title: Elemental mapping in achromatic atomic-resolution energy-filtered transmission electron microscopy.
abstract: We present atomic-resolution energy-filtered transmission electron microscopy (EFTEM) images obtained with the chromatic-aberration-corrected FEI Titan PICO at the Ernst-Ruska Centre, Jülich, Germany. We find qualitative agreement between experiment and simulation for the background-subtracted EFTEM images of the Ti-L2,3 and O-K edges for a specimen of SrTiO3 oriented down the [110] zone axis. The simulations utilize the transition potential formulation for inelastic scattering, which permits a detailed investigation of contributions to the EFTEM image. We find that energy-filtered images of the Ti-L2,3 and O-K edges are lattice images and that the background-subtracted core-loss maps may not be directly interpretable as elemental maps. Simulations show that this is a result of preservation of elastic contrast, whereby the qualitative details of the image are determined primarily by elastic, coherent scattering. We show that this effect places a constraint on the range of specimen thicknesses which could theoretically yield directly useful elemental maps. In general, interpretation of EFTEM images is ideally accompanied by detailed simulations.
authors: School of Physics, University of Melbourne, Parkville, VIC 3010, Australia.
authors: B D
authors: BD
authors: Forbes
authors: Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors: L
authors: L
authors: Houben
authors: Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich, Germany; Central Facility for Electron Microscopy, RWTH Aachen University, D-52074 Aachen, Germany.
authors: J
authors: J
authors: Mayer
authors: Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors: R E
authors: RE
authors: Dunin-Borkowski
authors: School of Physics, University of Melbourne, Parkville, VIC 3010, Australia. Electronic address: lja@unimelb.edu.au.
authors: L J
authors: LJ
authors: Allen
keywords: Achromatic EFTEM; Elemental mapping; Preservation of elastic contrast