Harvard researchers revealed last month that they had finally created metallic hydrogen, a form of hydrogen that can superconduct electricity without resistance and at room temperature, achieving the so called "holy grail of high-pressure physics."

Only Sample Of Metallic Hydrogen Disappeared

The creation of this material is something that scientists have been aiming for over the past eight decades. The material produced is also the only known sample of metallic hydrogen on Earth. Researchers, however, reported that the sample has disappeared.

The metallic hydrogen the researchers created was stored in a laboratory at a temperature close to absolute zero in a diamond vice but now, researchers said that sample was either misplaced or degraded.

"It's either someplace at room pressure, very small, or it just turned back into a gas," said Isaac Silvera, natural sciences professor at Harvard who is also one of the researchers involved in the experiment, adding that they do not know what happened to the material.

Silvera and Ranga Dias, also from Harvard, claimed they were able to create a tiny sample of metallic hydrogen by compressing hydrogen atoms in a diamond anvil to an extremely high pressure of 495 gigapascals.

When the pair used a low-pressured laser to measure the pressure of the system earlier this month though, the energy from the layer appears to have destroyed the diamond vice. Silvera said that the diamond shattered like it was baking soda.

Attempt To Replicate Experiment That Created Metallic Hydrogen

The researchers said that they are preparing a new experiment to see if they can reproduce the pressure they achieved the first time that they were able to produce the metallic hydrogen.

Skepticisms

Some scientists who have performed similar experiments though expressed their skepticism regarding the material shortly after the Harvard researchers announced that they have produced the elusive material.

Geophysicist Alexander Goncharov, who has criticized the methods used in Silvera's lab before, is one of those unconvinced saying that it is far from clear that the shiny material that the pair produced is actually hydrogen.

Other researchers think that the pair overestimated the pressure that they reached by relying on imprecise calibration. Physicist Eugene Gregoryanz, from the University of Edinburgh, said that part of the problem is that the researchers took only one detailed measurement of their sample at the highest pressure, which makes it difficult to know how pressure shifted during the experiment.

Researchers urged the pair to redo the measurements to remove doubts.

Physicist Paul Loubeyre, from France's Atomic Energy Commission in Bruyères-le-Châtel said he did not find the paper convincing at all.

"If they want to be convincing, they have to redo the measurement, really measuring the evolution of pressure," he said.

Silvera and Dias, however, are confident about their work and even urged other teams to try to reproduce the experiment as they have already shown how they achieved the high pressures and material in the lab.

"This disappearance doesn't say anything about the validity of the sample. Anyone who does high pressure works knows that you have failures like this," Silvera said.