Abstract
The energy band structure of semiconductors with the space group Dis investigated using as a starting point results of pseudopotential calculations of the energy band structures of GaAs and Gap. The changes in the energy bands which take place when one goes from the zineblende to the chalcopyrite structure are illustrated, and the arrangement of valence and conduction band states near κ = (0, 0, 0) in the first Brillouin zone of the chalcopyrite structure is discussed. The results indicate that the top two valence bends of a semiconductor with the chalcopyrite structure cross. This suggests that for a particular photon energy the absorption coefficients for radiation polarised parallel and perpendicular to the tetragonal axis might become equal in value.