TeYu Chien, a UW
assistant professor in the Department of Physics and Astronomy, uses a
low-temperature
scanning tunneling microscope in his lab to observe nanomaterials.
Chien is the lead
author of a paper that appears in the journal Scientific Reports. His research
determined that
the electric field is responsible for the alteration of the fracture toughness
of
nanomaterials,
which are used in state-of-the-art electronic devices. (UW Photo)
(January 8, 2016) Mechanical
properties of nanomaterials can be altered due to the application of voltage,
University of Wyoming researchers have discovered.
The researchers, led by TeYu Chien, a UW assistant professor
in the Department of Physics and Astronomy, determined that the electric field
is responsible for altering the fracture toughness of nanomaterials, which are
used in state-of-the-art electronic devices. It is the first observed evidence
that the electric field changes the fracture toughness at a nanometer scale.
This finding opens the way for further investigation of
nanomaterials regarding electric field-mechanical property interactions, which
is extremely important for applications and fundamental research.
Chien is the lead author of a paper, titled “Built-in
Electric Field Induced Mechanical Property Change at the Lanthanum
Nickelate/Nb-doped Strontium Titanate Interfaces,” that was recently published
in Scientific Reports. Scientific Reports is an online, open-access journal
from the publishers of Nature. The journal publishes scientifically valid
primary research from all areas of the natural and clinical sciences.
Other researchers who contributed to the paper are from the
University of Arkansas, University of Tennessee and Argonne National Laboratory
in Argonne, Ill.
Chien and his research team studied the surfaces of the
fractured interfaces of ceramic materials, including lanthanum nickelate and
strontium titanate with a small amount of niobium. The researchers revealed
that strontium titanate, within a few nanometers of the interfaces, fractured
differently from the strontium titanate away from the interfaces.
The two ceramic materials were chosen because one is a
metallic oxide while the other is a semiconductor. When the two types of
materials come into contact with each other, an intrinsic electric field will
automatically be formed in a region, known as the Schottky barrier, near the
interface, Chien explains. The Schottky barrier refers to the region where an
intrinsic electric field is formed at metal/semiconductor interfaces.