In order to understand these experimental
results, the latest refinements in
ab initio
theory, such as the inclusion of van der
Waals forces, were then deployed at the
IPCMS. Referring to Figure
➊
c
, in the
absence of
d
band electrons in the Co
spin up channel at E
F
, Co surface states
can hybridize with the electron orbitals of
the molecule to provide metal/molecule
hybrid states that will intersect E
F
. The
large number of electrons that make up
these hybrid spin up states (
green in
panel c
) allows this interface interaction
to dominate, in the expression of the spin
polarization of the current, the metal/
molecule hybridization induced by the Co
d
band in the spin-down channel
(red in
panel c).
This spin-polarized interface, or
spinterface, seems to possess the
properties of an ideal spin- polarized
current source. Indeed, the high spin
polarization of the current flowing
through this interface comes from the
Co magnetism, which remains robust
against thermal disorder toward industrial
applications. The effect requires only
one molecule, which suggests possible
nanodevices. Finally, the spin polarization
of the molecule’s orbitals forming the
spinterface could allow better injection of
these spins within organic semiconductors
for inter-device spin transport.
These studies, published in January
2013 in
Scientific Reports
, thus reveal a
promising candidate in the quest for the
spintronics Holy Grail, which is discovering
an ideal spin-polarized current source.
The CNRS and Strasbourg University have,
of course, already filed a patent application
[1] concerning these industrially very
promising interfaces. IPCMS researchers
are currently exploring the fundamental
and applied implications of this discovery,
including the study of technological
demonstration devices that would fully
reveal the portency
of this work.
Metal/molecule hybrid electron states
An ideal spin-polarized current source?
CASSIOPEE beamline
ASSOCIATED PUBLICATION
Direct observation of a highly spin-polarized
organic spinterface at room temperature
F. Djeghloul, F. Ibrahim, M. Cantoni, M. Bowen*,
L. Joly, S. Boukari, P. Ohresser, F. Bertran, P.
Le Fevre, P. Thakur, F. Scheurer, T. Miyamachi,
R. Mattana, P. Seneor, A. Jaafar, C. Rinaldi, S.
Javaid, J. Arabski, J.P. Kappler, W. Wulfhekel,
N.B. Brookes, R. Bertacco, A. Taleb-Ibrahimi,
M. Alouani, E. Beaurepaire, and W. Weber
Scientific Reports 3 (2013) 1272
REFERENCE
[1] FR 2012/ 12 53564 “Source de courant
polarisée en spin”, M. Bowen, W. Weber,
L. Joly, E. Beaurepaire, F. Scheurer,
S. Boukari, M. Alouani, patent pending.
* IPCMS-DMONS, 23 rue du Loess PB 43,
67034 Strasbourg, France
CORRESPONDING AUTHOR
19
SOLEIL
HIGHLIGHTS
2013
