Liquid helium is squeezed into "metal" under high pressure

A joint research team at the Sandia National Laboratories in the United States and the University of Rostow in Germany recently successfully squeezed liquid germanium (heavy hydrogen) into metal at high pressure, which is closer to the ultimate goal of generating solid metal hydrogen. The research results are published in the latest issue of the journal Science.

Helium is a stable form of hydrogen isotopes, the element symbol is generally D or 2H, its nucleus consists of a proton and a neutron, in nature, the content is about 7000 of the general hydrogen, can be used for thermonuclear reactions, is It is called "future natural fuel." Back in 1935, two researchers, Flebel Huntington and Eugene Vigner, proposed for the first time that the theory that metallic hydrogen can be obtained under ultra-high pressure is indeed possible, that is, liquid or solid hydrogen at millions of atmospheres. Under high pressure into a conductive body, because the conductivity is a metal, it is called metal hydrogen. Since then, various research teams have tried to obtain metal hydrogen samples to prove that this theory is correct, but so far it has not been successful. Nevertheless, theorists have speculated that metal hydrogen is a high-temperature superconductor and is a high-density, high-energy storage material.

According to a recent report by the Physicist Organization Network, researchers have used techniques based on squeezing samples between two diamond tips. It is hoped that it will be possible to convert hydrogen-rich compounds into metalloids. However, due to the problem of the sample material becoming over-reacted, it has been found that using the double diamond tip method cannot achieve the final result.

In this experiment, the researchers chose another route and developed a new way to increase the pressure without causing other problems. They used a large Z machine that Sandia National Laboratories could create a 20 mega-Gaussian magnetic field. For the first time, the liquid helium sample was pressurized, then it was oscillated and moved by an Z electrode machine through an electrode, which in turn impacted the helium that the front container had. Causes a shock wave to pass through the sample, allowing it to be further compressed. Researchers used common metal identification methods after the material was concentrated to measure to what extent the sample reflects light. Test results show that when the sample is condensed, it goes from a transparent state to being reflected. This clearly shows that liquid helium has changed from an insulator to a piece of metal. (Reporter Hualing)