Designing two-dimensional ferroelectrics by stacking engineering

Abstract

Ferroelectrics can function as non-volatile memory thanks to their switchable electric polarization by an electric field. However, realizing ferroelectricity at ultrathin thicknesses remains a challenge in materials science. To tackle this challenge, we artificially created a two-dimensional ferroelectric material using the van der Waals assembly. By manipulating its stacking order, we successfully transformed boron nitride, a non-ferroelectric van der Waals compound, into a ferroelectric material. The resulting ferroelectrics are stable up to room temperature despite their sub-nanometer thickness, enabling non-volatile memory applications. We further demonstrated the versatility of the design principle by converting semiconducting transition metal dichalcogenides into ferroelectrics in a similar manner.