Scientists at the Lawrence Berkeley Laboratory and the University of California have discovered a very interesting feature in a metal: it is the conductor of electricity, but not the heat. The compound will be of great utility in fields such as car engines or electronics.
Most metals fulfill a property called Wiedemann-Franz law that relates electrical conductivity to thermal conductivity. In other words, if it is the conductor of electricity, so is the heat. This law, however, does not apply to some transition metals like vanadium. Vanadium dioxide, for example, changes from insulation to conductor as a function of temperature.
There is a new international discovery as far as the properties of metals are concerned, this was achieved by a team of scientists from Berkeley Lab, a University of Berkeley, California. Where metal electrons of vanadium dioxide are able to conduct electricity, but not heat, this through a property that was discovered.
Junqiao Wu is the physicist who leads this research, according to his own words “This has been a totally unexpected discovery.” Using results from simulations and X-ray scatter tests, they found where it could be triggered.
The Wiedemann-Franz conductivity law states that good conductors of electricity are also good conductors of heat, which with this discovery of this property is not being fulfilled, which would be breaking this law.
“In vanadium dioxide, electrons move in unison, as in a fluid, instead of in all directions as in ordinary metals. For electrons, heat is a random motion. Normal metals transport heat in such an efficient way because there are many possible microscopic configurations by which electrons can travel. In vanadium dioxide, the coordinated motion of the electrons, as if they were the band of a parade, acts to the detriment of the thermal conductivity. It is an effect of the least number of configurations available for electrons to jump randomly. ”
What can be the future and applications of metal vanadium dioxide?
“This material can be used to help stabilize temperature,” says Fan Yang who has a postdoctoral degree and is a researcher at Berkeley Lab’s Molecular Foundry, where this discovery was made.
A movement in unison
The physicist at Berkeley University Junqiao Wu has explained how the electrons act in this compound: “In vanadium dioxide, electrons move in unison, as in a fluid, instead of in all directions as in the common metals “.
“For the electrons, heat is a random motion.” Normal metals transport heat in such an efficient way because there are many possible microscopic configurations by which electrons can travel.In vanadium dioxide, the coordinated motion of electrons, As if they were the band of a parade, acts to the detriment of thermal conductivity.It is an effect of the smallest number of configurations available for the electrons to jump randomly, “he says.
A compound that isolates heat at room temperature
Although some compounds that have been able to transmit electricity better than heat have been found to date, vanadium dioxide does so at room temperature rather than at extremely low temperatures, which makes it different from the rest.
In addition, the amount of electricity it transmits can be adjusted by small concentrations of other metals. Scientists have also discovered that vanadium dioxide is transparent at temperatures of 30 degrees Celsius and absorbs infrared radiation above 60 degrees.
The discovery of this compound can be decisive to dissipate the heat of the engines while generating electrical energy and even becomes an excellent insulator of the heat in windows. Investigators will now need to do some testing before marketing this compound.
This research is still under development, but it is clear that in the future there may be multiple uses that can be given to it, taking advantage of new properties discovered.
The advance in this type of discoveries is due to the research that is carried out in research centers, in this case the Berkeley Lab, that since its foundation in 1931 has been able to help to make significant changes for the development of the humanity.