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Fig. 18.
Simulation of a molecular QCA wire made of bis-ferrocene molecules.
Fig. 19.
Fabrication defects in the case of a QCA wire made of bis-ferrocene molecules.
(A) Top view of a gold grain after molecule deposition: misalignment and tilt defect
are sketched. (B) Section of a bis-ferrocene SAM on gold: vertical shifts may occur due
to the roughness inside a gold grain or at the interface of two grains; higher molecule-
molecule distance is caused by the number of hexane-dithiol elements.
computed. Then, they could be used as the driver for the second molecule (Mole-
cule 2) of the wire. So, the second bis-ferrocene molecule is simulated in presence
of a driver, whose charge distribution emulates the logic state of the Molecule
1. In this way, the charge distribution of Molecule 2 is computed and used as
driver for the following cell (Molecule 3) and so on. As depicted in Fig.
18
(B), at
a generic point of the wire the charge configuration of
Molecule i
is computed
as the response to
Molecule
i −
1
,assumingthatthe
Molecule i
is in the neutral
state (charge delocalized) at the beginning and ready to switch its logic state
under the effect of
Molecule
i −
1
. As a result, the aggregated charges (D1, D2
and D3) of the (
Molecule i
) become the driver system of the adjiacent molecule
(
Molecule
i
+
1
) in the following step of information propagation. By iterat-
ing this method for all the molecules in the wire, it is possible to simulate the
information propagation through the wire.
S II-D - How to Create SOA for Molecules.
In order to experimentally
demonstrate the QCA functionalities, a bis-ferrocene molecular wire like the
one in Fig.
18
(A) should be fabricated, using a gold nanowire upon which the
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