Formation of a quasicrystalline Pb monolayer on the 10-fold surface of the decagonal Al-Ni-Co quasicrystal

Abstract

Lead has been deposited on the 10-fold surface of decagonal Al72Ni11Co17 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 C60 molecules on this surface showed that the pores are Pb-containing. 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.