Point Defects in Two-Dimensional γ‑Phosphorus Carbide

Defects are inevitably present in
two-dimensional (2D) materials
and usually govern their various properties. Here, a comprehensive
density functional theory-based investigation of seven kinds of point
defects in a recently produced γ allotrope of 2D phosphorus
carbide (γ-PC) is conducted. The defects, such as antisites,
single C or P, and double C and P and C and C vacancies, are found
to be stable in γ-PC, while the Stone–Wales defect is
not presented in γ-PC due to its transition-metal dichalcogenides-like
structure. The formation energies, stability, and surface density
of the considered defect species as well as their influence on the
electronic structure of γ-PC is systematically identified. The
formation of point defects in γ-PC is found to be less energetically
favorable than in graphene, phosphorene, and MoS2. Meanwhile,
defects can significantly modulate the electronic structure of γ-PC
by inducing hole/electron doping. The predicted scanning tunneling
microscopy images suggest that most of the point defects are easy
to distinguish from each other and that they can be easily recognized
in experiments.