Ab initio Calculations of phase transition and electronic propertie of Scandium compounds

The structural, electronic, and elastic properties of ScN and ScP in NaCl (B1 phase) and CsCl (B2 phase) structures and the phonon dispersion. The nature of the bandgap of ScN is subject to some controversy. ScN is a semiconductor in the rocksalt (B1) phase and a semimetal in the CsCl (B2) phase. The rocksalt (B1) configuration is found to be the most probable with the possibility of a transition to the CsCl (B2) at high pressures. One very interesting result we obtained is that ScSb, ScAs, ScP are found to be wide and direct bandgap semiconductors in the zinc blende (B3) phase. In this phase, the top of the valence band of ScN is at X but the bottom of its conduction band is at W, but this indirect X–W gap is very close to the X–X gap. It has also been found that in some cases, these materials have similar lattice constants, so that their combination could make possible the fabrication of heterostructures. However, their lattice constants are very different from that of ScN.