Designing layered 2D skyrmion lattices in moir\'e magnetic hetero-structures

TL;DR

This theoretical study demonstrates how moiré magnetic heterostructures can host stable, controllable skyrmion lattices without external magnetic fields, advancing potential spintronic and magnonic device applications.

Contribution

It introduces a method to generate layered skyrmion lattices in moiré heterostructures through stacking-dependent magnetism and chiral interlayer interactions, without needing permanent magnetic fields.

Findings

Moiré skyrmion lattices emerge at large periodicity in CrBr3/CrI3 heterostructures.

Layered ferromagnetic and antiferromagnetic skyrmion lattices can be realized without external fields.

The study suggests creating colorful skyrmion lattices for advanced spintronic applications.

Abstract

Skyrmions are promising for the next generation of spintronic and magnonic devices, but their zero-field stability and controlled nucleation through chiral interactions remain challenging. In this theoretical study, we explore the potential of moir\'e magnetic heterostructures to generate ordered skyrmion lattices from the stacking-dependent magnetism in 2D magnets. We consider heterostructures formed by twisting ultrathin CrBr_3 films on top of CrI_3 substrates, assuming a moderate interfacial Dzyaloshinskii-Moriya interaction. At large moir\'e periodicity and appropriate substrate thickness, a moir\'e skyrmion lattice emerges in the interfacial CrBr_3 layer due to the weaker exchange interactions in CrBr_3 compared to CrI_3. This lattice is then projected to the remaining layers of the CrBr_3 film via emergent chiral interlayer fields. By varying the pristine stacking configurations within the ultrathin CrBr_3 film, we realize layered ferromagnetic and antiferromagnetic skyrmion lattices without the need for a permanent magnetic field. Our findings suggest the possibility of creating colorful skyrmion lattices in moir\'e magnetic heterostructures, enabling further exploration of their fundamental properties and technological relevance.