Identification of skyrmion transition mechanisms by sub-10 nm maps of the transition rate

In addition to the conventional radial symmetric collapse of magnetic skyrmions, recent studies predicted the occurrence of skyrmion annihilation processes via the chimera skyrmion state [1-3]. Here, we demonstrate the realization of both the radial symmetric and the chimera transition mechanism in the ultra-thin film system fcc-Pd/Fe/Ir(111) [4]. Scanning tunneling microscopy is used to create transition rate maps of magnetic switching events induced by single electron events. In combination with energy density maps of the transition states obtained by atomistic spin simulations parametrized from first principles, they allow for the identification of both annihilation mechanisms. It is further shown, that a transition between both mechanisms can be achieved by the application of external in- and out-of-plane magnetic fields, yielding a sound agreement between experiment and theory.

[1] Meyer et al., Nat. Commun. 10, 3823 (2019)

[2] Heil et al., Phys. Rev. B 100, 134424 (2019)

[3] Desplat et al., Phys. Rev. B 99, 174409 (2019)

[4] Muckel et al., Nat. Phys. 17, 395-402 (2021)