It was pointed out that the lowest-energy configuration of a class of vicinal (100) surfaces had equally spaced steps; each with a height of 2 atomic units. This resulted in a single-domain surface upon which the surface Si-Si dimers were aligned parallel to the step edges. The interaction of As with vicinal (100) surfaces was crucial for GaAs growth on Si. The present scanning tunnelling microscopic, low-energy electron diffraction, and X-ray photo-emission results yielded a consistent picture of the interaction of As with vicinal (100). It was found that, depending upon the temporal order of As exposure and surface heating, the directions of the As-As dimers could be reproducibly made to lie perpendicular or parallel to the step edge. In the latter case, the step array on the Si substrate was completely rearranged. Any GaAs which was grown on a given type of dimer arrangement was controllably oriented at 90º with respect to that on the other type.

R.D.Bringans, D.K.Biegelsen, L.E.Swartz: Physical Review B, 1991, 44[7], 3054-63