Pressure-induced phase transformations in AlAs: Comparison between<i>ab initio</i>theory and experiment

Abstract

Results of first-principles calculations of the structural properties of the compound AlAs in three crystallographic structures, i.e., B3 (zinc blende), B1 (rock salt), and B8 (nickel arsenide), are presented. AlAs is found to undergo a phase transition from the B3 to B8 structure at 6.1 GPa, in good agreement with recent experimental value of 7\ifmmode\pm\else\textpm\fi{}5 GPa (uncertainty due to hysteresis). The B1 structure is found to lie slightly higher in energy than the B8 structure. The values of the c/a ratio for AlAs in the B8 structure are 1.592 and 1.597 for the present calculation and experiment, respectively.