title: Direct Atom Imaging by Chemical-Sensitive Holography.
abstract: In order to understand the physical and chemical properties of advanced materials, functional molecular adsorbates, and protein structures, a detailed knowledge of the atomic arrangement is essential. Up to now, if subsurface structures are under investigation, only indirect methods revealed reliable results of the atoms' spatial arrangement. An alternative and direct method is three-dimensional imaging by means of holography. Holography was in fact proposed for electron waves, because of the electrons' short wavelength at easily accessible energies. Further, electron waves are ideal structure probes on an atomic length scale, because electrons have a high scattering probability even for light elements. However, holographic reconstructions of electron diffraction patterns have in the past contained severe image artifacts and were limited to at most a few tens of atoms. Here, we present a general reconstruction algorithm that leads to high-quality atomic images showing thousands of atoms. Additionally, we show that different elements can be identified by electron holography for the example of FeS2.
authors.affiliation: Experimental Physics I, TU Dortmund , 44221 Dortmund, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Lühr
authors.affiliation: Experimental Department I, Max Planck Institute of Microstructure Physics , 06120 Halle, Germany.
authors.forename: Aimo
authors.initials: A
authors.lastname: Winkelmann
authors.affiliation: Department 5 - Materials Engineering, BAM - Federal Institute for Materials Research and Testing , 12205 Berlin, Germany.
authors.forename: Gert
authors.initials: G
authors.lastname: Nolze
authors.affiliation: Experimental Physics I, TU Dortmund , 44221 Dortmund, Germany.
authors.forename: Dominique
authors.initials: D
authors.lastname: Krull
authors.affiliation: Experimental Physics I, TU Dortmund , 44221 Dortmund, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Westphal
keywords: Holography; atomic imaging; electron backscattering; electron diffraction; photoemission