Regensburg 2013 – wissenschaftliches Programm
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KR: Fachgruppe Kristallographie
KR 5: Poster - Crystallography
KR 5.2: Poster
Mittwoch, 13. März 2013, 15:00–17:30, Poster B2
Digital electron diffraction: a new approach for determining crystal symmetry at the nanometre scale — Richard Beanland1, Paul J Thomas2, David I Woodward1, Pam A Thomas1, and •Rudolf A Römer1,3 — 1Department of Physics, The University of Warwick, Coventry CV4 7AL, UK — 2Gatan UK Ltd, 25 Nuffield Way, Abingdon, Oxon, OX14 1RL, UK — 3Centre for Scientific Computing, The University of Warwick, Coventry CV4 7AL, UK
The functional properties of materials are normally determined by their symmetry. This is equally true on the nano-scale as it is at the macro-scale. Whilst for bulk material the structure and symmetry can routinely be solved by X-ray diffraction, there is no comparable technique for nanostructured materials. Electron diffraction has the required nano-scale resolution and sensitivity, but overlapping data from different diffracted beams has limited its use to date. Here, we demonstrate that computer control of beam tilt and image capture in a conventional transmission electron microscope can be used to overcome this problem, quickly providing very rich diffraction datasets. The technique requires no new hardware, no more expertise than conventional electron diffraction and takes less than two minutes to acquire and process a complete data set. We apply the new technique to the question of a centrosymmetry phase of VO2 and show large differences between theory and experiment for every oxide so far examined.