1T-CrO₂ monolayer: a high-temperature Dirac half-metal for high-speed spintronics

Two-dimensional (2D) materials with complete spin-polarization, high-speed conduction electrons, large Curie temperatures and robust ferromagnetic ground states are desirable for spintronic applications. Based on first-principles calculations, we demonstrate that the 1T-CrO₂ monolayer is an intrinsic 3d ferromagnetic Dirac half metal (DHM) with two symmetry protected Dirac cones near the Fermi level. The Fermi velocities (3.21 × 10⁵ m s^-1 and 4.85 × 10⁵ m s^-1) of the Dirac cones are in the same order as that of graphene, indicating its excellent transport properties. Its 2.48 eV half-metallic gap is large enough to prevent the spin-flip transition. Moreover, the two Dirac cones are robust against biaxial strain of up to ±4%. The robust ferromagnetism is mainly contributed by the 3d states of Cr and its Curie temperature is up to 507 K. Our results indicate that the ferromagnetic 1T-CrO₂ monolayer is a promising candidate for high temperature, high efficiency spintronics applications.