University of Edinburgh make precursor to metallic hydrogen

British researchers think they have come close to creating a long-sought new state for hydrogen.

They have put a sample of the familiar gas under so much pressure that it takes on a previously unseen solid crystalline form.

The team tells the journal Nature that this phase may be just a step away from so-called metallic hydrogen.
Predicted 80 years ago, this exotic substance could lead to ultra-fast computers and even super rocket fuel.

"We think we’ve reached a state of the material that is probably the precursor to metallic hydrogen," explained Ross Howie, formerly at Edinburgh University but now based in China.

The study (published in Nature) provides evidence that at above 350 GPa (3,500,000 atm) and at room temperature hydrogen adopts a novel structure. Interestingly the results are suggestive that this new phase could prove to be the precursor to the long sought metallic phase of hydrogen, predicted over 80 years ago by theory.

As the simplest, lightest and most abundant element of the Universe, hydrogen is of fundamental interest in many fields of science. At high pressure and low temperatures, hydrogen is predicted to transform from a molecular system to a metallic (atomic) state. This behaviour is crucial to planetary science as hydrogen is believed to be found in the centre of Jovian planets and to be the source of their exceptionally high magnetic fields. This predicted state is also believed to exhibit rich phenomena such as superconductivity and super-fluidity, which would result in many technological breakthroughs. Reaching such conditions with hydrogen in the experimental laboratory however has been a great challenge in the field of high pressure research: only 4 years ago it was limited to less than half of the pressure recorded in the study.

Through new technological breakthroughs in the containment of hot hydrogen in diamond anvil cell experiments, Philip Dalladay-Simpson, Ross Howie and Eugene Gregoryanz at the Centre for Science at Extreme Conditions report that above 350 GPa hydrogen adopts a novel phase, phase V.

Nature – Evidence for a new phase of dense hydrogen above 325 gigapascals