Regensburg 2022 – scientific programme
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MA: Fachverband Magnetismus
MA 30: Surface Magnetism
MA 30.9: Talk
Thursday, September 8, 2022, 11:30–11:45, H48
Atomistic spin simulations of electric-field assisted nucleation and annihilation of magnetic skyrmions — •Moritz A. Goerzen1, Stephan v. Malottki1,4, Grzegorz J. Kwiatkowski2, Pavel F. Bessarab2,3, and Stefan Heinze1 — 1Institute of Theoretical Physics and Astrophysics, University of Kiel, Germany — 2University of Iceland, Reykjavík, Iceland — 3St. Petersburg, Russia — 4Thayer School of Engineering, Dartmouth College, Hannover, USA
We demonstrate electric-field assisted thermally activated writing and deleting of magnetic skyrmions in ultrathin transition-metal films.
We apply an atomistic spin model which is parameterised from density functional theory (DFT) calculations for a Pd/Fe bilayer on the Ir(111) surface for electric fields of E= 0,± 0.5 V/Å.
Based on harmonic transition-state theory [1,2], we calculate the transition rates for skyrmion nucleation and annihilation. Using these rates we quantify the probability for electric-field assisted deleting and writing of skyrmions by means of Master equations.
The magnetic-field dependent skyrmion probability can be directly related to the free energy differences of the skyrmion and the ferromagnetic state and
resembles a Fermi-Dirac distribution function. The obtained probability function
at opposite electric fields is in striking agreement with experimental results [3].
[1] Bessarab et al., Sci. Rep. 8, 3433 (2018)
[2] von Malottki et al., Phys. Rev. B 99, 060409 (2019)
[3] Romming et al., Science 341, 636 (2013)