We have investigated via Monte Carlo simulations the microstructure of the CuAu-I ordered phase in III-V semiconductor alloys of (${\mathit{A}}_{1\mathrm{-}\mathit{x}}$${\mathit{B}}_{\mathit{x}}$)C grown on (001) substrates. The Fourier power spectra of atomic configurations in the computer-generated structures could reproduce the features of the electron-diffraction patterns reported previously. Among the three possible variants of the CuAu-I structure, a simulated (001) epilayer contains two variants which have their tetragonal c-axis parallel to the (001) plane. We have found that the CuAu-I ordering occurs even in an off-stoichiometric alloy with x=0.25, but a low-deposition rate at a low growth temperature forms a short-range-order state of a ${\mathrm{Cu}}_3$Au type. © 1996 The American Physical Society.

• Received 9 February 1996

DOI:https://doi.org/10.1103/PhysRevB.54.10814