▎ 摘　　要

In this work, we predict two novel ternary graphene-like structures, B4P4C4 and B2P2C8 monolayer. Their structural, mechanical and electronic properties are systematically investigated based on first-principles methods. The results show that the intrinsic and the strained materials possess excellent dynamic, thermal and mechanical stability, which provide the possibility for experimental preparation. Calculation results show that the intrinsic B4P4C4 monolayer has the Dirac feature. Particularly, the intrinsic B2P2C8 monolayer exhibits unique double Dirac points and non-trivial topological property. It is found that the Dirac states in B4P4C4 monolayer can be effectively regulated by applying horizontal strain, exhibiting the characteristics of a semiconductor with a direct or indirect band gap even an intriguing semiconductor-metal transition. In contrast, the intrinsic B2P2C8 monolayer is not sensitive to biaxial strain and its stability and semi-metal state preserve well like graphene, which benefits by its non-trivial topological property. Additionally, the calculated Young's modulus and Poisson's ratio show the mechanical anisotropy and excellent resistance of deformation of both the structures. Our work expands the 2D material family and these outstanding properties make B4P4C4 and B2P2C8 monolayer promising candidates for potential applications in battery, super capacitor, sensor and other fields.