Metallic hydrogen, once theory, becomes reality!

Nearly a century after it was theorised, Harvard scientists claim to have succeeded in creating the rarest and potentially one of the most valuable materials on the planet - atomic metallic hydrogen.
In addition to helping scientists answer fundamental questions about the nature of matter, the material is theorised to have a wide range of applications, including as a room-temperature superconductor.
"This is the holy grail of high-pressure physics," said Professor Isaac Silvera from Harvard University in the US.
"It's the first-ever sample of metallic hydrogen on Earth, so when you're looking at it, you're looking at something that's never existed before," said Silvera.

To create it, researchers squeezed a tiny hydrogen sample at 495 gigapascal, or more than 71.7 million pounds-per-square inch - greater than the pressure at the centre of the Earth.
At those extreme pressures, solid molecular hydrogen breaks down and the tightly bound molecules dissociate to transform into atomic hydrogen, which is a metal, Silvera said.

While the research offers an important new window into understanding the general properties of hydrogen, it also offers tantalising hints at potentially revolutionary new materials.
"One prediction that's very important is metallic hydrogen is predicted to be meta-stable," Silvera said.
"That means if you take the pressure off, it will stay metallic, similar to the way diamonds form from graphite under intense heat and pressure, but remains a diamond when that pressure and heat is removed," he said.

Understanding whether the material is stable is important, Silvera said, because predictions suggest metallic hydrogen could act as a superconductor at room temperatures.
"That would be revolutionary. As much as 15 per cent of energy is lost to dissipation during transmission, so if you could make wires from this material and use them in the electrical grid, it could change that story," he said.
Among the holy grails of physics, a room temperature superconductor could radically change our transportation system, making magnetic levitation of high-speed trains possible, as well as making electric cars more efficient and improving the performance of many electronic devices, said Ranga Dias, post-doctoral fellow at Harvard.

The material could also provide major improvements in energy production and storage - because superconductors have zero resistance energy could be stored by maintaining currents in superconducting coils, and then be used when needed.