Nearly a century after it was theorized, scientists from Harvard University have created the first-ever sample of one of the rarest materials on the planet: metallic hydrogen. The atomic metallic hydrogen has a potentially wide range of applications, including as a room-temperature superconductor.
“This is the Holy Grail of high-pressure physics,” said Isaac Silvera, Thomas D. Cabot Professor of the Natural Sciences. “You’re looking at something that’s never existed before.”
In their experiments, Silvera and postdoctoral fellow Ranga Dias squeezed a tiny hydrogen sample at 495 gigapascal (GPa), or more than 71.7 million pounds per square inch — greater than the pressure at the center 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 transform into atomic hydrogen, a metal.
Some researchers predict that the atomic metallic hydrogen has "meta-stable” characteristics, much like diamonds.
"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,” said Silvera.
A room temperature superconductor, according to Dias, could change the transportation system, enabling magnetic levitation of high-speed trains. The material could also provide major improvements in energy production and storage, allowing more powerful rocket propellants needed for humans to explore space.
Also: Read more Materials & Coatings tech briefs.
Transcript
00:00:08 We have made a new material it's a material that has never existed on earth before: metallic hydrogen. Hydrogen is the simplest atom in the periodic table of the elements, it consists of a single proton with the single electron around it, at room temperature, it exists as a gas but if you cool hydrogen down to low temperatures it actually
00:00:34 liquefies and if I cool it to about just under 14 degrees it forms a solid. Imagine my fingers are molecules here with the two atoms, if you compress it to a high enough density eventually you will get to a pressure or a density where the molecules dissociate and it forms an atomic solid and this is a metal. You have two diamonds sitting opposite to each other inside here we load the sample as a
00:01:08 liquid state, but as soon as you pressurize it, the molecules get closer together it becomes a solid, and then we're squeezing the solid, and even though this device looks very small we can generate pressure more than the center of earth. You never know how it's going to be applied but imagine that it's metastable and you can make electrical wires out of it, you could conduct electricity across
00:01:32 the country without dissipation, you could make magnets which are used in MRI, for example, that would work at room temperature. Right now the magnets have to be cooled with liquid helium. NASA has supported some of our research because it turns out that if it's metastable and you could cause it to convert to molecular hydrogen, it releases an enormous amount of energy and it would
00:01:55 revolutionize rocketry and it's a very nice thing to achieve.
