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

Abstract 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 C 3 N monolayers. The injection of charge eliminates the structural abnormalities introduced by the N vacancy in the C 3 N monolayer. Furthermore, the introduction of an extra charge augments both the ideal strength and ultimate strain along the Armchair (AM) orientation for both V N -C 3 N and V C -C 3 N monolayers. Further, a tunable local magnetization is demonstrated with applied uniaxial strain in positively charged V N -C 3 N monolayer. Band gap of negatively charged V N -C 3 N 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 V C -C 3 N monolayer transforms from nonmagnetic to magnetic ground-state, while negatively charged V C -C 3 N monolayer switches back and forth from magnetic to nonmagnetic ground-state. Injecting a charge into V N -C 3 N monolayer significantly alters light absorption in the near infrared and visible region, but not the case for V C -C 3 N 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 C 3 N-based nanoelectronic devices and functional materials.