Title
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Atomic electric fields revealed by a quantum mechanical approach to electron picodiffraction
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Author
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Abstract
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By focusing electrons on probes with a diameter of 50 pm, aberration-corrected scanning transmission electron microscopy (STEM) is currently crossing the border to probing subatomic details. A major challenge is the measurement of atomic electric fields using differential phase contrast (DPC) microscopy, traditionally exploiting the concept of a field- induced shift of diffraction patterns. Here we present a simplified quantum theoretical interpretation of DPC. This enables us to calculate the momentum transferred to the STEM probe from diffracted intensities recorded on a pixel array instead of conventional segmented bright- field detectors. The methodical development yielding atomic electric field, charge and electron density is performed using simulations for binary GaN as an ideal model system. We then present a detailed experimental study of SrTiO3 yielding atomic electric fields, validated by comprehensive simulations. With this interpretation and upgraded instrumentation, STEM is capable of quantifying atomic electric fields and high-contrast imaging of light atoms. |
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Language
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English
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Source (journal)
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Nature communications
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Publication
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2014
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ISSN
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2041-1723
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DOI
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10.1038/NCOMMS6653
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Volume/pages
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5
(2014)
, 8 p.
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Article Reference
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5653
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ISI
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000347227700003
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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