Localization of inelastic electron scattering in the low-loss energy regime

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Ultramicroscopy

OSTI ID:1049810

Idrobo Tapia, Juan C ^[1]; Pennycook, Stephen J ^[1]

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1. ORNL

The spatial resolution and contrast level in electron energy-loss spectroscopy (EELS) imaging depend on the delocalization of the inelastic electron scattering cross sections. Theoretical calculations within the dipole approximation provide the lower limit for the delocalization of low loss signals, and suggest that atomic resolution EELS imaging in the low loss energy regime (<50 eV) should be possible. Here, we directly measure the localization of the inelastic electron scattering at different energy loss in the low loss regime using a clean open edge of monolayer graphene. Our results demonstrate that the delocalization depends both on the energy loss and the specific electron excitation mode contributing to the energy loss. While the plasmons are delocalized over 1.2 nm, sub-nm enhancement is observed at the edge for the low-loss signal at 11 eV, indicating the possible formation of a one-dimensional plasmon (or inter-band transition) at the edge of monolayer graphene. Our results also suggest that if the initial states or final states are atomically localized, atomic resolution EELS imaging could be obtained even in the lowloss region of the spectra.

• Research Organization: Oak Ridge National Laboratory (ORNL); Shared Research Equipment Collaborative Research Center
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1049810
• Journal Information: Ultramicroscopy, Journal Name: Ultramicroscopy Vol. 119; ISSN 0304-3991; ISSN ULTRD6
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
APPROXIMATIONS
CROSS SECTIONS
DIPOLES
ELECTRONS
ENERGY-LOSS SPECTROSCOPY
EXCITATION
PLASMONS
RESOLUTION
SCATTERING
SPATIAL RESOLUTION
SPECTRA