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arXiv · 1606.02598

Topologically stable magnetization states on a spherical shell: curvature stabilized skyrmions

Volodymyr P. Kravchuk·Ulrich K. Rößler·Oleksii M. Volkov·Denis D. Sheka·Jeroen van den Brink·Denys Makarov·Hagen Fuchs·Hans Fangohr·Yuri Gaididei
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Abstract

Topologically stable structures include vortices in a wide variety of matter, such as skyrmions in ferro- and antiferromagnets, and hedgehog point defects in liquid crystals and ferromagnets. These are characterized by integer-valued topological quantum numbers. In this context, closed surfaces are a prominent subject of study as they form a link between fundamental mathematical theorems and real physical systems. Here we perform an analysis on the topology and stability of equilibrium magnetization states for a thin spherical shell with easy-axis anisotropy in normal directions. Skyrmion solutions are found for a range of parameters. These magnetic skyrmions on a spherical shell have two distinct differences compared to their planar counterpart: (i) they are topologically trivial, and (ii) can be stabilized by curvature effects, even when Dzyaloshinskii-Moriya interactions are absent. Due to its specific topological nature a skyrmion on a spherical shell can be simply induced by a uniform external magnetic field.

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Volodymyr P. Kravchuk, Ulrich K. Rößler, Oleksii M. Volkov, Denis D. Sheka, Jeroen van den Brink, Denys Makarov, Hagen Fuchs, Hans Fangohr, Yuri Gaididei. 2016-09-02. Topologically stable magnetization states on a spherical shell: curvature stabilized skyrmions. https://doi.org/10.1103/physrevb.94.144402

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