Quantum Nucleation of Skyrmions in Magnetic Films by Inhomogeneous Fields

TL;DR

This paper models the quantum nucleation of individual skyrmions in magnetic thin films induced by localized inhomogeneous magnetic fields, providing a theoretical framework for controlled skyrmion creation at zero temperature.

Contribution

It introduces a quantum tunneling model for skyrmion nucleation driven by local magnetic field distortions in ultra-thin magnetic films, using spin path integrals and collective coordinate approximation.

Findings

Calculated tunneling rates depend on local field strength and spot size.

Identified parameters for experimental observation of quantum skyrmion nucleation.

Provided a theoretical basis for controlled skyrmion creation in magnetic films.

Abstract

Recent experiments have reported on controlled nucleation of individual skyrmions in chiral magnets. Here we show that in magnetic ultra-thin films with interfacial Dzyaloshinskii-Moriya interaction, single skyrmions of different radii can be nucleated by creating a local distortion in the magnetic field. In our study, we have considered zero temperature quantum nucleation of a single skyrmion from a ferromagnetic phase. The physical scenario we model is one where a uniform field stabilizes the ferromagnet, and an opposing local magnetic field over a circular spot, generated by the tip of a local probe, drives the skyrmion nucleation. Using spin path integrals and a collective coordinate approximation, the tunneling rate from the ferromagnetic to the single skyrmion state is computed as a function of the tip's magnetic field and the circular spot radius. Suitable parameters for the observation of the quantum nucleation of single skyrmions are identified.