Scientists
from Georgia State University and the Georgia Institute of Technology
have found a new way to examine certain properties of electrons in
graphene—a very thin material that may hold the key to new technologies
in computing and other fields.
Ramesh
Mani, associate professor of physics at GSU, working in collaboration
with Walter de Heer, Regents’ Professor of physics at Georgia Tech,
measured the spin properties of the electrons in graphene, a material
made of carbon atoms that is only one atom thick.
The research was published this week in the online-only journal Nature Communications.
Electrons, which follow orbits around the nucleus in atoms, have two important characteristics—charge and spin.
The
electric charge is the basis of most electronic devices, but spin—which
Mani and co-workers examined using a new technique—forms the basis of
new “spintronic” devices, and can serve as a building block for new
computers in a field called quantum computing, as well as other
technologies.
Graphene
is thought to be a key material for spintronic devices, but it is so
new that scientists must perform a lot of research on it to understand
its capability. The GSU and Georgia Tech study propels this research
forward.
“We
tried to use the electrical resistance to detect spin resonance. When
you shine microwaves on the device, and the microwave energy equals the
spin-splitting energy,” Mani explained.
“The
device absorbs the microwave energy, and that changes the resistance of
the device. But this is usually such a small effect that one hardly
expects to see it. Fortunately, this material allowed us to see the
effect. Measuring spin resonance electrically is especially useful for
nanoscale devices.”
“By
doing such a measurement, we can measure properties like the spin
splitting energy, and the spin relaxation time directly,” he continued.
“There have been other measurements, but those have been a little more
indirect.”
With
the advance in measuring the properties of an electron’s spin in
graphene, it will allow scientists to carry out further studies of this
novel material—giving researchers ways to optimize graphene for
spintronic applications.
Mani
noted that that the experiments which were conducted at GSU, were very
labor intensive. Simply creating graphene—which de Heer’s laboratory
accomplished—is very time consuming and requires enormous experience.
Measurements
use very sophisticated equipment, requiring the researchers to immerse
samples in liquid Helium at temperatures close to absolute zero—about
-460 F.
Atlanta has become a center for graphene research, Mani said.
“The
confluence of available experimental capability in Atlanta, a hotbed
for graphene science and technology, made possible this important
advance in the world of spintronics physics,” he explained.
The team included Mani of GSU, de Heer, John Hankinson and Claire Berger of Georgia Tech.
Source: Georgia State University
