Alexei Gruverman (left) with Haidong Lu, Gruverman’s graduate student and the lead author on the paper.
A team led by University of Nebraska-Lincoln physicist Alexei Gruverman in
collaboration with researchers in Spain
and at the University
of Wisconsin has
discovered a significantly more efficient method of data storage that offers
great promise for the future of technology.
Gruverman’s research on electronic materials is done at the nanoscale, where
objects exhibit unexpected chemical and physical properties. One nanometer is
equal to one billionth of a meter. Central to his research is the scanning
probe microscopy technique which is based on exerting highly localized
mechanical, electrical, or magnetic influence on an object by using a tiny
physical probe and measuring the object’s response. The technique works much
like a person’s sense of touch, Gruverman said.
“If you are in a dark room and want to find out whether the surface of
this desk is smooth or rough, solid, or soft what do you do?” he said,
pointing to his desktop. “You touch it with your finger, press a bit, and
scan with your finger and feel the response.”
Similarly, the tip of the probe—whose radius measures about 10 nm and is too
tiny to be seen by the naked eye—can scan a surface and offer researchers
feedback. The probe also can be used to electrically change the local
properties of ferroelectric materials, which are important electronic materials
used in memory devices. The change that occurs is similar to what happens when
magnetic materials are remagnetized by a magnetic field. By applying an
electric potential to the probe, a nanoscale-size bit of electrical information
can be stored in the ferroelectric material. This principle is central to data
storage, like in hard disk drives.
To date, researchers have relied on the electrical voltage to store
information. However, Gruverman’s team found that the same bit could be written
simply by pressing harder against the ferroelectric material’s surface. In a
sense and in this case, the probe’s needle works much like a nanoscopic typewriter
in its ability to write data in a very specific area on a ferroelectric film
and leave data behind without damaging the surface. That finding makes the
research team the first to demonstrate that mechanical force can be used to
change an area’s polarization.
“It’s a completely voltage-free switching of polarization, which is
what makes the results of this research unique,” Gruverman said.
The finding is groundbreaking because it opens up a new way to store data
significantly more densely than has previously been available.
While Gruverman is hesitant to say such a finding could pave the way to a
new generation of data storage devices like computers and cell phones, whose
production ultimately is at the mercy of many other factors, it does establish
the scientific basis that makes it possible, he said.
The team’s findings were published in Science.