modes. A general approach for describing the dynamics of the antiferromagnetic domain wall string is developed, it is utilized for estimation of eigenfrequencies of the low-frequency modes.