First Principles Calculation of the Energy Band Structure of Diamond

A first principles calculation of the energy band structure of diamond is performed using a muffin tin potential constructed from atomic functions and including the parametrized exchange term due to Slater. The crystal wave functions are expanded in 2s and 2p like functions obtained by integrating the Schrödinger equation for a single atom with a potential equal to the muffin tin potential inside the muffin tin radius and a constant elsewhere. The method gives a good valence band but a poorer conduction band. Excluding three centre integrals, varying the parameter in the exchange term and altering the electron configuration of the carbon atom does not appreciably change the band structure. Finally, including non muffin tin parts of the crystal potential improves the conduction band.