Researchers have identified a metal that conducts electricity without conducting heat – an incredibly useful property that defies our current understanding of how conductors work.
The metal, found in 2017, contradicts something called the Wiedemann-Franz Law, which basically states that good conductors of electricity will also be proportionally good conductors of heat, which is why things like motors and appliances get so hot when you use them regularly.
But a team in the US showed this isn’t the case for metallic vanadium dioxide(VO2) – a material that’s already well known for its strange ability to switch from a see-through insulator to a conductive metal at the temperature of 67 degrees Celsius (152 degrees Fahrenheit).
“This was a totally unexpected finding,” said lead researcher Junqiao Wu from Berkeley Lab’s Materials Sciences Division back in January 2017.
“It shows a drastic breakdown of a textbook law that has been known to be robust for conventional conductors. This discovery is of fundamental importance for understanding the basic electronic behaviour of novel conductors.”
Not only does this unexpected property change what we know about conductors, it could also be incredibly useful – the metal could one day be used to convert wasted heat from engines and appliances back into electricity, or even create better window coverings that keep buildings cool.
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.
Vanadium dioxide, on the other hand, is usually only a conductor at warm temperatures well above room temperature, which means it has the ability to be a lot more practical.