It only took eighty years, but at last, we may have had a glimpse of elusive metallic hydrogen. Hydrogen is the most abundant element in the universe, and when placed under high pressure, like in the center of gas giants like Jupiter, it begins to behave like a metal.
Researchers at the University of Edinburgh used diamond anvils to apply pressure on hydrogen molecules of 3.25 million atmospheres, which they saw enter a new phase of solid state. This is called Phase V, believed to be the start of metallic hydrogen.
Hydrogen is usually found in the form of molecules: two atoms of hydrogen are linked together and share their two electrons. It was predicted in 1935 that this molecular bond would break under sufficient compression and that the atoms would be organized into an atomic solid metallic configuration, with electrons loosely bound to the atoms just like copper or iron.
“The past 30 years of high-pressure research have seen numerous claims that metallic hydrogen has been created in the laboratory, but all of these claims have later been disproved,” said Professor Eugene Gregoryanz, who led the research, in a statement. “Our study presents the first experimental evidence that hydrogen can behave as predicted, although at much higher pressures than previously thought.
The newly discovered phase is not the pure metallic state predicted by the theory, but rather the initial phase in which molecular bonds are broken but the metallic properties have not fully emerged. The study suggests that the long sought-after metallic hydrogen state requires even higher pressure. And the diamond anvils used in this experiment may not be sufficient to produce the press
The study is likely to be met with skepticism, which is published in Nature. High-pressure techniques and small samples can make big mistakes, so the work of the team will be carefully inspected.
If the results are confirmed, the metallic hydrogen will have to be achieved using different techniques. Probably the pressure needed to produce it exceeds our current capabilities.