Observation of a Simple-Cubic Phase of GaAs with a 16-Atom Basis (SC16)

An SC16 phase of GaAs has been observed at high pressure. The phase is obtained by heating the high-pressure Cmcm phase to above ~400K at ~14GPa and is found to be stable on cooling back to room temperature. The detailed structure has been refined. On pressure decrease, the SC16 phase is found to be stable down to atmospheric pressure. From high-temperature studies, the equilibrium range for the SC16 structure is 13 to 14.5 GPa.