Deterministic and Efficient Switching of Sliding Ferroelectrics

TL;DR

This paper introduces a neural network-based approach to model 2D sliding ferroelectrics, demonstrating high Curie temperatures and a universal method for deterministic polarization switching using inclined electric fields.

Contribution

The study develops a multi-task equivariant neural network for accurate potential prediction in boron nitride bilayers, enabling efficient polarization switching strategies applicable to various 2D ferroelectric materials.

Findings

Achieved a Curie temperature of up to 1500K in simulations.

Discovered that inclined electric fields enable deterministic and lower-threshold polarization switching.

Demonstrated universality of the inclined field strategy for other 2D ferroelectric systems.

Abstract

Recent studies highlight the scientific importance and broad application prospects of two-dimensional (2D) sliding ferroelectrics, which prevalently exhibit vertical polarization with suitable stackings. It is crucial to understand the mechanisms of sliding ferroelectricity and to deterministically and efficiently switch the polarization with optimized electric fields. Here, applying our newly developed DREAM-Allegro multi-task equivariant neural network, which simultaneously predicts interatomic potentials and Born effective charges, we construct a comprehensive potential for boron nitride ($\mathrm{BN}$) bilayer. The molecular dynamics simulations reveal a remarkably high Curie temperature of up to 1500K, facilitated by robust intralayer chemical bonds and delicate interlayer van der Waals(vdW) interactions. More importantly, it is found that, compared to the out-of-plane electric field, the inclined field not only leads to deterministic switching of electric polarization, but also largely lower the critical strength of field, due to the presence of the in-plane polarization in the transition state. This strategy of an inclined field is demonstrated to be universal for other sliding ferroelectric systems with monolayer structures belonging to the symmetry group $p \bar{6} m 2$, such as transition metal dichalcogenides (TMDs).