Recent research at Oak Ridge National Laboratory helps explain mysterious experimental vanadium dioxide (V02) results that have puzzled scientists for decades. Scientists have been aware that vanadium dioxide shows several dissimilar phases when it acts as an insulator at lower temperatures, although the exact nature of the phase behavior has not been understood since vanadium dioxide research began in the early 1960s.
University of Tennessee-Knoxville’s Alexander Tselev, working with ORNL’s Center for Nanophase Materials Sciences, in a team with Igor Luk’yanchuk from the University of Picardy in France used a condensed matter physics 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.”
Optical, Electronic and Optoelectronic Applications
In the materials science world, vanadium dioxide is most known for its rapid and abrupt phase transition that basically changes the material from a metal to an insulator. The phase transformation takes place at about 68 degrees Celsius.
“These features of electrical conductivity make vanadium dioxide an excellent candidate for numerous applications in optical, electronic and optoelectronic devices,” Tselev said.
Devices that could benefit of the novel properties of VO2 include motion detectors, lasers, and pressure detectors, which could take advantage of the increased sensitivity provided by the property changes of vanadium dioxide. The material is already used in technologies such as infrared sensors.
“In physics, you always want to understand how the material ticks,” according to Sergei Kalinin, of the Center for Nanophase Materials Sciences. “The thermodynamic theory will allow you to predict how the material will behave in different external conditions.”
Interplay between Ferroelastic and Metal−Insulator Phase Transitions in Strained Quasi-Two-Dimensional VO2 Nanoplatelets Alexander Tselev, Evgheni Strelcov , Igor A. Luk’yanchuk , John D. Budai , Jonathan Z. Tischler , Ilia N. Ivanov , Keith Jones , Roger Proksch , Sergei V. Kalinin and Andrei Kolmakov Nano Lett., 2010, 10 (7), pp 2734–2734 DOI: 10.1021/nl102049b