Observation of a novel form of ordering in Al0.5In0.5As and (Ga,Al)0.5In0.5As

Abstract We have found a novel form of ordering in Al 0.5 In 0.5 As and (Ga,Al) 0.5 In 0.5 As as grown on (001) substrates by molecular beam epitaxy (MBE). Electron diffraction patterns reveal a four-fold periodicity along the [1 1 0] direction as well as the more usual two-fold periodicity along 〈1 1 1〉 directions. The morphology of the latter type of ordering is also different from its normal form.