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.