When the spin-orbit coupling (SOC) is absent, almost all the proposed
half-metals with the twofold degenerate nodal points at the K (or K') in
two-dimensional (2D) materials are misclassified as "Dirac half-metals" owing
to the way graphene was utilized in the earliest studies. Actually, each band
crossing point at K or K' is described by a 2D Weyl Hamiltonian with definite
chirality; hence, it must be a Weyl point. To the best of our knowledge, there
have been no reports of a genuine (i.e., fourfold degenerate) Dirac point
half-metal in 2D yet. In this Letter, we proposed for the first time that the
2D d0-type ferromagnet Mg4N4 is a genuine Dirac half-metal with a fourfold
degenerate Dirac point at the S high-symmetry point, intrinsic magnetism, high
Curie temperature, 100% spin-polarization, robustness to the SOC and uniaxial
and biaxial strains, and 100% spin-polarized edge states. The work can be seen
as a starting point for future predictions of intrinsically magnetic materials
with genuine Dirac points, which will aid the frontier of topo-spintronics
researchers