"This is the Holy Grail of high-pressure physics," said Isaac Silvera, professor of Natural Sciences at Harvard University. "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."
In 1935, scientists predicted that molecular hydrogen would become an atomic metal at 25gigapascals (GPa) pressure, however this proved to be surprisingly challenging.
In their experiments, Prof Silvera and postdoctoral fellow Ranga Dias, finally formed a metallic hydrogen sample at 495GPa, greater than the pressure at the centre of the Earth. At such extreme pressures solid molecular hydrogen, which consists of molecules on the lattice sites of the solid, breaks down, and the tightly bound molecules dissociate to transforms into atomic hydrogen, which is a metal.
“One prediction that’s very important is metallic hydrogen is predicted to be meta-stable,” Prof Silvera explained. “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 remain diamonds when that pressure and heat are removed.
“As much as 15% of energy is lost to dissipation during transmission,” he added, “so if you could make wires from this material and use them in the electrical grid, it could change that story.”
A room temperature superconductor could 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.
The material could also provide major improvements in energy production and storage. Because superconductors have zero resistance, superconducting coils could be used to store excess energy, which could then be used whenever it is needed. Metallic hydrogen could also be used as a more powerful rocket propellant.