COMPARISON OF CARBON AND BORON-NITRIDE IN A HYPOTHETICAL ALL-SP2-BONDED TETRAGONAL PHASE

We have examined BN in an all-sp2 phase similar to that previously suggested for carbon. Although calculations predict that carbon in this structure, called bct-4, will be metallic, the band overlap in bct-4 BN is predicted to be very small or zero. Hence it is suggested that the BN structure is more likely to be stable than the carbon. The antisymmetric potential in the BN structure also causes a gap in the density of states between the second and third occupied bands. As in the carbon case, the lattice match between bct-4 and the zinc-blende (100) surface for BN is nearly perfect. Thus, epitaxial growth of the bct-4 BN phase may be possible.