Superconductivity at room temperature is the dream of every scientist who works with condensed matter or an engineer who works with something that needs the perfect conduction of electricity – or the electronics industry, which benefits greatly from superconductivity. And a group of physicists has just reached this important milestone, in a study described in Nature.
Superconductors are materials that conduct electricity almost perfectly – without any loss. Have you noticed that when you use some equipment that demands a lot of energy for a long time – like a shower, or a drill -, the power cables get hot? Heating is one of the forms of energy loss with resistance. In a superconductor this does not occur. They can also revolutionize transportation, helping to develop electromagnetic levitation trains.
The search for the perfect driver
Discovered in 1911, superconductivity has been one of the main fields of research in condensed matter physics ever since. However, size is the challenge that even today scientists had to cool superconductors, even more than a century after the discovery. Another necessary point is the high pressures. But nobody has been able to solve this yet.
In 2019, scientists achieved superconductivity at -23 ° Celsius. It is already a very good result, compared to temperatures close to absolute zero (-273 ° C). However, it is still impractical for large-scale use. Superconductivity at room temperature will open the door in the not too distant future.
“Because of the low temperature limits, materials with such extraordinary properties have not transformed the world in the way that many could imagine,” says Ranga Dias, from the Department of Physics and Astronomy at the University of Rochester in a press release. “However, our discovery will break these barriers and open the door to many potential applications.”
However, even if cooling is no longer necessary, there is still much progress to be made – unless you use superconductivity only in the fall and winter of high-latitude countries. The superconductor developed by the team works only up to 15 ° C – a rare temperature in countries like Brazil, and few places achieve this during spring and summer.
In addition, the new superconductor still requires high pressures for operation. It is not like a copper wire, which you connect, weld and use.
The search for the perfect material
We know that the best conductors – thermal and electrical – of daily life are in the group of metals. However, although copper and iron are also on the list, superconductivity at room temperature is widely considered with hydrogen – light, abundant and resistant.
“In order to have a high temperature superconductor, you want stronger connections and lighter elements. These are the two basic criteria ”, explains Dias. “Hydrogen is the lightest material and the hydrogen bond is one of the strongest.”
But, as we know, hydrogen is a gas at our pressures and temperatures. In places like Jupiter’s nucleus, it becomes what we call metallic hydrogen, a splendid conductor, but some say it was never actually confirmed in the laboratory, although some scientists claim the creation. The most promising creation came in 2017, by scientists from Harvard University.
In this discovery, however, scientists did not just use hydrogen. They used a combination of hydrogen, carbon and sulfur, the carbonaceous sulfur hydride. Although the temperature is promising – 15 ° C -, they needed a pressure equivalent to about 2.6 million atmospheres on Earth – something quite overwhelming.
The new steps, therefore, will focus on reducing pressure, in addition to attempts to increase the temperature, and enable a global use of the material.
The study was published in the journal Nature. With information from Science Alert, Nature News and University of Rochester.