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Topic Name: Plastic as a circuit spintronics
Category: Organic electronics
Research persons: Christoph Boehme , John Lupton
Location: Salt Lake City, United States
Details
Researcher : Christoph Boehme & John Lupton
Physicists at the University of Utah just make a board spintronics based on a
plastic semiconductor similar to that used in organic light emitting diodes
(Oled). A first that paves the way for an even more miniaturized electronics.
The electronics based on monitoring currents in materials, particularly
charges in semiconductors. But the charged particles component atoms have
another characteristic proper quantum spin.
It can give an analogy classic - but not to be taken literally. If one
considers the electron as a small sphere uniformly loaded, it is possible to
find some forms of the electromagnetism in conjunction with the light emission
of electrons. An idea comes to mind, to consider a motion on itself of the
electron, which gives a kinetic moment. The idea does not stand up to scrutiny
in classical physics, because the electron would then turn on itself faster than
light. In quantum mechanics, however, one discovers that the electron must be
equipped with a kinetic moment christened own spin and, moreover, that, in
order to exist, it does not use the image of a ball in rotation. This analogy
can be left exploitable condition to consider a kinetic moment not quantified
that may exist in two states, spin up and spin down, corresponding to a rotation
in two senses reversed.
A single electron to store one bit
In recent years, a new branch of electronics has been created, including
through the work of Nobel Prize French Albert Fert. It is the spintronics, in
which the movement of electrons is controlled not by their office but thanks to
their spin. This progress has already led to miniaturize the magnetic storage
media and should lead to still further miniaturization of electronic components,
including transistors.
Until now, binary information processed by computers is marked by the
presence or absence of charges in semiconductors, which must therefore include
hundreds of thousands of atoms to store these charges. In a circuit spintronics,
a single electron is enough to store binary information. The potential gain for
the miniaturization is evident.
The LED, or light-emitting diodes, though well known for their use in display
devices, are also semi-conductors. They are carried out, such as transistors,
inorganic materials (gallium arsenide, silicon, zinc). Recently versions using
organic polymers appeared - Oled Less expensive to produce, they are less
effective than LED, which convert from 43 to 64% of electricity to light. The
Oled do not allow such performances. Some estimates suggested a theoretical
limit of 25%.
A Oled in MEH-PPV
Christoph Boehme and John Lupton, two researchers at the University of Utah,
have decided to study this problem a little closer, with the idea of progress in
the field of organic semiconductor applied to the spintronics. They have just
published their findings in the August 17 issue of Nature Materials.
They considered a Oled made of a plastic semiconductor, more precisely, a
polymer MEH-PPV (Poly (2-methoxy-5-(2'-ethyl-hexyloxy)-14-phenylene vinylene.
In the bombing for a few nanoseconds with microwaves to try to align the spins
of pairs of electrons-holes in the semiconductor, they actually produced waves
spins whose guidance ranges.
Unfortunately, even if it means that the spintronics is achievable with
organic semiconductors, Oled used by the team have produced little light. The
study of the emission mechanism remains in line with the pessimistic forecasts
of a limit of 25% in the conversion of electricity.
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