Multiferroicity in the Flatland

Multiferroicity and magnetoelectricity (i.e. the coexistence and coupling between long-range magnetic and electric dipolar order) constitute two related landmark phenomena in quantum physics, where profound fundamental aspects (i.e. microscopic interactions between charge and spin degrees of freedom) are intimately related to technological milestones (multifunctional devices tuned by electric/magnetic fields). In this context, the reduction of dimensionality from 3D to 2D has been boosted by the recent discoveries of multiferroicity in NiI2 layers [1], obtained via a joint theory-experiments approach down to the single-layer limit. I will show several examples of first-principles modelling for multiferroic and magnetoelectric 2D-materials, including vanadium dihalide-monolayers (featuring 120-degree frustrated magnetic structures, which develop on the underlying triangular lattice and induce ferroelectric polarization) and domain walls in CrI3 layers (where ferroelectric polarization can be induced in both Néel- and Bloch-types), highlighting the potentiality of cross-coupling phenomena in van der Waals materials.

 

[1] Song Q., Occhialini C.A., Ergecen E., Ilyas B., Amoroso D., Barone P., Kapeghian J., Watanabe K., Taniguchi T., Botana A., Picozzi S., Gedik N., Comin R., Evidence for a single-layer van der Waals multiferroic, Nature 602, 601 (2022)