Local Manipulation of Polar Skyrmions and Topological Phase Transitions

TL;DR

This paper demonstrates how local electric potentials can reversibly manipulate polar skyrmions and induce topological phase transitions in ferroelectric oxide superlattices, revealing potential for tunable topological states.

Contribution

It introduces a phase-field simulation method to control skyrmion phases locally via electric potential, showing reversible erasure and topological transitions.

Findings

Skyrmions can be erased and recovered reversibly with small electric potentials.

Topological transitions occur at the edges of electrodes and can switch between different skyrmion states.

Skyrmion shrinking and bursting significantly reduce dielectric permittivity.

Abstract

Topological phases such as polar skyrmions have been a fertile playground for ferroelectric oxide superlattices, with exotic physical phenomena such as negative capacitance. Herein, using phase-field simulations, we demonstrate the local control of the skyrmion phase with electric potential applied through a top electrode. Under a relatively small electric potential, the skyrmions underneath the electrode can be erased and recovered reversibly. A topologically protected transition from the symmetric to asymmetric skyrmion bubbles is observed at the edge of the electrode. While a topological transition to a labyrinthine domain requires a high applied potential, it can switch back to the skyrmion state with a relatively small electric potential. The topological transition from +1 to 0 occurs before the full destruction of the bubble state. It is shown that the shrinking and bursting of the skyrmions leads to a large reduction in the dielectric permittivity, the magnitude of which depends on the size of the electrode.