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NanoMat 2018 Nano Research & Applications
ISSN: 2471-9838 Page 24
April 26-27, 2018
Rome, Italy
17th Edition of International Conference on
Emerging Trends in
Materials Science and
Nanotechnology
T hree dimensional (3D) topological insulating (TI) state, in
which the bulk is insulator with an energy band gap while
the surface is gapless conductor, has been reported in some
materials and attracted significant attention. On the other
hand, 2D TI states have been experimentally reported only in
few materials, such as quantum wells of HgTe/CdTe or InAs/
GaSb. In 2D TI state, quantum SHE (QSHE) is observed with a
bulk energy gap but gapless helical edge states protected by
time reversal symmetry, in which opposite spin states forming
a Kramers doublet counter propagate. Although 2D TI states
are theoretically predicted for graphene, atomically thin 2D
carbon layer, experimental observation is rare. On the other
hand, atom-thin transition metal dichalcogenide (TMDC) layers
are attracting significant attention from various viewpoints. It
has been recently predicted that 1T’-phase of such layers can
be within 2D TI states due to the band inversion. Thus, it is
indispensable to realize 2D and 1D TI states in various atom-
thin materials. For the creation of TI states, introduction of
spin-orbit interactions (SOIs) is crucial. Recently, challenge
of introduction of SOI into graphene has been experimentally
reported by somemethods [e.g., surface decoration by (1) right-
mass adatoms or (2) heavy nanoparticles, and (3) using heavy
substrates]. In the talk, I will present (1) and (2) using small-
amount of hydrogen atoms and Pt or Bi2Te3 nanoparticles,
respectively, which result in introduction of large SOI gaps and
subsequent emergence of the 2D TI states. Moreover, I will
present that 1T’ phase of MoS2, one of TMDC family, which is
created by laser beam irradiation, can be within the 2DTI states.
These observation must open doors to 2D topological phases
of graphene and atom-thin TMDCs and those application to
low-power and voltage-controlled spintronics devices.
Biography
J Haruyama is a Professor of Aoyama Gakuin University, Tokyo, and a Vis-
iting Professor of The University of Tokyo, Institute for Solid State Physics.
He graduated from Waseda University, Tokyo, Japan, in 1985. Then, he
joined Quantum Device Laboratory, NEC Corporation, Japan and worked
until 1994. He received his PhD in Physics fromWaseda University in 1996.
During 1995–1997, he worked with The University of Toronto, Canada, and
also Ontario Laser and Lightwave Research Center, Canada as a Visiting
Scientist. Since 1997, he has been working at Aoyama Gakuin University. He
was also a Visiting Professor at NTT Basic Research Laboratories, Japan,
and a Researcher for Zero-emission Energy Center grant, Kyoto University,
Japan.
Spin-orbit interaction and topological phase in atom-thin layers
J Haruyama1, 2
1Aoyama Gakuin University, Japan
2Institute for Solid State Physics - University of Tokyo, Japan
J Haruyama, Nano Res Appl, Volume:4
DOI: 10.21767/2471-9838-C1-008