An international team of
scientists, including University of Nebraska-Lincoln (UNL) physicist Evgeny
Tsymbal, has discovered a new class of materials that could prove to be useful
in developing new methods of creating computer memory.
The research team, led by
Christos Panagopoulos of Nanyang Technological University in Singapore,
explored layered heterostructures at the atomic scale, in which different
materials were deposited in layers a few atoms thick. They discovered that the
new class of materials boasts an attractive property—ferroelectricity, which
may be used to create new types of data storage devices.
A ferroelectric material exhibits
spontaneous electric polarization, characterized by a positive electric charge
on one side of the material and negative on the opposite side. The polarization
can be reversed by applying an electric field—from a battery, for example. These
two possible polarization orientations make these materials attractive for
developing computer memory because each orientation could correspond to 0 or 1.
“Our discovery shows a
possibility that researchers could engineer properties at the atomic scale and
create new, artificial materials exhibiting novel functional properties not
existing in their constituents,” says Tsymbal, who is Charles Bessey
Professor of Physics and director of UNL’s Materials Research Science and
Engineering Center (MRSEC). “This significantly broadens the class of
known ferroelectric materials and provides possibilities to design new
The new materials were fabricated
and characterized by researchers from the Foundation for Research and
Technology-Hellas in Greece, Nanyang Technological University in Singapore, and
Sungkyunkwan University in South Korea. Using advanced synthesis methods,
scientists were able to fabricate heterostructures by depositing atomic layers
of different materials, layer-by-layer, in stacks of thickness of a few nanometers.
Although neither of the constituent materials were ferroelectric, the composed
heterostructures showed a pronounced ferroelectric polarization.
The nature of this phenomenon was
unclear at first, but UNL scientists led by Tsymbal found the explanation of
this behavior. They modeled the atomic structure and electronic properties of
these materials by performing computations at UNL’s Holland Computing Center,
which indicated that interfaces between the constituent materials in the
heterostructures were responsible for the observed novel properties.
“Crucially, our computations
and analysis were decisive for the understanding of the origin of
ferroelectricity in the experimentally synthesized heterostructures,”
Tsymbal says. “We were able to elucidate the microscopic mechanism
responsible for their exciting properties.”
In addition, Tsymbal says, the
discovered materials exhibited magnetoelectricity, an important functional
property that allows it to affect electric polarization by the application of a
“This functionality is
especially interesting because of potential application in
electrically-controlled data storage with significantly reduced energy
consumption,” Tsymbal says. “Our MRSEC dedicates strong efforts to
study magnetoelectric materials and has international recognition in this field
The findings were reported in Nature Communications.
Source: University of Nebraska-Lincoln