کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1677642 1518358 2012 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Imaging of light and heavy atomic columns by spherical aberration corrected middle-angle bright-field STEM
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فناوری نانو (نانو تکنولوژی)
پیش نمایش صفحه اول مقاله
Imaging of light and heavy atomic columns by spherical aberration corrected middle-angle bright-field STEM
چکیده انگلیسی

Simultaneous detection of both light and heavy atomic columns is theoretically and experimentally explored with spherical aberration (Cs)-corrected middle-angle bright-field (MABF) scanning transmission electron microscopy (STEM). Optimized MABF STEM visualizes both light O atomic columns and heavy Sr and Ti–O atomic columns for SrTiO3(001) as distinct bright spots and dark spots with characteristic bright rings, respectively, over practical ranges of the probe-forming lens defocus and sample thickness, although medium-heavy Ti–O atomic columns appear as blurred dark spots. The difference in contrast between heavy and light atomic columns is greater than that of annular BF STEM images. The formation of distinctive bright and dark spots is interpreted simply as the difference in the degrees of localization and inelastic absorption of channeling electrons in individual atomic columns by analyses of convergent wave fields inside the crystal in both real and reciprocal space. In addition, Bloch wave expansion of MABF STEM images suggests that bright rings are formed mainly by 2p-like convergent Bloch wave fields localized on heavy atomic columns.


► Middle-angle bright-field (MABF) STEM is theoretically and experimentally explored.
► Optimized MABF STEM readily visualizes both light and heavy atomic columns.
► These images are robust for defocus and sample thickness.
► This technique offers intuitive interpretation of atomic column positions in local areas.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ultramicroscopy - Volume 120, September 2012, Pages 48–55
نویسندگان
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