Physicists Have Identified a Metal That Conducts Electricity But Not Heat
A research team in the United States, lead by Jungiao Wu from Berkeley Lab’s Materials Science Division has identified a metal that conducts electricity without conducting heat – an incredibly useful property that defies our current understanding of how conductors work.
The metal, known as metallic vanadium dioxide (VO2), was discovered in 2017 and contradicts the Wiedemann-Franz Law, which states that good conductors of electricity are also proportionally good conductors of heat. Another peculiar property of VO2 is its ability to switch from a transparent insulator to a conductive metal at a temperature of 67C (152F)
Researchers already knew of a handful of other materials that conduct electricity better than heat, but they only display those properties at temperatures hundreds of degrees below zero, which makes them highly impractical for any real-world applications.
“The electrons were moving in unison with each other, much like a fluid, instead of as individual particles like in normal metals,” said Wu.
“For electrons, heat is a random motion. Normal metals transport heat efficiently because there are so many different possible microscopic configurations that the individual electrons can jump between.”
Interestingly, when the researchers mixed the vanadium dioxide with other materials, they could ‘tune’ the amount of both electricity and heat that it could conduct – which could be incredibly useful for future applications.
For example, when the researchers added the metal tungsten to vanadium dioxide, they lowered the temperature at which the material became metallic, and also made it a better heat conductor.
That means that vanadium dioxide could help dissipate heat from a system, by only conducting heat when it hits a certain temperature. Before that it would be an insulator.