Reversible nonvolatile control of anomalous valley Hall effect in a multiferroic van der Waals heterostructure

Controlling the anomalous valley Hall (AVH) effect by external means is crucial for valleytronic devices in practical applications; however, most of the previously proposed control approaches are either irreversible or volatile. Here, we present a general scheme for achieving nonvolatile electrical control of the AVH effect based on multiferroic van der Waals heterostructure. Using density functional theory calculations and k center dot p model analysis, we further demonstrate the feasibility of this design principle by stacking ferromagnetic monolayer VSe2 on ferroelectric monolayer Al2S3. The reversible switching of AVH can be finely manipulated by reversing the ferroelectric polarization of Al2S3 via electric field. The regulated AVH state of VSe2 can be stably preserved due to the ferroelectric nonvolatility of Al2S3. In addition, the sign of valley polarization can be simultaneously inverted by reversing ferroelectric polarization. Our results not only provide the basis for an intrinsic ferroelectricity controlled ferrovalley, but also uncover an outstanding candidate for realizing bidirectional and nonvolatile switching valleytronic devices.

Automated summary

This study presents a general scheme for achieving nonvolatile electrical control of the anomalous valley Hall (AVH) effect based on multiferroic van der Waals heterostructure. By stacking ferromagnetic monolayer on ferroelectric monolayer, the reversible switching of AVH can be finely manipulated, and the ferroelectric nonvolatility ensures the stability of the AVH state. In addition, the sign of the valley polarization can be inverted by reversing ferroelectric polarization.