Carbon Phosphide Monolayers: Novel 2D Materials

Monolayers of carbon phosphide are investigated using the particle swarm optimization and first-principles methods. The calculated results for $\alpha $-, $\beta $-, and $\gamma $- phases of carbon phosphide show novel properties including the presence of Dirac cones in the band structure. These configurations are composed of sp$^{\mathrm{2}}$ hybridized C atoms and sp$^{\mathrm{3}}$ hybridized P atoms in a hexagonal network with three-fold coordinated atoms. $\alpha $- and $\beta $- phases are semiconducting with highly anisotropic electronic and mechanical properties whereas $\gamma $-CP is semi-metallic with a high electron mobility. Our results suggest that the group IV-V binary monolayers can be considered as a new family of 2D materials for electronics and optoelectronics applications at nanoscale.