Metallic hydrogen, once theory, becomes reality

Harvard researchers have succeeded in producing the rarest, and potentially one of the most precious, minerals on the world, over a century after it was first imagined.

Isaac Silvera, a professor of natural sciences at Thomas D. Cabot University, and postdoctoral researcher Ranga Dias invented the substance, called atomic metallic hydrogen. The substance is predicted to have a wide range of uses, including as a superconductor at room temperature, in addition to aiding researchers in understanding fundamental concerns about the nature of matter. An article that appeared in Science on January 26 describes how the unusual substance was created.

This is the pinnacle of high-pressure physics, according to Silvera. It is the first sample of metallic hydrogen ever found on Earth, so anything you see when you look at it is brand-new.

It was produced by Silvera and Dias by compressing a little sample of hydrogen to a pressure of 495 gigapascal, or more than 71.7 million pounds per square inch, which is higher than the pressure in the Earth's core. According to Silvera, solid molecular hydrogen, which is made up of molecules on the solid's lattice sites, breaks down at very high pressures, and the firmly bonded molecules dissociate to change into atomic hydrogen, which is a metal.

The study provides a crucial new insight into understanding hydrogen's general characteristics, but it also provides intriguing suggestions about potentially ground-breaking new materials.

One crucial prediction, according to Silvera, is that metallic hydrogen will be meta-stable. Accordingly, if the pressure is released, it will remain metallic, much like how diamonds develop from graphite when subjected to high heat and pressure yet continue to be diamonds when the pressure and heat are released.

According to Silvera, it is crucial to know whether the substance is stable because it has been predicted that metallic hydrogen may function as a superconductor at ambient temperature.

He declared, "That would be revolutionary." "Up to 15% of energy is lost during transmission due to dissipation, so if wires made of this material could be used in the electrical grid, that narrative might change."

A room temperature superconductor, one of physics' holy grails, might, according to Dias, fundamentally alter our transportation system by enabling magnetic levitation of high-speed trains, enhancing the efficiency of electric automobiles, and enhancing the functionality of several electronic gadgets.

Since superconductors have no resistance, energy might be saved by sustaining currents in superconducting coils and then used as needed thanks to the material's potential benefits in energy generation and storage.

Metallic hydrogen, the most explosive rocket fuel yet found, may play a crucial role in assisting mankind in exploring the furthest reaches of space even if it has the potential to change life on Earth.

Metallic hydrogen can only be created by using a vast amount of energy, according to Silvera. It becomes the most potent rocket propellant known to man and might completely change the field of rocketry if it is converted back to molecular hydrogen.

The "specific impulse" (a measure of how quickly a propellant is blasted from the rear of a rocket in seconds) of the most potent fuels currently in use is 450 seconds. In contrast, it is predicted that metallic hydrogen has a particular impulse of 1,700 seconds.

You could easily explore the distant planets with it, Silvera suggested. The ability to launch heavier payloads and launch rockets into orbit with only one stage as opposed to two makes this possibility highly significant.

Silvera and Dias used diamond, one of the world's hardest materials, to make the novel substance.

Silvera and Dias, however, employed two tiny pieces of meticulously polished synthetic diamond that were subsequently treated to make them even harder and positioned opposite each other in a structure known as a diamond anvil cell in place of real diamond.

Diamond powder is used to polish diamonds, and this process can remove carbon from the surface, according to Silvera. "We discovered flaws in the diamond using atomic force microscopy, which could lead to it weakening and breaking."

He suggested using a reactive ion etching procedure to remove a thin layer off the diamond's surface that was about five microns thick, or roughly one-tenth of a human hair. A thin film of alumina was then applied to the diamonds to stop the hydrogen from soaking into their crystal structure and weakening them.

After more than 40 years of research and over a century after it was initially postulated, Silvera said it was exciting to witness the substance for the first time.

It was a lot of fun, he remarked. 'Ranga was running the experiment, and we believed we may make it, but when he called and said, 'The sample is glowing,' I sprinted over there and saw metallic hydrogen.

We changed the lab because "I said right away that we have to make the measurements to confirm it," he added. It's a remarkable accomplishment, and even if it only exists under extreme pressure in this diamond anvil cell, the finding is basic and transformational.

Provided by Harvard University