Scientists crack materials mystery in vanadium dioxide

November 23, 2010
Theoretical research at Oak Ridge National Laboratory can help explain experimental results in vanadium dioxide, such as the formation of thin conductive channels (seen in white) that can appear under strain in a nanoscale vanadium dioxide sample.

(PhysOrg.com) -- A systematic study of phase changes in vanadium dioxide has solved a mystery that has puzzled scientists for decades, according to researchers at the Department of Energy's Oak Ridge National Laboratory.

Scientists have known that vanadium dioxide exhibits several competing phases when it acts as an insulator at lower temperatures. However, the exact nature of the phase behavior has not been understood since research began on vanadium dioxide in the early 1960s.

Alexander Tselev, a research associate from the University of Tennessee-Knoxville working with ORNL's Center for Nanophase Materials Sciences, in collaboration with Igor Luk'yanchuk from the University of Picardy in France used a theory to explain the observed phase behaviors of vanadium dioxide, a material of significant technological interest for optics and electronics.

"We discovered that the competition between several phases is purely driven by the lattice symmetry," Tselev said. "We figured out that the metallic phase lattice of vanadium oxide can 'fold' in different ways while cooling, so what people observed was different types of its folding."

Vanadium dioxide is best known in the materials world for its speedy and abrupt phase transition that essentially transforms the material from a metal to an insulator. The phase change takes place at about 68 degrees Celsius.

"These features of make vanadium dioxide an excellent candidate for numerous applications in optical, electronic and optoelectronic devices," Tselev said.

Devices that might take advantage of the unusual properties of VO2 include lasers, motion detectors and pressure detectors, which could benefit from the increased sensitivity provided by the property changes of vanadium dioxide. The material is already used in technologies such as .

Researchers said their theoretical work could help guide future experimental research in vanadium dioxide and ultimately aid the development of new technologies based on VO2.

"In physics, you always want to understand how the material ticks," said Sergei Kalinin, a senior scientist at the CNMS. "The thermodynamic theory will allow you to predict how the material will behave in different external conditions."

The results were published in the American Chemical Society's Nano Letters. The research team also included Ilia Ivanov, John Budai and Jonathan Tischler at ORNL and Evgheni Strelcov and Andrei Kolmakov at Southern Illinois University.

The team's theoretical research expands upon previous experimental ORNL studies with microwave imaging that demonstrated how strain and changes of crystal lattice symmetry can produce thin conductive wires in nanoscale vanadium dioxide samples.

Explore further: Scientists Formulate Intelligent Glass That Blocks Heat Not Light

Related Stories

Researcher discovers new materials

July 10, 2006

A research team led by Carnegie Mellon University Materials Science and Biomedical Engineering Professor Prashant Kumta has discovered a nanocrystalline material that is cheaper, more stable and produces a higher quality ...

Nano-sandwich Triggers Novel Electron Behavior

May 4, 2009

(PhysOrg.com) -- A material just six atoms thick in which electrons appear to be guided by conflicting laws of physics depending on their direction of travel has been discovered by a team of physicists at the University of ...

Putting a Strain on Nanowires Could Yield Colossal Results

September 17, 2009

(PhysOrg.com) -- In finally answering an elusive scientific question, researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have shown that the selective placement of strain ...

Recommended for you

New nanomaterial maintains conductivity in 3-D

September 4, 2015

An international team of scientists has developed what may be the first one-step process for making seamless carbon-based nanomaterials that possess superior thermal, electrical and mechanical properties in three dimensions.

Graphene made superconductive by doping with lithium atoms

September 2, 2015

(Phys.org)—A team of researchers from Germany and Canada has found a way to make graphene superconductive—by doping it with lithium atoms. In their paper they have uploaded to the preprint server arXiv, the team describes ...

Making nanowires from protein and DNA

September 3, 2015

The ability to custom design biological materials such as protein and DNA opens up technological possibilities that were unimaginable just a few decades ago. For example, synthetic structures made of DNA could one day be ...

For 2-D boron, it's all about that base

September 2, 2015

Rice University scientists have theoretically determined that the properties of atom-thick sheets of boron depend on where those atoms land.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.