Structure and reactivity of Bi allotropes on the fivefold icosahedral Al-Pd-Mn quasicrystal surface.

The growth of Bi on a pseudomorphic Bi monolayer on the fivefold surface of the icosahedral Al?Pd?Mn quasicrystal has been investigated using low energy electron diffraction and scanning tunnelling microscopy. Initially randomly oriented pseudocubic islands are formed with a preference for an even number of layers. Subsequently a morphological transformation takes place to hexagonal Bi islands, which align along high symmetry directions of the substrate. The Bi flux is found to have a strong effect on which island structure is preferred. When C60 is adsorbed on the three different allotropes of Bi present in this system, hexagonal C60 islands are formed in each case. On the pseudocubic and hexagonal islands, the C60 islands are aligned with the substrate. We discuss the energetic, kinetic and geometrical factors which influence the morphological transformation referred to above.