Vertical Ferroelectricity in Van der Waals Materials: Models and Devices

TL;DR

This paper proposes a generic van der Waals stacking model for vertical ferroelectricity, demonstrating its feasibility through first-principles calculations on specific material combinations, and highlighting its potential for next-generation information storage.

Contribution

It introduces a new tri-layer van der Waals model for vertical ferroelectricity, enabling flexible material combinations with low switching barriers.

Findings

Ferroelectric phase transition achieved between symmetric stacking states.

Estimated polarizations of 1.83 and 1.35 pC/m for specific models.

Model applicable to various van der Waals semiconducting materials.

Abstract

Ferroelectricity has a wide range of applications in functional electronics and is extremely important for the development of next-generation information storage technology, but it is difficult to achieve due to its special symmetry requirements. In this letter, based on van derWaals stacking, a generic model is proposed for realizing ferroelectric devices, where a freely movable center layer is packaged in two fixed and symmetrically stacked layers. In this model, the ferroelectric phase transition can be realized between the two equivalent and eccentric ground stacking-states with opposite polarizations. By means of first-principles calculations, taking the h-BN/h-BN/h-BN and h-BN/Graphene/h-BN as feasible models, we carefully evaluate the magnitude of ferroelectricity. The corresponding polarizations are estimated as 1.83 and 1.35 pC/m, respectively, which are comparable to the sliding ferroelectricity. Such a new tri-layer model of vertical ferroelectricity can be constructed by arbitrary van derWaals semiconducting materials, and usually holds low switching barrier. Optimized material combinations with remarkable polarization are highly expectable to be discovered from the huge candidate set for future information storage.