Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 59: Metal Substrates I
O 59.3: Talk
Wednesday, April 2, 2014, 16:30–16:45, WIL A317
Growth of ultrathin Pb layers on the Ni3Al(111) surface studied by AES/LEED/STM/DFT — •Katarzyna Krupski and Aleksander Krupski — Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
The morphology, atomic and electronic structure of ultrathin Pb layers deposited on the Ni3Al(111) face in ultrahigh vacuum at the substrate temperature, ranging from 200 K to 950 K, were investigated with the use of Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), directional elastic peak electron spectroscopy (DEPES), scanning tunnelling microscopy (STM). Density functional theory calculations (DFT) with the use of CASTEP code were used to describe atomic and electronic structure of the Pb/Ni3Al(111) system. The analysis of AES and STM measurements indicate that two-dimensional growth of the first Pb monolayer wetting layer takes place. For T = 200 K, lead on the Ni3Al(111) grows layer-by-layer, while for T = 300 K flat three atomic-layer-high islands seem to grow after the completion of the first lead monolayer. Above 350 K, the Stranski-Krastanov growth mode is observed. The ordered LEED paterns are observed. Above θ > 1.0 ML, a three-dimensional growth of the Pb islands was observed with a strongly preferred atomic-scale magic height (N), hexagonal shape and flat-tops. At coverage θ = 3.5 ML, only islands containing N = 3, 5, 7 and 11 atomic layers of Pb are observed. At the higher coverage θ = 5.5 ML, three types of regular hexagonal islands with side lengths of 25, 30 and 45 nm are observed. Furthermore, three different island adsorption configurations were observed.