CrI₃/Y₂CH₂ Heterointerface-Induced Stable Half-Metallicity of Two-Dimensional CrI₃ Monolayer Ferromagnets

Two-dimensional (2D) CrI₃ monolayer ferromagnets are key to the development of future miniature spintronic devices and modulating them into a half-metal will greatly expand the application scenarios of CrI₃ in nanospintronics. Nevertheless, existing strategies to induce half-metallicity of a CrI₃ monolayer remain experimentally challenging and have unstable issues. In this work, the introduction of a 2D electride [Y₂C]²⁺·2e^- as an auxiliary layer is shown to be an effective way to achieve the generation of stable half-metallicity in the CrI₃ monolayer. When the fully hydrogenated Y₂CH₂ and ferromagnetic CrI₃ monolayer combine to form a heterostructure, surprisingly the appropriate amount of charge injection (0.72 e) turns CrI₃ into a half-metal. Hetero-interfacial half-metallicity in CrI₃ is an intrinsic one and does not require any chemical functionalization or external physical modification. Therefore, it is advantageous for practical applications of CrI₃ in miniature spintronic devices, such as magnetic tunnel junctions, spin valves or spin field-effect transistors. A new strategy of the stable CrI₃/Y₂CH₂ heterostructure was successfully developed to induce the half-metallicity of 2D CrI₃ ferromagnets, which is experimentally feasible and half-metallic stable enough. This work paves the way for the application of the CrI₃ monolayer in half-metallic-based spintronics.