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 Transport Properties through Ferrocene Molecules by First-principles Calculations and Nonequilibrium Green’s Function Formalism
Hiroshi Mizuseki, Rodion V. Belosludov, A. A. Farajian, Tomoki Uehara, and Yoshiyuki Kawazoe
Molecular devices are potential candidates for this next
step, and they would make it possible to realize the
most advantageous devices. However, source of
expenditure is necessary that such a large number of
organic molecules can be obtained by synthetic
chemistry, so any means of exploring their properties
and behavior in order to predict the relevant properties
of a molecule in advance of its synthesis would be
extremely useful. Our group has covered a wide range of
molecular materials[1] which have potential application
in molecular electronics using first-principles
calculations and nonequilibrium Green’s function
formalism. There are supramolecular enamel wires[2],
porphyrin[3, 4] and ferrocene[5] molecules and so on. In
this presentation, we will present our recent study on
the transport properties of a ferrocene-based molecule
wire using the nonequilibrium Green’s function
formalism for quantum transport and the density
functional theory (DFT) of electronic structures using
local orbital basis sets. The ferrocene has high degree
of chemical and thermal stability in different
environments and a wealth of synthetic methods for the
construction of a variety of relatively complex
ferrocene-based systems. Molecular wires based on
ferrocene molecules are compact and linear, which may
allow one to incorporate such wires into bulky molecules
to create a shielded molecular wire. Iron substitution
by different metals will also affect electron transport
through the cyclopentadienyl ring. First, the transport
properties of two ferrocenedithiolate systems with
different five-member ring connections have been
estimated and the results of the calculations reveal
that the iron atom enhances the conductivity of the
ferrocene molecule compared with all-organic molecules.
Moreover, the conductance through the ferrocene molecule
depends on the position of sulfur atoms. The molecule
has a higher electrical conductivity at low bias when
the same cyclopentadienyl ring is connected to an Au
electrode by sulfur atoms. The I-V characteristics show
that, in this case the transport properties of the
molecule have metallic features. The transmission
coefficients of ferrocenedithiolate molecules changed
with applied bias. This is attributable to the shift of
energy levels and the change of molecular orbital shape
by the electric field. The several structures of
molecular wire based on ferrocene molecules have been
proposed and their transport properties have been also
estimated and analyzed.
References
1. http://www-lab.imr.edu/~mizuseki/nanowire.html
2. R.V.Belosludov, A.A.Farajian, H.Mizuseki, K.Ichinoseki and Y.Kawazoe, Jpn. J. Appl. Phys., 43, 2061 (2004).
3. R.V.Belosludov, A.A.Farajian, H.Baba, H.Mizuseki and Y.Kawazoe, Jpn. J. Appl. Phys., 44, 2823 (2005).
4. A.A.Farajian, R.V.Belosludov, H.Mizuseki and Y.Kawazoe, Thin Solid Films, 499, 269 (2006).
5. Uehara, R.V.Belosludov, A.A.Farajian, H.Mizuseki and Y.Kawazoe, Jpn. J. Appl. Phys., in press.
Dr. Hiroshi Mizuseki received his degree from Tohoku
University, Japan, in 1995. He has been working mainly
on computational materials science at Institute for
Materials Research, Tohoku University. His research
interests are theoretical study of transport properties
of nanometer-scale systems such as molecular devices and
atomic/molecular wires. Dr. Mizuseki has
authored/co-authored more than 90 scientific papers.
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