Tunable magnetic anisotropy, Curie temperature, and band alignment of two-dimensional ferromagnet VSiSnN4 via nonvolatile ferroelectrical control

The emergence of multiferroic materials, which possess both ferromagnetic (FM) and ferroelectric (FE) properties, drive advancements in magnetoelectric applications and the next generation of spintronics. Based on first-principles calculations, we investigate an engineered two-dimensional multiferroic van der Waals heterostructures consisting of FM VSiSnN4 monolayer (ML) and fully hydrogenated FE AlN bilayer. We find that the magnetic anisotropy of VSiSnN4 ML is tunable between out-of-plane and in-plane, and a phase transition between semiconductor and metal is induced in VSiSnN4/AlN bilayer when the FE polarization direction of AlN bilayer is reversed. Surprisingly, when the FE polarization of AlN bilayer is upward, the Curie temperature of VSiSnN4/AlN bilayer can be significantly increased from 204 to 284 K. Such nonvolatile and tunable magnetic anisotropy, Curie temperature, and band alignment in VSiSnN4/AlN multiferroic heterostructure are highly promising for future low-current operation of data storage and logic devices.