Structure and reactivity of Bi allotropes on the fivefold icosahedral Al–Pd–Mn quasicrystalsurface

Abstract

The growth of Bi on a pseudomorphic Bi monolayer on the fivefold surface ofthe icosahedral Al–Pd–Mn quasicrystal has been investigated using low energyelectron diffraction and scanning tunnelling microscopy. Initially randomly orientedpseudocubic 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 fluxis found to have a strong effect on which island structure is preferred. WhenC60 is adsorbed on the three different allotropes of Bi present in this system, hexagonalC60 islands are formed in each case. On the pseudocubic and hexagonal islands, theC60 islands are aligned with the substrate. We discuss the energetic, kinetic and geometricalfactors which influence the morphological transformation referred to above.