Börge Göbel
Magnetic skyrmions have attracted enormous research interest since their discovery a decade ago. Especially the non-trivial real-space topology of these nano-whirls leads to fundamentally interestingand technologically relevant effects –the skyrmion Hall effect of the texture and the topological Hall effect of the electrons. Furthermore, it grants skyrmions in a ferromagnetic surrounding great stability even at small sizes, making skyrmions aspirants to become the carriers of information in the future. Still, the utilization of skyrmions in spintronicdevices has not been achieved yet, among others, due to shortcomings in theircurrent-driven motion. In this talk, we present recent trends in the field of topological spin textures that go beyond skyrmions. The majority of these objects can be considered the combination of multiple skyrmions or the skyrmion analogues in different magnetic surroundings, as well as three-dimensional generalizations. Weclassify the alternative magnetic quasiparticles –some of them observed experimentally, others theoretical predictions –and present the most relevant and auspicious advantages of this emerging field.A special focus is on magnetic antiskyrmions[1], bimerons[2], antiferromagnetic skyrmions[3]and hopfions[4].These objects (shown in Fig. 1)exhibitadvantageous emergent electrodynamiceffectscompared to skyrmions, either due to their lower symmetry or due to a compensated topological charge.
[1] J. Jena*, B. Göbel*, T. Ma, V. Kumar,R. Saha, I. Mertig, C. Felser, S. Parkin. “Elliptical Bloch skyrmion chiral twins in an antiskyrmion system”Nature Communications11, 1115 (2020)[2] B. Göbel, A. Mook, J. Henk, I. Mertig, O. Tretiakov.“Magnetic bimerons as skyrmion analogues in in-plane magnets”Phys. Rev. B. 99, 060407(R)(2019)
[3]B. Göbel, A. Mook, J. Henk, I. Mertig,“Antiferromagneticskyrmion crystals: Generation,topological Hall, and topological spin Hall effect”Phys. Rev. B.96, 060406(R)(2017)
[4] B. Göbel, C. Akosa, G. Tatara, I. Mertig.“Topological Hall signatures of magnetic hopfions”Phys. Rev. Research2, 013315 (2020)