First-principles study on mechanical and electronic properties of C₃N monolayer collaboratively regulated by charged vacancy defect and uniaxial strain

The first-principles approach is adopted to investigate the collaborative effects of uniaxial strain and charged vacancy on the structural, mechanical, and electrical properties of C3N monolayers. The injection of charge eliminates the structural abnormalities introduced by the N vacancy in the C3N monolayer. Furthermore, the introduction of an extra charge augments both the ideal strength and ultimate strain along the Armchair (AM) orientation for both VN-C3N and VC-C3N monolayers. Further, a tunable local magnetization is demonstrated with applied uniaxial strain in positively charged VN-C3N monolayer. Band gap of negatively charged VN-C3N monolayer exhibits an increase, followed by a decrease, with increasing AM tensile strain, while it increases with increasing Zigzag (ZZ) tensile strain. When uniaxial tensile strain is applied, positively charged VC-C3N monolayer transforms from nonmagnetic to magnetic ground-state, while negatively charged VC-C3N monolayer switches back and forth from magnetic to nonmagnetic ground-state. Injecting a charge into VN-C3N monolayer significantly alters light absorption in the near infrared and visible region, but not the case for VC-C3N monolayer. Additionally, the effects of AM tensile strain on light absorption are insignificant for all systems. Our findings may provide the theoretical and experimental foundation for the design of new C3N-based nanoelectronic devices and functional materials.