It is well known that various kinds of metals,able to conduct electricity, at the same time quite hot. This is due to a number of chemical and physical properties of materials, but electrical and thermal conductivity almost always go hand in hand. However, as we know, nothing is possible in our world. For example, according to the editors of Sciencealert, a group of researchers from the laboratory at the University of Berkeley (USA) was able to create a metal that conducts electricity well, but does not heat up.
Which metal has unique properties?
According to scientists, the new metal (or rathermetal connection) that conducts electricity without conducting heat challenges our current understanding of how conductors work. Since its very existence contradicts what is called the Wiedemann-Franz law. Without going into details, this physical law states that good conductors of electricity will also be proportionally good conductors of heat. This explains, for example, that appliances that use electricity for their work heat up over time. But let's not delay the intrigue anymore. A team of scientists from the United States showed that this phenomenon is not observed in vanadium oxide, which has a strange ability to “switch” from an insulating material to a conductive metal at a temperature of 67 degrees Celsius.
It was a completely unexpected discovery, -said lead researcher Junquaoo Wu of Berkeley Lab's materials science department. This discovery is fundamental to understanding the basic principle of the new conductors. A new unexpected property not only changes what we know about conductors, but can also be incredibly useful. For example, metal can one day be used to convert waste heat from engines and appliances back into electricity.
So no physical laws of vanadium oxidedoes not break. It is worth noting that the researchers already knew about several other materials that conduct electricity better than heat, but they show these properties only at temperatures below zero, which makes them extremely impractical for use in real life. Vanadium oxide, on the other hand, is usually only a conductor of electricity at positive temperatures above room temperature, which means that it has a lot more practicality. To discover this strange property, the team studied how electrons move in the crystal lattice of vanadium oxide, as well as how much heat is generated at that moment.
Surprisingly, they found thatthe thermal conductivity that could be attributed to the electrons in the material was 10 times less than the value predicted by the Wiedemann-Franz law. The reason for this, apparently, is the way electrons move through the material.
Electrons move synchronously with each other. As a liquid, and not as separate particles, which is observed in ordinary metals. For electrons, thermal conductivity is a random movement. Ordinary metals transfer heat efficiently, because there are many different possible microscopic configurations of electron behavior and they can move randomly. But the coordinated movement of electrons in vanadium dioxide is detrimental to heat transfer, since there are fewer “movement opportunities”. In this case, the electrical conductivity in this case does not suffer.
Interestingly, when the researchers mixed oxidevanadium with other metals, they were able to "adjust" the amount of electricity and heat that it can conduct, which can be incredibly useful for future applications. For example, when experts added a metal called tungsten to vanadium oxide, they made it the best heat conductor. Want to know more news from the world of high technology? Subscribe to us on Yandex.Zen.
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By adjusting thermal conductivity in this way,the material can be effectively used to automatically dissipate heat in hot summers, because it will have high thermal conductivity, but prevent its loss in the cold winter due to low thermal conductivity at lower temperatures.