Mechanical and electronic properties of graphitic carbon nitride (g-C3N4) under biaxial

Using the first-principles density functional theory calculations, we investigate the mechanical and electronic properties of biaxially strained graphitic carbon nitride (g-C3N4). The results show highly isotropic mechanical properties and large linear elasticity of g-C3N4. Moreover, both the Perdew-Burke-Ernzehof (PBE) and Heyd-Scuseria-Ernzerhof (HSE06) band gaps reach the maximum values at 10% strain. The bonding properties are analyzed based on the electronic localization function (ELF). In addition, the photon transition between band gap is weak, suggesting the monolayer g-C3N4 is not suitable for a solar cell material. Enough biaxial strain can induce the spin splitting of g-C3N4, and it is found that the spin-unrestricted band gap of g-C3N4 can be overestimated. This work provides valuable insights for designing the new elastic electronic and spintronic devices based on two-dimensional g-C3N4.