Noncontact Atomic Force Microscopy - Yale School of Engineering ...

Atom Manipulation on Cu(110)-O Surface with LT-AFM
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Tu-1220
Yasuhiro Sugawara, Yukinori Kinoshita, Yan Jun Li, Yoshitaka Naitoh, and Masami
Kageshima
Department of Applied Physics, Osaka University, Suita, Japan
Manipulation of single atoms and molecules is an innovative experimental technique
of nanoscience. So far, a scanning tunneling microscopy (STM) has been widely used to
fabricate artificial structures by laterally pushing, pulling or sliding single atoms and
molecules. However, the driving forces involved in manipulation have not been
measured. Recently, an atomic force microscopy (AFM) has been also used to manipulate
single atoms and molecules. Atom manipulation with an AFM is particularly promising,
because it allows the direct measurement of the required forces [1].
Recently, we investigated the forces in AFM lateral manipulation for a top single Cu
atom (super Cu atom) on the Cu(110)-O surface. In the case of Cu-adsorbed AFM tip, the
super Cu atom on the surface was pulled at a lateral tip position on the adjacent binding
site. In contrast, in the case of O-adsorbed AFM tip, the super Cu atom was pushed over
the top of the super Cu atom. Thus, we found that the forces (attractive or repulsive
forces) to move an atom laterally on the surface strongly depend on the atom species of
the AFM tip apex and the surface.
In the present study, in order to further clarify the manipulation process depending on
the chemical nature of tip-sample interaction, we investigate the full tip-sample potential
landscape necessary to manipulate atoms.
All experiments were performed by using homebuilt noncontact AFM using frequency
modulation technique operating in ultrahigh vacuum at a temperature of about 78 K. The
AFM tip apex was coated with Cu or O atoms in situ by slightly making a tip-sample
mechanical contact on the Cu(110)-O surface prior to the imaging. The tip-sample
potentials are determined form the frequency shift versus distance curves by
mathematical analysis. We found that the tip-sample potentials to move the super Cu
atom laterally on the surface strongly depend on the atom species of the AFM tip apex
and the surface. These results strongly suggest that the chemical nature of tip-sample
interaction plays an important role in lateral atom manipulation. Furthermore, we discuss
the pathways for moving the super Cu atom.
Reference
[1] M. Ternes, C. P. Lutz, C. F.
Hirjibehedin, F. J. Gissibl and
Andreas J. Heinrich. Science,
319, 66 (2008).
(a) (b)
Figure 1: AFM images (a) before and (b) after atom
manipulation performed on Cu(110)-O surface at 78K.