Multiple Dirac states in two-dimensional topological half-metallic CrB2C2

Recently, Dirac states in two dimensional materials have drawn great attention because of its desirable transport properties. In this paper, we predicted a two-dimensional hexagonal CrB2C2, which exhibits stable mechanical and thermal properties. Young's modulus of CrB2C2 is 485.67 N/m, which is comparable with that of graphene. In addition, CrB2C2 is half-metallic, and the ferromagnetic Curie temperature is about 1500 K, which is far above room temperature. A CrB2C2 nanosheet exhibits multiple Dirac states in the spin minority channel and forms compensated electron-hole pockets. The Fermi velocity of two different Dirac states is about 4.18×105 and 3.42×105 m/s. In the electronic band structure, the Dirac state at the K point is weakly gapped by 0.38 meV under a spin orbital interaction, while the other one could be topological nontrivially gapped by 37.4 meV, and the bottom Dirac band exhibits a nonzero Chern number at about 0.25 eV above the Fermi energy.