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Good news: Boffins have finally built room-temperature superconductors. Bad news: You'll need a laser, a diamond anvil, and a lot of pressure
Lead scientist explains all to El Reg: 'Pressure is the most versatile parameter to create such conditions'
Updated Scientists say they have forged the world’s first room-temperature superconductor: a powder-like material capable of conducting electricity with zero resistance.
Superconducting properties emerge from the substance – described as “carbonaceous sulfur hydride” in a research paper published in Nature on Wednesday – when it's at a balmy 287.7 Kelvin (15°C, 58°F). One important caveat, though: the powder must be crushed under 39 million pounds per square inch, which is about 2.6 million times the atmospheric pressure on Earth.
The carbonaceous sulfur hydride superconductor experiment ... So it's not going to fit into your pocket, yet. Source: University of Rochester, USA. Click to enlarge
Ordinary metal loses its electrical resistance as its temperature is brought down to absolute zero, which is cool (no pun intended) but not very practical as it requires a lot of energy and equipment to pull this off. Scientists have sought for years the holy grail of a room-temperature superconductor as superconductivity has game-changing uses: near-lossless transmission of electricity through power grids; improved medical imaging and electronics; new forms of propulsion for public transit, etc.
“Because of the limits of low temperature, materials with such extraordinary properties have not quite transformed the world in the way that many might have imagined,” said Ranga Dias, co-author of the study and an assistant professor of physics and mechanical engineering at the University of Rochester in the US. “However, our discovery will break down these barriers and open the door to many potential applications."
Below is a video illustrating the research work.
As you may have gathered by now, this new material isn’t quite ready for production, yet. At the moment, its superconductivity only emerges in a contraption that involves crushing a minuscule amount of the powder between two diamond anvils and firing a laser at it.
But it manages to work because the high pressure restricts each atom’s ability to vibrate, allowing electrons to flow with a lot less resistance, a key component in superconductivity.
Drama as boffins claim to reach the Holy Grail of superconductivityREAD MORE
“A conductor consists of a lattice of atoms,” Dias explained to El Reg. “For electricity to flow, electrons must move through this lattice with as little obstruction as possible. Pressure is the most versatile parameter to create such conditions. With applied pressure, a hydrogen rich lattice enables such a condition to occur at room temperature.”
The material is created from a black powder of carbon and sulfur placed inside a hydrogen-rich environment. It is then pressed in a chamber between the diamonds and zapped with a 10mW green-colored 532nm laser. The material then transforms into something that can superconduct electricity: its electrical resistance vanishes as its electrons are free to move unhindered. Before this substance can be used in real-world applications, the team needs to figure out, among other things, how to make the powder at larger quantities.
“The next challenge will be to produce these materials that are stable at ambient pressure so they will be economical to mass produce,” Dias told us. Although the team has probed the material's superconductive properties, the academics don’t quite know its exact molecular structure.
“We also do not know how many carbon, sulphur, and hydrogen atoms there are in the primitive description of the material,” he added. “We have some idea but don’t know the exact answer. We also don’t know the structure, because of its light mass. It prevents us from doing X-ray diffraction. We have been developing a new set of tools to solve this problem. We need to find the correct structure before this can be used.” ®
Updated to add
The journal Nature has now retracted the study after "questions were raised regarding the manner in which the data in this paper have been processed and analyzed," after the boffins allegedly used "non-standard, user-defined procedure."
"The authors maintain that the raw data provide strong support for the main claims of the original paper. Nevertheless, we are of the opinion that these processing issues undermine confidence in the published magnetic susceptibility data as a whole, and we are accordingly retracting the paper," the journal said.