Created material that violates physical laws?
It is Well known that various metals that can conduct electricity, at the same time is quite heated. 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, in our world there is nothing, nothing is possible. For example, as reported by the editorial Board , a group of researchers from the laboratory of the University of Berkeley (USA) was able to create a metal that conducts electricity well, but it is not heated.
According to scientists, (or metal compound) that conduct electricity without conducting heat challenges our current understanding of how the conductors. Since its very presence contradicts what is called the law of Wiedemann-Franz. If you do not go into detail, then this physical law States that good conductors of electricity will also be proportionally good conductors of heat. This explains, for example, that devices that use the electricity over time heat up. But won't delay the suspense. A team of scientists from the USA showed that this phenomenon is not observed in the vanadium oxide, which has a strange capacity «switch» with the material being an insulator to a conductive metal at a temperature of 67 degrees Celsius.
It was a completely unexpected discovery — said lead researcher Junchao Wu of Department of materials science Laboratory in Berkeley. This discovery is of fundamental importance for understanding the basic principle of operation of the new conductors. A new unexpected property not only changes what we know about conductors, but can be incredibly useful. For example, the metal may one day be used to convert waste heat from engines and appliances back into electricity.
So no physical laws of vanadium oxide does not break. It is worth noting that the researchers already knew about a few other materials that conduct electricity better than heat, but they exhibit these properties only at temperatures below zero, making them extremely impractical for use in real life. Vanadium oxide, on the other hand, is usually only a conductor with positive temperature above room temperature, which means that it has to be much more practical. To access this strange property, the team studied how electrons move in the crystal lattice of vanadium oxide, and also how much heat this moment is generated.
Surprisingly, they found that the thermal conductivity, which could be attributed to electrons in the material, was 10 times less than the value predicted by the Wiedemann-Franz. The reason for this apparently lies in the way movement of electrons through the material.
The Electrons move synchronously with each other. As fluid, not as individual particles, which is observed in ordinary metals. For electrons the thermal conductivity — is a random movement. Common metals transfer heat efficiently because there are many different possible microscopic configurations of the behavior of electrons and they are unable to move erratically. But the coordinated motion of electrons in vanadium dioxide is detrimental to heat transfer because there is less «opportunities for movement». The conductivity in this case does not suffer.
Interestingly, when the researchers mixed oxide of vanadium with others , they could «configure» the quantity of electricity and heat that it can conduct that can be incredibly useful for future applications. For example, when the experts added a metal called tungsten to the vanadium oxide, they have made it a better conductor. Want more news from the world of high technology? Follow us on .
Tuning thus the thermal conductivity, the material can be effectively applied to automatically dissipate heat in the hot summer, because it will have high conductivity, but to prevent its loss in the cold winter, due to low thermal conductivity at lower temperatures.
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