Fig. 5: Origin of phase transition and device prototype.

a, b Band alignment of the VBi2Te4/In2Se3 heterostructure with P↑ and P↓ states. c, d Plane-averaged charge density difference and differential charge density distributions of the VBi2Te4/In2Se3 heterostructure with P↑ and P↓ states. The isosurface value is 0.0003 eÅ-3. e, f Schematic representation of multiferroic memory device designed based on the VBi2Te4/In2Se3 heterostructure. The data writing process relies on the ferroelectric In2Se3, while the data reading process is realized by detecting the electric or optical signal of the VBi2Te4 monolayer.