The (100) surface of the Al13Co4 quasicrystalline approximant

2012 ◽  
Vol 1517 ◽  
Author(s):  
Vincent Fournée ◽  
Émilie Gaudry ◽  
Marie-Cécile de Weerd ◽  
Renee D. Diehl ◽  
Julian Ledieu
Keyword(s):  
Density Functional Theory ◽  
Electron Diffraction ◽  
Density Functional ◽  
Low Energy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Low Energy Electron Diffraction ◽  
Surface Models ◽  
Low Energy Electron

ABSTRACTThe structure of the (100) surface of the orthorhombic Al13Co4quasicrystalline approximant is described based on a combined scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and density functional theory (DFT) study. We discuss the interplay between the surface structure and the cluster substructure of this approximant as well as possible off-stoichiometry effects that could explain the discrepancies found in the literature on possible surface models.

COMBINED HRLEED AND STM INVESTIGATIONS ON THE INITIAL STAGES OF Cu HETEROEPITAXY Ru(0001)

1997 ◽  
Vol 04 (06) ◽  
pp. 1167-1171 ◽  
Author(s):  
CH. AMMER ◽  
K. MEINEL ◽  
H. WOLTER ◽  
A. BECKMANN ◽  
H. NEDDERMEYER
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Strain Relaxation ◽  
Local Scale ◽  
Low Energy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Layer Structures ◽  
Low Energy Electron

Recent scanning tunneling microscopy (STM) observations revealed different layer structures in the heteroepitaxial Cu/Ru(0001) system with increasing film thickness attributed to various stages of strain relaxation. High-resolution low-energy electron diffraction (HRLEED) analysis permits one to derive more exactly both lattice periodicities and lattice rotations. Furthermore, the representative character of local STM results can be proved. However, STM measurements are needed to identify and to assign the satellite spots to coexistent different superstructures which are superposed incoherently in the diffraction pattern. Generally, the integral LEED results confirm the crystallographic data obtained by STM in a local scale.

scholarly journals Lateral ordering of PTCDA on the clean and the oxygen pre-covered Cu(100) surface investigated by scanning tunneling microscopy and low energy electron diffraction

2014 ◽  
Vol 10 ◽  
pp. 2055-2064 ◽  
Author(s):  
Stefan Gärtner ◽  
Benjamin Fiedler ◽  
Oliver Bauer ◽  
Antonela Marele ◽  
Moritz M Sokolowski
Keyword(s):  
Electron Diffraction ◽  
Scanning Tunneling Microscopy ◽  
Low Energy ◽  
Energy Electron ◽  
Scanning Tunneling ◽  
Structure Model ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Lattice Planes

We have investigated the adsorption of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) on the clean and on the oxygen pre-covered Cu(100) surface [referred to as (√2 × 2√2)R45° – 2O/Cu(100)] by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Our results confirm the (4√2 × 5√2)R45° superstructure of PTCDA/Cu(100) reported by A. Schmidt et al. [J. Phys. Chem. 1995, 99,11770–11779]. However, contrary to Schmidt et al., we have no indication for a dissociation of the PTCDA upon adsorption, and we propose a detailed structure model with two intact PTCDA molecules within the unit cell. Domains of high lateral order are obtained, if the deposition is performed at 400 K. For deposition at room temperature, a significant density of nucleation defects is found pointing to a strong interaction of PTCDA with Cu(100). Quite differently, after preadsorption of oxygen and formation of the (√2 × 2√2)R45° – 2O/Cu(100) superstructure on Cu(100), PTCDA forms an incommensurate monolayer with a structure that corresponds well to that of PTCDA bulk lattice planes.

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