Interface-engineered magnetic anisotropy in MnX2 ferromagnets via 2D electride substrates

Abstract

Manipulating the magnetic anisotropy and achieving giant voltage-controlled magnetic anisotropy (VCMA) coefficients in two-dimensional (2D) ferromagnets represent a critical milestone for enabling next-generation spintronic devices. Here, we propose the interfaces formed by layered MnX2 (X = S, Se, Te) and 2D electride substrates, offering an exceptional platform to overcome the limits of traditional magnetic films. Using first-principles calculations, we show that the 2D electride substrates serve as ideal electron reservoirs, inducing a massive interfacial charge injection and a profound reconstruction of the electronic structure of ferromagnets. This enhanced proximity effect not only amplifies their magnetic anisotropy energy by nearly an order of magnitude, but also induces a perpendicular-to-in-plane easy-axis switching in MnTe2. In addition, biaxial strain and external electric field have been identified as versatile methods to enable the deterministic manipulation of magnetic behaviors in the proposed heterostructures. Notably, the strain-engineered MnTe2/Ca2N system exhibits an enhanced VCMA coefficient of 258 fJ/Vm, significantly outperforming conventional transition-metal interfaces. This giant magnetoelectric response, originating from the high electric-field sensitivity of spin–orbit coupling between specific interfacial Te-derived p-orbitals, establishes electride-based 2D ferromagnets as a compelling candidate for next-generation Magnetoelectric Random Access Memory.