Pressure Induced Metastable Amorphization of BAs: Evidence for a Kinetically Frustrated Phase Transformation

A transformation from the zinc blende (zb) to an amorphous crystal structure was observed at 125 GPa, just slightly above the calculated equilibrium transition pressure to the rock salt phase [Phys. Rev. B 36, 6058 (1987)]. This is the first evidence that pressure induced amorphization in [ital AB] compounds is a kinetically frustrated process. The amorphous state persisted on further loading to 165 GPa, and throughout downloading to 0 GPa. The Birch coefficients of the equation of state for the zb phase were determined to be [ital B][sub 0]=148[plus minus]6 GPa and [ital B][sub 0][sup [prime]]=3.9[plus minus]0.3, in good agreement with theoretical calculations.