Skyrmions in the moir\'e of van der Waals 2D magnets

TL;DR

This paper investigates the formation and control of skyrmions in 2D van der Waals magnets influenced by moiré patterns, revealing new mechanisms for skyrmion creation and manipulation with potential applications in information storage.

Contribution

It introduces a novel origin of skyrmions in 2D magnets based on moiré pattern-induced modulation of interlayer magnetic coupling, and demonstrates their tunability and dynamics.

Findings

Moiré skyrmions are doubly degenerate with opposite topological charges.

Moiré periodicity and skyrmion positions can be tuned by strain and interlayer translation.

Skyrmion lattices and metastable skyrmion excitations can be controlled by magnetic field and current pulses.

Abstract

We explore the skyrmion formation and control possibilities in 2D magnets from the ubiquitous moir\'e pattern in vdW heterostructures. Using the example of a ferromagnetic monolayer on an antiferromagnetic substrate, we demonstrate a new origin of skyrmions in the 2D magnets, from the lateral modulation of interlayer magnetic coupling by the locally different atomic registries in moir\'e. The moir\'e skyrmions are doubly degenerate with opposite topological charge, and trapped at an ordered array of sites with the moir\'e periodicity that can be dramatically tuned by strain and interlayer translation. At relatively strong interlayer coupling, the ground states are skyrmion lattices, where magnetic field can switch the skyrmion vorticity and location in the moir\'e. At weak interlayer coupling limit, we find metastable skyrmion excitations on the ferromagnetic ground state that can be deterministically moved between the ordered moir\'e trapping sites by current pulses. Our results point to potential uses of moir\'e skyrmions both as information carriers and as drastically tunable topological background of electron transport.