Title

LaBr2 bilayer multiferroic moiré superlattice with robust magnetoelectric coupling and magnetic bimerons

Publication Name

npj Computational Materials

Abstract

Two-dimensional (2D) van der Waals (vdW) materials provide the versatile playground to stack two or more vdW layers for creation of superior materials with desired properties. Here we theoretically adopt a twisted stack-engineering of two LaBr2 monolayers to break space inversion symmetry for ferroelectricity and ultimately multiferroism. The enhancement and reversal of electric polarization are accompanied with the transition from interlayer ferromagnetic and antiferromagnetic orderings, demonstrating an effective magnetoelectric coupling effect with a mechanism dissimilar to that of the conventional multiferroics. Magnetization dynamics simulations show that such magnetic phase transition can excite topologically protected bimeron, and the skyrmion Hall effect can be suppressed by bilayer-bimeron stabilized in both ferromagnetic and antiferromagnetic configurations. Moreover, in the small-angle twisted moiré superlattice, the uniform polarization will evolve into a staggered domain structure, accompanied with the appearance of bimeron, which forms a significant discrepancy with the non-twisted stack-engineered multiferroic LaBr2 bilayer. This work provides a strategy for 2D multiferroic materials by twisted stack engineering of magnetic single layers.

Open Access Status

This publication may be available as open access

Volume

8

Issue

1

Article Number

159

Funding Number

DP190100150

Funding Sponsor

Australian Research Council

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Link to publisher version (DOI)

http://dx.doi.org/10.1038/s41524-022-00833-4