Structure determination of the Ge(111)-c(2×8) surface by medium-energy ion scattering

The Ge(111)-c(2×8) and the Si(111)-(7×7) reconstructions are directly compared by medium-energy ion scattering. The c(2×8) surface is shown to induce considerably less atomic displacements than the (7×7) structure. The data are in good agreement with a simple adatom model for the c(2×8) reconstructed surface. © 1988 The American Physical Society.