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Title: Random vs realistic amorphous carbon models for high resolution microscopy and electron diffraction

Amorphous carbon and amorphous materials in general are of particular importance for high resolution electron microscopy, either for bulk materials, generally covered with an amorphous layer when prepared by ion milling techniques, or for nanoscale objects deposited on amorphous substrates. In order to quantify the information of the high resolution images at the atomic scale, a structural modeling of the sample is necessary prior to the calculation of the electron wave function propagation. It is thus essential to be able to reproduce the carbon structure as close as possible to the real one. The approach we propose here is to simulate a realistic carbon from an energetic model based on the tight-binding approximation in order to reproduce the important structural properties of amorphous carbon. At first, we compare this carbon with the carbon obtained by randomly generating the carbon atom positions. In both cases, we discuss the limit thickness of the phase object approximation. In a second step, we show the influence of both carbons models on (i) the contrast of Cu, Ag, and Au single atoms deposited on carbon and (ii) the determination of the long-range order parameter in CoPt bimetallic nanoalloys.
Authors:
;  [1] ; ; ;  [2]
  1. Laboratoire Matériaux et Phénomènes Quantiques, CNRS-UMR 7162, Université Paris Diderot-Paris 7, Case 7021, 75205 Paris Cedex 13 (France)
  2. Laboratoire d'Etude des Microstructures, UMR CNRS/Onera, 29, avenue de la Division Leclerc, 92322 Châtillon (France)
Publication Date:
OSTI Identifier:
22258716
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 21; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARBON; ELECTRON DIFFRACTION; ELECTRON MICROSCOPY; IMAGES; MILLING; NANOSTRUCTURES; ORDER PARAMETERS; RANDOMNESS; SPATIAL RESOLUTION; SUBSTRATES; THICKNESS; WAVE FUNCTIONS