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Volume 6
Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212
Advanced Materials 2018
September 04-06, 2018
September 04-06, 2018 | Zürich, Switzerland
21
st
International Conference on
Advanced Materials & Nanotechnology
Fabrication ofmicro/nano-crystals of organicDirac fermion system: Nano-scale electro crystallization
Takako Konoike
International Center for Materials Nanoarchitectonics (MANA), Japan
Statement of the Problem:
Since the discovery of graphene, it attracted a great interest because the electrons in graphene
behave like massless Dirac fermions. It shows anomalous behaviors resulting from the peculiar liner dispersion. It has been
recognized that Dirac fermion system is also realized in organic conductor α-(BEDT-TTF)
2
I
3
under high pressure. This system
is composed of organic molecule BEDT-TTF and inorganic anions I
3
. These molecules are stacked alternatively and forming
a multi-layered structure of conducting and insulating layer, respectively. By taking advantage of its bulk nature, we have
experimentally studied the physical properties of Dirac fermions in this compound. In high magnetic field, the characteristic
edge state with spin current at the sample edges is theoretically predicted. By using the micro/nano crystals, which contains
large amount of edges, we aimed to observe the evidence of the edge state of this system.
Methodology:
Micro/nano crystal growth of α-(BEDT-TTF)
2
I
3
is based on nano-scale electrocrystallization was carried out
by using Nano-Wire Fabrication Kit, Iwata Glass Industrial Co., Ltd., The electrodes used in the crystal growth were made
on a silicon substrate with 300 nm SiO
2
. Platinum electrode was deposited on a masked substrate and 5 μm gap was made
by photolithography. The substrate was set into a saturated THF solution of above two molecules. DC current was applied
between the electrodes at 20°C in incubator during 24 h.
Findings:
The typical crystal obtained by this method is shown in Figure 2. The shape of the grown micro-crystal resembles
with that grown by usual electrocrystallization. The surface of the crystal is almost flat and specularly reflected suggesting that
the crystal is high purity.
Conclusion:
By using the nano-scale electro-crystallization, we could obtain high purity micro-crystals. We will study this
micro-crystal to detect the evidence of the edge state and spin current.
Figure 1:
Silicon substrate with platinum electrodes
Figure 2:
3D laser microscope image of one of micro-crystal
Recent Publications:
1. Katayama S, Kobayashi A and Suzumura Y (2006) Pressure-induced zero-gap semiconducting state in organic
conductor α-(BEDT-TTF) 2I3 salt. Journal of the Physical Society of Japan 75(5):054705.
2. Osada T, Uchida K and Konoike T (2011) Magneto transport of massless Dirac fermions in multilayer organic
conductors. Journal of Physics 334: 012049.
3. Konoike T, Uchida K and Osada T (2012) Specific heat of the multilayered massless Dirac fermion system. Journal of
the Physical Society of Japan 81:043601.
4. Konoike T, Sato M, Uchida K and Osada T (2013) Anomalous thermoelectric transport and giant Nernst effect in
multilayered massless Dirac fermion system. Journal of the Physical Society of Japan 82(7):073601.
Takako Konoike, Res. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C3-021