Buckling strain-enhanced thermal insulation in C₃N₄ monolayers: DFT and AIMD studies of electronic, optical and thermal properties

Density functional theory is used to study the physical properties of buckled C₃N₄ monolayers. Our findings reveal that increasing planar buckling transforms sp2 hybridization to sp³ hybridization, leading to a reduction in the band gap while maintaining dynamic stability. Ab initio molecular dynamics simulations indicate that both flat and buckled C₃N₄ monolayers exhibit thermal instability under the investigated conditions. The electrical transport behaviors show declined performances in terms of Seebeck coefficient and power factor when increasing buckling within the low temperature range. At intermediate temperature range, the lattice thermal conductivity decreases with increasing buckling due to enhanced phonon scattering. Our study also investigates the optical characteristics such as optical conductivity, refractive index and dielectric functions. The buckled C₃N₄ monolayer exhibits lower visible light optical activity than its flat configuration. Tuning planar buckling of C₃N₄ can be used as an alternative method to tune physical properties that will be beneficial for numerous applications in the development of both thermal and optoelectronic nanodevices.