Manipulation of magnetic skyrmions with a scanning tunneling microscope

The dynamics of a single magnetic skyrmion in an atomic spin system under the influence of a scanning tunneling microscope is investigated by computer simulations solving the Landau-Lifshitz-Gilbert equation. Two possible scenarios are described: manipulation with aid of a spin-polarized tunneling current and by an electric field created by the scanning tunneling microscope. The dynamics during the creation and annihilation process is studied and the possibility to move single skyrmions is showed.

Figure 1

Single magnetic skyrmion at $B_z=3$ T. Left: Triangular lattice with Néel type magnetic skyrmion. Right: Corresponding continuum picture.

Figure 2

Creation and annihilation of a skyrmion with current pulses from a spin-polarized STM tip. Left column: Creation with tip polarization $\mathbf{P}=-\widehat{\mathbf{z}}$. Right column: Annihilation with tip polarization $\mathbf{P}=+\widehat{\mathbf{z}}$. The pictograms show schematic the in-plane orientation of the magnetization.

Figure 3

Manipulation of a single Skyrmion with a spin-polarized STM. Left column: Slow velocity and moderate current strength. Right column: Fast velocity and high current.

Figure 4

Skyrmion creation with (a) spin-polarized current and (b) with electric field: configurations shortly after the process has started.

Figure 5

Annihilation of the magnetic skyrmion (a) with an electric field. Three phases: (b) shrinking, (c) core collapse, and (d) shock wave.