Ferroelectric control of electron half-metallicity in A-type antiferromagnets and its application to nonvolatile memory devices

Two-dimensional (2D) A-type antiferromagnetic van der Waals (vdW) materials with either intralayer ferromagnetic and/or intralayer antiferromagnetic coupling have sparked great interest due to their potential applications in spintronics. By first-principles design we predict that a heterostructure formed by sandwiching the 2D A-type antiferromagnet, 2H-VSe2, between the 2D out-of-plane ferroelectric, Sc2CO2, presents a semimetal band structure with a half-metallic conduction band. The mechanism giving rise to this peculiar structure cooperatively originates from the strong built-in electric field of the double-layer ferroelectric Sc2CO2, and from the charge transfer selectively occurring only at one interface. Based on the so-designed Sc2CO2/VSe2 multiferroic heterostructure, two concepts for nonvolatile memory devices are proposed, in which two states (1 and 0) are realized by switching the polarization direction of the ferroelectric layers. These results demonstrate that the combination of 2D ferroelectrics and A-type antiferromagnetic vdW materials provides not only a fascinating way to achieve half-metallicity in 2D materials, but also a route to the design of new types of nonvolatile ferroelectric memory devices.