bilayers*

New multiferroic platforms by sliding or rotation are being explored in two-dimensional (2D) materials [1,2,3]. Antiferromagnetically-coupled CrI₃ bilayers are one of the most studied magneto-electric multiferroic 2D materials [4]. Without considering magnetism, those bilayers possess a crystalline point of inversion, which can only be removed by antiparallel spin configuration between their two monolayers [4]. However, relative rotations between layers break the crystalline point of inversion, resulting in an inherent electric dipole moment P. Magnetoelectric couplings can be enhanced this way on a two-dimensional bilayer that is experimentally accessible [5].

References: 

[1] Wu et al. ACS Nano, 11, 6382-6388, 2017.

[2] Marmolejo-Tejada et al. Nano Lett. 22, 19, 2022.

[3] Junyi Ji et al. Phys. Rev. Lett. 130, 146801, 2023.

[4] Sun et al. Nature 572, 497, 2019.

[5] Poudel et al. Phys. Rev. B 107, 195128, 2023.