(July 24, 2015) It
doesn’t happen often that a young scientist makes a significant and unexpected
discovery, but postdoctoral researcher Stephen Wu of the U.S. Department of
Energy's Argonne National Laboratory just did exactly that. What he found—that
you don't need a magnetic material to create spin current from insulators—has
important implications for the field of spintronics and the development of
high-speed, low-power electronics that use electron spin rather than charge to
carry information.
Wu’s work upends prevailing ideas of how to generate a
current of spins. “This is a discovery in the true sense,” said Anand
Bhattacharya, a physicist in Argonne's Materials Science Division and the
Center for Nanoscale Materials (a DOE Office of Science user facility), who is
the project's principal investigator. “There’s no prediction of anything like
it.”
Spin is a quantum property of electrons that scientists
often compare to a tiny bar magnet that points either “up” or “down.” Until now
scientists and engineers have relied on shrinking electronics to make them
faster, but now increasingly clever methods must be used to sustain the
continued progression of electronics technology, as we reach the limit of how
small we can create a transistor. One such method is to separate the flow of
electron spin from the flow of electron current, upending the idea that
information needs to be carried on wires and instead flowing it through
insulators.