Curved carbon to pave way for future nanoelectronics
By ANIMonday, January 24, 2011
LONDON - A new scientific discovery has paved the way for unprecedented control over the spin of electrons and may have a big impact on applications for spin-based nanoelectronics.
Researchers from the Nano-Science Center at the Niels Bohr Institute, University of Copenhagen, in collaboration with Japanese researchers, have shown how electrons on thin tubes of graphite exhibit a unique interaction between their motion and their attached magnetic field - the so-called spin.
The electron’s spin has great potential as the basis for future computer chips, but this development has been hindered by the fact that the spin has proved difficult to control and measure.
In flat graphite layers the movement of the electrons do not affect the spin and the small bar magnets point in random directions. As a result, graphite was not an obvious candidate for spin based electronics at first.
“However, our results show that if the graphite layer is curved into a tube with a diameter of just a few nanometers, the spin of the individual electrons are suddenly strongly influenced by the motion of the electrons. When the electrons on the nanotube are further forced to move in simple circles around the tube the result is that all the spins turn in along the direction of the tube”, said the researchers Thomas Sand Jespersen and Kasper Grove-Rasmussen at the Nano-Science Center at the Niels Bohr Institute.
It has previously been assumed that this phenomenon could only happen in special cases of a single electron on a perfect carbon nanotube, floating freely in a vacuum - a situation that is very difficult to realize in reality.
Now the researchers’ results have shown that the alignment takes place in general cases with arbitrary numbers of electrons on carbon tubes with defects and impurities, which will always be present in realistic components.
The interaction between motion and spin was measured by sending a current through a nanotube, where the number of electrons can be individually controlled.
The findings were published in the journal Nature Physics. (ANI)
