BAND-STRUCTURE CALCULATIONS FOR BORON NITRIDES WITH 3 DIFFERENT CRYSTAL-STRUCTURES

The band structures of zincblende, hexagonal and wutzite BN have been calculated using the full-potential linear augmented-plane-wave (FLAPW) method systematically. The present results of zincblende and hexagonal BN are compared wth earlier calculations. For the wurtzite structure, the present work is the first ab initio calculation. The possibility of inter-layer states of hexagonal BN playing a crucial role in intercalation problems - which are already being studied experimentally - is discussed on the basis of the variation of the energy levels with respect to the variation of the c axis: the GAMMA //1** plus inter-layer state becomes the minimum of the conduction band with about 15% expansion of the c axis. A total-energy calculation gives bulk moduli of 3. 53 and 3. 49 Mbar for zincblende and wurtzite structures, respectively.