Comparative Hartree-Fock and density-functional theory study of cubic and hexagonal diamond

An analysis of the electronic properties of bulk cubic and hexagonal diamond calculated using the ab initio packages CRYSTAL98 and the Vienna Ab initio Simulation Package is presented. We apply these ab initio methods to the study of cubic diamond, including the calculation of electronic properties (such as the band structure, electronic density of states, the indirect bandgap E-g(indirect), the valence band width and the conduction band width) and mechanical properties (such as the equilibrium lattice constant a(0) and the bulk modulus B). The combination of theoretical techniques that yield results that most accurately match experiment for cubic diamond are then used to calculate the electronic properties of the hexagonal diamond polymorph.