Using the first-principles method combined with the anharmonic oscillator model, the electronic, linear, and nonlinear optical properties of four C3 N4 polymorphs are investigated. The calculations show that the third-order susceptibilities and nonlinear refractive indices increase with the increase of volume of C3 N4 polymorphs below 1.5 eV, whereas the plasmon frequencies and relativistic nonlinear refractive indices decrease. The obtained results indicate that the spinel C3 N4 has some potential applications in nonlinear optics.
Bibliographical noteFunding Information:
The authors are grateful to the National Science Foundation of China (20373073 and 90201015), the NationalBasic Research Program of China (No. 2004CB720605) for financial supports.