Science, Art, Litt, Science based Art & Science Communication
Compressing simple molecular solids with hydrogen at extremely high pressures, engineers and physicists have, for the first time, created material that is superconducting at room temperature.
The research team combined hydrogen with carbon and sulfur to photochemically synthesize simple organic-derived carbonaceous sulfur hydride in a diamond anvil cell a research device used to examine miniscule amounts of materials under extraordinarily high pressure.
The carbonaceous sulfur hydride exhibited superconductivity at about 58 degrees Fahrenheit and a pressure of about 39 million psi. This is the first time that superconducting material has been observed at room temperatures.
First discovered in 1911, superconductivity gives materials two key properties. Electrical resistance vanishes. And any semblance of a magnetic field is expelled, due to a phenomenon called the Meissner effect. The magnetic field lines have to pass around the superconducting material, making it possible to levitate such materials, something that could be used for frictionless high-speed trains, known as maglev trains.
Powerful superconducting electromagnets are already critical components of maglav trains,magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) machines, particle accelerators and other advanced technologies, including early quantum supercomputers.
But the superconducting materials used in the devices usually work only at extremely low temperatures—lower than any natural temperatures on Earth. This restriction makes them costly to maintain—and too costly to extend to other potential applications. "The cost to keep these materials at cryogenic temperatures is so high you can't really get the full benefit of them," Dias says.
Previously, the highest temperature for a superconducting material was achieved last year in the lab of Mikhail Eremets at the Max Planck Institute for Chemistry in Mainz, Germany, and the Russell Hemley group at the University of Illinois at Chicago. That team reported superconductivity at -10 to 8 degrees Fahrenheit using lanthanum superhydride.
To have a high temperature superconductor, you want stronger bonds and light elements. Those are the two very basic criteria. Hydrogen is the lightest material, and the hydrogen bond is one of the strongest.
Solid metallic hydrogen is theorized to have high Debye temperature and strong electron-phonon coupling that is necessary for room temperature superconductivity. However, extraordinarily high pressures are needed just to get pure hydrogen into a metallic state, which was first achieved in a lab in 2017 by Harvard University professor Isaac Silvera and Dias.
Source: Room-temperature superconductivity in a carbonaceous sulfur hydride , Nature (2020). DOI: 10.1038/s41586-020-2801-z