Beyond graphene silicene and germanene novel two dimensional electronic

Abstract #3178, Honolulu PRiME 2012, © 2012 The Electrochemical Society
Beyond graphene: silicene and germanene novel two-
dimensional electronic materials
Guy Le Lay a, Andrea Resta a, Benedicte Ealet a Paola De
Padova b and Thomas Bruhn c and Patrick Vogt c
a Aix-Marseille University, CNRS-CINaM, Campus de
Luminy, Case 913, 13288, Marseille France.
b CNR-ISM, via Fosso del Cavaliere 100, Rome, Italy.
c Technische Universität Berlin, Hardenbergstrasse 36,
10623 Berlin, Germany.
Due to its unique physical properties graphene, a 2D
honeycomb arrangement of carbon atoms, has attracted
tremendous attention. Silicene and germanene, the
graphene equivalents for silicon and germanium, could
follow this trend, opening new perspectives for
applications, especially due to their compatibility with Si-
based electronics. Free standing silicene and germanene
have been theoretically predicted and are conjectured to
have a buckled honeycomb atomic arrangement of sp3/sp2
hybridized Si/Ge atoms [1]. Still, silicene and germanene
would share essentially the same electronic properties as
graphene, namely an electronic dispersion resembling that
of relativistic Dirac fermions at the K points of the
Brillouin-zone, the so-called Dirac points.
Recently we have succeeded in providing compelling
evidences of the first synthesis of epitaxial silicene on a
silver (111) template [2]. We have also started the quest
for germanene in a similar manner upon depositing
germanium onto a gold (111) substrate. STM observations
indicate the presence of large islands exhibiting a
honeycomb-like structure, hence the system appears
promising for the discovery of epitaxial germanene.
The demonstration that silicon can form sheets of
silicene, a two dimensional honeycomb low buckled
structure, which does not exist in Nature, is tantalizing for
new physics and potential applications.
Since, silicon can be considered the workhorse of
electronic industry, this synthesis should have a major
impact for novel electronic devices –possibly for more
than Moore- because of the compatibility with existing Si
technologies. Indeed, a key issue in this direction will be
the transfer on an insulating substrate, like, possibly AlN
[3].
Furthermore, silicene is predicted to have non-
trivial topological properties [4]. Hence, silicene could
offer the possibility, if interfaced with a s-wave
superconductor, for advances in the long quest for
Majorana fermions [5].
Finally, the epitaxial growth of silicene has
opened up the route to the synthesis of germanene, also
with nontrivial band topology and a gap induced by
effective spin orbit coupling for the π orbitals at the K
point in low-buckled geometry corresponding nearly to
room temperature [6].
[1] S. Cahangirov et al., Phys. Rev. Lett. 102, 236804
(2009)
[2] P. Vogt et al., Phys. Rev. Lett., in press
[3] M. Houssa et al. J. Electrochem. Soc. 158, H107
(2011).
[4] [Cheng-Cheng Liu, Wanxiang Feng, and Yugui Yao,
Phys. Rev. Lett. 107, 076802 (2011).
[5] Xiao-Liang Qi and Shou-Cheng Zhang, Rev. Mod.
Phys. 83, 1057 (2011).
Acknowledgements: support from FET-Open grant
number 270749 for the project “2D-NANOLATTICES"
Downloaded on 2013-04-17 to IP
202.194.6.206
/site/terms_use
address. Redistribution subject to ECS license or copyright; see。