# Magnetic Skyrmion Annihilation by Quantum Mechanical Tunneling

## TL;DR

This paper investigates quantum tunneling as a mechanism for magnetic skyrmion annihilation, providing calculations of lifetimes and identifying conditions where tunneling effects could be experimentally observed.

## Contribution

It introduces a detailed analysis of quantum tunneling in skyrmion annihilation, extending understanding beyond classical over-the-barrier processes.

## Key findings

- Tunneling rate varies strongly with material parameters.
- Conditions for observable tunneling effects are identified.
- Skyrmion tunneling could be observed in PdFe/Ir(111) under high magnetic fields.

## Abstract

Magnetic skyrmions are nano-scale magnetic states that could be used in various spintronics devices. A central issue is the mechanism and rate of various possible annihilation processes and the lifetime of metastable skyrmions. While most studies have focused on classical over-the-barrier mechanism for annihilation, it is also possible that quantum mechanical tunneling through the energy barrier takes place. Calculations of the lifetime of magnetic skyrmions in a two-dimensional lattice are presented and the rate of tunneling compared with the classical annihilation rate. A remarkably strong variation in the crossover temperature and the lifetime of the skyrmion is found as a function of the values of parameters in the extended Heisenberg Hamiltonian, i.e. the out-of-plane anisotropy, Dzyaloshinskii-Moriya interaction (DMI) and applied magnetic field. Materials parameters and conditions are identified where the onset of tunneling could be observed on a laboratory time scale. In particular, it is predicted that skyrmion tunneling could be observed in the PdFe/Ir(111) system when an external magnetic field on the order of 6 T is applied.