The effect of switchable electronic polarization states on the electronic properties of two-dimensional multiferroic TMBr 2 /Ga 2 SSe 2 (TM = V-Ni) heterostructures.

Multiferroic van der Waals (vdW) heterostructures (HSs) prepared by combining different ferroic materials offer an exciting platform for next-generation nanoelectronic devices. In this work, we investigate the magnetoelectric coupling properties of multiferroic vdW HSs consisting of a magnetic TMBr 2 (TM = V-Ni) monolayer and a ferroelectric Ga 2 SSe 2 monolayer using first-principles theory calculations. It is found that the magnetic orderings in the magnetic TMBr 2 layers are robust and the band alignment of these TMBr 2 /Ga 2 SSe 2 HSs can be altered by reversing the polarization direction of the ferroelectric layer. Among them, VBr 2 /Ga 2 SSe 2 and FeBr 2 /Ga 2 SSe 2 HSs can be switched from a type-I to a type-II semiconductor, which allows the generation of spin-polarized and unpolarized photocurrent. Besides, CrBr 2 /Ga 2 SSe 2 , CoBr 2 /Ga 2 SSe 2 and NiBr 2 /Ga 2 SSe 2 exhibit a type-II band alignment in reverse ferroelectric polarization states. Moreover, the magnetic configuration and band alignment of these TMBr 2 /Ga 2 SSe 2 HSs can be further modulated by applying an external strain. Our findings suggest the potential of TMBr 2 /Ga 2 SSe 2 HSs in 2D multiferroic and spintronic applications.