(CTN NEWS) – What’s lustrous and has the ability to conduct electricity? The typical answer is a metal.
Then, there’s hydrogen, an initially colorless and odorless gas. At first glance, it doesn’t appear to possess metallic characteristics.
However, since the late 1800s, physicists have postulated the possibility of creating metallic hydrogen under specific conditions.
These theories gained momentum, partly because metallic hydrogen is believed to exist throughout the solar system.
For instance, the core of Jupiter is thought to consist of metallic hydrogen. The tremendous pressure within the gas giant compresses the gas into a superconductive metal, giving rise to the planet’s robust magnetic field.
But on Earth, experimental challenges have rendered metallic hydrogen an enigmatic substance for nearly a century.
The journey to create metallic hydrogen is a fascinating exploration within the realm of high-pressure physics.
The pursuit of this elusive form of hydrogen has been motivated by the predictions made by physicists Eugene Wigner and Hillard Bell Huntington in 1935.
They proposed that hydrogen could potentially become metallic under extreme pressures, roughly estimated at 25 gigapascals (GPa).
However, the actual pressures required for this transformation have proven to be even more astounding.
Over the years, several research groups have claimed to have successfully achieved metallic hydrogen, only to face skepticism and debate, primarily due to issues related to measurement accuracy, calibration procedures, and the ability to reproduce the results.
A notable example is a 2019 study that reported the existence of semimetallic hydrogen at a pressure of 350 GPa.
These experiments have become feasible through the use of a remarkable device known as a diamond anvil cell, which can exert immense pressures on a minuscule sample of hydrogen gas or liquid.
One of the intriguing observations made in these experiments is that when the pressure exceeds 33 GPa, the hydrogen atoms begin moving away from each other, instead of drawing closer together as expected.
This peculiar behavior indicates that the hydrogen molecules might undergo a phase transition, potentially giving rise to a solid state with metallic properties.
The pursuit of metallic hydrogen continues, and researchers are hopeful due to promising indications in recent studies.
Notably, a darkening of the hydrogen sample suggests that the “band gap” is closing, which is a significant aspect of its metallic state.
The band gap refers to the energy gap between the conduction zone and the valence band. In a metallic state, these two bands overlap, creating electrical conductivity.
The potential properties of metallic hydrogen are a matter of great scientific interest, possibly including its ability to remain in a liquid state while exhibiting superconducting properties at more manageable temperatures.
Achieving metallic hydrogen would have profound implications for various fields, including condensed matter physics, materials science, and potentially revolutionize technologies that rely on superconductors.
Many superconductors currently require extremely low temperatures to function, making them impractical for certain applications.
The ability to harness metallic hydrogen as a high-temperature superconductor could open new possibilities and innovations in a wide range of industries.
The quest for metallic hydrogen is a testament to human curiosity and the relentless pursuit of scientific knowledge.
The journey is filled with challenges, and the highest pressures that can be reached are mind-boggling.
Still, researchers remain undeterred in their quest to explore this fascinating frontier within high-pressure physics.
While the prospect of hydrogen superconductors is undoubtedly intriguing, there are significant challenges to overcome before they can be practically applied in industrial contexts.
Pure metallic hydrogen, which is the ideal candidate for superconductivity, remains beyond the reach of current technological capabilities due to the extreme pressures required to achieve this state.
Researchers, including Eugene Gregoryanz, have shifted their focus towards hydrides as a more attainable avenue. Hydrides are compounds that combine metals with hydrogen.
Although they still necessitate high pressures, the pressures required for hydrides to exhibit superconductivity are considerably lower than those needed for pure hydrogen.
However, even these reduced pressures are currently impractical for widespread industrial use.
In essence, the pursuit of hydrogen superconductors, whether through pure metallic hydrogen or hydrides, remains a fascinating scientific endeavor.
While they may not be immediately utilized in industry, the underlying physics and materials science involved in this research hold substantial potential.
The quest for high-temperature superconductors and the development of innovative technologies are ongoing, driven by the promise of transformative applications in various fields.
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