Energy Bands in Boron Nitride and Graphite

The tight-binding approximation has been applied for calculation of the band structure of planar hexagonal crystal layers of graphite and boron nitride. The theoretical width of the valence band of 15.9 eV in graphite and the distance between the centers of $\pi$ and $\sigma$ band of 5.3 eV as obtained in the present calculation are in good agreement with Chalkin's experimental work yielding 15 and 5 eV, respectively. For boron nitride, the width of the energy gap and the width of the valence band were calculated to be 4.9 and 6.8 eV, respectively.