Phase stability and elasticity of ScO at high pressure.

An investigation into the high-pressure behavior of ScO was conducted using first-principle calculations based on density functional theory within the generalized gradient approximation. Nine candidate phases were considered and simulated, C-, B-, A-RES, RhO(II), GdS, US, AlEr, corundum and PPv respectively. Our results demonstrate phase transitions of ScO from C- to B-RES phase at 15 GPa, then to GdS phase at 18 GPa. Elastic constants of ScO present softening from about 270 GPa to 337 GPa, associated with a semiconductor-to-metal crossover. The GdS-type ScO is both mechanically and dynamical stable at least up to 302 GPa supported by the mechanically stable criteria and the phonon spectrum. [ABSTRACT FROM AUTHOR]