Scientists have created a new state of hydrogen. Meet what is likely a completely new phase of matter: phase V hydrogen, which researchers revealed through crushing Earth’s lightest element with so much pressure that it assumed a never-before-seen solid crystalline form.
This phase may just be a step closer to metallic hydrogen, which in the 1930s was first proposed and believed to lead to ultra-efficient computer devices and other breakthroughs.
University of Edinburgh doctoral student Philip Dalladay-Simpson and his colleagues Ross T. Howie and Eugene Gregoryanz conducted the study and detailed their findings in the journal Nature published on Jan. 7.
Hydrogen, typically in gas form on Earth, can turn solid when cooled to certain low temperatures, but turns into a metal once it solidifies. Jupiter is believed to be largely made of this, such that this hydrogen crushed at extremely high pressures is considered a peek into the inner atmosphere of the giant planet.
Creation Of Phase V Hydrogen
"This paper does not claim a metallic state, but claims that it is a precursor to the metallic state,” clarified co-author Howie, citing the similarities between what they saw in their experiment and what is forecasted theoretically for a solid metallic hydrogen state.
The team used a two-diamond anvil setup, where the gems were placed opposite each other and a small amount of hydrogen was placed between them for compression. They then pumped up the pressure to 384 gigapascals or 55 million pounds per square inch (psi).
To illustrate this extremely high pressure, Earth’s atmosphere is 100 kilopascals (15 psi) at sea level, while on Jupiter the atmosphere weighs 29 million psi at around 10,000 miles below tops of the clouds. This is where hydrogen is suggested to be in a liquid metal state.
In the experiment, when the pressure reached 325 gigapascals (47 million psi), the hydrogen turned solid and for the first time the elemental form was nearly at room temperature, according to the researchers. So, in the process of trying to create metallic hydrogen, they were able to come up with a new phase of the element.
Dalladay-Simpson said the hydrogen state was created at much higher pressures and temperatures than previous research. "When we use pressure we force the molecules to interact," he explained, adding that this pressure then leads H2 bonds to begin breaking.
A Step Away From Metallic Hydrogen?
The team tested the phase V hydrogen by firing a laser at it, observing the changes in the light's wavelength.
This signaled the new structure of the material, which the researchers could not confirm as a metal just yet. They could not test the conductivity because the space between the diamond anvils was so tiny that electrodes for testing would hardly fit, the authors explained.
To make sure the element took on a metallic state without testing conductivity, the researchers would have to increase the pressure even more, at 450 gigapascals at most, but such might shatter the diamond anvils.
The researchers hope to raise the pressures and test the limits of the anvils in future studies.
Paving The Way For Next-Gen Computers, Super Fuel
Movement in the fluid state of metallic hydrogen in Jupiter is considered the likely source of the planet’s massive magnetic field, and NASA's Juno probe will be exploring that possibility when it arrives at the planet this year. The spacecraft is expected to arrive in Jupiter on July 4 after a five-year journey.
Fascination surrounds metallic hydrogen not only because it may account for a majority of the internal composition of Jupiter and other planets, but also because this state of hydrogen could herald a new kind of zero-resistance conduction. A material that can offer infinite electrical conductivity will certainly boost the performance of next-generation computers.
"It's been predicted that metallic hydrogen could be a room-temperature superconductor, which is still yet to be achieved with any material," Howie said in a different interview.
Metallic hydrogen is also predicted to lead to the creation of a super fuel, which can generate significantly greater thrust than the standard hydrogen used in rockets today.
Howie said, however, that the practical applications may not be clear at this point because they are working with small quantities.
Back in 2011, scientists at Germany’s Max Planck Institute for Chemistry claimed to have created metallic hydrogen, but never really confirmed it and they received scrutiny and criticism from other scientists.