HAADF-STEM imaging with sub-angstrom probes: a full Bloch wave analysis.
J Electron Microsc (Tokyo)
; 53(3): 257-66, 2004.
Article
en En
| MEDLINE
| ID: mdl-15332652
ABSTRACT
A full coherent Bloch wave calculation is presented to investigate high-angle annular dark-field image formation for sub-angstrom probes in scanning transmission electron microscopy (STEM). With increasing illumination angle, the contribution of the 1s bound state increases to a maximum at an optimum probe angle, after which we find increasing contributions from high-angle plane wave states around the periphery of the objective aperture. Examination of image contributions from different depths within a crystal shows an oscillatory behavior due to the beating between 1s and non-1s states. The oscillation period reduces with decreasing probe size, while the relative contribution from a specific depth increases. This signifies a changeover from a projection mode of imaging to a depth-slicing mode of imaging. This new mode appears capable of resolving three-dimensional atomic structures in future generation aberration-corrected STEM.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Algoritmos
/
Microscopía Electrónica de Transmisión de Rastreo
/
Modelos Teóricos
Idioma:
En
Revista:
J Electron Microsc (Tokyo)
Año:
2004
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
JAPAN
/
JAPON
/
JAPÃO
/
JP