The X-ray diffraction intensity from antiphase boundaries in a quadruple-period ordered alloy was derived by introducing statistical probabilities for the antiphase boundaries and their associated phase shifts. By fitting experimental data, an average distance between neighbouring antiphase boundaries of some 130, 400 and 5nm along the [110], [¯110] and [001] directions, respectively, was obtained. The short distance along the [001] growth direction produced a narrow streak along [001] in an intensity contour map. It was also found that the antiphase boundaries broadened the ordering peaks, while their effect upon the intensity ratio between ordering peaks was negligible. Static atomic displacements, which were associated with bond-length disparities, were also included in the calculations.

X-Ray Study of Antiphase Boundaries in the Quadruple-Period Ordered GaAs0.87Sb0.13 Alloy. Z.Zhong, V.Holý, J.H.Li, J.Kulik, J.Bai, T.D.Golding, S.C.Moss: Journal of Applied Physics, 2001, 90[2], 644-9