Band gaps and dielectric functions of cubic and hexagonal diamond polytypes calculated by many‐body perturbation theory

摘要: Band structures for diamond polytypes are calculated by density functional theory with local approximation and the band energies at high symmetry k-points corrected using GW method. The gap energy is 5.627 eV 3C-diamond, 4.683 eV 2H-diamond, 5.983 eV 4H-diamond, 5.950 eV 6H-diamond. For dielectric function calculations, electron–hole interaction treated Bethe–Salpeter equation. Anisotropic response of hexagonal demonstrated 2H-diamond has significant anisotropic optical absorption property. Comparison available experimental data 3C-diamond discussed.