Newswise — Researchers
at the University of Arkansas have found a way to
create switching in nanoscale materials, opening
the path to using these new properties for memory
devices, nanomotors, nanoswitches or nanosensors.
Researchers Sergey Prosandeev, Inna Ponomarena,
Igor Kornev, Ivan Naumov and Laurent Bellaiche, professor
of physics in the J. William Fulbright College of
Arts and Sciences, report their findings in an upcoming
issue of Physical Review Letters .
“The properties of nanoscale objects are often different
from the properties of objects at the macroscopic
scale,” Prosandeev said. A nanometer is a billionth
of a meter – things found at the nanoscale are smaller
than bacteria, and possibly the size of a virus,
atom or molecule. “We try to study the new properties
of objects at the nanoscale to understand how to
apply them to technology.”
Prosandeev and his colleagues study piezoelectric
compounds, materials that change shape in an electric
field, or create an electric field when they change
shape. Such materials, currently used in medical
ultrasound and naval sonar, appear to lose these
properties at the nanoscale because they lose their
this “loss” is governed by a vortex within
the nanodot, where the charges, which swirl in an
almost circular motion, cancel one another.
The researchers decided to calculate the possibility
of switching the direction of the vortex, which would
open up the possibility of using these nanoscale
materials in switches, sensors and other devices.
“We use very complex but extremely close to nature
computations,” Prosandeev said. The researchers looked
at what would happen if they used an inhomogeneous
electric field arising, for example, from two different
charges located away from the nanodot.
They found that the charges directed the vortex
of the nanodot: when the charges were moved, the
vortex moved, and when they swapped the two charges,
the vortex adopted an opposite direction.
This vortex can be used to influence the change
from electrical to mechanical energy and back, which
is what drives piezoelectric compounds at the macro
scale, Prosandeev said.