ENERGY BANDS AND OPTICAL PROPERTIES OF HEXAGONAL BORON NITRIDE AND GRAPHITE

The band structure of hexagonal boron nitride in the two-dimensional approximation is computed using the tight-binding approximation in a semi-empirical way. The results are compared with those of the isoelectronic compound graphite and are shown to be in agreement with the basic experimental data. Three-dimensional band structure calculations have also been performed and the effect of the different spatial structure of boron nitride and graphite lattices on the electronic levels at the saddle point is shown to produce a doublet in the optical excitation spectrum of BN. © 1969 Società Italiana di Fisica.