The Puzzle of Contrast Inversion in DNA STM Imaging

DNA has been at the center of an imaging effort since the invention of the scanning tunneling microscope (STM). In some of the STM imaging reports the molecules appeared with negative contrast, i.e., “submerged” under the metal background and darker. We demonstrate the phenomenon of contrast inversi...

Full description

Saved in:
Bibliographic Details
Published in:The journal of physical chemistry. B 2005-08, Vol.109 (30), p.14270-14274
Main Authors: Shapir, Errez, Yi, Juyeon, Cohen, Hezy, Kotlyar, Alexander B, Cuniberti, Gianaurelio, Porath, Danny
Format: Article
Language:English
Subjects:
DNA - ultrastructure
Microscopy, Scanning Tunneling
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:DNA has been at the center of an imaging effort since the invention of the scanning tunneling microscope (STM). In some of the STM imaging reports the molecules appeared with negative contrast, i.e., “submerged” under the metal background and darker. We demonstrate the phenomenon of contrast inversion in DNA STM imaging by controlled and spontaneous contrast inversions and by the dependence of the DNA apparent height with respect to the surface on the imaging bias voltage. Using these characterizations, we formulate a model explaining the above phenomenon by resonant tunneling through virtual states in the vacuum between the STM tip and the DNA molecule.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp052738e