Jan 09

New hints on the metallization of Hydrogen

Recently scientist from the Edinburgh’s Centre for Science at Extreme Conditions  have come close to creating a long-sought new state for hydrogen. The group used a set-up called a diamond anvil cell to compress its sample of molecular hydrogen. This apparatus is essentially two gems that have been placed in opposition to each other. Their polished tips, comparable in size to the width of a human hair, are made to press into a cavity containing the sample.

In their experiments, the scientists are able to achieve in excess of 350 gigapascals (3.5 million atmospheres) at room temperature. These pressures are not dissimilar to what would be experienced at the centre of the Earth. The big squeeze on the molecules of hydrogen gas turns them first into a liquid and then into a solid.


As the pressure gets ever more intense, the atoms in the hydrogen molecules pack closer and closer together,
and the electrical conductivity in the crystalline material increases.
Ultimately, the hydrogen atoms should stack so efficiently that their electrons become shared -just as in a metal. However, the team does not quite see this phase, but rather something that is probably just short of it. The work puts new constraints on where the full metallic hydrogen phase might exist:  possibly below 450 gigapascals at room temperature.

The ambient temperature is very significant, because if metallic hydrogen can ultimately be produced this way it opens the door potentially to a new type of perfect (zero resistance) conductor – a material to 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…
Scientists are also fascinated by metallic hydrogen because they think it may account for a large fraction of the internal composition of planets such as Jupiter.
Link to the original work published in Nature (letter) on January 7th, 2016.
BBC reportage.