Al on Si(111): Phase diagram and atomic mechanisms

Low-energy electron microscopy and diffraction not only allow one to determine the structure of adsorption-induced surface phases, but also to follow the nucleation and motion of phase boundaries as well as the surface material transport associated with phase transformation, decomposition, and desorption. By use of these methods for the well-known Al/Si(111) system, unexpected phase relations are uncovered—such as the thermal decomposition of the (√7×√7)R19.1° phase into a disordered and a strained substitutional phase—and these relations are linked to surface atomic mechanisms. © 1996 The American Physical Society.