Density functional calculation of band-parameters for boron nitride at normal and high pressures

The present work employs the total-energy pseudopotential technique within the framework of the density-functional theory with both the local-density approximation (LDA) and the generalized gradient approximation (GGA) for the exchange-correlation functional so as to calculate the structural, electronic, chemical bonding and elastic properties of BN in the zinc-blende structure at normal and high pressures. The results are generally in good agreement with the available experimental data. We found that in many cases (except may be for elastic constants) the GGA improves agreement with experiment. The calculations showed that the transition pressure for BN from the zinc-blende phase to the rocksalt phase is much smaller than previously reported theoretical values.