Skyrmions Driven by Intrinsic Magnons

We study the dynamics of a Skyrmion in a magnetic insulating nanowire in the presence of time-dependent oscillating magnetic field gradients [1]. These ac fields act as a net driving force on the Skyrmion via its own intrinsic magnetic excitations. Making use the generalized micromagnetic equations of motion for the quantum propagation of a skyrmion in a magnetic insulator [2], we include the unavoidable coupling of the external field to the magnons, which gives rise to time-dependent dissipation for the Skyrmion. We demonstrate that the magnetic ac field induces a super-Ohmic to Ohmic crossover behavior for the Skyrmion dissipation kernels with time-dependent Ohmic terms. The ac driving of the magnon bath at resonance results in a unidirectional helical propagation of the Skyrmion in addition to the otherwise periodic bounded motion.

[1] Christina Psaroudaki and Daniel Loss, Skyrmions Driven by Intrinsic Magnons, Phys. Rev. Lett. 120, 237203 (2018).
[2] Christina Psaroudaki, Silas Hoffman, Jelena Klinovaja, and Daniel Loss, Quantum Dynamics of Skyrmions in Chiral Magnets, Phys. Rev. X 7, 041045 (2017).