Formation Of A Quasicrystalline Pb Monolayer On The 10-fold Surface Of The Decagonal Al-ni-co Quasicrystal

摘要

Lead has been deposited on the 10-fold surface of decagonal Al_(72)Ni_(11)Co_(17) at room temperature to form an epitaxial quasicrystalline single-element monolayer. The overlayer grows through nucleation of nanometer-sized irregular-shaped islands and the coverage saturates at 1 MLE. The overlayer is well-ordered quasiperiodically as evidenced by LEED and Fourier transforms of STM images. LEED measurements also indicate that annealing the film to 600 K improves the structural quality, but STM shows that this causes the film to develop pores. Adsorption of C_(60) molecules on this surface showed that the pores are Pb-con-taining. Electronic structure measurements using X-ray photoemission spectroscopy indicate that the chemical interaction of the Pb atoms with the substrate is weak, and that Pb does not desorb from the surface upon annealing.