Towards two-dimensional van der Waals ferroelectrics

Research on two-dimensional van der Waals ferroelectrics has witnessed an explosion over the past few years. This Perspective formulates a framework by which results can be analysed, reviews recent progress, discusses mechanisms and properties for applications, and outlines challenges to be addressed. The discovery of ferroelectricity in two-dimensional (2D) van der Waals (vdW) materials has brought important functionalities to the 2D materials family, and may trigger a revolution in next-generation nanoelectronics and spintronics. In this Perspective, we briefly review recent progress in the field of 2D vdW ferroelectrics, focusing on the mechanisms that drive spontaneous polarization in 2D systems, unique properties brought about by the reduced lattice dimensionality and promising applications of 2D vdW ferroelectrics. We finish with an outlook for challenges that need to be addressed and our view on possible future research directions.